Background

The frequency and significance of recurrent lupus nephritis (LN) is unclear. We evaluated the features of subclinical recurrent LN seen on early posttransplant biopsies and determined the significance of recurrent LN.

Methods

Allograft biopsies were examined from all pts at our institution with ESRD due to LN. Recurrent LN was defined as deposits by immunofluorescence (IF) that stained for at least 2 immunoglobulins, excluding other causes of immune complex deposition. Clinical and laboratory data at the time of first and subsequent biopsies were obtained. Transplant pts with a history of LN without recurrence served as controls.

Results

Recurrence was seen in 7/48 (15%) patients. The mean age at transplant was 44 yrs; 6/7 were female. The mean time to recurrence on biopsy was 41 mos(range 2.5 to 67). In all pts, first recurrence was incidental. 4 were protocol biopsies; biopsy indications in 3 were BK viremia (n=2) or increased serum creatinine (SCr) (n=1). By light microscopy, changes were varied: Glomeruli were normal in 2 cases. 5 showed mild mesangial expansion; 2 of these showed a membranous pattern and had minor basement membrane (GBM) abnormalities including pinholes. By IF, a full-house pattern was noted in 5 cases. IF was trace to 3+ in the mesangium and/or GBM for IgG, IgA and C3 (n=6), IgM (n=7) and C1q (n=4). All 6 early biopsies with electron microscopy (EM) had mesangial deposits. 2 had a membranous pattern with subepithelial deposits; one additional case showed few GBM deposits. 2 had tubuloreticular inclusions. Podocyte foot process effacement was minimal to diffuse, corresponding to GBM deposits. Mean proteinuria was 258mg/day (range 47-759); mean SCr was 1.3mg/dL (range 0.9-1.5). Controls had mean proteinuria of 113mg/day (range 65-153)(p=0.17) and mean SCr of 1.4mg/dL (range 1-2). 2 pts with proteinuria at >400mg/24 hr received prednisone and MMF for recurrent LN (mesangioproliferative and membranous). Follow-up was available for all pts at mean 95 months(range 30-168 months). One pt with class I LN had no further biopsies, normal function and no proteinuria. Of those with class II, one pt showed additional GBM deposits, 2 showed resolution of deposits, and one had proliferative LN, with graft loss from recurrent LN. 2 pts with membranous LN did not progress.

Conclusion

Early subclinical LN can be detected on biopsy and progresses in a subset of pts. Increased detection of LN occurs with IF or EM, which should be performed even if pts have minimal proteinuria.

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