RESUMEN

We evaluated the effect of Ascaris lumbricoides on Giardia duodenalis infection and TH1/TH2 type immune mechanisms toward this parasite in 251 rural parasitized and 70 urban non-parasitized school children. The children were classified according to light (0-5000 eggs/g faeces) or moderate (>5001-50,000 eggs/g faeces) A. lumbricoides infection. Anti G. duodenalis skin hyper-reactivity, IgE, IgG, IL-13, IFN γ, IL6 and IL-10 levels were compared among G. duodenalis infected and non-infected children according to light or moderate A. lumbricoides infection. It was found that 62% of the A. lumbricoides moderately infected children were co-infected by G. duodenalis compared to 45% of the lightly infected group. After treatment, 42% of the A. lumbricoides moderately group were infected with G. duodenalis compared to 11% of their lightly counterparts, being A. lumbricoides IL-10 levels higher (p<0.0001) in the moderately infected group. In the A. lumbricoides lightly parasitized children, G. duodenalis infection was associated to a significant increase (p<0.005) of the levels of G. duodenalis IL-13, IFN-γ, IL-6, IgE, IgG and skin test hyper reactivity. In contrast, there was no effect of G. duodenalis infection in the elevation of these parameters among the A. lumbricoides moderately parasitized group, being those levels similarly lower as those observed in the control group. Inverse correlations were found between the levels of anti G duodenalis antibodies, skin test hyper-reactivity and cytokines with the intensity of A. lumbricoides infection (p>0.0001) and A. lumbricoides IL-10 levels (p>0.0001), suggesting that co-infection with A. lumbricoides may affect both TH1 and TH2 type immunity against G. duodenalis that may play an important role in the susceptibility to the infection after chemotherapy in children from endemic areas.

Asunto(s)

Ascariasis/inmunología , Giardiasis/inmunología , Inmunomodulación , Animales , Anticuerpos/inmunología , Ascariasis/complicaciones , Ascariasis/epidemiología , Ascariasis/parasitología , Ascaris lumbricoides/fisiología , Estudios de Casos y Controles , Niño , Citocinas/inmunología , Giardia lamblia/fisiología , Giardiasis/complicaciones , Giardiasis/epidemiología , Giardiasis/parasitología , Interacciones Huésped-Patógeno , Humanos , Hipersensibilidad/inmunología , Inmunoglobulinas/inmunología , Recuento de Huevos de Parásitos , Población Rural , Índice de Severidad de la Enfermedad , Pruebas Cutáneas , Balance Th1 - Th2 , Venezuela/epidemiología

RESUMEN

Asthma and other respiratory diseases have increased in the last years among Venezuelan children from helminthic endemic areas where the infection by Ascaris lumbricoides has been associated to bronchial airway inflammation in parasitized individuals. The aim of this work was to investigate the possible associations between the development of bronchial hyper reactivity and the immune response against A. lumbricoides in urban and rural children. We evaluated 470 school children from rural and urban communities. Pulmonary function tests were performed and >or=20% PC(20) changes were considered as a positive diagnostic of bronchial hyper reactivity. The prevalence and intensity of A. lumbricoides infection was determined by faecal examination. Specific serum IgE levels using a modified ELISA and skin prick tests against A. lumbricoides and the common allergen Dermatophagoides pteronyssinus were done. The number of circulating lymphocyte sub populations was determined by flow cytometry analysis. In rural children, bronchial hyper reactivity was associated with increased specific levels of anti-A. lumbricoides IgE (p<0.0001) and skin test positivity for A. lumbricoides (p<0.0001). The percentage of FEV1 predictive values correlated inversely (p<0.0001) with anti-A. lumbricoides IgE levels. Elevated numbers of circulating CD3+CD4+ and CD20+CD23+ cells were found in rural children with bronchial hyper reactivity compared to their asymptomatic counterparts. They correlated positively with anti-A. lumbricoides IgE levels (p<0.005 and <0.0001, respectively). In contrast, in urban children, bronchial hyper reactivity was associated with elevated anti-D. pteronyssinus IgE levels (p=0. 0089), skin hyper reactivity towards this aero allergen (p=0.003) and to an increase in the number of CD3+CD8+ (p<0.0001). Our results suggest that the IgE response against A. lumbricoides infection may be involved in the development of bronchial hyper reactivity among rural children from endemic areas and also that improved hygienic conditions in the urban environment is associated with increased responses to airborne allergens.

