P077 Anti-A titers in ABO incompatible transplantation – An OPO’S experience

Abstract

Aim The UNET system allows blood type B patients to receive blood type A2 or A2B donor kidneys. To qualify for the program, patients must satisfy titer criteria set by the transplant center. We developed protocols for these types of transplants. Literature states “perform Anti-A titer” and does not differentiate the target sub-group cell to use for titer. We hypothesize that since A2 cells express weaker antigenicity than A1 cells, testing A2 titers would be more representative of the clinical situation and be adequate to ensure a safe transplant. Our aim is to validate the use of Anti-A2 titers for the purpose of A2 or A2B donor kidney transplants for B recipients. Methods Patient titers were performed using donor red blood cells from A2 donors and reagent A2 control cells using the gel method. Sub-grouping of donor’s A blood type was determined. Titers and scores were determined for both IgM and IgG Anti-A2. Post- transplant outcomes were analyzed. Pre- and post- transplant titers were performed, as well as the creatinine level one month post- transplant, and the most recent creatinine level as of May 1, 2016. We also looked at the average Anti-A1 titers as compared to the average Anti-A2 titers of 63 patients. Results Download : Download high-res image (1MB) Download : Download full-size image Average A1 and A2 Titer and Score of 63 Recipients 1. A1 Pre-titer IgM was 3.0 × higher than A2 Pre-titer IgM. 2. IgM score of A1 was 1.6 × higher than IgM score of A2. 3. A1 Pre-titer IgG was 4.3 × higher than A2 Pre-titer IgG. 4. IgG score of A1 was 2.1 × higher than IgG score of A2. Conclusions Our preliminary results suggest that performing Anti-A2 titers is an effective way of measuring the potential blood group B recipient’s risk to receiving a blood group A2 or A2B deceased donor kidney. Furthermore, we suggest that using a blood group B patients Anti-A1 titer to qualify him/her for this “A2/ A2B donor to B recipient “ program will unnecessarily eliminate many patients from receiving a successful transplant. To date 20 patients have been successfully transplanted using this protocol. Detailed outcome data is pending on the additional 12 recipients.