Previous reports have indicated that inflammatory mechanisms may be involved in the pathogenesis of Dupuytren's disease and it has even been suggested that this condition is a T-cell mediated autoimmune disorder. We investigated peripheral blood lymphocyte subsets from 21 patients with Dupuytren's disease and compared them with ten healthy blood donors. The Dupuytren's patients had an increase in DR+ T-cells compared with healthy controls. Furthermore, patients with both palmar and plantar involvement had a higher percentage of DR+ T-cells than those with only the palm affected. The percentage of circulating CD5+ B-cells was lower in the Dupuytren's patients compared with the control group; this feature was marginally significant for the whole group of Dupuytren's patients but was strongest in the group of patients with both palmar and plantar involvement. These findings support previous suggestions that immunological mechanisms, involving activated T-cells and probably also B-cells, are involved in the pathogenesis of Dupuytren's disease.