Increase of unidentified HLA antigens in pulmonary tuberculosis.

We studied the HLA-A, B,C and DR antigens in 50 patients with advanced pulmonary tuberculosis in an effort to detect some genetic factors which may predispose to the development of this disease. We found a decrease in HLA-A3, A9, B5, B8, B13, B17 and B27. The incidence of "double blank" antigens in the locus A was 18% (2.5% in controls, p less than 0.0005) in the locus B 16% (1.5% in controls, p less than 0.0005) and 28% in the DR locus (7% in controls, p less than 0.0005). Our results suggest that the cells responsible for the immune response in patients with tuberculosis appear to have a diminished number of HLA antigens serologically determined. That phenomenon could be explained by several hypothesis like poor expression of these proteins or masking for another substance. In spite of the mechanism, this abnormal membrane expression of HLA antigens could be important for the development of the disease since the cell-cell interactions critical for the mounting of an adequate immune response might not be appropriate.