Monitoring of serum TWEAK levels guides glucocorticoid dosages in the treatment of systemic lupus erythematosus

Background Accurate assessment of systemic lupus erythematosus (SLE) disease activity is critical. Currently existing indices or measures for assessment are either expensive, intricate, or inaccurate. The novel indices with higher sensitivity and specificity have become one of the aims of the investigators. This study was designed to explore the relationship between serum tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and systemic lupus erythematosus disease activity index (SLEDAI) as well as its role in guiding glucocorticoid dosages in the treatment of SLE. Of 59 patients with SLE, 20 patients with subacute cutaneous lupus erythematosus (SCLE), 13 patients with discoid lupus erythematosus (DLE) and 32 healthy volunteers, soluble TWEAK level was determined in both serum and urine. Monomeric C-reactive protein, antinuclear antibody, interleukin 6, complements, erythrocyte sedimentation rate, and white blood cells were measured in serum samples. Moreover, SLEDAI-2K was used for evaluating the disease. Finally, methylprednisolone was administrated orally to SLE patients with the doses depending on serum TWEAK levels. Results We found that serum TWEAK levels are higher in patients with SLE (383.0 ± 45.37 ng/ml, p < 0.001 for both) or SCLE (129.1 ± 25.73 ng/ml, p < 0.05 for both) than in patients with DLE (78.38 ± 22.85 ng/ml) or in healthy controls (78.38 ± 22.85 ng/ml). Also, serum TWEAK levels correlate positively with SLEDAI-2K in patients with SLE (r2 = 0.101, p < 0.001), whereas urine TWEAK levels reflect renal damage in patients with lupus nephritis. Moreover, serum TWEAK levels had a higher correlation coefficient with SLEDAI-2K scores compared with the other serum parameters. Furthermore, TWEAK-based glucocorticoid therapy is associated with lower SLEDAI-2K scores and fewer flares in patients with SLE. Conclusions Serum TWEAK is a useful biomarker reflecting SLE disease, and monitoring of serum TWEAK levels can improve the outcomes of glucocorticoid therapy for patients with SLE.