Dichotomy between immunoglobulin synthesis by cells in gut and blood of patients with hypogammaglobulinaemia.

Eleven of fifteen patients with late-onset hypogammaglobulinaemia were found to have significant numbers of immunoglobulin-containing cells in the lamina propria of the gut. In six of them typical plasma cells were detected. In contrast the blood lymphocytes of only two of these patients could be induced to synthesise immunoglobulin by stimulation with pokeweed mitogen in vitro. Moreover, one patient in whom immunoglobulin-containing cells and plasma cells were detected in the rectum and jejunum failed to show similar cells in a peripheral lymph-node even after immunisation with pneumococcal polysaccharide type-III antigen in the drainage area of the node. It is possible, therefore, that the gut is a privileged site for the differentiation of B cells in these patients.