Lupus nephritis: clinical characteristics, serological associations, pattern of pro- and anti-inflammatory markers

The present study aimed to investigate the prevalence, clinical, and laboratory characteristics of renal involvement in a large cohort of Ukrainian patients with systemic lupus erythematosus (SLE). Methods. A total of 380 patients with SLE were enrolled in this cross-sectional study, including 176 with lupus nephritis (LN) and 204 with non-renal SLE. Patients were reviewed for demographic details, clinical SLE manifestations, SLE Disease Activity Index 2000 (SLEDAI-2K), and SLICC/ACR Damage Index. Laboratory evaluations included complete blood count with an erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), high-sensitivity CRP (hs-CRP), anti-CRP antibodies, serum creatinine, complement C3 and C4 levels, urinalysis, 24-hour urine protein, specific autoantibodies, interleukin-6 (IL-6), IL-10. Results. There was a significantly higher frequency of malar rash, lymphadenopathy, splenomegaly, serositis, pulmonitis, fever, necrotizing vasculitis, and a history of arterial/venous thrombosis in patients with LN; while Raynaud's phenomenon, Sjogren's syndrome, peripheral nervous system manifestations occurred more often in patients with non-renal SLE. Patients with LN were found to have higher ESR levels and lower IL-10 levels. Either frequency of anti-dsDNA positivity and its titer were higher in the LN group with no differences regarding other autoantibodies. C3 and C4, CRP, hs-CRP, anti-CRP, and IL-6 levels showed no significant difference between the groups. Multivariate analysis demonstrated that LN was positively associated with pulmonitis (OR 5.34 (95% CI 1.88-15.10), p=0.002), arterial/venous thrombosis (OR 6.80 (95% CI 1.87-24.70), p=0.004), anti-dsDNA positivity (OR 6.22 (95% CI 1.89-20.50), p=0.003), higher SLEDAI-2K score (OR 1.15 (95% CI 1.08-1.23), p<0.001) and negatively associated with Raynaud's syndrome (OR 0.20 (95% CI 0.08-0.49), p<0.001) and younger age at disease onset (OR 0.96 (95% CI 0.93-0.99), p=0.003). In the LN group, 27 patients (15.3%) had nephrotic syndrome. In multivariate logistic analysis, male sex (OR 5.21 (95% CI 1.77-15.30), p=0.003) and higher SLICC/ACR score (OR 2.12 (95% CI 1.45-3.09), p<0.001) were associated with increased risk of nephrotic syndrome, whereas lymphadenopathy (OR 0.31 (95% CI 0.12-0.80), p=0.02) was associated with decreased risk of nephrotic syndrome development. Conclusions. Our cohort of Ukrainian LN patients showed different characteristics in demographic, clinical, and laboratory findings compared to patients with non-renal SLE. These features are mostly on par with LN patients of other nationalities around the world.