Preponderance of IgM from blood lymphocytes in response to infantile rotavirus gastroenteritis.

Immune responses triggered by acute rotavirus infection in infants are poorly defined. To obtain indirect evidence as to gut immune response to rotavirus, the solid phase enzyme linked immunoassay (ELISPOT) of immunoglobulin and specific antibody secreting cells among circulating blood lymphocytes was used. Seventeen well nourished patients from seven to 25 months of age were studied during the peak of rotavirus infection, and in convalescence. A transient but distinct immunoglobulin secreting cell response in IgM and IgG, but not in IgA, classes was found during the diarrhoeal phase. This response included a quantitatively prominent activation of specific antibody secreting cells against rotavirus in the IgM class, mean (95% confidence interval (CI)) 82 (32, 210)/10(6) cells v 8 (4, 17)/10(6) cells in convalescence, p = 0.01. The response in the IgA class was not significant. The results indicate that local immune mechanisms are activated in rotavirus diarrhoea. They further suggest that although IgA is the predominant immunoglobulin operative in the gastrointestinal tract, this may not be the case in infantile rotavirus enteritis.