Cells isolated from endoscopical biopsy specimens

For a better understanding of local immunological factors in the pathogenesis of ulcerative colitis (UC), we isolated colonic mucosal lymphocytes (CML) from endoscopical biopsy specimens and studied their immunological characteristics. CML were isolated by a DTT-collagenase-cotton column method. Viability of isolated cells exceeded 90%, and the average yield per biopsy specimen was 1.2 +/- 0.6 X 10(4) (mean +/- SD). A large proportion of the CML isolated in this way were small lymphocytes and the numbers were higher in UC patients than in the controls. The percentage of T cells among the CML was higher in UC than in the controls, but the percentages of B cells did not differ. Peripheral blood lymphocytes from healthy controls showed very low levels of spontaneous synthesis of IgG, IgA, and IgM, but when cultured with PWM, these cells showed a high level of IgG and IgM synthesis but only a moderately elevated IgA production. In contrast, CML from healthy controls had a high level of spontaneous synthesis of IgG, IgA, and IgM; after culture with PWM, IgG synthesis roughly doubled and IgA synthesis increased tenfold compared with that of PBL. IgM synthesis was on the same level as in PBL. Although both PBL and CML cultured with PWM showed similar synthesis of IgG, IgA, and IgM in UC and healthy controls, the spontaneous synthesis of IgA and IgM in CML from patients with UC was approximately double that in the controls. Furthermore, in UC both PBL and CML had decreased Con A-induced suppressor-cell activity compared with controls. A defect of suppressor-cell activity and an increased number of T cells may play a role in the pathogenesis of UC.