Abstract
Background and objectives Systemic lupus erythematosus (SLE) is a complex autoimmune disorder characterized by chronic immune complex deposition and involvement of multiple organ systems. Among individuals with SLE, a greater percentage are at a higher risk of developing lupus nephritis (LN). Renal biopsies play a pivotal role in diagnosing, managing, and predicting the prognosis of LN. The classification of LN relies heavily on light microscopy findings, supplemented by histochemistry, direct immunofluorescence, and electron microscopy. Lupus nephritis is categorized into six distinct classes based on the quantitative evaluation of histological lesions. The study aimed to analyze and correlate demographic data, biochemical parameters, serological values, and histopathological features in patients with LN who underwent renal biopsies to categorize the different classes of LN based on the WHO and International Society of Nephrology (ISN)/Renal Pathology Society (RPS) 2003 classification systems. The study also aimed to establish correlations with the National Institutes of Health (NIH) activity and chronicity indices of LN. Methods and results This retrospective study included 102 patients diagnosed with SLE who underwent renal biopsies confirming LN. Among the 102 cases of LN, patients were grouped into two categories: those with active LN (61 cases) and those without active LN (41 cases). The most commonly observed histological subtype was class IV/V LN, followed by isolated class IV LN, both of which were associated with higher activity scores based on the NIH scoring system for LN. The findings emphasize that the majority of patients with SLE present with features of active disease (class IV or combined class IV/V) at the time of diagnosis and often progress to chronicity within a short timeframe. Additionally, the presence of antibodies related to other autoimmune diseases also had an impact on patients' progression to end-stage renal disease (ESRD) and overall prognosis. Conclusion The study highlights the critical role of histological classification in diagnosing and predicting the prognosis of LN. Active LN, particularly class IV or class IV/V combined, is more common at diagnosis and often progresses to chronicity. Regular monitoring using the modified NIH activity and chronicity scores, along with routine renal profiling and urine analysis, is essential to support the need for repeat renal biopsies during treatment. This approach enables the early detection of higher-class transitions. The prognostic value of histological scoring has been well established, underscoring the importance of both activity and chronicity indices in guiding therapeutic strategies.