DEREGULATED PRODUCTION OF INTERLEUKIN-4 (IL4) IN AUTOIMMUNE THYROID-DISEASE ASSAYED WITH A NEW RADIOIMMUNOASSAY

A sensitive, reproducible and specific radioimmunoassay for human inte rleukin-4 (IL4) has been developed. Using I-125-labeled IL4 and polycl onal rabbit antisera raised against recombinant human IL4, a competiti ve inhibition assay was developed which could detect 5 pg/ml of human IL4. Other interleukins, growth factors, hormones, peptides and lectin s did not affect the assay. IL4 was measured in supernatants of cultur e media of stimulated human peripheral blood mononuclear cells (PBMC). Kinetics of IL4 production in PHA-stimulated PBMC from seven normal s ubjects revealed that the peak levels of IL4 were seen at 24 h and the n declined. Peak IL4 levels in PHA stimulation of PBMC from untreated patients with autoimmune thyroid diseases (Graves' disease and chronic thyroiditis) were significantly higher than normal controls. However, after treatment, IL4 production decreased to normal. The present stud y demonstrates the usefulness of quantitating human IL4 produced by PB MC and that there exists a deregulated production of IL4 in autoimmune thyroid diseases.