RESUMEN
Accessibility to adequate health services is a basic human right. Israeli road blocks and checkpoints inhibit access to health care for the Palestinian population. While other studies have dealt with the impact of the barriers, few are based on actual measurements of transport times between locations. Geographical information systems (GIS) and network analysis were used to generate different estimations of accessibility based on the existing road network and transport barriers. The population negatively affected were mainly people living outside urban centres and in governorates with no general hospital. Quantitative measurements using GIS can be used to confirm qualitative studies based on interviews and questionnaires and improve the understanding of the results. Working with a spatial analysis tool also helps to pinpoint weaknesses in the current infrastructure, thus improving the efficiency of future investments to improve health care in the West Bank.
Asunto(s)
Árabes , Sistemas de Información Geográfica , Accesibilidad a los Servicios de Salud/estadística & datos numéricos , Transportes/estadística & datos numéricos , Necesidades y Demandas de Servicios de Salud , Humanos , Medio Oriente , Factores de TiempoRESUMEN
Accessibility to adequate health services is a basic human right. Israeli road blocks and checkpoints inhibit access to health care for the Palestinian population. While other studies have dealt with the impact of the barriers, few are based on actual measurements of transport times between locations. Geographical information systems [GIS] and network analysis were used to generate different estimations of accessibility based on the existing road network and transport barriers. The population negatively affected were mainly people living outside urban centres and in governorates with no general hospital. Quantitative measurements using GIS can be used to confirm qualitative studies based on interviews and questionnaires and improve the understanding of the results. Working with a spatial analysis tool also helps to pinpoint weaknesses in the current infrastructure, thus improving the efficiency of future investments to improve health care in the West Bank
RESUMEN
Accessibility to adequate health services is a basic human right. Israeli road blocks and checkpoints inhibit access to health care for the Palestinian population. While other studies have dealt with the impact of the barriers, few are based on actual measurements of transport times between locations. Geographical information systems [GIS] and network analysis were used to generate different estimations of accessibility based on the existing road network and transport barriers. The population negatively affected were mainly people living outside urban centres and in governorates with no general hospital. Quantitative measurements using GIS can be used to confirm qualitative studies based on interviews and questionnaires and improve the understanding of the results. Working with a spatial analysis tool also helps to pinpoint weaknesses in the current infrastructure, thus improving the efficiency of future investments to improve health care in the West Bank
Asunto(s)
Sistemas de Información Geográfica , Servicios de SaludRESUMEN
Human immunodeficiency virus type 1 (HIV-1) infects target cells by binding to CD4 and a chemokine receptor, most commonly CCR5. CXCR4 is a frequent alternative coreceptor (CoR) in subtype B and D HIV-1 infection, but the importance of many other alternative CoRs remains elusive. We have analyzed HIV-1 envelope (Env) proteins from 66 individuals infected with the major subtypes of HIV-1 to determine if virus entry into highly permissive NP-2 cell lines expressing most known alternative CoRs differed by HIV-1 subtype. We also performed linear regression analysis to determine if virus entry via the major CoR CCR5 correlated with use of any alternative CoR and if this correlation differed by subtype. Virus pseudotyped with subtype B Env showed robust entry via CCR3 that was highly correlated with CCR5 entry efficiency. By contrast, viruses pseudotyped with subtype A and C Env proteins were able to use the recently described alternative CoR FPRL1 more efficiently than CCR3, and use of FPRL1 was correlated with CCR5 entry. Subtype D Env was unable to use either CCR3 or FPRL1 efficiently, a unique pattern of alternative CoR use. These results suggest that each subtype of circulating HIV-1 may be subject to somewhat different selective pressures for Env-mediated entry into target cells and suggest that CCR3 may be used as a surrogate CoR by subtype B while FPRL1 may be used as a surrogate CoR by subtypes A and C. These data may provide insight into development of resistance to CCR5-targeted entry inhibitors and alternative entry pathways for each HIV-1 subtype.
