Lupus nephritis is a serious complication of systemic lupus erythematosus (SLE) in which the immune system attacks the kidneys, causing inflammation of the small filtering units called glomeruli. Because the kidneys are responsible for filtering waste and regulating fluid balance, this inflammation can impair kidney function and, if untreated, may progress to permanent kidney damage. Lupus nephritis represents one of the most significant organ manifestations of SLE and is an important driver of morbidity in affected individuals. The condition is not caused by an inherited genetic change; it arises from the autoimmune process underlying SLE, in which the immune system mistakenly targets the body's own tissues. Precise prevalence estimates for lupus nephritis are not well established as a standalone condition, and individual experience varies considerably in terms of disease course and severity. This summary reflects clinical data available as of 2026.

Lupus nephritis can present in a range of ways, and not all individuals experience all features. Severity varies considerably from person to person and can change over time. Common signs may include swelling (edema) in the legs, ankles, or around the eyes due to fluid retention, foamy or frothy urine caused by protein leaking into the urine (proteinuria), blood in the urine (hematuria), high blood pressure (hypertension), and decreased urine output. Some individuals experience fatigue and more general symptoms related to their underlying SLE, such as joint pain or skin rashes. In others, kidney involvement may be identified through laboratory testing before noticeable symptoms develop. Kidney function can be assessed through blood tests measuring creatinine and other markers, as well as through urine tests. The degree of kidney inflammation and the specific pattern of involvement are classified using an internationally recognized system based on kidney biopsy findings, ranging from mild mesangial changes to more severe diffuse proliferative forms. Not all individuals experience all features, and severity varies considerably.

Lupus nephritis is not caused by an inherited genetic change and does not follow a Mendelian inheritance pattern. It is an autoimmune complication of SLE, in which the immune system produces antibodies that form immune complexes. These complexes deposit in the kidney's filtering structures, triggering inflammation and tissue damage. The precise reasons why some individuals with SLE develop kidney involvement while others do not are not fully understood. Factors including the nature of the autoimmune response, the types and quantities of autoantibodies produced, and individual biological differences in immune regulation all appear to contribute. Environmental triggers and genetic background influencing immune function may play a role in overall SLE susceptibility, but lupus nephritis itself is not caused by a single identifiable genetic change.

Diagnosing lupus nephritis typically involves a combination of clinical evaluation, laboratory tests, and kidney biopsy. Individuals with SLE are routinely monitored for signs of kidney involvement through urine protein-to-creatinine ratios, urinalysis examining for blood and casts in the urine, and serum creatinine measurements to assess kidney function. Elevated levels of certain autoantibodies, including anti-double-stranded DNA antibodies, and reduced complement levels may suggest active lupus activity affecting the kidneys. A kidney biopsy provides definitive information about the pattern and severity of kidney involvement and guides treatment decisions. The International Society of Nephrology and Renal Pathology Society classification system is commonly used to characterize biopsy findings. Early recognition and biopsy-guided classification are important for tailoring treatment appropriately.

Treatment for lupus nephritis is individualized based on the severity and class of kidney involvement, overall health, and response to therapy. Management goals include controlling active inflammation, preventing kidney function decline, and minimizing treatment-related side effects. Immunosuppressive therapy forms the foundation of treatment for active lupus nephritis; corticosteroids are frequently used to reduce acute inflammation, often in combination with other immunosuppressive agents. Two FDA-approved medications are available specifically for lupus nephritis. Voclosporin (brand name Lupkynis) received FDA approval in January 2021 and is used in combination with standard background immunosuppression. Belimumab (brand name Benlysta) received FDA approval for lupus nephritis in July 2017 and works by targeting a protein involved in B-cell survival that drives the autoimmune process. Several additional agents are under active investigation in clinical trials, including cell therapies and other biologic approaches. Blood pressure management, kidney-protective strategies, and monitoring for treatment-related complications are also important components of care. Individuals are encouraged to work closely with a multidisciplinary team including nephrology and rheumatology specialists. Consulting with your healthcare provider is essential to determine the most appropriate treatment plan for your specific situation.

The prognosis of lupus nephritis varies considerably depending on the class and severity of kidney involvement, how promptly treatment is initiated, and individual responses to therapy. Some individuals achieve remission with treatment and maintain stable kidney function over the long term, while others may experience disease flares or progressive kidney damage despite treatment. Regular monitoring of kidney function and disease activity is important for detecting changes early and adjusting treatment as needed. Outcomes have improved with advances in understanding and treatment of both SLE and lupus nephritis, and access to specialized multidisciplinary care can support better outcomes. Individual experiences differ substantially, and prognosis is best discussed with a healthcare team familiar with the specific clinical picture.

Lupus nephritis is an active area of biomedical research, with numerous clinical trials currently underway investigating new treatment approaches. Studies are exploring a range of therapeutic strategies including CAR-T cell therapies targeting immune cells, novel biologic agents, and combination treatment regimens. Research is also investigating biomarkers that may help predict disease course and treatment response. The research landscape includes both early-phase safety studies and later-phase trials evaluating efficacy in broader patient populations. Individuals interested in participating in clinical trials can search ClinicalTrials.gov or speak with their healthcare team to explore options that may be relevant to their situation.