Decreased chronic cellular and antibody-mediated injury in the kidney following simultaneous liver-kidney transplantation

In simultaneous liver-kidney transplantation (SLK), the liver can protect the kidney from hyperacute rejection and may also decrease acute cellular rejection rates. Whether the liver protects against chronic injury is unknown. To answer this we studied renal allograft surveillance biopsies in 68 consecutive SLK recipients (14 with donor-specific alloantibodies at transplantation [DSA+], 54 with low or no DSA, [DSA-]). These were compared with biopsies of a matched cohort of kidney transplant alone (KTA) recipients (28 DSA+, 108 DSA-). Overall 5-year patient and graft survival was not different: 93.8% and 91.2% in SLK, and 91.9% and 77.1% in KTA. In DSA+ recipients, KTA had a significantly higher incidence of acute antibody-mediated rejection (46.4% vs. 7.1%) and chronic transplant glomerulopathy (53.6% vs. 0%). In DSA- recipients at 5 years, KTA had a significantly higher cumulative incidence of T cell-mediated rejection (clinical plus subclinical, 30.6% vs. 7.4%). By 5 years, DSA+ KTA had a 44% decline in mean GFR while DSA+SLK had stable GFR. In DSA- KTA, the incidence of a combined endpoint of renal allograft loss or over a 50% decline in GFR was significantly higher (20.4% vs. 7.4%). Simultaneously transplanted liver allograft was the most predictive factor for a significantly lower incidence of cellular (odds ratio 0.13, 95% confidence interval 0.06-0.27) and antibody-mediated injury (odds ratio 0.11, confidence interval 0.03-0.32), as well as graft functional decline (odds ratio 0.22, confidence interval 0.06-0.59). Thus, SLK is associated with reduced chronic cellular and antibody-mediated alloimmune injury in the kidney allograft.