Natural killer cells in coeliac disease.

Lymphoma is a well recognized but unexplained complication of coeliac disease. Natural killer (NK) cells are a distinct population of lymphocytes with the capacity to lyse some tumour cell-lines in vitro and there is evidence that they may play a role in immune surveillance and protection against the development of malignancy. Using a monoclonal antibody (Leu 11b) and a functional assay, we have measured NK cell numbers and activity in 32 patients with treated coeliac disease (9 of whom had evidence of hyposplenism), 10 splenectomized subjects, 14 biopsied, control patients and 26 normal subjects. The proportions (mean +/- SD) of Leu 11b + cells in normals (17 +/- 5%) and coeliac patients (19 +/- 7%) were similar. NK activity in all the coeliac patients (34 +/- 15%) was not significantly different from normal (31 +/- 15%) and control (26 +/- 15%) subjects. NK activity was correlated with % Leu 11b + cells (r = 0.64; p less than 0.01). The NK activity in patients with hyposplenism associated with coeliac disease (32 +/- 18%) and after splenectomy (29 +/- 15%) was similar to that in normals. We conclude that the increased risk of malignancy in patients with coeliac disease is not due to deficient NK cell numbers or activity.