P1791HLA DESENSITIZATION- INDIAN EXPERIENCE
Authors: Bansal Shyam , Gade Ashwini 
Published: June 2020

Abstract

Background and Aims
There are many barriers to kidney transplant and one of them is presence of donor specific antibodies (DSAs) in the recipients. Presence of strong DSA is considered a relative contraindication for kidney transplantation, however, if DSAs are of weak to moderate then desensitization is attempted in many centres with good success rate. Desensitizing such patients can be an acceptable approach to increase the donor pool and facilitating transplants. This is a retrospective analysis of patients who underwent desensitization at our centre after availability of luminex single antigen (LSA) assay

Method
Between April 2014 and December 2018, 825 patients underwent kidney transplantation at our centre. Patients who were CDC negative but positive FCXM were further analysed with LSA to know the presence and strength of DSAs. Our protocol for desensitization consisted of plasmapheresis (PP) 1.5 volume by double filtration on alternate day and low dose IV IG 100 mg/kg after each PP. Whenever MFI was &lt;1000 and/or FCXM was negative, patient was taken for transplant with thymoglobulin induction of 1.5 mg/kg for 2-3 doses. All patients were maintained on triple immunosuppression consisting of tacrolimus, mycophenolate mofetil and corticosteroids. We did not routinely followed DSAs in these patients post-transplant if there was no clinical indication. All adverse events during follow up including new onset diabetes after transplant (NODAT), infections, acute rejections (AR), graft loss and death

Results
Out of 825 patients, 15 underwent HLA incompatible transplants, of which, 8 were males. All patients were first transplant and 11/13 had history of some sensitizing events in the form of blood transfusion and/or pregnancy. The mean dialysis duration was 8.6 ±14.6 months. FCXM was positive in all the patients with 5 patients had T cell flow positive, 8 had B cell flow positive and 2 had both T & B cell FCXM positivity. Most patients had weak to moderate positive flow cross match. On further evaluation by LSA, all these patients had DSAs, with 3/15 had MFI &lt;1000, 6 had MFI between1000-2000, and remaining 6 had MFI &gt;2000, out of which one patient had MFI of 7195 and six patients had multiple DSAs. These patients underwent desensitization with PP and IVIG and the end point of treatment was either MFI &lt; 1000 or FCXM negative. Post- transplant DSAs were done in patients with high MFI or clinically indicated. Two patients had increase in post-transplant DSA titres requiring post-transplant plasmapheresis. The mean follow up was 29±6 months.
On follow up, only 1 patient developed borderline cellular rejection one year after transplant, which responded with pulse steroids. Three patients had biopsy for asymptomatic rise in creatinine but it showed patchy ATN with no evidence of rejection.. One patient developed transient CMV viremia, one patient developed lymph node tuberculosis (TB) and two patients had UTI, all of them responded to treatment. There was no graft or patient loss till last follow up.

Conclusion
This study shows that HLA desensitisation is feasible and successful in if patients are selected carefully and evaluate thoroughly. HLA incompatible transplant can provide a new lease of life to those patients who would otherwise not get a kidney due to lack of paired exchange and deceased donor program