Asunto(s)

Ascariasis/epidemiología , Ascariasis/inmunología , Ascaris lumbricoides , Hiperreactividad Bronquial/parasitología , Enfermedades Endémicas , Animales , Ascariasis/complicaciones , Subgrupos de Linfocitos B , Hiperreactividad Bronquial/diagnóstico , Niño , Ambiente , Femenino , Humanos , Hipersensibilidad/diagnóstico , Inmunoglobulina E/sangre , Recuento de Linfocitos , Masculino , Prevalencia , Pruebas de Función Respiratoria , Enfermedades de la Piel/complicaciones , Enfermedades de la Piel/diagnóstico , Pruebas Cutáneas , Subgrupos de Linfocitos T , Venezuela/epidemiología

RESUMEN

It is well established that malnutrition affects the immune response and increases the susceptibility to parasitic infection. In the present study we evaluated some aspects of the cellular and cytokine network that regulate the IgE responses, which are important components of host defence mechanisms against helminthic parasites in children infected with the intestinal helminth Ascaris lumbricoides, and with differing degrees of malnutrition. We found a defective T cell response in malnourished children, as indicated by diminished levels of circulating total (CD3+), helper (CD4+), IL-2-receptor-bearing (CD4+CD25+) and memory helper T cell responses (CD4+CD45RO+) in keeping with the decreased specific IgE levels against Ascaris lumbricoides. In contrast, the proportions of total B cells (CD20+), and those bearing the low-affinity IgE receptor (CD23+) were increased in the moderated malnourished children. Moreover, serum IL-4 levels and total IgE were also increased in these children. We suggest that malnutrition can cause an imbalance in T cell subpopulations that may lead to a defective T cell maturation and a decreased specific anti-Ascaris IgE response thus increasing the susceptibility to such infections. The high levels of total IgE observed may be related to a non-specific stimulation of the proliferation of activated B cells, probably caused by helminthic parasites and other infectious agents that are frequent in malnourished children.

Asunto(s)

Anticuerpos Antihelmínticos/biosíntesis , Antígenos de Diferenciación de Linfocitos T/sangre , Ascariasis/inmunología , Ascaris lumbricoides/inmunología , Inmunoglobulina E/biosíntesis , Trastornos Nutricionales/inmunología , Análisis de Varianza , Animales , Antígenos CD/metabolismo , Niño , Heces/parasitología , Citometría de Flujo , Humanos , Inmunoglobulina E/sangre , Interleucina-4/sangre , Recuento de Linfocitos , Trastornos Nutricionales/epidemiología , Trastornos Nutricionales/parasitología , Recuento de Huevos de Parásitos , Prueba de Radioinmunoadsorción , Venezuela/epidemiología

RESUMEN

The aim of this work was to evaluate in an open, noncomparative study the use of secnidazole in oral suspension given to Venezuelan children infected with Giardia intestinalis, from a community in Carapita, a slum area in Caracas. Seventy children from 2 to 11 years old (38 males and 32 females) were treated with a single oral dose of secnidazole (30 mg/Kg of body weight), after clinical and parasitological evaluation to make the diagnosis of active giardiasis. The effectiveness of treatment was determined by clinical examination and parasitological evaluation of feces samples 15 days after treatment. The results showed 95% of clinical cure with a significant decrease of the frequency of gastrointestinal symptoms. The parasitological cure was 98%, there were 4 failures at the end of treatment. Side effects observed after treatment were of mild intensity, lasting only few hours. These results show that a simple dose of secnidazole in an oral suspension is an effective, safe and well tolerated treatment for giardiasis in children and that this drug may be used as a mass treatment in risk populations.

