EVIDENCE FOR GENETIC-REGULATION OF SUSCEPTIBILITY TO TOXOPLASMIC ENCEPHALITIS IN AIDS PATIENTS

The frequency of HLA-DQ antigens in AIDS patients with toxoplasmic enc ephalitis (TE) were examined. HLA-DQ3 was significantly more frequent in white North American AIDS patients with TE (85.0%) than in the gene ral white population (51.8%; P = .007, corrected P = .028) or randomly selected control AIDS patients who had not developed TE (40.0%; P = . 016). In contrast, the frequency of HLA-DQ1 was lower in TE patients t han in healthy controls (40.0% vs. 66.5%, P = .027), but this differen ce did not reach statistical significance when corrected for the numbe r of variables tested (corrected P = .108 for the general white popula tion). HLA-DQ3 thus appears to be a genetic marker of susceptibility t o development of TE in AIDS patients, and DQ1 may be a resistance mark er. These HLA associations with disease indicate that development of T E in AIDS patients is affected by a gene or genes in the HLA complex a nd that HLA-DQ typing may help in decisions regarding TE prophylaxis.