Studies on lymphocyte subpopulations in human colonic biopsy specimens by colonoscopy

Lymphocytes, isolated by the enzymatic technique, from colonic mucosal specimens obtained from eight patients with ulcerative colitis (UC), two with ischemic colitis, two with antibiotic-associated colitis, and 15 controls by colonoscopic biopsy were used to examine T and B cells. In control biopsy specimens, the mononuclear cell yield averaged 3.6 +/- 0.3 (SEM) X 10(6)/g with a viability of 93 +/- 1%, while T and B cells expressed as a percentage of total lymphocyte counts were 65 +/- 1% and 15 +/- 1%, respectively. T and B cells in the ascending, transverse, and sigmoid colon and rectum did not present any differences. In involved tissue at the active stage of UC, the mononuclear cell yield averaged 11.4 +/- 2.1 X 10(6)/g, and T and B cells constituted 49 +/- 3% and 43 +/- 4%, respectively. After treatment for two months with salazosulfapyridine, mononuclear cell yields in five cases of UC were significantly reduced to an average of 3.9 +/- 0.8 X 10(6)/g as compared to the pretreatment level (P less than 0.01). The percentage of T cells was significantly increased from 48 +/- 2% to 62 +/- 2% (P less than 0.01), and that of B cells was significantly reduced from 39 +/- 2% to 27 +/- 3% (P less than 0.01). These results revealed a significant difference in the subpopulations of mucosal lymphocytes in the involved sites in the active stage of UC as compared to normal controls, suggesting that immunological abnormalities may be implicated in the etiology of this disease and that disease remission on salazosulfapyridine treatment is associated with a correction of the colonic lymphocyte abnormalities.