Circulating Immune Complexes in Hashimoto's Thyroiditis

Publisher Website
Google Scholar
Abstract
Circulating immune complexes (IC) were determined in sera from 41 patients with Hashimoto's thyroiditis by a polyclonal rheumatoid factor (pRF) assay based on the inhibition of the agglutination of IgG‐coated latex particles. Elevated levels of IC were found in 63% (26/41) of the sera. There was a significant correlation (Rho = 0.91, P < 0.001) between results obtained before and after treatment of sera with dithiothreitol (DTT). By precipitation with 2.5% polyethylene glycol (PEG) before pRF inhibition assay, the activity of IC was found in only 7% (3/41) of the sera. Size chromatography studies of the sera showed the inhibitory activity predominantly in the intermediary region. When found in the IgM‐region the activity was not reduced by DTT. By use of a polyethylene glycol complement consumption test (PEG‐CC) the occurrence of IC was 10% (4/41). It was not possible to find any correlation between the detectable IC and the presence of microsomal, thyroglobulin, or thyroid‐stimulating antibodies. Based on our studies the sizes of IC seemed to be heterogeneously distributed and the majority were not precipitated by PEG (2.5%, final concentration). The antibodies involved in the formation of complexes seemed to be of IgG or IgA classes. HLA‐D typing of the patients showed a non‐significant association between HLA‐Dw5 and low levels of IC while the presence of HLA‐Dw4 was significantly associated with a high level of IC (P < 0.05).