Session Time: 2:30pm-4:00pm
Presentation Time: 2:30pm-2:42pm
Location: Room 312
Post-transplant (tx) IgG donor-specific antibodies (DSA), but not IgM DSA has been identified as one of the major causes of late graft loss. Considering the impact that post-tx IgG DSA has on late graft loss, it may be important to understand why and how many pre-tx IgM convert to IgG DSA post-tx. Our aim was to learn more about the IgM-IgG conversion post-tx and determine if immunosuppression affected this conversion.
Methods: We retrospectively analyzed 218 consecutive kidney tx patients at a single center, transplanted between 1/06 and 12/10, with a minimum 3 year follow-up. We excluded 20 patients from the analysis due to HLA-matched tx, insufficient patient information, or lack of patient sera. Sera sampling occurred pre-tx, 1, 3, 6, 9, 12 months post-tx and annually thereafter. Antibody identification was determined by LABScreen single antigen beads.
Results: 14% (28/198) of patients had pre-tx IgG DSA and 26% (51/198) of patients had pre-tx IgM DSA but were negative for IgG DSA. Of the 51 patients, 22 patients (43%) converted pre-tx IgM to IgG DSA post-tx of the same specificity, with >50% (12/22) converting within the 1st year. Interestingly, significantly more Class II antibodies (44%), all DQ-specific, converted as compared to Class I antibodies (16%), Figs. A & B. Patients on an induction + main immunosuppression combination of Thymoglobulin (Thymo) + Tacrolimus (Tac) had the least conversion (15%) as compared to patients on anti-CD25 + Tac (42%) and anti-CD25 + cyclosporine (73%), Fig. C. Delayed graft function, acute rejection, nonadherence, and BK virus positivity was not shown to affect pre-tx IgM to post-tx IgG conversion.
Conclusion: Significantly more Class II Abs convert post-tx. Induction with Thymo combined with Tac as the main immunosuppression may be most effective in preventing post-tx IgG DSA conversion from pre-tx IgM. More studies are needed to further understand the conversion and confirm the effect immunosuppression has on the process.
CITATION INFORMATION: Nguyen A, Everly M, Rebellato L, Haisch C, Briley K, Bolin P, Kendrick S, Morgan C, Maldonado A, Terasaki P. Pre-Transplant IgM to Post-Transplant IgG DSA Conversion May Be Affected by Immunosuppression. Am J Transplant. 2016;16 (suppl 3).
To cite this abstract in AMA style:Nguyen A, Everly M, Rebellato L, Haisch C, Briley K, Bolin P, Kendrick S, Morgan C, Maldonado A, Terasaki P. Pre-Transplant IgM to Post-Transplant IgG DSA Conversion May Be Affected by Immunosuppression. [abstract]. Am J Transplant. 2016; 16 (suppl 3). https://atcmeetingabstracts.com/abstract/pre-transplant-igm-to-post-transplant-igg-dsa-conversion-may-be-affected-by-immunosuppression/. Accessed July 17, 2019.
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