*Purpose: Diagnosing rejection in VCA recipients relies on clinical exam and biopsy which are both easily confounded by common causes of skin irritation. dd-cfDNA in recipient plasma originating from injured or apoptotic donor allograft cells is a proven non-invasive indicator of allograft rejection in renal transplant recipients but has not been evaluated in VCA recipients.

*Methods: VCA patients presenting for evaluation at the outpatient plastic surgery clinic during periods of graft stability without clinical or histologic evidence of rejection, and/or during episodes of suspected clinical and/or biopsy proven rejection were included in this study. dd-cfDNA levels were collected prospectively at each visit with two commercially available kits. Based on established values in renal transplant, a dd-cfDNA level > 1% was considered suggestive of a rejection event.

*Results: 5 VCA recipients (3 bilateral and 1 unilateral upper limb, 1 lower abdominal wall, penis, and scrotum) were enrolled in this study. One patient had no clinical or biopsy evidence of rejection with dd-cfDNA level <1% and 1 patient had dd-cfDNA levels >4% at three time points surrounding an episode of biopsy proven BANFF CTA 2007 Grade III rejection. 1 patient with a stable graft and no clinical concern for rejection had a routine dd-cfDNA level >1%. A final patient with non-specific skin changes but biopsy evidence of severe acute cell mediated rejection had dd-cfDNA level <1%.

*Conclusions: These data reflect the first attempt to characterize dd-cfDNA in human upper extremity VCA recipients. Although these early results are conflicting, larger cohorts with careful correlation with biopsy findings are needed to fully characterize dd-cfDNA level trends in extremity VCA recipients.

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