Asunto(s)

Antiprotozoarios/administración & dosificación , Giardiasis/tratamiento farmacológico , Metronidazol/análogos & derivados , Administración Oral , Animales , Antiprotozoarios/efectos adversos , Niño , Preescolar , Interpretación Estadística de Datos , Femenino , Giardiasis/diagnóstico , Humanos , Masculino , Metronidazol/administración & dosificación , Metronidazol/efectos adversos , Áreas de Pobreza , Factores de Riesgo , Factores Socioeconómicos , Venezuela

RESUMEN

We evaluated helminthic infection and anthropometric indicators of nutritional status in a group of school-age children from a slum area of Caracas, Venezuela. The proportions of children at or below the 10th percentiles for height/age and weight/age were significantly higher in those presenting helminthiasis than in those uninfected. Although this could partially reflect a codependence of both helminthic infection and undernutrition or poverty, when the children were administered regular anthelmintic treatment for a year their anthropometric values improved significantly. When they were re-evaluated 8 months after the end of anthelmintic administration, the degree of reinfection by the most common helminth, Ascaris lumbricoides, was significantly higher in the growth-retarded children. These results confirm the relationship between helminthic infection and decreased growth rates in underprivileged populations, and indicate that children at nutritional risk are more susceptible to such infections, even after a prolonged parasite-free period.

Asunto(s)

Antihelmínticos/uso terapéutico , Helmintiasis/tratamiento farmacológico , Trastornos Nutricionales/prevención & control , Áreas de Pobreza , Antropometría , Niño , Estudios de Seguimiento , Helmintiasis/complicaciones , Helmintiasis/epidemiología , Humanos , Trastornos Nutricionales/epidemiología , Trastornos Nutricionales/etiología , Recurrencia , Venezuela/epidemiología

RESUMEN

The blood concentrations of haemoglobin were investigated in 82 children aged 2-9 years. Fifty-seven (31 boys and 26 girls) were stool-positive for Giardia intestinalis but the other 25, used as controls, were negative. The mean (S.D.) haemoglobin concentration among the infected children was significantly lower pre-treatment than that for the control group [11.6 (1.2) v. 12.6 (1.5) g/dl; P < 0.05]. Treatment of the infected children with a single oral dose of secnidazole (30 mg/kg) led to a significant increase in their mean haemoglobin level 15 days later, from 11.6 (1.2) g/dl pre-treatment to 12.4 (1.2) g/dl post-treatment (P < 0.05). The results indicate that the therapeutic control of giardiasis could be important in programmes to combat anaemia in children living in endemic areas.

Asunto(s)

Antiprotozoarios/uso terapéutico , Giardiasis/tratamiento farmacológico , Hemoglobinas/análisis , Metronidazol/análogos & derivados , Anemia/sangre , Anemia/etiología , Anemia/prevención & control , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Giardiasis/sangre , Giardiasis/complicaciones , Humanos , Masculino , Metronidazol/uso terapéutico , Resultado del Tratamiento

RESUMEN

BACKGROUND: Previous studies have indicated that there may be an association between infection by the intestinal protozoan Giardia lamblia and the expression of allergic disease. OBJECT: We evaluated a group of children who attended the Outpatient Clinic of the Children's Hospital in Caracas, Venezuela, a group in which both allergic disease and giardiasis were common. METHODS: We performed feces examination and measured total and specific serum IgE (immunoglobulin E) in these children. RESULTS: We found that 70% of the children infected with G. lamblia presented symptoms of allergy, in contrast to 43% of the non-Giardia parasitized group (P <.05). In addition, the G. lamblia parasitized children showed significantly higher levels of total serum IgE (1194 IU/mL) than the non-Giardia group (822 IU/mL) (P <.005). Children infected with G. lamblia showed higher levels of specific serum IgE antibody against food allergens compared both with the non-parasitized group (P <.0001) and children infected with parasites other than Giardia (P <.05). In contrast, IgE responses against the house dust mite Dermatophagoides pteronyssinus were similar in all the groups studied. CONCLUSIONS: These results reveal a clear relationship between giardiasis and allergy, possibly because infection by this protozoon enhances sensitization towards food antigens, due to increased antigen penetration through damaged intestinal mucosa.