Asunto(s)
Infecciones por VIH/virología , VIH-1/fisiología , Receptores CCR3/metabolismo , Receptores de Formil Péptido/metabolismo , Receptores de Lipoxina/metabolismo , Receptores Virales/metabolismo , Internalización del Virus , Línea Celular , VIH-1/genética , Humanos , Datos de Secuencia Molecular , Análisis de Secuencia de ADN , Productos del Gen env del Virus de la Inmunodeficiencia Humana/genéticaRESUMEN
Inherited deficiencies in components of the classical complement pathway are strong disease susceptibility factors for the development of systemic lupus erythematosus (SLE) and there is a hierarchy among deficiency states, the strongest association being with C1q deficiency. We investigated the relative importance of the different complement pathways regarding clearance of apoptotic cells. Phagocytosis of labelled apoptotic Jurkat cells by monocyte-derived macrophages in the presence of sera from individuals with complement deficiencies was studied, as well as C3 deposition on apoptotic cells using flow cytometry. Sera from individuals deficient in C1q, C4, C2 or C3 all showed decreased phagocytosis. Mannose binding lectin (MBL) and the alternative pathway did not influence phagocytosis. Notably, the components of the complement classical pathway, including C1q, were equally important in clearance of apoptotic cells. This indicates that deposition of C3 fragments is of major significance; we therefore studied C3 deposition on apoptotic cells. Experiments with MBL-deficient serum depleted of C1q or factor D confirmed the predominance of the classical pathway. At low dilution, sera deficient of C1q, C4 or C2 supported C3 fragment deposition demonstrating alternative pathway activation. In conclusion, we have found that complement-mediated opsonization and phagocytosis of apoptotic cells, particularly those undergoing secondary necrosis, are dependent mainly upon an intact classical pathway. The alternative pathway is less important, but may play a role in some conditions. C1q was not more important than other classical pathway components, suggesting a role in additional pathogenetic processes in SLE other than clearance of apoptotic cells.
Asunto(s)
Vía Clásica del Complemento/fisiología , Macrófagos/fisiología , Fagocitosis/inmunología , Apoptosis , Estudios de Casos y Controles , Activación de Complemento , Complemento C1q/deficiencia , Complemento C2/deficiencia , Complemento C3/deficiencia , Complemento C4/deficiencia , Humanos , Células Jurkat , NecrosisRESUMEN
In vitro studies suggest that the membrane G protein-coupled receptor GPR30 is a functional estrogen receptor (ER). The aim of the present study was to determine the possible in vivo role of GPR30 as a functional ER primarily for the regulation of skeletal parameters, including bone mass and longitudinal bone growth, but also for some other well-known estrogen-regulated parameters, including uterine weight, thymus weight, and fat mass. Three-month-old ovariectomized (OVX) GPR30-deficient mice (GPR30(-/-)) and wild-type (WT) mice were treated with either vehicle or increasing doses of estradiol (E(2); 0, 30, 70, 160, or 830 ng.mouse(-1).day(-1)). Body composition [bone mineral density (BMD), fat mass, and lean mass] was analyzed by dual-energy-X ray absorptiometry, while the cortical and trabecular bone compartments were analyzed by peripheral quantitative computerized tomography. Quantitative histological analyses were performed in the distal femur growth plate. Bone marrow cellularity and distribution were analyzed using a fluorescence-activated cell sorter. The estrogenic responses on most of the investigated parameters, including increase in bone mass (total body BMD, spine BMD, trabecular BMD, and cortical bone thickness), increase in uterine weight, thymic atrophy, fat mass reduction, and increase in bone marrow cellularity, were similar for all of the investigated E(2) doses in WT and GPR30(-/-) mice. On the other hand, E(2) treatment reduced longitudinal bone growth, reflected by decreased femur length and distal femur growth plate height, in the WT mice but not in the GPR30(-/-) mice compared with vehicle-treated mice. These in vivo findings demonstrate that GPR30 is not required for normal estrogenic responses on several major well-known estrogen-regulated parameters. In contrast, GPR30 is required for a normal estrogenic response in the growth plate.
