Background: Membranous glomerulopathy (MG) is one of the most common glomerulonephritides involving the renal transplant. We sought to determine the utility of phospholipase A2 receptor (PLA2R) staining for the detection of recurrent MG. We also evaluated for increased evidence of antibody-mediated rejection in the de novo group, as some have reported.
Methods: Twenty-two cases of MG occurring in renal transplant biopsies were identified, who had a tissue diagnosis documenting the primary native renal disease. There were 12 biopsies from 11 patients with recurrent MG and 12 biopsies from 11 patients with de novo MG. Morphologic evaluation and PLA2R staining was performed in all cases.
Results: Ten of 12 (83%) recurrent MG and 1 of 12 (8%) de novo MG biopsies showed positive glomerular staining for PLA2R, giving PLA2R a sensitivity of 83% (95% confidence interval, 51%-97%) and specificity of 92% (95% confidence interval, 60%-100%) for recurrent MG. There were 2 of 12 (17%) de novo and 1 of 12 (8%) recurrent biopsies showing the presence of microcirculation inflammation. Peritubular capillary C4d staining was negative in all cases.
Conclusion: Recurrent MG is strongly correlated with PLA2R positivity, with a sensitivity of 83% and specificity of 92% for recurrent MG. There was no morphologic evidence of an association between antibody-mediated rejection and de novo MG, because both groups had a similar degree of microcirculation inflammation and peritubular capillary C4d staining. Most interestingly, PLA2R staining was almost always negative in de novo MG, suggesting a different mechanism in this unique form of MG.