Asunto(s)

Giardiasis/epidemiología , Giardiasis/inmunología , Hipersensibilidad/epidemiología , Anticuerpos Antiprotozoarios/sangre , Niño , Preescolar , Femenino , Hipersensibilidad a los Alimentos/parasitología , Giardiasis/sangre , Humanos , Hipersensibilidad/parasitología , Inmunoglobulina E/sangre , Masculino , Hipersensibilidad Respiratoria/parasitología , Venezuela/epidemiología

RESUMEN

BACKGROUND: House-dust mites contain components that are allergenic in mite-sensitive patients, and a number of these have been produced in recombinant form. METHODS: In the present study, we evaluated by skin prick testing the positivity to native Der p 2 and recombinant Der p 2, Der p 5, and Der p 7 allergens of Dermatophagoides pteronyssinus in patients with rhinitis, asthma, or a combination of these diseases, who were positive to whole-mite extract. RESULTS: In all patients, the positivity to both native and recombinant Der p 2 was high. In patients with either rhinitis or asthma, the reactivity to Der p 5 and 7 was significantly lower than to Der p 2. However, in patients with combined disease, the positivity to the minor allergens was almost as high as that to Der p 2. CONCLUSIONS: These results raise the question of whether patients with combined allergic rhinitis and asthma, when compared to those with either of these diseases alone, are predisposed to react to a wider range of mite allergens, or, inversely, whether patients who respond to the minor allergens are more susceptible to suffering the combined disease.

Asunto(s)

Asma/inmunología , Glicoproteínas/inmunología , Ácaros/inmunología , Rinitis Alérgica Perenne/inmunología , Clima Tropical , Administración por Inhalación , Adolescente , Adulto , Alérgenos/inmunología , Animales , Antígenos Dermatofagoides , Niño , Polvo/efectos adversos , Escherichia coli/genética , Femenino , Glutatión Transferasa/genética , Humanos , Masculino , Persona de Mediana Edad , Proteínas Recombinantes de Fusión/inmunología , Pruebas Cutáneas , Venezuela

RESUMEN

House dust mites are the most important source of allergens in the tropical environment, and aqueous whole body extracts of these organisms have wide use in the diagnosis and treatment of allergic diseases. However, it has been reported that mite excretions have a high allergenic activity. Because of this, we have evaluated spent house-dust mite culture medium as an alternative source of allergens from these organisms. We demonstrated that the extraction of allergens from this material is more efficient in alkaline solutions such as ammonium bicarbonate, and when the extraction process is extended to 48 hours. When the purification process is complemented with dialysis and ammonium sulphate precipitation, the toxicity of the extract decreases and its allergenic activity increases. The electrophoretic pattern of proteins of the spent culture medium extract showed bands that bound specific IgE antibodies, but this extract may be deficient in one of the principle allergens of mites, Der pII. The extract stimulates immediate hypersensitivity skin reactions in house-dust allergic patients, and produces RAST inhibitions with their sera. The allergenic activity of this extract is comparable to that of the 1st. International Standard for house-dust mite extracts. These results demonstrate that spent house-dust mite culture medium is an appropriate source of allergens from these organisms, and because of its low commercial value, may be an economical alternative for the production of allergenic extracts.

Asunto(s)

Alérgenos , Medios de Cultivo Condicionados , Ácaros/inmunología , Animales , Humanos , Hipersensibilidad Inmediata/inmunología , Ratones , Proteínas/análisis , Pruebas Cutáneas

RESUMEN

Helminthic infection can stimulate the interleukin-4 (IL-4)-dependent polyclonal synthesis of immunoglobulin E (IgE) in children endemically exposed to these parasites. As such children are also frequently at nutritional risk, in this study we considered the possible influence of malnutrition on serum IL-4 levels and the IgE response in helminthic infection. We evaluated 85 Ascaris-infected children living in an urban slum area of Caracas, Venezuela, and found that the serum levels of IL-4 and total IgE were significantly higher in malnourished children than in their well nourished counterparts. In contrast, the specific anti-Ascaris IgE antibody response was significantly lower in the malnourished group. After anthelmintic treatment of the children, the total serum IgE and IL-4 levels decreased significantly in the well nourished group, while the specific anti-Ascaris IgE antibody response increased. No significant change was detected, however, in the malnourished group. Our results suggested that malnutrition potentiates the polyclonal stimulation of IgE synthesis induced by helminths. As specific IgE antibody has been implicated in the resistance to helminthic infection, and the polyclonal stimulus diminishes this response, these factors may increase the susceptibility of malnourished children to such parasites.

