[Association between HLA antigens and leukemia in the population of Vojvodina]

One of the most fascinating areas of research within the field of histocompatibility at present time concerns an observation that a major human histocompatibility system, HLA, is deeply involved in development of a great number of diseases.

HLA class I antigens were investigated in 225 cases with various kinds of leukemia: 112 patients with acute myeloblastic leukemia (AML), 31 with acute lymphoblastic leukemia (ALL), 44 with chronic myelocytic leukemia (CML) and 38 with chronic lymphocytic leukemia (CLL). Applying method of microlymphocytotoxicity, 13, 19 and 8 antisera were used for A, B and C loci respectively. Control group comprised 300 unrelated persons, whose phenotypic frequencies were used to calculate the relative risk (RR), while for values of RR greater than 1, we calculated etiologic fraction (EF), and for negative RR values we calculated preventive fraction (PF).

Results of investigation showed that RR in AML was: for A2 = 1.144, for A3 = 1.038, for A29 = 1.814, for A34 = 2.69, for B7 = 1.06, for B14 = 1.74, for B17 = 1.65 and for B21 = 2.49 and B35 = 1.77 with value of chi 2 test of 4.62 and 4.63; that RR in ALL was: for A1 = 1.61, for A2 = 1.1, for A10 = 1.23, for A11 = 1.57, for A30 = 1.4, for A32 = 2.2, for B7 = 2.81 with value of chi 2 test 4.39; that RR in CML was: for A2 = 1.21, for A32 = 1.89, for B7 = 1.52, for B12 = 1.2 and for B15 = 3.28 with value of chi 2 test of 5.89; and that RR in CLL was: for A1 = 1.35 with value of chi 2 test of 3.973, RR for A2 = 1.02, for A28 = 1.97, for A32 = 1.25, for B5 = 1.44, for B8 = 1.27, for B13 = 1.91 without statistically significant differences of frequencies except for A1. Investigation of differences between haplotype frequencies among controls and patients showed statistically significant difference of A10 B40 haplotype in CML with RR value 7.24, while there were no statistically significant differences between controls and other leukemias.

Our results of investigation showed statistically significant differences between HLA frequencies in the control group and investigated diseases, and that the relative risk is under 1, and values of chi 2 test under borderline values for B21 and B35 in AML, for B7 in ALL, for B15 in CML and for A1 in CLL.

Results of this investigation point to an association between HLA system and leukemias. This association is of great importance because it provides a new tool for investigation of genetics and etiology of abovementioned diseases.