Enumeration of Paneth cells in coeliac disease: comparison of conventional light microscopy and immunofluorescence staining for lysozyme.

By conventional light microscopy, a reduced number of Paneth cells per intestinal crypt was found in the jejunal mucosa of patients with untreated or gluten-challenged coeliac disease as compared with histologically normal control specimens. A much better detection sensitivity was obtained when Paneth cells were counted by fluorescence microscopy after immunostaining for lysozyme with a rhodamine-labelled rabbit IgG conjugate. This method showed that there was no numerical reduction of Paneth cells in coeliac disease, but that the proportion of cells with a low lysozyme content was increased. Most of these cells were probably missed by conventional microscopy in which identification of Paneth cells is principally based on a substantial cellular complement of acidophilic granules. A reduced number of lysozyme-containing granules in coeliac disease may reflect increased discharge enhanced secretory activity, or a raised turnover of the Paneth cells.