Membranous (class V) renal disease in systemic lupus erythematosus may be more common than previously reported: results of a 6-year retrospective analysis.

BACKGROUND: The actual incidence and prevalence of the various histological classes (based on World Health Organization classification) of lupus nephritis (LN) are not known but seem to vary with sex, age, and ethnicity. We have analyzed renal biopsies in patients with systemic lupus erythematosus (SLE) at our center, and hereby report our experience.
METHODS: All renal biopsies performed at the University of Mississippi between January 1999 and December 2004 in patients with SLE were retrospectively analyzed. Results were validated by a detailed review of renal biopsy reports and additional records were reviewed for data specific to LN disease activity.
RESULTS: There were 92 renal biopsies performed in patients with SLE during a 6-year period. These included 84 African Americans (72 women and 12 men), 5 whites (4 women and 1 man), and 3 unknown race (1 F, 2 M) subjects. The prevalence of LN classes in our cohort was as follows: class I (0%), class II (9.8%), class III (8.7%), class IV (36.9%), class V (40.2%), and class VI (4.3%). Prevalence of class V LN among males was high at 40%.
CONCLUSION: In contrast to previous literature, isolated membranous lupus nephritis (MLN) was much more prevalent in this series-40% versus 14%. Also, no sex difference in the prevalence of MLN was seen. This biopsy cohort suggests that MLN/class V disease may be more common than previously reported especially in African American population.