Abstract: TH-PO110

Clinicopathological Characteristics of Thrombospondin Type 1 Domain–Containing 7A-Positive Membranous Nephropathy

Session Information

Category: Glomerular

  • 1004 Clinical/Diagnostic Renal Pathology and Lab Medicine

Authors

  • Hara, Shigeo, Kobe University Graduate School of Medicine, Kobe, Japan
  • Nishi, Shinichi, Kobe University Graduate School of Medicine, Kobe, Japan
  • Yoshimoto, Akihiro, Kobe City Medical Center General Hospital, Kobe, Japan
Background

Recent studies suggested the possible association of Thrombospondin type 1 domain–containing 7A (THSD7A)-positive membranous nephropathy (MN) and malignancy; however, the clinicopathological characteristics of THSD7A-positive MN have been still poorly characterized.

Methods

Among 164 consecutive cases of pathologically-proven MN, 7 cases were immunohistologically positive for THSD7A (4.2%) and defined as THSD7A-positive MN. Clinical characteristics including renal function, proteinuria levels, and incidence of specific disease entities such as malignancy and other disorders were obtained from the data base record. IgG subclass profiles were examined in 6 cases using frozen sections. PLA2R1 immunostaining were evaluated in all cases.

Results

The patient age ranged from 42 to 73 (mean 63.7). Male-female ratio was 5:2. The median levels of serum creatinine and proteinuria were 0.84 mg/dl (range 0.53 – 1.4) and 7.41 g/gCr (0.37 – 16.1), respectively. Two patients had cancer concomitantly at the time of renal biopsy; one had small cell carcinoma in the lung and the other had prostatic adenocarcinoma. THSD7A immunostaining was available in the lung cancer case, which was negative for THSD7A. Two patients had concurrent incidence of inflammatory diseases; one had Kimura’s disease, a chronic eosinophilic inflammatory disorder of unknown etiology, and the other had eosinophilic pneumonia in addition to asthma. Remaining three patients had no specific disease entity at the time of MN diagnosis, classified as primary MN. IgG subclass showed IgG4-dominant or co-dominant phenotype in 5 cases. One case with prostatic cancer had IgG2 and IgG3-dominant distribution. One case showed PLAR1 positivity (dual positive for PLA2R1 and THSD7A).

Conclusion

In contrast to the major distribution of IgG4-dominant/co-dominant phenotype, THSD7A-positive MN tends to be associated with various disease entities.

Funding

  • Government Support - Non-U.S.