Clinical significance of the determination of antibodies to thrombospondin type 1 containing domain 7A (THSD7A) in membranous nephropathy

Background. Membranous nephropathy (MN) is an immunocomplex glomerular disease, which is the most common cause of nephrotic syndrome in adults. Numerous studies have established that autoantibodies against the target podocyte autoantigens, including the thrombospondin type 1 domain containing 7A (THSD7A), play a leading role in the development of idiopathic MN.Aim. To evaluate the prevalence of anti-THSD7A autoantibodies (anti-THSD7A AB) in a group of Russian patients with MN.Materials and methods. Serum titers of anti-THSD7A AB were tested in 61 patients with biopsy-proven MN and 12 healthy controls.Results. The prevalence of anti-THSD7A AB was not differing significantly in patients with MN and in the control group (110.9 [71.63; 210.62] and 159.25 [125.64; 231.97] pg/ml, respectively; p=0.111). When comparing subgroups of anti-PLA2R-negative patients and patients who did not receive immunosuppressive therapy with the control group, there were also no statistically significant differences in the Anti-THSD7A AB levels (p>0.05). In the MN group, 1 (1.6%) patient was anti-THSD7A-positive: a 60-year-old man with anti-PLA2R-negative MN and the presence of hormonally inactive adenomas of both adrenal glands and colon polyps (villous adenoma with focal moderate dysplasia, tubulo-villous and tubular adenoma with focal moderate severe dysplasia).Conclusion. THSD7-associated MN is a rare variant of MN and is usually detected in PLA2R-negative patients. Screening for malignancies in THSD7A-positive MN patients is proposed.