Non-typical anti-GBM disease with intraglomerular granulomatous reaction and anti-PLA2R-negative membranous nephropathy in the context of IgM/κ paraproteinemia

Concurrent glomerular PCDH7 deposits in PLA2R-associated membranous nephropathy

The understanding of membranous nephropathy (MN) has undergone impressive advancements in the last 5 years, particularly due to identification of novel antigenic targets. M-type phospholipase A2 receptor (PLA2R) and thrombospondin type 1 domain-containing 7A (THSD7A) account for approximately 70% and 1-5% of the target antigens in primary MN, respectively. Recently, more novel/putative antigens have been identified in the remaining cases of MN that include exostosin 1/exostosin 2 (EXT1/EXT2), neural epidermal growth factor-like 1 protein (NELL-1), semaphorin 3B (SEMA3B) and protocadherin 7 (PCDH7). However, comparatively little is known about the PCDH7 among these novel antigens. As such, we herein described a unique case of positive glomerular PCDH7 deposits in PLA2R-associated MN, which may offer a deeper insight into the role of PCDH7 in MN and improve our understanding of glomerular diseases in the post-COVID era, particularly with the emerging variants.