Asunto(s)

Anticuerpos Antihelmínticos/biosíntesis , Ascariasis/inmunología , Ascaris lumbricoides/inmunología , Inmunoglobulina E/biosíntesis , Trastornos Nutricionales/inmunología , Animales , Antihelmínticos/uso terapéutico , Especificidad de Anticuerpos , Ascariasis/sangre , Ascariasis/tratamiento farmacológico , Niño , Heces/parasitología , Humanos , Interleucina-4/sangre , Trastornos Nutricionales/parasitología , Estado Nutricional , Recuento de Huevos de Parásitos , Áreas de Pobreza

RESUMEN

Total and Ascaris-specific serum IgE levels were measured in a group of 98 Ascaris-infected children from a slum area of Caracas, Venezuela, in whom the infections were eliminated by regular treatment for 22 months with the anthelmint Oxantel/Pyrantel ('Quantrel'). The children were re-evaluated at the end of the treatment programme, and then 8 months later, at which time reinfection was assessed. Total IgE levels at the beginning of the study were significantly higher in the children who became reinfected after treatment, compared with those who did not. The anthelmint treatment caused a significant decrease in the total IgE levels in most of the children, and after a period of 8 months without treatment these continued to decrease in the non-reinfected group, but increased again in the reinfected children. The reverse pattern was found for Ascaris-specific IgE antibody levels, and in fact an inverse correlation was found between total and anti-Ascaris IgE levels. Striking associations were found between reinfection and high pretreatment values of total IgE, but low levels of specific IgE antibody. These data support the concept that specific IgE antibody may participate in the protection against helminthic infection, and suggest that the polyclonal stimulation of IgE synthesis caused by these parasites may reduce the effectiveness of such responses. The results also indicate that different individuals have varying propensities to respond polyclonally to the helminths, and this influences their resistance to infection.

Asunto(s)

Anticuerpos Antihelmínticos/sangre , Ascariasis/inmunología , Ascaris/inmunología , Inmunoglobulina E/sangre , Animales , Niño , Preescolar , Humanos , Áreas de Pobreza , Recurrencia , Venezuela

RESUMEN

It is well known that helminthic infection can cause a polyclonal stimulation of the synthesis of IgE, which is dependent on interleukin-4 (IL-4) production, and it has been suggested that this can modulate the expression of allergic reactivity in tropical populations. We evaluated the effect of regular anthelmintic treatment, for a period of 22 months, on certain aspects of the allergic reactivity of children in a slum area of Caracas, Venezuela, where helminths are endemic. The treatment (Oxantel-Pyrantel; Quantrel) effectively eliminated intestinal helminthic infection and resulted in a significant decrease in the initially elevated total serum IgE levels. IL-4 was detectable in the serum, and a significant reduction in IL-4 was also observed after treatment. In contrast, both the immediate-hypersensitivity skin-test reactivity and serum levels of specific IgE antibody against environmental allergens were markedly increased in the treated children. In a group of children who were also evaluated in the same slum, but who declined treatment, a substantial increase in helminthic infection occurred, which was related to an acute deterioration of the socioeconomic conditions of Venezuela over the course of our study period. This was paralleled by a considerable increase in total IgE levels in these children and a decrease in the skin-test reactivities and specific IgE levels. The application of Prausnitz-Küstner passive transfer tests and analysis of specific IgE antibody levels indicated that the polyclonal stimulation of IgE synthesis by helminthic parasites results in mast cell Fc epsilon receptor saturation and suppression of specific IgE antibody synthesis. This inhibition of allergic reactivity is reversible by anthelmintic treatment.

Asunto(s)

Antihelmínticos/uso terapéutico , Helmintiasis/tratamiento farmacológico , Helmintiasis/inmunología , Hipersensibilidad/parasitología , Inmunoglobulina E/efectos de los fármacos , Áreas de Pobreza , Adolescente , Análisis de Varianza , Distribución de Chi-Cuadrado , Niño , Preescolar , Humanos , Hipersensibilidad/inmunología , Inmunoglobulina E/sangre , Parasitosis Intestinales/tratamiento farmacológico , Parasitosis Intestinales/inmunología , Factores Socioeconómicos , Clima Tropical , Venezuela

