Immunological studies on Crohn's disease. V. Enumeration of circulating lymphocytes subsets using monoclonal antibodies.

We found normal levels of suppressor cell activity and reduced natural killer (NK) and antibody dependent cell-mediated cytotoxicity (ADCC) activities in patients with Crohn's disease (CD). To further characterize these activities, studies were carried out using monoclonal antibodies. There were no changes in the proportion of OKT4+ (helper/inducer T cells), OKT8+ or Leu 2+ (suppressor/cytotoxic T cells) and Leu 7+ (large granular lymphocytes: LGL, NK + K cells), thereby suggesting that suppressor cell activity in CD is likely to be normal both in function and in number, and that depressed NK and ADCC activities are not due to a reduction in the number of NK or K cells but rather to functional defects. Using a double staining method, we noted a low percentage of both Leu 2 and Leu 7 positive cells in CD.