Conversion to belatacept immunosuppression is a therapeutic option for renal-transplant recipients with calcineurin inhibitors (CNI) toxicity, but it associates with high risk of acute rejection. Gradual conversion and serial immune monitoring with urinary chemokine CXCL9 may allow increasing safety of this maneuver.

We converted kidney transplant recipients with signs of toxicity to CNI or other immunosuppressive drugs to belatacept over a 2-month period. We monitored renal function, metabolic profile, and circulating lymphocyte subsets. We also quantified urinary CXCL9 over a 12-month follow-up period.

Between September 2016 and March 2017, 35 patients were successfully switched to belatacept immunosuppression at 3.3 (1.3–7.2) years after transplant. Two patients had a reversible rise in serum creatinine, associated with acute rejection in one case. Urinary CXCL9 increased before serum creatinine. After conversion, blood pressure and HbA1c significantly declined while eGFR and proteinuria remained stable. The percentage of circulating effector T cells and memory B cells significantly declined.

Conversion from CNI to belatacept, in this setting, was feasible and safe, provided it was performed over a 2-month time-period. Monitoring urinary CXCL9 may further increase safety through earlier identification of patients at risk for acute rejection. The procedure associates with improved blood pressure, metabolic profile, and reduced circulating effector T and B cells.

对于具有钙调神经磷酸酶抑制剂（CNI）毒性的肾移植接受者，转换为belatacept免疫抑制是一种治疗选择，但它与急性排斥反应的高风险相关。使用尿趋化因子CXCL9的逐步转换和连续免疫监测可以提高该操作的安全性。

我们在2个月内将对CNI或其他免疫抑制药物有毒性迹象的肾脏移植接受者转换为belatacept。我们监测了肾功能，代谢状况和循环淋巴细胞亚群。我们还对12个月的随访期间的尿液CXCL9进行了定量。

在2016年9月至2017年3月之间，有35例患者在移植后3.3（1.3–7.2）年成功转换为贝拉西普免疫抑制。两名患者的血清肌酐水平可逆升高，其中一例伴有急性排斥反应。血清肌酐升高前尿CXCL9升高。转换后，血压和HbA1c显着下降，而eGFR和蛋白尿保持稳定。循环效应T细胞和记忆B细胞的百分比显着下降。

在这种情况下，只要在两个月的时间内进行，从CNI转换为belatacept是可行和安全的。监测尿液CXCL9可以通过及早发现有急性排斥反应风险的患者来进一步提高安全性。该过程与改善血压，代谢状况和减少循环效应T细胞和B细胞有关。