HLA-A, -B, -C and -DR antigen profile in pulmonary tuberculosis in North India

Investigations for the HLA-A, -B, -C and -DR antigens were conducted on 124 random North Indian patients with confirmed diagnosis of pulmonary tuberculosis by the demonstration of acid fast bacilli in the sputum. 109 appropriately matched controls from the same ethnic background were also tissue typed. No significant deviation was observed in the HLA-A, -B, and -C locus antigens. With the HLA-DR typing, there was a marginal increase in DR2 and a concurrent significant decrease in DRw6 in the patient group. These deviations were, however, insignificant when correction for the P value was made. ABO blood group typing results indicate that blood group 'O' may afford protection against TB. The involvement of both DR2 and DRw6 is interesting as it is also implicated in leprosy, another mycobacterial disease. The results suggest the possibility of a common gene in the MHC for both tuberculosis and leprosy.