Multiple sclerosis immunogenetics: a) associations between HL A antigens and high measles antibody levels. b) Existence of common MLR/immune response determinants in MS patients

Antimeasles antibody titers were investigated in patients with multiple sclerosis (MS) and a nonhomogeneous distribution of such titers was observed in relation to HL A (human leucocyte antigen A) phenotypes. The highest antimeasles levels were found in patients bearing HL A3 and HL A9 types, which were shown to correlate with the illness. Homogeneity was also investigated at the MLR (mixed lymphocyte reaction) locus by means of 2 way mixed lymphocyte cultures. The strongly reduced activation implied that MS subjects have at least 1 common MLR (Ir) determinant, responsible for their peculiar susceptibility to developing demyelination. The mechanisms through which MLR locus may influence such susceptibility are considered in relation to the virus or viruses that appear to be involved in the etiopathogenesis of MS.