Prolonged cold ischemia storage (CIS) of donor transplants is a major risk factor for acute and chronic graft tissue injury. Despite strong clinical correlations between donor specific alloantibody (DSA) reactivity and transplant outcome, the relationships between posttransplant inflammation and the development of DSA with different specificities have not been addressed. The goal of this study was to test how increased CIS time influences humoral alloimmunity in mouse model of renal transplantation.

B6 (H-2^b) mice received BALB/c (H-2^d) renal allografts subjected to 0.5 h or 6 h CIS in University of Wisconsin solution. Second recipient kidney was removed at the time of transplantation. Serum creatinine levels were <0.4 mg/dl in all recipients at d.60 posttransplant. The grafts from 0.5 h CIS group had moderate segmental sclerosis in a limited number of glomeruli and perivascular cell infiltrates. In contrast, 6 h CIS grafts had extensive glomerular injury including thickened capillary loops, segmental or global sclerosis and conspicuous thrombotic microangiopathy with red cell congestion, intracapillary fibrin thrombi, and mesangiolysis.

Recipient serum was analyzed for donor MHC class I (D^d) and class II (I-A^d) reactive IgG DSA by ELISA on d.14 posttransplant. Compared to 0.5 h CIS group, 6 h CIS recipients had significantly higher levels of DSA against donor class II (OD 0.56±0.08 vs 0.24±0.01 at 1:500 serum dilution) but not class I (OD 0.51±0.06 vs 0.43±0.11) MHC molecules. At 60 d. posttransplant, 6 h CIS recipients had higher frequency of spleen ASCs producing donor class I and class II reactive IgG DSA than 0.5 h CIS controls (12.4±2.3 vs 5±2.9 cells and 8.5±3.5 vs 2.7±0.9 cells per 10×10⁶ splenocytes for D^d– and I-A^d-reactive ASCs, respectively). Notably, both groups had comparable frequencies of IFNγ producing donor-reactive T cells at 60 d. posttransplant suggesting that the augmented humoral rather than cellular immune responses account for the transplant glomerulopathy observed in 6 h CIS recipients.

Our data show that prolonged CIS enhances early DSA responses against donor MHC class II but not class I antigens and promotes the generation of donor class I and class II reactive long-lived ACSs. This is the first indication that posttransplant inflammation not only facilitates DSA development but also shapes the specificity of early DSA responses and may thus influence renal allograft pathology.

CITATION INFORMATION: Gorbacheva V, Fan R, Baldwin W, Valujskikh A. Early Alloantibody Responses Against Donor MHC Class I and Class II Molecules Are Differentially Affected by Prolonged Cold Ischemia Storage of Renal Allografts. Am J Transplant. 2016;16 (suppl 3).

« Back to 2016 American Transplant Congress