RESUMO
A serological study was performed in 122 individuals: 75 leprosy patients and 47 healthy controls. The ELISA test was performed for IgG and IgM using the glycolipid PGL-I antigen from Mycobacterium leprae. Circulating immune complexes (CIC) were isolated by PEG 6000 precipitation method and after dissociation with an acid solution, the IgG and IgM specific against PGL-I were tested with the ELISA test. The multibacillary patients had high levels of antibodies, compared with paucibacillary patients and controls. The antibodies isolated from the CIC presented a similar spectrum spectral distribution as the serology. A positive correlation between the levels of free and CIC bound antibodies was observed. In contrast with tuberculosis patients, specific antibodies present in CIC were not responsible for false-negative results found in some multibacillary patients' serology, since no or very low levels of specific antibodies were found in PEG precipitated serum of these patients. No relation was observed with specific antibody levels detected in CIC during leprosy reactions.
Assuntos
Complexo Antígeno-Anticorpo/sangue , Antígenos de Bactérias/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Glicolipídeos/análise , Hanseníase/imunologia , Adolescente , Adulto , Anticorpos Monoclonais/análise , Especificidade de Anticorpos , Feminino , Humanos , Hanseníase/patologia , Masculino , Pessoa de Meia-Idade , Valores de Referência , Sensibilidade e EspecificidadeRESUMO
The authors studied 70 leprosy patients and 20 normal individuals, comparing the traditional sera collection method and the finger prick blood with the conservation on filter paper for specific antibodies against the native phenolic glycolipid-I (PGL-I) from Mycobacterium leprae. The finger prick blood dried on filter paper was eluated in phosphate buffer saline (PBS) containing 0.5% gelatin. The classical method for native PGL-I was performed for these eluates, and compared with the antibody determination for sera. It was observed that there is a straight correlation comparing these two methods; although the titles found for the eluates were lower than those obtained for serology. This blood collection method could be useful for investigation of new leprosy cases in field, specially in contacts individuals.
Assuntos
Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/imunologia , Coleta de Amostras Sanguíneas/métodos , Glicolipídeos/sangue , Hanseníase/imunologia , Mycobacterium leprae/imunologia , Adolescente , Adulto , Idoso , Antígenos de Bactérias/sangue , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Hanseníase/sangue , Modelos Lineares , Masculino , Pessoa de Meia-IdadeRESUMO
A survey of an emerging tuberculosis epidemic among the Yanomami Indians of the Amazonian rain forest provided a unique opportunity to study the impact of tuberculosis on a population isolated from contact with the tubercle bacillus for millennia until the mid-1960s. Within the Yanomami population, an extraordinary high prevalence of active tuberculosis (6.4% of 625 individuals clinically examined) was observed, indicating a high susceptibility to disease, even among bacille Calmette-Guérin-vaccinated individuals. Observational studies on cell-mediated and humoral immune responses of the Yanomami Indians compared with contemporary residents of the region suggest profound differences in immunological responsiveness to Mycobacterium tuberculosis infection. Among the Yanomami, a very high prevalence of tuberculin skin test anergy was found. Of patients with active tuberculosis, 46% had purified protein derivative of tuberculosis reactions <10 mm; similarly 58% of recent bacillus Calmette-Guérin vaccines exhibited skin test reactions <5 mm. The Yanomami also had higher titers of antibodies against M. tuberculosis glycolipid antigens (>70%) than the control subjects comprised of Brazilians of European descent (14%). The antibodies were mostly of the IgM isotype. Among the tuberculosis patients who also produced IgG antibodies, the titers of IgG4 were significantly higher among the Yanomami than in the control population. Although it was not possible to analyze T-cell responses or patterns of lymphokine production in vitro because of the remoteness of the villages from laboratory facilities, the results suggest that the first encounter of the Yanomami Indian population with tuberculosis engenders a diminished cell-mediated immune response and an increased production antibody responses, relative to other populations with extensive previous contact with the pathogen. These findings suggest that tuberculosis may represent a powerful selective pressure on human evolution that over centuries has shaped the nature of human immune responses to infection.
Assuntos
Anergia Clonal , Indígenas Sul-Americanos , Teste Tuberculínico , Tuberculose/imunologia , Anticorpos Antibacterianos/sangue , Anticorpos Antiprotozoários/sangue , Anticorpos Antivirais/sangue , Brasil/epidemiologia , Humanos , Tuberculose/epidemiologia , Tuberculose/etnologiaRESUMO
Circulating immune complexes (CIC) were assayed in sera of leprosy patients. Using an immunoassay for two mycobacterial antigens--phenolic glycolipid-I (PGL-I) and glycolipid IV (SL-IV)--sera from 65 patients with leprosy (38 lepromatous, 18 borderline, and 9 tuberculoid) were studied. The CIC were isolated by polyethylene glycol (PEG) precipitation, washed, treated with an acid buffer, neutralized, and tested using an enzyme-linked immunosorbent assay (ELISA). We demonstrated that CIC could contain IgG and IgM antibodies reacting against PGL-I and SL-IV. The high levels of antibodies in the precipitable CIC showed concordance with high levels in the original sera, although some patients presented high levels of precipitable CIC in the absence of high titers of antibodies in their sera. It was concluded that some of the CIC observed in patients with leprosy were composed of IgG and IgM immunoglobulins against specific mycobacterial antigens.
Assuntos
Anticorpos Antibacterianos/sangue , Complexo Antígeno-Anticorpo/sangue , Antígenos de Bactérias/imunologia , Hanseníase/imunologia , Mycobacterium leprae/imunologia , Adolescente , Adulto , Idoso , Precipitação Química , Ensaio de Imunoadsorção Enzimática , Glicolipídeos/imunologia , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Pessoa de Meia-Idade , Mycobacterium tuberculosis/imunologia , PolietilenoglicóisRESUMO
Analysis of cell-mediated immunity [(CMI) as judged from the Mantoux, Fernandez, and Mitsuda reactions and the presence of granulomas in biopsy material] against humoral immunity (measurements of anti-PGL-I, PGL-Tb1, and SL-IV IgG and IgM antibody titers by ELISA) were performed in selected human populations. The investigations yielded data indicating that humoral (B-cell) responses preceded protective CMI in both tuberculosis and leprosy. The B-cell responses were unrelated to (unfavorable) cell-mediated delayed-type hypersensitivity (DTH). Notwithstanding the difficulty in inferring sequential events from studies in humans, it was shown that in humoral responses there was an initial rise of specific IgM immunoglobulins that switched afterward to IgG production during subclinical tuberculosis and leprosy infections. In patent tuberculosis disease the IgM-to-IgG switch was observed in the majority of patients; in patent leprosy disease the switch was impaired in the majority of patients. The clinical, immunological, and laboratory data indicated that the B-cell responses were suppressed as protective CMI was re-established in the patients during the protracted subclinical infection. According to the data, the diagnosis of subclinical tuberculosis and leprosy may be accomplished using ELISA. The yearly risk of tuberculosis in apparently healthy persons but with significant antibody titers was estimated at 44%; the yearly risk for leprosy has not yet been established. The clinical, epidemiologic, and diagnostic implications of these findings are discussed.