Asunto(s)
Desarrollo Óseo/fisiología , Estrógenos/metabolismo , Ovariectomía , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Tejido Adiposo/anatomía & histología , Tejido Adiposo/crecimiento & desarrollo , Animales , Densidad Ósea , Femenino , Fémur/citología , Fémur/crecimiento & desarrollo , Placa de Crecimiento/citología , Placa de Crecimiento/crecimiento & desarrollo , Ratones , Ratones Mutantes , Tamaño de los Órganos , Receptores de Estrógenos/metabolismo , Timo/anatomía & histología , Timo/crecimiento & desarrollo , Útero/anatomía & histología , Útero/crecimiento & desarrolloRESUMEN
The influence of complement on immune responses to polysaccharides is debatable. We examined the serum concentrations of IgM and IgG antibody against Salmonella O-antigen specific oligosaccharides representing the serogroups B, C and D, and against capsular polysaccharides of Streptococcus pneumoniae serotypes 6 and 23 in C2-deficient adults and in healthy controls. A sharp contrast of findings was found for antibodies against the CO antigen, an activator of the mannan-binding lectin (MBL) pathway of complement activation. The C2-deficient group showed normal IgM and markedly low IgG antibody levels. Similar findings were made in adults with low concentrations of MBL. This suggests that the recruitment of classical pathway C3 convertase through the MBL pathway is critically involved in isotype switching of antibodies against MBL pathway activating antigens during immune system maturation. The findings imply a new role of the MBL pathway, and an additional link between innate and acquired immunity. Specific IgM against BO was moderately low in C2 deficiency. Other differences for the Salmonella antigens were not found. Markedly raised IgM antibody levels against pneumococcal polysaccharides in C2 deficiency probably Salmonella reflected past infections. The absence of a concomitant increase of specific IgG might possibly be explained by impaired IgM to IgG switching.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Proteínas Portadoras/fisiología , Complemento C2/deficiencia , Vía Clásica del Complemento , Cambio de Clase de Inmunoglobulina , Inmunoglobulina G/sangre , Antígenos O/inmunología , Polisacáridos Bacterianos/inmunología , Salmonella/inmunología , Adulto , Especificidad de Anticuerpos , Cápsulas Bacterianas/inmunología , Colectinas , Convertasas de Complemento C3-C5/metabolismo , Humanos , Isotipos de Inmunoglobulinas/inmunología , Inmunoglobulina M/sangre , Salmonella/clasificación , Serotipificación , Streptococcus pneumoniae/inmunologíaRESUMEN
OBJECTIVE: To study the association between disease activity and complement activation prospectively in patients with systemic lupus erythematosus (SLE). PATIENTS AND METHODS: Twenty-one SLE patients were examined monthly for 1 yr. Disease activity, autoantibodies, conventional complement tests and the following complement activation products were investigated: C1rs-C1inh complexes, C4bc, Bb, C3a, C3bc, C5a and the terminal SC5b-9 complement complex (TCC). RESULTS: Modest variation in disease activity was noted. None of the patients had nephritis. Flare was observed at 27 visits. Four patients had anti-C1q antibodies in conjunction with modestly low C1q concentrations. The complement parameters were rather constant during the observation period. Slightly to moderately decreased C4 (0.05-0.10 g/l) was found in 10 patients and severely decreased C4 (<0.05 g/l) in seven patients. Decreased C4 was not associated with increased complement activation. Complement activation products were either normal or slightly elevated. TCC was the only activation product correlating significantly with score for disease activity at flare. None of the variables tested predicted flares. CONCLUSION: Complement tests are of limited importance in routine examination of SLE without nephritis, although TCC is suggested to be one of the most sensitive markers for disease activity.
