ANTIBODIES AGAINST MICA ALLELES IN PATIENTS AWAITING KIDNEY TRANSPLANTATION AND DURING THE POST-TRANSPLANT COURSE.

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ANTIBODIES AGAINST MICA ALLELES IN PATIENTS AWAITING KIDNEY TRANSPLANTATION AND DURING THE POST-TRANSPLANT COURSE.
Yizhou Zou MD ¹, Zhengnan Wang BSN ¹, Guido Sireci MD ² and Peter Stastny MD ¹. ¹ Internal Medicine, Univ of TX Southwestern Medical Center, Dallas, TX and ² Biopathology, Univ of Palermo, Palermo, Italy .

Previously we have reported on the development of antibodies against MICA alleles in kidney transplant recipients. These alloantibodies can now be determined using a new assay using Luminex beads bound to soluble recombinant MICA*01, 02, 04, 08 and 09 produced in insect cells. In the present study we have analyzed serum from 85 kidney transplant recipients on the waiting list at our institution and 66 patients transplanted within the last four years in Palermo. Many of the patients in both groups were sensitized and some were regrafts (waiting list: 15%; post-tx: 7.6%) and their sera were found to contain anti-HLA and anti-MICA antibodies. The latter were detected in 21/85 (24.7%) waiting list patients and in 15/66 (22.7%) of the transplanted recipients. Both HLA and MICA antibodies were observed in 14 recipients and MICA only without HLA in 22 of the recipients.The most frequent MICA antibodies were against MICA *09 followed by MICA *01 and MICA *08. Immunization against mismatched MICA alleles appears to occur frequently during transplantation and can also develop after pregnancy or transfusions. Further studies will be required to determine whether patients who produce alloantibodies against MICA alleles are at risk for transplant rejection even when no HLA antibodies are detected.