High sensitivity and maximal specificity for membranous nephropathy

In a retrospective study (panel n=360), the indirect immunfluorescence test (IIFT) developed by EUROIMMUN (Anti-PLA2R IIFT (IgG)) revealed a specificity of 100 % for primary MN in the determination of autoantibodies against PLA2R.1

Bioptically proven primary MN  1005248
Secondary form of MN 17017
Non-membranous nephropathy  90090
Healthy blood donors 1530153

The relatively low sensitivity (52 %) is assumed to be due to immunosuppressive therapy, which was used in many of the primary MN patients (47 out of 100) at the time of blood withdrawal. In this and a second study it was shown that the anti-PLA2R titer of patients decreased below the detection limit after treatment with Rituximab, cyclophosphamide or steroids.1,2

A second retrospective study (panel n=1061) for the determination of anti-PLA2R autoantibodies using an enzyme linked immunoadsorbent assay  (ELISA) (Anti-PLA2R ELISA (IgG)) yielded a sensitivity of 96 % with respect to the EUROIMMUN Anti-PLA2R IIFT (IgG). The specificity amounted to 99.9 % including borderline sera.3

*Sera from primary MN patients with positive anti-PLA2R IIFT results.
Primary MN198*190
Sensitivity19896.0 %
Secondary MN270
Other glomerulonephritides 2300
Other autoimmune diseases3150
Healthy blood donors2911
Specificity83699.9 %

The two anti-PLA2R test systems from EUROIMMUN (IIFT and ELISA) revealed a remarkable correlation regarding qualitative and quantitative assessment of anti-PLA2R autoantibodies (see figure). Generally, the few serum samples which were negative with Anti-PLA2R ELISA (IgG) but positive with Anti-PLA2R IIFT (IgG) presented with low titers in the IIFT. All sera with anti-PLA2R titers greater than 1:100 in the IIFT were also positive in the ELISA.3

Modified from: Dähnrich et al., Clin Chim Acta 421, 213-218 (2013)
Comparison ELISA vs. IIFT