Asunto(s)
Activación de Complemento , Proteínas Inactivadoras del Complemento C3b , Complemento C4b , Lupus Eritematoso Sistémico/diagnóstico , Lupus Eritematoso Sistémico/inmunología , Adulto , Anciano , Autoanticuerpos/análisis , Proteínas Sanguíneas/análisis , Proteínas Inactivadoras del Complemento 1/análisis , Proteínas Inactivadoras del Complemento 1/inmunología , Complemento C1q/análisis , Complemento C1q/inmunología , Complemento C3/análisis , C3 Convertasa de la Vía Alternativa del Complemento , Complemento C3b/análisis , Complemento C4/análisis , Complemento C5a/análisis , Complejo de Ataque a Membrana del Sistema Complemento , Proteínas del Sistema Complemento/análisis , Femenino , Glicoproteínas/análisis , Humanos , Masculino , Persona de Mediana Edad , Nefritis , Fragmentos de Péptidos/análisis , Valor Predictivo de las Pruebas , Estudios ProspectivosRESUMEN
OBJECTIVE: To compare autoantibody responses to the collagen-like region of Clq (ClqCLR) with responses to double stranded DNA (dsDNA) and native rat collagen type II during changes of disease activity in patients with systemic lupus erythematosus (SLE). METHODS: IgG antibodies to ClqCLR, dsDNA, and collagen type II were determined by ELISA in serial samples from 33 patients with SLE with different disease manifestations. Antibodies to dsDNA were also detected with the Crithidia luciliae test. RESULTS: Distinct antibody responses in conjunction with flare were observed, but the markers were more clearly related to clinical groups and to severity of disease than to changes of disease activity. Anti-ClqCLR antibodies were detected in 2/10 patients with mild flares, 7/12 patients with severe extrarenal flares, and in 10/11 of the patients with active lupus glomerulonephritis. Findings with regard to anti-dsDNA antibodies were similar. Antibody responses to collagen type II were detected in 7/12 of the patients with severe extrarenal disease, and were less frequently found in the other patients. ELISA absorption and elution experiments with anti-ClqCLR antibodies in the patient sera did not suggest cross reactivity with collagen type II and dsDNA. CONCLUSION: Serial investigation of 33 patients with SLE showed that antibodies to ClqCLR and dsDNA are markers of severe SLE, particularly SLE with kidney involvement. Antibodies to collagen type II are possible markers of severe extrarenal SLE with vasculitis and serositis. Analysis of anti-ClqCLR antibodies provided no evidence of cross reactivity with collagen type II and dsDNA.
Asunto(s)
Autoanticuerpos/sangre , Colágeno/inmunología , Complemento C1q/inmunología , ADN/inmunología , Lupus Eritematoso Sistémico/inmunología , Anticuerpos Antinucleares/química , Anticuerpos Antinucleares/inmunología , Especificidad de Anticuerpos , Colágeno/química , Complemento C1q/química , Complemento C1q/metabolismo , Reacciones Cruzadas , Ensayo de Inmunoadsorción Enzimática , Humanos , Lupus Eritematoso Sistémico/sangre , Estudios Prospectivos , Estructura Terciaria de ProteínaRESUMEN
OBJECTIVES: The main purposes were to document manifestations associated with prolonged or clinically unexplained C3 deficiency and to approximate how often hypocomplementaemia of this kind is caused by C3 nephritic factors (C3 NeF), i.e. autoantibodies to alternative pathway C3 convertases. We also wished to distinguish between C3 NeF types I and II and to assess coincident autoantibody responses to the collagen-like region of C1q (C1qCLR). SETTING: The investigation was based on serum samples referred to a specialized laboratory for complement analysis in the course of several years. SUBJECTS: Twenty-five persons with C3 concentrations lower than 0.43 g L-1, a third of the normal, were included in the study. RESULTS: Analysis using three methods provided evidence of C3 NeF in 20 persons with equal frequencies of C3 NeF types I and II. We also gave evidence of antibody specificity differences for the two types of C3 NeF. Six patients with C3 NeF type II showed antibodies to C1qCLR. Membranoproliferative glomerulonephritis was the predominant diagnosis and two patients had partial lipodystrophy reflecting the well-known association between these diseases and C3 NeF. Anaphylactoid purpura, systemic lupus erythematosus, and severe infection, mainly meningococcal disease, were also observed. CONCLUSIONS: The study group was probably fairly representative of C3 deficiency syndromes as encountered in clinical practice. The findings emphasize the heterogeneity of C3 NeF, and that acquired C3 deficiency syndromes caused by C3 NeF should perhaps be considered more often in diagnostic work.
