Lupus nephritis: current update

Lupus nephritis (LN) is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). The general consensus is that 60% of lupus patients will develop clinically relevant nephritis at some time in the course of their illness [1]. Prompt recognition and treatment of renal disease is important, as early response to therapy is correlated with better outcome [2]. The present review summarizes our current understanding of SLE pathogenesis, summarizes how the disease is diagnosed and treated, and expands on new emerging therapies.Most SLE patients develop nephritis early in the course of their disease. The vast majority of patients who develop nephritis are younger than 55 years, and children are more likely to develop severe nephritis than are elderly patients [3]. In a recent retrospective study, male sex, young age (<33 years), and non-European ancestry were found to be determinants of earlier renal disease in patients with SLE. Asian, African Caribbean, and African American ethnicities may present with more severe nephritis than other ethnic groups [4].Proteinuria is the characteristic feature of renal disease in lupus. In a comprehensive review of LN, proteinuria was reported in 100% of patients, with nephrotic syndrome being reported in 45 to 65% [5]. Microscopic hematuria was found to occur in about 80% of patients during the disease course, invariably associated with proteinuria. Macroscopic hematuria is rare in LN. Hypertension is not common but is present more frequently in patients with severe nephritis. About one-half of all patients with LN will have a reduced glomerular filtration rate, and occasionally patients present with acute kidney injury. Renal tubular function is often disturbed, resulting in urinary excretion of Tamm-Horsefall proteins, light chains and β2-microglobulin [5].Ideally, urinary protein excretion is gauged using a 24-hour urine collection. Although universally practiced, variable results may occur over a s