HLA and adult T cell leukaemia: HLA-linked genes controlling susceptibility to human T cell leukaemia virus type I.
HLA antigens of patients with adult T cell leukaemia (ATL), T cell malignant lymphoma (T-ML), and healthy carriers of human T cell leukaemia virus type I (HTLV-I) were investigated in an endemic area of ATL in Japan. Sixty-two patients with ATL were subdivided into three groups based on their clinical features, including two unclassified patients; 36 acute type, 10 chronic type, and 14 smouldering type. The frequency of HLA-Bw62 was significantly increased in acute ATL, compared with control (Pc less than 0.0002). Increased frequency of HLA-DQw3 was observed in patients with ATL, T-ML positive for the antibody to HTLV-I (Ab-positive), and Ab-positive healthy carriers, compared with control (Pc less than 0.001, Pc less than 0.01 and Pc less than 0.0001, respectively). In addition, class I HLA antigens of peripheral lymphocytes of patients with ATL, especially acute ATL, showed altered expression, either extra antigens or decreased antigens. Analysis of 21 families, where more than two members were Ab-positive, showed that there was no linkage between the HLA complex and susceptibility to the virus infection. In 44 couples, in which either or both spouses were Ab-positive, no association with class I HLA antigens was found in either Ab-positive spouses or Ab-negative spouses. These findings might indicate that one class II HLA-linked gene controlled susceptibility to HTLV-I infection, and another class I HLA-linked gene exerted an influence on the clinical course of ATL.