Deregulated production of interleukin-8 (IL-8) in autoimmune thyroid disease studied by newly developed IL-8 radioimmunoassay.

We have developed a sensitive, reproducible and specific radioimmunoassay for human interleukin-8 (IL-8). Using 125I-labelled IL-8 and polyclonal rabbit antisera raised against recombinant human IL-8, a competitive inhibition assay was developed which could detect 5 pg/ml of human IL-8. Other interleukins, growth factors, hormones, peptides and lectins did not affect the assay. IL-8 measured in supernatants of culture media of stimulated human peripheral blood mononuclear cells (PBMC). Kinetics of IL-8 production in SAC-stimulated PBMC from seven normal subjects revealed that the production of IL-8 was detectable within 12 h and reached a plateau at 24 h. IL-8 levels in SAC-stimulation of PBMC from untreated patients with autoimmune thyroid diseases (Graves' disease and chronic thyroiditis) were significantly higher than in normal controls. However, after treatment, IL-8 production decreased to normal. The present study demonstrates the usefulness of quantitating human IL-8 produced by PBMC and the presence of a deregulated production of IL-8 in autoimmune thyroid diseases.