Asunto(s)
Autoanticuerpos/sangre , Complemento C1q/inmunología , Factor Nefrítico del Complemento 3/fisiología , Complemento C3/deficiencia , Adolescente , Adulto , Niño , Preescolar , Humanos , Persona de Mediana Edad , SíndromeRESUMEN
The collectins, a group of humoral C-type lectins, have globular and collagen-like regions and share structural features with the complement protein C1q. The question was asked if autoantibodies to the collagen-like region of C1q (anti-C1qCLR) might cross-react with collectins, such as mannan-binding protein (MBP), lung surfactant protein A (SP-A) and bovine conglutinin (BK). Anti-C1qCLR antibodies of the systemic lupus erythematosus (SLE) type and anti-C1qCLR antibodies of the hypocomplementemic urticarial vasculitis syndrome (HUVS) type were investigated. Cross-absorption and elution experiments combined with antibody detection by enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis gave no evidence of cross-reactive anti-C1qCLR antibodies. However, one serum with HUVS type anti-C1qCLR antibodies contained anti-MBP antibodies that were cross-reactive with SP-A. Judging from results of ELISA inhibition experiments and immunoblot analysis, four SLE sera contained antibodies to native BK, while two sera with HUVS type anti-C1qCLR antibodies contained antibodies to epitopes of denatured BK. This might imply that autoimmunity to collagen-like structures is not restricted to C1qCLR in HUVS and HUVS/SLE overlap syndromes.
Asunto(s)
Autoanticuerpos/química , Proteínas Portadoras/inmunología , Complemento C1q/inmunología , Proteolípidos/inmunología , Surfactantes Pulmonares/inmunología , Seroglobulinas/inmunología , Animales , Autoanticuerpos/sangre , Autoanticuerpos/efectos de los fármacos , Sitios de Unión de Anticuerpos , Unión Competitiva/inmunología , Bovinos , Colectinas , Reacciones Cruzadas , Ensayo de Inmunoadsorción Enzimática , Glicoproteínas/inmunología , Humanos , Immunoblotting , Lectinas/inmunología , Mananos/inmunología , Proteína A Asociada a Surfactante Pulmonar , Proteínas Asociadas a Surfactante Pulmonar , Seroglobulinas/farmacologíaRESUMEN
OBJECTIVE: To evaluate the results of complement analysis for assessment of disease activity and severity, and prediction of flares in systemic lupus erythematosus (SLE). METHODS: Patients with mild extra-renal flares, severe extra-renal flares or flares of lupus glomerulonephritis were followed for eight months, with investigations being performed every second month. Findings in initial samples four months before the flares were compared with findings in a control group with stable disease. C-reactive protein, and circulating C1q, C4 and C3 were determined together with two types of complexes containing C1 inhibitor (C1 INH), C1 INH-C1r-C1s and C1 INH-C1r-C1s-C1 INH, and the C3 breakdown product C3d. RESULTS: Enhanced formation of C1 INH-C1r-C1s appeared to be a marker of low specificity and was mainly seen in patients with extra-renal disease. Concentrations of C1 INH-C1r-C1s-C1 INH, C3d, C1q and C3 clearly varied according to disease activity in patients with severe disease. Interestingly, high C1 INH-C1r-C1s-C1 INH values were found four months before the flares in all but one patient with lupus glomerulonephritis. Assessment of the relative predictivity for a subsequent flare indicated low C1q to be the most reliable marker, the predictivity of the complexes being: low C1q > high C1 INH-C1r-C1s-C1 INH > low C3 > high C3d > low C4. CONCLUSION: The importance of C1q and C1-related events in SLE may be underestimated. In addition, our results demonstrate the relevance of serial complement analysis for the assessment of disease activity and severity.
