HUMAN-LEUKOCYTE ANTIGEN SYSTEM IN CLOZAPINE-INDUCED AGRANULOCYTOSIS

Forty-three schizophrenic patients participating in this study were se rotyped for human leukocyte antigens (HLA-A, -B, -C, -DR, -DQ antigens ). Thirty-six of them were hospitalised in two state mental hospitals and 7 in our general hospital, psychiatric unit. The patients from our unit were typed for HLA before commencing clozapine treatment whereas the patients from state hospitals were typed after commencing treatme nt. Three out of 43 patients developed agranulocytosis. One had a comb ination of both 'high-risk' haplotypes (HLA-B 16(38,39), DR4, DQ3 and HLA-DR2, DQ1), another had HLA-DR2, DQ1, whereas the last had a totall y different haplotype. Between non-agranulocytic patients 1 was found to carry the HLA-B16(38,39), DR4, DQ3 haplotype and 14 (out of 40) had the HLA-DR2, DQ1. Taking into account other factors supposed to be in volved (a noxious metabolite, and the presence of a humoral cytotoxic factor) we must admit that despite the finding of a high-risk haplotyp e in Jewish populations there are other aspects of this question await ing clarification.