Clinical and pathological features of idiopathic membranous nephropathy in young people.

Aim: To investigate the clinico-pathological features of idiopathic membranous nephropathy (IMN) in youth. Methods: Patients with biopsy-proven IMN in Peking University Third Hospital from May 2015 to October 2017 (n = 147) were enrolled in this study. Patients were divided into youth (= 35 years old), middle-age (35-65 years old) and elderly group (> 65 years old) accordingly. Medical records of patients were retrospectively analyzed. Results: Youth group exhibited shorter duration from onset to biopsy (3.49 +/- 4.25 months in youth vs 8.71 +/- 12.24 months in elderly) and milder clinical presentations in terms of less proteinuria and higher serum albumin (P < 0.05). Furthermore, lower anti-phospholipase A2 receptor (PLA2R) antibody titre (65.36 +/- 101.14 RU/mL in youth vs 137.45 +/- 215.12 RU/mL in middle-age), less C3 deposits (35.14% in youth vs 65.00% in elderly) and higher 6-month remission rate (63.64% in youth vs 36.00% in middle-age) were observed in youth (P < 0.05). Multiple linear regression confirmed C3 deposits (P = 0.005) and anti-PLA2R (P = 0.040) were independent factors influencing proteinuria, and age is an independent influencing factor for time from onset to biopsy (P = 0.043). Older age (OR = 2.044, 95% CI: 1.073-3.896, P = 0.030) and higher anti-PLA2R (OR = 1.413, 95% CI: 1.020-1.959, P = 0.038) were significantly associated with non-remission by 6 months. Conclusion: Younger patients with IMN tend to have rapider onset and quicker remission than older patients. Milder clinical presentations in youth are associated with lower anti-PLA2R antibody titre and less C3 deposits.