Circulating levels of soluble scavenger receptors [SCD5 and SCD6] in primary and secondary Sjogren syndrome patients

ABSTRACT

To determine the existence of circulating levels of soluble scavenger receptors [sCD5 and sCD6] in Sjogren's syndrome patients, either 1ry or 2ry to rheumatoid arthritis [RA] and/or systemic lupus erythematosus [SLE]. Also, to analyze the correlation with clinical and immunological features of Sjogren's syndrome. Twelve consecutive RA patients, seven SLE patients and nine primary Sjogren's syndrome patients were studied. We used a specific enzyme-linked immunosorbent assay [ELISA] to determine sCD5 and sCD6 levels. Immunological tests included antinuclear antibodies [ANA] tested with [indirect immunofluorescence using HEP-2 as the substrate], rheumatoid factor [RF] quantitative [Integra-400- Roche Diagnostics] and complement factors [C3 and C4] [Integra-400- Roche Diagnostics]. We also estimated precipitating antibodies to extractable nuclear antigens Ro/SS-A and La/SS-B autoantibodies with ELISA [Shield Diagnostics]. Detectable levels of sCD5 were found in 4 [25.7%] RA patients with mean +/- standard error values of 9.4 +/- 4.3 ng/mL; 2 SLE patients [18.2%] with mean +/- standard error values of 8.2 +/- 4.1ng/mL and 4 [41%] primary Sjogren's syndrome patients with mean +/- standard error values of 3.56 +/- 2.9ng/mL. Detectable levels of sCD6 were found in 3 [24.3%] RA patients with mean +/- standard error values of 39.6 +/- 9.61ng/mL; 1 SLE patient [14.3%] with mean +/- standard error values of 33.7 +/- 8.3 ng/mL and 6 [70%] primary Sjogren's syndrome patients with mean +/- standard error values of 26.3 +/- 7.9ng/mL On the other hand, when the CD5 and CD6 levels were compared according to the presence or absence of immunological features [i.e. hypo-complementemia] patients showed higher levels of circulating soluble scavenger receptors [sCD5 and sCD6] [p<0.05 and p<0.01] respectively than those without immunological features. Patients involved in this study showed higher levels of circulating sCD5 and sCD6 when compared with controls. Moreover, the existence of some immunological features [i.e. hypo-complementemia] was associated with high levels of both soluble scavenger receptors