HLA, GM, AND KM POLYMORPHISMS AND IMMUNITY TO INFECTIOUS-DISEASES IN SOUTH-AMERINDS

Isolated South Amerinds, a population at very high risk from infectiou s disease, mount good immune responses to pneumococcal polysaccharides , viral antigens and other immunogens. No unusual immunoglobulin allot ype or HLA antigen, which might explain the high risk from infectious disease, was found among them. Responses are examined in relation to t he immunogenetic markers that are most prevalent. Amerinds with Gm 1,2 ,17,21 responded less well than persons without this haplotype to 10 o f 12 pneumococcal polysaccharides, and those who were homozygous at th e HLA class I loci responded less well to viral antigens. However, the se differences are not strong and there are few such findings relative to the number of possibilities examined. The most distinctive immunog enetic characteristic of these populations is their low level of polym orphism at all tested loci. Their susceptibility to infectious agents can be attributed to this genetic uniformity and a consequent ability of pathogens to adapt to the population.