[A study of immunoglobulin-producing cells in the colonic mucosa of children with Crohn's disease (author's transl)].

The immunoglobulin-producing cells of the rectal and colonic mucosae were studied on 12 biopsies obtained from 6 children, aged from 13 to 18 years, suffering from Crohn's disease involving the ileum and colon or the colon only. After incubation with immune sera specifically directed against alpha, gamma and mu chains, the fluorescent plasmocytes present in a predetermined surface area of the chorion were counted in the patients and in a control group of 5 children. Compared with controls, children with Crohn's disease had less IgA-producing plasmocytes per surface area (mean: 32.3 and 44.3 respectively) and a lower ratio of these plasmocytes to total immunoglobulin-producing cells (patients: 79%, controls: 85%). The decrease in IgA-producing cells was more pronounced in the colon but was also observed in the rectum, despite normal histology.