Recurrent atypical antiglomerular basement membrane nephritis in the kidney transplant

Atypical anti-glomerular basement membrane (GBM) nephritis can be defined as linear GBM staining for monotypic or polytypic immunoglobulin (Ig) by immunofluorescence (IF) without a diffuse crescentic pattern. We describe the clinicopathologic features of 6 patients (18 biopsies) in this first series of recurrent atypical anti-GBM nephritis in the transplant. Recurrent glomerulonephritis occurred at a mean of 3.8 months post-transplant (range 1-7 months). 3 index biopsies were for clinical indication and 3 were protocol biopsies. Glomerular histologic changes were mild, with 2 showing segmental endocapillary hypercellularity, one focal glomerular microangiopathy, and the others no significant glomerular histologic changes. All 6 allografts showed monotypic linear glomerular Ig staining by IF: IgG kappa (n=2), IgG lambda, IgA kappa, IgA lambda, and IgM lambda. Follow up biopsies were available for 5 patients and showed similar histologic and IF findings, without evidence of significant progression. No patients had detectable serum anti-GBM or monoclonal proteins. The mean serum creatinine on follow up (24-62 months post-transplant) was 1.8 mg/dL (range 0.93 – 2.77 mg/dL); no grafts were lost to recurrent disease. This series demonstrates that monotypic atypical anti-GBM recurs in the allograft and supports that this disease is due to a circulating monoclonal protein.