Polyclonal nature of the intestinal mucosal lymphocyte populations in inflammatory bowel disease

To define the clonality of the intestinal lymphocytes involved in the immune response of inflammatory bowel disease, we performed a molecular genetic analysis of the arrangement of the immunoglobulin and antigen-specific T-cell receptor genes of isolated lamina propria lymphocytes derived from resected intestinal specimens of 12 patients with Crohn's disease, 5 patients with chronic ulcerative colitis, and 7 patients with other gastrointestinal diseases. The sensitivity of this technique is sufficient to detect a monoclonal population when there is as little as 1% clonal expansion in a mixed cell population. In all these groups of patients, deoxyribonucleic acid from the non-T cells demonstrated only a germ-line gene pattern, and no non-germ-line rearrangements of immunoglobulin genes as assessed by an immunoglobulin-joining heavy-chain gene probe. Deoxyribonucleic acid from the lamina propria T cells showed a rearrangement pattern of the antigen-specific T-cell receptor β- and γ-chain genes that is characteristic of polyclonal T cells as assessed by T-constant β- and T-joining γ-gene probes. These results indicate that the lamina propria non-T- and T-lymphocyte populations in inflammatory bowel disease and controls are polyclonal.