Natural Antibodies and Alloreactive T Cells Long after Kidney Transplantation.

Background: The relationship between circulating effector memory T and B cells long after transplantation and their susceptibility to immunosuppression are unknown. To investigate the impact of antirejection therapy on T cell-B cell coordinated immune responses, we assessed IFN- γ -producing memory cells and natural antibodies (nAbs) that potentially bind to autoantigens on the graft.
Methods: Plasma levels of IgG nAbs to malondialdehyde (MDA) were measured in 145 kidney transplant recipients at 5-7 years after transplantation. In 54 of these patients, the number of donor-reactive IFN- γ -producing cells was determined. 35/145 patients experienced rejection, 18 of which occurred within 1 year after transplantation.
Results: The number of donor-reactive IFN- γ -producing cells and the levels of nAbs were comparable between rejectors and nonrejectors. The nAbs levels were positively correlated with the number of donor-reactive IFN- γ -producing cells ( r _s  = 0.39, p =0.004). The positive correlation was only observed in rejectors ( r _s  = 0.53, p =0.003; nonrejectors: r _s  = 0.24, p =0.23). Moreover, we observed that intravenous immune globulin treatment affected the level of nAbs and this effect was found in patients who experienced a late ca-ABMR compared to nonrejectors ( p =0.008).
Conclusion: The positive correlation found between alloreactive T cells and nAbs in rejectors suggests an intricate role for both components of the immune response in the rejection process. Treatment with intravenous immune globulin impacted nAbs.
Competing Interests: The authors declare no conflicts of interest.
(Copyright © 2021 Nicole M. van Besouw et al.)