RESUMEN

Infection by helminthic parasites can cause the polyclonal stimulation of IgE synthesis, possibly via an enhanced production of interleukin-4 (IL-4), and this has been suggested to influence the allergic reactivity of tropical populations where these parasites are endemic. We evaluated a group of urban slum children in Caracas, Venezuela, with a high prevalence of helminthic infection (70.8%), to establish the relationship between the elevated IgE levels (3696 IU/ml) induced by these parasites and various aspects of the allergic response. Although the absolute levels of IL-4 detected in the sera of these children were low (0.65 +/- 0.20 ng/ml), a strong positive correlation (r = 0.78) was found between these and serum IgE. The cutaneous immediate hypersensitivity reactivity to extracts of common environmental allergens was relatively low (17.5% to house dust), although that to Ascaris extract was moderately high (49.4%). Significant inverse correlations were found between total IgE levels and the different skin test reaction diameters, including Ascaris. The positivity of Prausnitz-Kustner passive transfer tests was low in this group (34%), with a strong inverse correlation (r = -0.75) being found between this and total IgE levels. Significant inverse correlations were also found between total IgE levels and specific IgE antibody to environmental allergens, and to Ascaris antigen. We suggest that the polyclonal production of IgE stimulated by helminthic infection can suppress the allergic response to environmental and parasite allergens via both mast cell saturation and inhibition of specific IgE production.

Asunto(s)

Helmintiasis/inmunología , Hipersensibilidad/inmunología , Alérgenos/inmunología , Animales , Anticuerpos Antihelmínticos/sangre , Antígenos Helmínticos/inmunología , Ascariasis/epidemiología , Ascaris/inmunología , Niño , Preescolar , Heces/parasitología , Femenino , Helmintiasis/epidemiología , Humanos , Inmunoglobulina E/sangre , Interleucina-4/sangre , Masculino , Áreas de Pobreza , Prevalencia , Análisis de Regresión , Pruebas Cutáneas , Población Urbana , Venezuela/epidemiología

RESUMEN

In order to better understand the possible relationship between allergic reactivity and infection with G. lamblia, specific IgE responses and skin test reactivity were evaluated in allergic or nonallergic Venezuelan children, with or without G. lamblia infection. Two groups of children were studied: one from our Allergy Clinic and the other from a slum area of Caracas. The total serum IgE levels in children from the slum area were significantly higher in those with intestinal helminthic parasites and giardiasis, compared with those with helminthiasis only (P < .001). In atopic children with giardiasis we also found an enhanced IgE antibody response to common environmental allergens (P < .05). As G. lamblia produces intestinal mucosal damage, we also studied the reactivity to cow milk and found that 22% of the children belonging to the low socioeconomic level demonstrated the presence of significant levels of specific IgE against this antigen. Of these milk-positive subjects, 40% were infected by G. lamblia in contrast to only 21% of the milk-negative children (P < .05). These results suggest that children with giardiasis may be exposed to greater amounts of intestinally absorbed antigens. We also studied the specific allergic response to G. lamblia, and found that in an unselected group of children of low socioeconomic level, 25% had positive skin tests, as did 50% of persons with symptomatic giardiasis. The presence of serum anti-Giardia IgE was also demonstrated in 22% of patients with giardiasis.

Asunto(s)

Giardia lamblia/aislamiento & purificación , Giardiasis/complicaciones , Hipersensibilidad/parasitología , Animales , Anticuerpos Antiidiotipos/inmunología , Especificidad de Anticuerpos , Niño , Preescolar , Giardiasis/epidemiología , Humanos , Inmunoglobulina E/sangre , Prevalencia , Pruebas Cutáneas , Venezuela/epidemiología

RESUMEN

We examined a group of urban slum children in Caracas, Venezuela, and demonstrated the relationship that exists between poverty, conditions of hygiene and the prevalence of helminth infection. Concordant with the high prevalence of helminth infection in these children, the total serum levels of immunoglobulin E (IgE) and blood eosinophilia were elevated and were directly related to the degree of poverty and lack of sanitary facilities. However, in contrast, the reverse pattern was observed for the specific allergic response to these parasites. Thus, the immediate hypersensitivity skin test reactivity to Ascaris antigens, and the serum levels of specific anti-Ascaris IgE antibody, were lowest in the poorest children, who had the highest prevalence of helminth infection and the highest total IgE levels. As allergic-type reactions may participate in protective mechanisms against helminths, these results suggest that poverty and poor sanitary conditions may, by influencing the IgE response, compromise the resistance of such children to parasitic infections.

