Jejunal lysozyme activity and the Paneth cell in coeliac disease

SUMMARY The jejunal mucosa of patients with coeliac disease contains significantly fewer Paneth cells (PCC) per crypt (p < 0.001) and tissue lysozyme activity (JLA) P < 0.001) when compared with a group of subjects with normal jejunal mucosa. Neither PCC nor JLA return to normal with complete clinical recovery and otherwise complete histological recovery on a gluten free diet. There is a significant linear correlation between JLA and PCC suggesting that the Paneth cell is the principal source of jejunal lysozyme. The Paneth cell occupies a prominent site at the base of the small intestinal crypt and is a secretory cell discharging its granules in response to pilo-carpine (Cordier, 1923). It has been estimated that the adult small intestine contains 2 x 108 cells (Creamer and Pink, 1967) constituting an aggregate gland of similar size to the pancreas (Toner, 1968). Although the function of the cell and secretions remains unknown, the possibilities of dipeptidase digestive activity (Van Genderen and Engel, 1938) and nutritional support of the epithelial cell (Crea-mer, 1967) have both been proposed. Alternatively, a role in non-specific immunity is suggested by the finding that the cell contains and secretes lysozyme (Peeters and Van Trappen, 1975) and has phagocytic properties (Erlandsen and Chase, 1972). Little is known of the function and structure of the Paneth cell in disease but it has been reported that, in coeliac disease, reduced numbers of Paneth cells are found in patients who respond incompletely to gluten withdrawal (Creamer and Pink, 1967). The purpose of the present study, therefore, was to determine whether lysozyme was measurable in homogenates of small bowel biopsies and whether this was quantitatively related to the number of Paneth cells in the tissue. The effect of coeliac disease on these measurements was studied and compared with those in a group of subjects with normal jejunal mucosa