Immunoglobulin secretion by isolated intestinal lymphocytes: spontaneous production and T-cell regulation in normal small intestine and in patients with coeliac disease.

The in vitro secretion of immunoglobulins by small intestinal lymphocytes isolated from 47 patients with normal histology and 23 patients with treated and untreated coeliac disease was examined using an enzyme linked immunosorbent assay. In control patients, duodenal lymphocytes spontaneously secreted higher levels of IgM than jejunal lymphocytes (p less than 0.05). Significantly higher levels of both IgA (p less than 0.05) and IgM (p less than 0.001) were secreted by jejunal lymphocytes of 10 patients with untreated coeliac disease than cells isolated from normal jejunal tissue. IgM and IgA secretion by duodenal lymphocytes isolated from control patients was increased in a dose dependent manner by coculture with autologous peripheral blood T lymphocytes. This effect was not observed with jejunal lymphocytes of control or treated coeliac patients. Peripheral T-cells of untreated coeliac patients, however, showed significant helper effects (p less than 0.05) for IgM and IgA secretion by autologous jejunal lymphocytes. The results suggest that jejunal lymphocytes of patients with untreated coeliac disease show major differences in their capacity to synthesise and secrete immunoglobulins in vitro and the enhanced secretion might result from changes in T-cell immunoregulatory function.