Asunto(s)
Proteína C-Reactiva/metabolismo , Activación de Complemento/fisiología , Complemento C1q/metabolismo , Lupus Eritematoso Sistémico/inmunología , Adolescente , Adulto , Anciano , Estudios de Casos y Controles , Complemento C3/metabolismo , Complemento C4/metabolismo , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Sensibilidad y Especificidad , Índice de Severidad de la EnfermedadRESUMEN
OBJECTIVES: A case is described of complex reactions associated with exposure to diphenylmethane diisocyanate (MDI), with some immunologic observations. METHODS: Medical history, clinical examinations, and analyses of immunologic parameters and the 4,4'-MDI-related amine 4,4'-diaminodiphenylmethane (MDA) in hydrolyzed serum and urine were used. RESULTS: The patient, a mechanic whose medical history suggested repeated attacks of a work-related pulmonary or systemic disease, was examined because of acute respiratory disorder, rhinoconjunctivitis, and a late systemic reaction after exposure to polyurethane pyrolysis products, including 4,4'-MDI (air level 15 micrograms.m3). Spirometry showed a partly reversible obstructive dysfunction, and a skin-prick test was positive versus isocyanates conjugated with human serum albumin (HSA). MDA was detected in hydrolyzed serum (5.6 ng.ml) and urine (1.6 micrograms.g creatinine-1). In serum, there were specific immunoglobulin (Ig) G (IgG1 and IgG4) and IgE antibodies to 4,4'-MDI-HSA and other isocyanates (phenylisocyanate, toluene diisocyanate, p-toluene monoisocyanate, hexamethylene diisocyanate) conjugated with HSA, a very high total IgE, a raised total IgG, and moderate neutrophilia and eosinophilia. The specific antibodies declined, but were still increased five years later. Furthermore, the values of circulating immune complexes were high. In vitro, the circulating immune complexes in serum increased after the addition of 4,4'-MDI-HSA. The patient had anti-Clq antibodies, which probably accounted for part of the circulating immune complexes. CONCLUSIONS: The reactions associated with MDI exposure (in combination with exposure to pyrolysis products) had features compatible with immediate hypersensitivity and with a complement-mediated immune-complex reaction.
Asunto(s)
Alérgenos/efectos adversos , Conjuntivitis Alérgica/inducido químicamente , Isocianatos/efectos adversos , Exposición Profesional/efectos adversos , Hipersensibilidad Respiratoria/inducido químicamente , Rinitis Alérgica Perenne/inducido químicamente , Alérgenos/inmunología , Complejo Antígeno-Anticuerpo/sangre , Complejo Antígeno-Anticuerpo/inmunología , Humanos , Inmunoglobulina E/sangre , Inmunoglobulina G/sangre , Isocianatos/inmunología , Masculino , Persona de Mediana Edad , Poliuretanos/efectos adversosRESUMEN
Exposure to antidepressants inhibited mitogen stimulation of cultured human lymphocytes. The lowest concentration that cause total inhibition of mitogen (phytohaemagglutinin, PHA) stimulation (the minimum inhibitory concentration, MIC) was 20, 30, 40, 60 and 120 mumol/litre for fluoxetine, clomipramine, amitriptyline, imipramine and citalopram, respectively. The lymphocytes were more sensitive to all of the antidepressants when stimulated with concanavalin A than with PHA. When the lymphocytes were preincubated with the drugs at the MIC for 24 hr before mitogen stimulation, amitriptyline, citalopram and imipramine did not suppress mitogen (PHA) stimulation whereas fluoxetine and clomipramine caused 50 and 60% inhibition. For all of the antidepressants, preincubation at 2.5 x MIC for 24 hr completely inhibited mitogen stimulation. The results show that antidepressants can affect lymphocytes by inhibiting blastogenesis and that there were large differences in potency between the drugs.
