Análise dos títulos séricos de IgA anti-antígeno glicolipídio fenólico 1 em pacientes com hanseníase e seus contatos menores de 15 anos

Abstract

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, which shows predilection for the peripheral nerves. The glycosylated phenolic group with a trisaccharide (PGL-1) is specific for the species, and is responsible for inducing high specific humoral immune response. Since its discovery in 1980, it has been employed in techniques to detect antibodies to M. leprae and it is used in seroepidemiological studies. The analysis of anti-PGL 1 antibodies in most cases is restricted to the IgM isotype in the serum. Other studies bring results with serum IgG and IgM, and IgA in saliva. The IgA isotype has been used as a diagnostic tool in other diseases, but not in leprosy. The present work studied the anti-PGL 1 IgA isotype in the serum of leprosy patients and contacts in endemic cities of Rio Largo and Santana do Ipanema, Alagoas. Of the 42 samples from leprosy patients, 42.85% were positive for anti-PGL IgA 1. When the patients were separated by multibacillary or paucibacillary classification, there was a higher positivity (45.4%) in the multibacillary form. The comparison with other isotypes IgG and serum IgM, anti-PGL 1 IgA showed the best correlation with IgM (r = 0.71, p <0.0001) than with IgG (r = 0.35, p = 0.02 ). In the group of leprosy contacts (n = 224), anti PGL 1 IgA was positive in 0.89%. When the contacts were separated in household and peridomiciliar contacts, two individuals from Santana do Ipanema, one intra and one peridomiciliar leprosy contact, were positive. There was significant difference between the titers of anti-PGL 1 IgA in patients and all contact groups (p = 0.0001). An important statistical significance (p <0.0001) was also observed when the contacts were divided according to the index case MB / PB and compared with patients MB / BP. Anti-PGL 1 IgA may be a potential tool in diagnosis; however, more studies shall be done. It is critical to follow-up leprosy contacts who present positive anti PGL-1 IgA who may present high risk of developing the disease.