The impact of donor specific antibodies (DSA) and optimal therapeutic intervention for DSA in kidney transplant (KT) recipients has been reported with variable results. We analyzed the incidence, characteristics and impact of DSA in 75 negative flow-crossmatch KT performed from January 2011 to May 2014. Patients were routinely screened for DSA at 3, 6, 9 and 12 months post KT while sensitized patients were screened monthly. DSA was also checked with graft dysfunction. DSA were identified in 17 patients (22.5%). Of these 17 patients, 35.5% had class 1 DSA, 41% had class 2 DSA and 23.5% had both class 1 and class 2 DSA. The DSA were pre-existing in 37.5%, de-novo in 58%, and both pre-existing and de-novo in 11.5%. 27 renal allograft biopsies were performed in 12 of the 17 patients with DSA.

Among patients with DSA, 35% (6/17) had acute humoral rejection (AHR) (5 within first year post-transplant and 1 delayed AHR at 19 months), while no patients in the non-DSA group developed AHR (0/58) (p<0.001). Of 6 patients with AHR, 2 had subclinical rejections. 2 of the 4 patients with clinical AHR lost the graft to rejection at 6 months and 3 years respectively. Patients with AHR received combination of IVIG, pulse steroids and increased maintenance immunosuppression (6) along with plasmapheresis (5), rituximab (3), bortezomib (2) and alemtuzumab (1).

The 1 yr and 3yr patient survival was 94% and 88% in the DSA group and 98% and 98% in the non-DSA group respectively (NS). Death censored allograft survival at 1 and 3 year post transplant was 93% and 87.5% in DSA group and 100% and 94% in the non-DSA group (NS). At mean 18 months follow up, the mean serum creatinine and mean proteinuria in the DSA group 1.64±0.51 mg/dl and 0.39±0.15g and in the non-DSA group was 1.47±0.55 mg/dl and 0.31±0.61g respectively (NS).

Conclusion: KT recipients with DSA have significantly higher rate of AHR compared to non-DSA group. In our experience, with serial DSA monitoring, frequent allograft biopsies and treatment of AHR, the patient survival and allograft function up to 3 years post-transplant can be comparable to the non-DSA group. DSA monitoring in KT recipients at specified intervals is warranted for post-transplant management.

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