RESUMEN
An enzyme-linked immunosorbent assay (ELISA) with purified collagenous C1q fragments in the solid phase was used for detection of C1q-specific immunoglobulins in the sera of twelve patients with systemic lupus erythematosus (SLE) or the SLE-like disease hypocomplementemic urticarial vasculitis syndrome (HUVS). By clinical criteria, four patients had SLE, and three HUVS. Five patients had overlap syndromes. All patients demonstrated high concentrations of C1q-specific IgG and markedly low concentrations of circulating C1q. Detection of C1q-specific IgG in SLE sera was facilitated by employment of saturating concentrations of collagenous C1q fragments in the solid-phase ELISA. When added to SLE serum, immune complex-fixed C1q inhibited binding of IgG to the C1q fragments, whereas addition of C1q alone had limited inhibitory effects. Under similar conditions, using approximately equimolar amounts of C1q relative to solid-phase C1q fragments, no ELISA inhibition was obtained after addition of C1q or immune complex-fixed C1q to a HUVS serum. Even in large excess, purified C1q did not inhibit binding of HUVS-IgG to solid-phase C1q fragments. Thus, possible interactions between HUVS-IgG and native Clq are probably of low affinity. By Western blot analysis, IgG reactive with the B and C chains of C1q was found in the eight patients with evidence of HUVS, five of whom also showed IgG binding to C'-C' and A'-B' dimers of collagenous C1q fragments. Sera from SLE patients were negative by Western blot analysis. It seems likely that C1q-specific IgG in SLE primarily recognizes assembled C1q molecules or collagenous C1q fragments expressing conformational epitopes of bound C1q. Interestingly, patients with evidence of HUVS fairly consistently had zymogen (C1r-C1s)2 complexes in their serum, while patients with SLE showed high concentrations of complexes containing Cl inhibitor, C1r and C1s. Different binding specificities of C1q-reactive IgG could be of importance with regard to pathogenetic mechanisms in SLE and HUVS. There was no correlation between findings of C1q-specific IgG and a variety of autoantibodies associated with SLE and SLE-like disease.
Asunto(s)
Colágeno/inmunología , Complemento C1q/inmunología , Inmunoglobulina G/inmunología , Adolescente , Adulto , Anticuerpos Antinucleares/análisis , Especificidad de Anticuerpos , Autoanticuerpos/análisis , Sitios de Unión , Western Blotting , Colágeno/análisis , Proteínas del Sistema Complemento/deficiencia , Proteínas del Sistema Complemento/inmunología , Ensayo de Inmunoadsorción Enzimática , Humanos , Inmunoglobulina G/análisis , Lupus Eritematoso Sistémico/inmunología , Persona de Mediana Edad , Urticaria/inmunologíaAsunto(s)
Autoanticuerpos/sangre , Glucuronidasa/inmunología , Autoanticuerpos/inmunología , Citoplasma/inmunología , Ensayo de Inmunoadsorción Enzimática , Humanos , Neutrófilos/inmunología , Elastasa Pancreática/inmunología , Peroxidasa/inmunología , Valores de Referencia , Vasculitis/sangre , Vasculitis/inmunologíaRESUMEN
We studied the activation and C1 inactivator-dependent dissociation of the first component of complement, the C1q(C1r-C1s)2 complex, in relation to recruitment of the classical activation pathway in the circulation of 24 patients with systemic lupus erythematosus (SLE). The patients were divided into three groups on a clinical basis, and were investigated during flares of disease activity. Group I had mild symptoms, group II major extrarenal manifestations, and group III manifest renal disease. High serum concentrations of trimer complexes containing C1 inactivator, activated C1r and zymogen C1s(C1 IA-C1r-C1s) were found in the majority of the patients. Some patients with high C1 IA-C1r-C1s concentrations showed no evidence of classical pathway activation, indicating that C1 activation was controlled by the action of C1 IA at the C1r level. By contrast, formation in serum of tetramer complexes in which C1 IA was firmly bound to both C1r and C1s (C1 IA-C1r-C1s-C1 IA) was associated with C2 and C3 cleavage in EDTA plasma, and with manifest hypocomplementemia. Low C1 IA-C1r-C1s-C1 IA values were observed in conjunction with substantial C2 cleavage in a few patients. Thus, C1 IA-C1r-C1s-C1 IA may not always be a sensitive indicator of classical pathway activation. Efficient recruitment of the classical pathway was related to disease severity, with some overlap between the clinical groups. In conclusion, C1 dissociation with formation of C1 IA-containing complexes was consistently found in patients with active SLE. The results suggested that C1 IA-dependent control of C1 activation was of biological significance in the disease.
