- In the US, approximately 35% of adults with systemic lupus erythematosus (SLE) have clinical evidence of nephritis at the time of diagnosis, with an estimated total of 50–60% developing nephritis during the first 10 years of disease.
- The prevalence of nephritis is significantly higher in African Americans and Hispanics than in whites, and is higher in men than in women.
- Renal damage is more likely to develop in nonwhite groups.
- Overall survival in patients with SLE is approximately 95% at 5 years after diagnosis and 92% at 10 years after diagnosis. The presence of lupus nephritis (LN) significantly reduces survival to approximately 88% at 10 years, with even lower survival in African Americans.
Case Definition for Lupus Nephritis (LN)
- For the purpose of these recommendations, LN is defined as clinical and laboratory manifestations that meet American College of Rheumatology (ACR) criteria (persistent proteinuria >0.5 gm per day or >3+ by dipstick, and/or cellular casts including red blood cells [RBCs], hemoglobin, granular, tubular, or mixed).
- A spot urine protein/creatinine ratio of >0.5 can be substituted for the 24-hour protein measurement.
- “Active urinary sediment” (>5 RBCs/high-power field [hpf], >5 white blood cells [WBCs]/hpf in the absence of infection, or cellular casts limited to RBC or WBC casts) can be substituted for cellular casts.
- An additional, perhaps optimal, criterion is a renal biopsy sample demonstrating immune complex–mediated glomerulonephritis compatible with LN.
- A diagnosis of LN should also be considered valid if based on the opinion of a rheumatologist or nephrologist.
Renal Biopsy and Histology
- The ACR recommends that all patients with clinical evidence of active LN, previously untreated, undergo renal biopsy (unless strongly contraindicated) so that glomerular disease can be classified by current International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification. (C)
- The ACR agrees that class I (minimal mesangial immune deposits on immunofluorescence with normal light microscopy) and class II (mesangial hypercellularity or matrix expansion on light microscopy with immune deposits confined to mesangium on immunofluorescence) generally do not require immunosuppressive treatment. (C)
Table 1. International Society of Nephrology/Renal Pathology Society 2003 Classification of LNa
- Class I
- Minimal mesangial LN
- Class II
- Mesangial proliferative LN
- Class III
- Focal LN (<50% of glomeruli with proliferative change outside mesangium)
- III (A): active lesions
- III (A/C): active and chronic lesions
- III (C): chronic lesions
- Class IV
- Diffuse LN (≥50% of glomeruli with proliferative change outside mesangium)
- Diffuse segmental (IV-S) or global (IV-G) LN
- IV (A): active lesions
- IV (A/C): active and chronic lesions
- IV (C): chronic lesions
- Class V
- Membranous LNb
- Class VI
- Advanced sclerosing LN (≥90% globally sclerosed glomeruli without residual activity)
a Adapted with permission from Markowitz GS, D’Agati VD. Kidney Int. 2007;71:491–5.
b Class V may occur in combination with class III or IV, in which case both will be diagnosed.
Table 2. Indications For Renal Biopsy In Patients With Systemic Lupus Erythematosus
Increasing serum creatinine without compelling alternative causes
(such as sepsis, hypovolemia, or medication)
Conﬁrmed proteinuria of ≥1.0 gm per 24 hours
(either 24-hour urine specimens or spot protein/creatinine ratios are acceptable)
Combinations of the following, assuming the ﬁndings are conﬁrmed in at least 2 tests done within a short period of time and in the absence of alternative causes:
a. proteinuria ≥0.5 gm per 24 hours plus hematuria, deﬁned as ≥5 RBCs per hpf
b. proteinuria ≥0.5 gm per 24 hours plus cellular casts
a See Table 4 for Quality of Evidence description.