Background: DSA formation in post-renal transplant patients is associated with chronic rejection and graft failure. Previous studies in our population indicate DSA formation is a strong predictor of graft loss ( ≥20% at 3 years). Detection of DSA may occur months or years after transplantation and often months before graft dysfunction, affording providers time to intervene. This pilot study assessed whether escalation of Mycophenolic acid (MPA) could reduce DSA and potentially stabilize renal function in DSA positive patients.

Methods: Thirty DSA positive transplant patients were enrolled and followed up to five years. MPA was escalated to a minimum daily dose of 1440 mg or equivalent, maximum dose never exceeding 2160 mg. Sera were collected at enrollment, monthly during escalation, every three months up to two years, then at routine clinic visits. CMV and BKV were routinely monitored. HLA single antigen beads were analyzed by Luminex to determine donor specificity and strength of antibodies. Immunosuppression consisted of thymoglobulin induction, calcineurin inhibitor, prednisone, and MPA.

Results: The study population included 87% non-Whites (25 AA/1 H) and 63% (19) received deceased donor kidneys. Development of DSA occurred one month to eight years post-transplant, with a mean of 3 years. Daily MPA dose was ≥1440 mg in 93%. Graft survival was 100% at two years, 87% at three years, and 77% at four years. Class I and Class II DSA remained stable over time. No patients tested positive for BKV, only one tested positive for subclinical CMV and cleared with treatment.

Conclusions: This pilot study indicates escalation of MPA is safe and may stabilize DSA in this high risk population. Five year follow up demonstrates improved long-term graft survival with MPA escalation compared to our local historic DSA-positive population receiving standard of care. Additional studies using larger cohorts are warranted.

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