Asunto(s)
Complemento C1/metabolismo , Complemento C2/metabolismo , Vía Clásica del Complemento/fisiología , Lupus Eritematoso Sistémico/inmunología , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
During activation, the first component of complement C1q (C1r-C1s)2 is dissociated in conjunction with the formation of complexes containing C1 esterase inhibitor (C1-INH). Trimer complexes, with zymogen C1s associated with a firm C1-INH-C1r complex (C1-INH-C1r-C1s) can be distinguished from tetramer complexes C1-INH-C1r-C1s-C1-INH) in which C1-INH is firmly bound to both proteases. In the present study a two-stage electroimmunoassay was developed for the specific measurement of C1-INH-C1r-C1s. In the first step, C1-INH and its complexes were immunoprecipitated with anti-C1-INH during electrophoresis in the presence of Ca2+. In the second step, C1s contained in C1-INH-C1r-C1s was dissociated in the presence of EDTA and was measured by immunoprecipitation with anti-C1s. C1-INH-C1r-C1s were consistently found in normal sera. Normal sera did not contain C1-INH-C1r-C1s-C1-INH as assessed with a previously described ELISA procedure. Sera and synovial fluids from two groups of patients with inflammatory arthritis were investigated. In rheumatoid arthritis patients (n = 15) C1-INH-C1r-C1s complexes were usually found at high concentration both in serum and synovial fluid. C1-INH-C1r-C1s-C1-INH complexes were also present with values that were higher in synovial fluid than in serum, in accord with previous findings of classical pathway activation in the inflamed joints of the patients. Patients with spondylarthritic syndromes (n = 7) had serum and synovial fluid C1-INH-C1r-C1s concentrations that were comparable to those of the rheumatoid arthritis patients. If at all present, C1-INH-C1r-C1s-C1-INH were detected in trace amounts. Thus, C1 activation in patients with spondylarthritic syndromes appeared to be efficiently controlled at the C1r level. Distinguishing between C1-INH-C1r-C1s and C1-INH-C1r-C1s-C1-INH may prove of value in further studies of the activation and control of C1 in disease.
Asunto(s)
Proteínas Inactivadoras del Complemento 1/análisis , Complemento C1r/análisis , Complemento C1s/análisis , Inmunoensayo/métodos , Enfermedades Reumáticas/inmunología , Líquido Sinovial/inmunología , Animales , Artritis Reumatoide/inmunología , Electricidad , Ensayo de Inmunoadsorción Enzimática , Humanos , Osteoartritis/inmunología , ConejosRESUMEN
Activation of the C1 complex in the presence of C1 inactivator (C1 IA) is known to result in the formation of tetramer C1 IA-C1r-C1s-C1 IA complexes that are dissociated from C1q. Both C1r and C1s of the tetramers are present in their activated forms. The present investigation concerned the generation of trimer complexes containing C1 IA, activated C1r, and zymogen C1s (C1 IA-C1r-C1s). C1 IA-C1r-C1s were released from C1q and were formed in high concentration during prolonged incubation (1 to 3 days) of normal serum at 37 degrees C without addition of activators. By contrast, dissociation of C1 with formation of C1 IA-C1r-C1s-C1 IA was complete within 30 min at 37 degrees C, when the serum was treated with heat-aggregated IgG (1 g/liter). On size exclusion chromatography (TSK-4000), C1 IA-C1r-C1s and C1 IA-C1r-C1s-C1 IA emerged with apparent m.w. of 320,000 and 460,000, respectively. The composition of the complexes was examined by absorption of serum with F(ab')2 anti-C1s- or anti-C1r-coated Sepharose beads. Eluates were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis combined with immunoblotting. Under nonreducing conditions, heat-aggregated IgG-treated serum showed high concentrations of C1 IA-C1r (m.w. 202,000) and C1 IA-C1s (m.w. 194,000), while serum incubated at 37 degrees C without activators showed high concentrations of C1 IA-C1r but no C1 IA-C1s. Under reducing conditions, heat-aggregated IgG-treated serum showed m.w. 120,000 and 110,000 complexes of C1 IA and the C1r and C1s light chains, respectively. Uncleaved C1s and the m.w. 120,000 complex was found in serum that was incubated at 37 degrees C without activators. Consistent with results obtained by size exclusion chromatography, analysis by crossed immunoelectrophoresis and by electroimmunoassay showed that C1s could be released from C1 IA-C1r-C1s in the presence of EDTA.