Ulcerative colitis in a patient with anti-B lymphocytotoxin and hypogammaglobulinemia

Lymphocytotoxins (LCT) have been recently reported in the serum of patients with inflammatory disease of the bowel, but up to now these antibodies have shown no specificity for B or T lymphocyte subpopulations. A 32-year-old patient with chronic ulcerative colitis, primary hypogammaglobulinemia and a very low number (0.5 to 1.5%) of B lymphocytes in peripheral blood is described. The presence in the serum of a LCT reacting specifically with B cells was demonstrated by cytotoxicity and direct immunofluorescence experiments. Intestinal immunofluorescence studies indicated a dichotomy between blood and gut immunoglobulins, and showed a heterogeneous distribution of plasma cells of the three major classes from the jejunum to the rectum. The significance of the association of hypogammaglobulinemia, chronic ulcerative colitis, and anti-B LCT is discussed. To explain the dissociation between blood and gut immunoglobulins, it is suggested that the intestine was, in this patient, a privileged site for differentiation of B cells.