HLA-DR3 associated genetic control of response to multiple skin tests with new tuberculins

Multiple skin testing with mycobacterial antigenic preparations reveals distinct reaction patterns, which might be relevant to the development of mycobacterial disease in man. Previous work has shown that HLA-DR associated factors correlate with the position of a leprosy patient in the immunopathological spectrum of leprosy. This study was undertaken to see whether these skin test patterns in healthy persons do show any association with HLA-DR types. Out of a group of 74 healthy Caucasoid individuals HLA-DR3 was observed to be absent from the 16 individuals who did not respond to any of the mycobacterial antigens tested. This is a striking difference from the distribution of HLA-DR3 both among the 17 individuals who responded to all mycobacterial antigens tested (P = 0.005) and the 41 individuals who responded to some but not all antigens (P = 0.015). These data show that an HLA-DR3 associated genetic factor controls, albeit indirectly, skin test responsiveness to mycobacterial antigens. It may be significant that this same HLA-DR determinant is implicated in deciding the type of disease to be developed by a leprosy patient.