Circulating Rotavirus-Speci®c Antibody-Secreting Cells (ASCs) Predict the Presence of Rotavirus-Speci®c ASCs in the Human Small Intestinal

Rotaviruses are the most important cause of infectious diarrhea in children throughout the world. Protection is most likely mediated by small-intestinal virus-speci®c IgA. However, neither fecal nor serum virus-speci®c IgA clearly correlates with protection against challenge. The capacity of rotavirus-speci®c antibodies and rotavirus-speci®c antibody-secreting cells (ASCs) in the circulation to predict the presence of ASCs in the intestines of children was evaluated. Mononuclear cells from intestinal biopsy samples and blood from 21 children were enriched for CD38, a marker of terminally differentiated B cells, and evaluated for the presence of virus-speci®c and total IgA- and IgG-secreting cells, by ELISPOT assay. Serum virus-speci®c IgA and IgG levels were determined by ELISA. The ratio of virus-speci®c to total IgA-secreting cells in the blood correlated with that found in the small, but not large, intestine. In contrast, serum rotavirus-speci®c IgA correlated less well with the presence of virus-speci®c ASCs in the small intestine. Rotaviruses are the most important cause of infectious diar-rhea in infants and young children throughout the world, with virtually all children infected by age 3 years [1, 2]. Rotaviru