Serum cryoglobulins and disease activity in systematic lupus erythematosus

Background: to determine the prevalence of cryoglobulins in iranian patients with systemic lupus erythematosus (sle) and evaluate the correlation of cryoglobulins with disease activity in these patients. materials and methods: in a cross‑sectional study, we investigated 80 consecutive women who fulfilled the 1982 revised criteria of the american college of rheumatology for the classification of sle. all the patients had undergone a medical interview and general physical examination by a rheumatologist for clinical and serologic characteristics of sle. for the determination of cryoglobulins, sera were collected by a standard protocol at 37°c, and after incubation at 4°c for seven days, the level of cryoglobulins was estimated for each patient. results: cryoglobulins were detected in the sera of 39 (48.8%) patients. all of these patients had cryocrit over 5%. disease was active in 30 patients [sledai ≥6 (dai: disease activity index)] and inactive in 50 (sledai <6). there was no significant difference between active and inactive patients for the presence of serum cryoglobulins (r = 0.086, p = 0.56). a significant positive correlation was observed between antinuclear antibody (ana), anti‑dsdna (dsdna: double‑stranded deoxyribonucleic acid), ch50 (ch50: total hemolytic complement assay), and c‑reactive protein (crp) (r = 0.21, p = 0.004, r = 0.65, p = 0.001, r = 0.45, p = 0.023, r = 0.38, p = 0.036, respectively). hepatitis c virus (hcv) infection was not detected in any of the sle patients. conclusion: although the presence of cryoglobulins in the sle patients correlated with positive anti‑ds dna and low ch50, it could not be predict activity of the disease.