Antilymphocyte antibodies in progressive systemic sclerosis

Sera from 19 patients with scleroderma were tested for antilymphocyte antibodies (ALA) by indirect immunofluorescence assay. ALA were found in 47% of the cases when tested at 0 degrees, and in 27% at 25 degrees C. Anti-T cell specificity was shown after separation of B and T cells. The heterogeneity of the ALA detected was clear both among different patients and in serum from the same patient. A monoclonal antibody (UCHT1) inhibited ALA binding to T cells completely in one case, and partially in another three, implying that with these 4 sera, the lymphocyte receptors for ALA were either identical or very close to the UCHT1 receptor. This study defines another immunological abnormality in scleroderma: the presence of cold-reactive anti-T cell specific ALA. Their pathogenicity requires further investigation.