Systemic lupus erythematosus (SLE) is a disease affecting blood vessels and connective tissue, which are damaged by deposition of pathogenic autoantibodies and immune complexes. Although a complex disease, SLE provides a number of insights into
autoimmune pathogenesis. Autoimmune disease, in general, is characterized by B cell hyperactivity which results in hypergammaglobulinemia and production of a variety of autoantibodies reactive to organ-nonspecific antigens such as DNA, RNA, and
cell
membrane structures. SLE patients usually show a marked increase in the number of activated and immunoglobulin-producing circulating B cells. Recently, cytokines with specific effects on immune regulation have been detected and extensively
studied.
One
of them, Interleukin-6 (IL-6), is an activated monocyte derived factor which stimulates B cell growth and differentiation.
We investigated the serum IL-6 levels of SLE patients in an attempt to demonstrate their relationship with the patients' clinical manifestation, and the serum levels of C-reactive protein (CRP), circulating immune complexes (CICs,) and soluble
interleukin-2 receptor (sIL-2R).
The study subjects consisted of 22 patients with SLE who had visited Severance Hospital from July 1986 to September 1987 and 10 normal controls. The patients' sera were stored at -70℃ and later analyzed.
The serum levels of IL-6 were measured by ELISA method with Inter Test-6X Human IL-6 ELISA kit; the serum CRP levels by fluorescence polarization immunoassay; the serum CIC levels by solid phase Clp binding assay; and the serum sIL-2R levels
ELISA
method.
@ES The results were as follows:
@EN The mean serum IL-6 level of SLE patients (1,366 pg/ml) was higher that of the controls (98pg/ml) (p<0.05). Among the SLE patients studied. the mean serum IL-6 level was higher in those with vasculitis than those without. ln the SLE patients
studied. a linear correlation was present between the measured serum IL-6 and CIC levels; however no correlation was present either between IL-6 and CRP levels, or between IL-6 level and platelet count. The mean sIL-2R level of the SLE patients
studied
(1,864 U/ml) was higher than that of the controls (300 U/ml). However, in the SLE patients studied, no correlation was present between the serum IL-6 and sIL-2R levels measured.
The high serum IL-6 level might play an important role in the pathogenesis of SLE.
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