ABSTRACT
Background: Our earlier studies on Human Leucocyte Antigens (HLA) in pulmonary tuberculosis patients revealed the association of HLA-DR2 antigen with susceptibility to pulmonary TB and DR2 antigen has been shown to influence the immunity to tuberculosis. Objectives: The present study was carried out to find out whether HLA-DR antigens are associated with susceptibility to spinal tuberculosis. Moreover, the role of HLA-DR antigens on lymphoproliferative response to Mycobacterium tuberculosis culture filtrate antigens was studied using Lymphocyte Transformation Test (LTT). Material and Methods: HLA-DR genotyping and lymphoproliferative response was carried out in 63 cured spinal TB patients and 63 control subjects (spouses of pulmonary and spinal TB patients). Results: A trend towards an increased frequency of HLA-DR9 antigen was observed in spinal TB patients compared to controls. A significantly decreased lymphocyte response to M. tuberculosis antigens was observed in HLA-DR9 antigen positive control subjects compared to HLA- DR9 antigen negative subjects (P=0.0009) whereas increased response was observed with DR9 positive cured spinal TB patients compared to HLA-DR9 antigen negative patients. Further, HLADR3 antigen positive patients showed a decreased lymphocyte response compared to HLA-DR3 antigen negative patients (P<0.05). Conclusion: The study suggests that HLA-DR9 antigen either alone or in combination with other HLA antigen as lhplotype and non-HLA genes may be associated with susceptibility to spinal TB and play a regulatory role on the immune response to M. tuberculosis in spinal tuberculosis patients.