Clinical and morphological correlations in patients with lupus nephritis: a retrospective study

Aim. To analyze associations between clinical and morphological features of kidney involvement in patients with systemic lupus erythematosus. Materials and methods. In the retrospective cohort study, we enrolled adult ( >= 18 years) patients with morphologically proven lupus nephritis (LN) stratified according to the ISN/RPS classification. Systemic lupus erythematosus was classified in accordance with ACR/EULAR classification criteria (2019). Antiphospholipid syndrome was diagnosed according to the 2006 classification criteria. Disease activity was assessed with SELENA-SLEDAI score. Results. We enrolled 62 patients with LN, among them 84% were females. Median age of SLE onset was 23 (16,3; 30,8) years. In all cases kidney involvement was accompanied by extrarenal manifestations, among which joint (82%), skin (57%) and hematological involvement (68%) was the most common. LN class I was proven in one patient, class II - in three patients, class III - in 24, including III+V in seven, class IV - in 18, including IV+V in two, class V - in 13, class VI - in three patients. APS nephropathy was diagnosed in 4 (6.5%) of patients with LN. The most common clinical manifestation was proteinuria (85%), however its prevalence, level and the frequency of nephrotic syndrome showed no significant differences between the LN classes. LN III/IV +/- V was characterized by the highest levels of serum creatinine (and the lowest eGFR) at the time of biopsy. Conclusion. LN is characterized by the high heterogeneity of the clinical and morphological manifestations, which makes LN class prediction impossible without kidney biopsy.