What does the presence of proteinuria indicate in SLE patients?

The presence of proteinuria in patients with systemic lupus erythematosus (SLE) is significant as it indicates kidney involvement, also known as lupus nephritis. Lupus nephritis is a common and serious complication of SLE, often reflecting the activity of the disease. The kidneys can be affected by the underlying autoimmune process, which leads to inflammation and damage, resulting in the leakage of protein into the urine. Monitoring protein levels is therefore crucial in assessing renal function and guiding treatment decisions in SLE patients. Hence, proteinuria serves as a valuable biomarker for both the presence of kidney involvement and the potential activity of the systemic disease.