One hundred twenty-five small intestinal biopsies of coeliac children and controls were investigated prospectively for gliadin binding by specific immunofluorescent staining of lamina propria cells, using a TRITC rabbit IgG antigliadinconjugate. In parallel, sera were investigated for serum gliadin antibodies by a red cell immunosorbent fluorescence test (RIFT). There was no epithelial or reticulin staining found with antigliadin. Exclusively in coeliac disease, i.e. in all active coeliacs, and in 71% of coeliacs on a gluten-free diet, gliadinand immunoglobulin-containing cells were detected. Among these, there was a relatively higher proportion of IgM-and IgGcontaining cells, compared to IdA. They are possibly involved in a local B-cell reaction to gliadin. Their absolute numbers per mucosal tissue unit were small. There was no correlation found between serum gliadin antibody titres of different immunoglobulin classes, and the respective local gliadin-and immunoglobulin-containing cells. It is concluded that lamina propria cells are not a main source of serum gliadin antibodies. Pathogenetic and diagnostic consequences of these data await further clarification.