FP150
ANALYSIS OF PREDICTIVE FACTORS FOR IMMUNOSUPPRESSIVE RESPONSE IN 47 CHINESE IDIOPATHIC MEMBRANOUS NEPHROPATHY PATIENTS WITH SERUM POSITIVE ANTI-PHOSPHOLIPASE A2 RECEPTOR ANTIBODIES

INTRODUCTION AND AIMS: We investigated the predictive value of dynamic change of anti-phospholipase A2 receptor (PLA2R) antibodies titers and 24-hour urine protein (24hUP) in treatment response of idiopathic membranous nephropathy(IMN).

METHODS: The serum anti-PLA2R antibodies were measured before and during treatment in 47 IMN patients with positive anti-PLA2R antibodies at baseline. Patients were treated with corticosteroid combined with cyclophosphamide (CTX group, n=23), or corticosteroid with cyclosporine (CYA group, n=24), respectively. We monitored serum anti-PLA2R titers and 24hUP one month, three and six months after starting immunosuppressive therapy.

RESULTS: At baseline, 47 patients were 42.5±13.6 years old with 29/18 male/female ratio. Their serum albumins were 27.1±5.6g/L, while median 24hUP were 5.80(3.56,9.41)g/d. Their serum creatinines were 74.9±22.0μmol/L, corresponding eGFR(CKD-EPI) 109.1±26.1mL/min ▪ 1.73m². The baseline anti-PLA2R antibodies were 66.4(31.9, 188.0)RU/mL. The differences of above mentioned baseline data between CTX and CYA groups were not statistically significant. 24hUP at one-month's follow-up were 3.37(2.15, 6.21)g/d and 5.22(3.08, 10.43)g/d(P=0.18), while anti-PLA2R titers were 3.56(1.61, 58.85)RU/mL and 30.09(3.80, 130.67)RU/mL(P=0.043).The differences of corresponding relative reduction between antibodies titers and 24hUP in each group were statistically significant [CTX group 94.2(69.1, 97.3)% vs. 46.8(7.2, 67.2)%, P<0.001;CYA group 54.6(-34.9, 94.7)% vs. 4.6(-57.2, 32.5)%, P=0.04]. At six-month's follow-up, 19 and 17 patients achieved composite remission (CR+PR) in CTX and CYA group, respectively. AUC of 24hUP and anti-PLA2R antibodies titers relative reduction in total patients at one-month's follow-up for predicting composite remission at six months were 0.730(95%CI 0.556~0.904,P=0.022) and 0.649(95%CI 0.478~0.820,P=0.138), respectively. The cutoff value of one-month's 24hUP relative reduction for predicting six-month's composite remission in CTX group was 15.27%, with high sensitivity (89.47%) and specificity (100%).

CONCLUSIONS: The reduction of antibodies titers occurred earlier than 24hUP in anti-PLA2R antibodies positive in IMN patients after immunosuppressive treatment. Compared with relative reduction of antibodies titers at one-month's follow-up, relative reduction of 24hUP at one-month's follow-up had better predictive value for response at six-month's follow-up.