Renal transplantation in HLA sensitized patients: Traversing the immunological barrier

Abstract

Successful renal transplantation across HLA barrier in sensitized individuals has been on the rise during the past decade, primarily due to improved desensitization regimes. The aim of this study was to share outcome of desensitization in renal transplant recipients with donor‐specific anti‐HLA antibodies (DSA). This was a retrospective analysis of all HLA immunized individuals who were prospective renal transplant recipients. All such patients underwent preconditioning as per the institutional desensitization protocol. Complement‐dependent cytoxicity‐based crossmatch (CDC‐XM), luminex‐based crossmatch (LM‐XM) and flowcytometry‐based crossmatch (FC‐XM) were done in all cases. If any of these tests turned out positive, single antigen bead assay (SAB) was performed. Desensitization for DSA was performed in 55 patients and all patients were followed‐up for 1 year to assess graft function and patient outcome. CDC‐XM being a less sensitive assay, could not detect incompatibility in 29 (52.73%) cases. After desensitization, even though SAB and LM‐XM results revealed an MFI within acceptable range, FC‐XM being an extremely sensitive assay, continued to give a positive result in eight (14.55%) cases. The mean ± SD number of pretransplant TPE were 3.44 ± 0.98 (2‐11). Out of 55, there were 10 patients who were lost to follow up. Patient and graft survival of 45 patients at 1 year was found to be 100%. Preconditioning for renal transplants in the form of immunosuppression with TPE is an extremely useful auxiliary for transplantation in HLA sensitized renal transplant recipients.

Luminex Crossmatch in kidney transplantation

“…Other studies explored clinical significance and other aspects of the LumXm and what benefits it can provide. LumXm was implemented in a pre‐transplant algorithm, in post‐transplant follow‐up, 19,21 and if combined with other tests, like the SAB, it can provide pertinent information for example in de novo DSA detection 21,26 . In addition, it is a technique with potential as it allows the standardization of donor HLA molecules' expression 24 .…”

“…While the manufacturer's criteria specify that samples showing ≥2 adjusted values are to be taken as positive, [11][12][13][14][15][16][17][18] some studies determined positivity while taking into consideration other criteria such as MFI 10,13,16,[19][20][21][22][23][24][25] and negative control beads' MFI 10,13,15-17 (Table 6).…”

“…It is worth noting that many studies to date have used different criteria to determine the positivity of the LumXm. While the manufacturer's criteria specify that samples showing ≥2 adjusted values are to be taken as positive, 11–18 some studies determined positivity while taking into consideration other criteria such as MFI 10,13,16,19–25 and negative control beads' MFI 10,13,15–17 (Table 6).…”

Outcome of desensitization in human leukocyte antigen and ABO incompatible living donor kidney transplantation: Single center experience of first 200 incompatible transplants

“…In accordance with THOA, kinship testing and comprehensive compatibility testing including CDC‐XM, LM‐XM, and FC‐XM followed by SAB was performed as per algorithm illustrated in Figure 2 19 …”

HLA desensitization based on results of the luminex technique in kidney transplant – A single-center experience

“…[ 6 9 10 ] There is hardly any Indian data about desensitization based on Luminex SAB, except from our group of three patients and another recent study, but both had short follow up. [ 11 12 ] We retrospectively analyzed the results of all desensitization performed at our center after the availability of the Luminex SAB technique after 2014.…”