Histocompatibility determinants in childhood postinfectious encephalomyelitis.

Postinfectious encephalomyelitis and multiple sclerosis have clinical, immunologic, and neuroradiographic similarities. We studied HLA determinants in six white children consecutively diagnosed with postinfectious encephalomyelitis. Each of the children had HLA determinants which have been associated with multiple sclerosis. Relative risk (RR) calculations demonstrated that these antigens and genotypes occurred significantly more often in patients with postinfectious encephalomyelitis than in the control population (A3, RR 6.14; B7, RR 6.14; DR2, RR 4.51; A3B7, RR 9.36; A3DR2, RR 5.83; B7DR2, RR 6.13; A3B7DR2, RR 10.90). These data suggest that children with postinfectious encephalomyelitis are genetically predisposed to this demyelinating disease. Although the same HLA determinants were found in these patients as in those with multiple sclerosis, studies of a larger number of postinfectious encephalomyelitis patients will be needed before it can be concluded that the two diseases share a common genetic propensity.