Increasing incidence of childhood class V lupus nephritis

Abstract

Objective: Class V lupus nephritis (LN) is reported to occur in 0-23% of patients with LN. To better characterize pediatric LN, we determined at a single center (1) the relative frequency of Class V LN on first and serial biopsies, (2) the frequency of transformation between LN classes on serial biopsies, (3) types of treatment received and outcome to date of different classes of LN.

Methods: All pediatric renal biopsies from 1985 to the present performed for diagnosis and classification of suspected LN were reviewed. Biopsy results were grouped into 2-3 year time intervals to assess trends in the distribution of WHO class diagnoses over time.

Results: Sixty patients underwent 97 renal biopsies. Class V LN was present in 28% (17/60) of patients on first biopsy, and in 37% (22/60) on most recent biopsy. Class V LN on first biopsy increased from 17% (8/46) before 1995 to 64% (9/14) after 1995 (p < 0.001). Age at presentation, age at biopsy, time to biopsy, and types of treatment did not differ before and after 1995. Transformation to Class V LN occurred in 19% (5/27) of patients having repeat biopsies. No transformation from Class V LN occurred on repeat biopsy. Renal outcome was available in 48 patients with followup of 4.7 +/- 3.2 years for Class V LN, and 5.2 +/- 2.4 years for non-Class V LN. Five percent (1/20) of Class V LN patients had renal dysfunction or had died compared to 21% (6/28) of non-Class V LN patients (p = NS).

Conclusion: We found (1) a greater frequency of Class V LN than has been reported, (2) a recent increase in the incidence of Class V LN at our institution, (3) frequent transformation between classes on serial biopsies, and (4) no regression of Class V lesions in patients who had repeat biopsies.