Asunto(s)

Anticuerpos Antihelmínticos/sangre , Ascariasis/epidemiología , Ascaris lumbricoides/inmunología , Inmunoglobulina E/sangre , Pobreza , Animales , Ascariasis/sangre , Ascariasis/inmunología , Niño , Heces/parasitología , Humanos , Higiene , Recuento de Huevos de Parásitos , Áreas de Pobreza , Prevalencia , Salud Pública , Venezuela/epidemiología

RESUMEN

The seropositivities for infection by Ascaris lumbricoides and Toxocara canis were determined in children (1-15 years old) of a slum area of Caracas, Venezuela, and the levels that indicate the presence of active infection were defined. In children aged from 1 to 3 years, approximately 10% were positive for either parasite, and this figure increased to about 30% in 4- to 6-year-olds. For toxocariasis, the percentage of positivity remained at this level up to the age of 15 years. Whilst the positivity in children 10-15 years of age was comparable for Ascaris and Toxocara, a peak of positivity (50%) was found for Ascaris at 7-9 years of age. These results indicate that for these urban slum children, infection by Toxocara is essentially as common as that by Ascaris and, thus, that toxocariasis represents a potential public health problem in the tropical environment that is largely overlooked.

Asunto(s)

Anticuerpos Antihelmínticos/sangre , Ascariasis/epidemiología , Toxocariasis/epidemiología , Adolescente , Animales , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Humanos , Lactante , Áreas de Pobreza , Prevalencia , Población Urbana , Venezuela/epidemiología

RESUMEN

Eosinophils were isolated from the blood of American cutaneous leishmaniasis (ACL) patients and healthy controls from the same endemic rural area (ERA) or from a non-endemic urban area (UA). For the purification of eosinophils a Percoll discontinuous gradient method was used. We obtained a good cell viability (between 90 to 95%) and the more pure layers, which were the densest, ranged from 85 to 95% eosinophils. A high proportion of the ACL patients and individuals from the ERA, had eosinophils in the low density layers (< 1.090 g/ml) and particularly at 1.070 g/ml. Using the immunoperoxidase (IP) staining and monoclonal antihuman IgE, surface IgE could be detected on eosinophils of different densities, and the hypodense fraction was the more positive. The phagocytic capacity for Leishmania promastigotes of eosinophils was also assessed. Eosinophils from the ERA group demonstrated the highest percentage of phagocytosis followed by the ACL patients. The UA group showed the lowest percentage, and the normodense fractions the lower phagocytic capacity. We found therefore that the hypodense layers had the highest percentage of detectable surface IgE and also the highest phagocytic capacity. We suggest that the surface IgE of activated eosinophils can contribute to their phagocytic function.

Asunto(s)

Eosinófilos/inmunología , Inmunoglobulina E/sangre , Leishmaniasis Cutánea/inmunología , Fagocitosis , Adulto , Animales , Recuento de Células , Femenino , Humanos , Técnicas In Vitro , Leishmania mexicana/inmunología , Leishmaniasis Cutánea/sangre , Leishmaniasis Cutánea/epidemiología , Masculino , Receptores de Antígenos de Linfocitos B/sangre , Población Rural , Población Urbana , Venezuela/epidemiología

RESUMEN

Se acepta que en la dermatitis atopica participan numerosos factores inmunologicos y no inmunologicos. Se revisan en este trabajo las principales alteraciones supuestas como son el papel de la alergia y de la IgE asi como de la inmunidad celular que se muestra deteriorada. Se piensa que la deficiencia de linfocitos T supresores podria involucrar al aumento de la IgE. Tambien se menciona el papel de los eosinofilos y otros polimorfonucleares. Entre los factores no inmunologicos se revisan el factor genetico, el psicologico y el bacteriano y la teoria del bloqueo beta adrenergico. Se concluye que todos estos factores podrian intervenir en mayor o menor grado dependiendo de cada individuo y que la dermatitis atopica es una enfermedad multifactorial

Asunto(s)

Dermatitis Atópica , Inmunidad Celular , Inmunoglobulina E