In order to better understand the role of Mycobacterium leprae nasal carriage in the maintenance of infection reservoirs and transmission of leprosy, we applied a polymerase chain reaction (PCR) that detected a 531-bp fragment of the pra gene of M. leprae on nasal swab specimens collected through a total population survey from individuals living in an area in which leprosy is endemic.
The much stronger association of DRB1*1501 with the multibacillary form than with the TT type of leprosy suggests a possible role in the differential immune response to M. leprae antigens.
The much stronger association of DRB1*1501 with the multibacillary form than with the TT type of leprosy suggests a possible role in the differential immune response to M. leprae antigens.
On the other hand, DRB1*0701, DQB1*0201 and DQA1*0201 were decreased in the multibacillary leprosy patients (MLP) compared to TT patients and controls, and DQB1*0503 was selectively decreased in TT patients, suggesting that these HLA alleles might play a role in modulating the immune response that determines the form of leprosy that develops in each patient.
These Th2 inducer epitopes on HSP65 (DR1 restricted) and HSP18 (DR7 restricted) were absent from TDB65-2 and TDB18-3 which exclusively triggered Th1 cells in both TT and LL forms of leprosy in the context of multiple DR alleles, DR15 being the major antigen-presenting allele.
Through comparative genomics, we have identified the homologous human NRAMP1 gene, alleles of which are now being used for tests of linkage with TB and leprosy.