HLA Antigens inCardiomyopathic Chilean Chagasics

SummaryThedistribution of HLAantigens in a sample of 124 Chagas serologically positive Chilean individuals was studied. The sample was subdivided according to the presence or absence of chagasic cardiomyopathy, in order to search for genetic differences associated with this pathological condition. Thefrequency of anti- gen B40 in the presence of antigen Cw3 was found to be significantly lower in subjects with cardiomyopa-thy. Wetentatively suggest that the presence of these antigens among noncardiomyopathics is associatedwith a decreased susceptibility to develop chagasic cardiomyopathy in the Chilean population. IntroductionChagasdisease is endemic to centralandnorthernChile.Theaffected areais semiaridandcomprises thetrans-verse valleys ofthe so-called Norte Chico, in political RegionsIII and IV(30°-32° S). The meanannualtem- peratures are around 16C and 30C duringthe winter and summer months,respectively. Theclimate is Med- iterraneantype. Rainfall is scanty andconcentrateddur- ing the