Introduction: whilst IgG HLA DSAs are associated with renal allograft rejection and graft loss, the role of IgM HLA DSAs is controversial. We investigate the significance of de novo IgM HLA DSAs in patients with T-Cell mediated rejection [TCMR], acute antibody mediated rejection [aAMR] and chronic antibody mediated rejection [cAMR].

Methods: 1667 CDC/FCXM negative renal transplant recipients receiving a steroid sparing, tacrolimus based regimen with monoclonal antibody induction were studied. We investigated 50 with TCMR, 50 with aAMR and 57 with cAMR. Patients were screened at the time of biopsy for IgG and IgM DSAs and compared with 50 control, unsensitised recipients with normal surveillance biopsies. Diagnosis of rejection was based on Banff criteria. Graft survival was compared in each cohort and categorised; IgG-/IgM-, IgG+/IgM-, IgG-/IgM+ and IgG+/IgM+.

Results: incidence of IgM DSAs in the aAMR group was 10/50 (20%), 5/50 (10%) in the TCR group, 18/57 (32%) in the cAMR group and 6/50 (12%) in the normal controls. Graft survival in the presence of an IgM DSA was not inferior in the aAMR/TCR groups when compared to controls and only significantly inferior in those groups with an IgG DSA (p=0.005).

Graft survival in the presence of an IgM DSA was not inferior in the cAMR/TCR when compared to controls and only significantly inferior in those groups with an IgG DSA (p<0.001).

Discussion: this study demonstrates that the presence of an IgM DSA alone or in association with an IgG DSA does not result in inferior outcomes. It is the presence of an IgG DSA in allograft rejection which significantly reduces graft survival.

CITATION INFORMATION: Gueret-Wardle A., Dodd P., Lucisano G., Hassan S., Brookes P., Santos-Nunez E., Firmin N., Goodall D., Roufosse C., Willicombe M., Taube D. IgM HLA DSAs Do Not Alter the Outcomes of Renal Allograft Rejection Am J Transplant. 2017;17 (suppl 3).

« Back to 2018 American Transplant Congress