Using Donor-Specific Antibodies to Monitor the Need for Immunosuppression

Using Donor-Specific Antibodies to Monitor the Need for Immunosuppression: Background: Experience with tolerance protocols has shown that none is perfect and that each escape from tolerance must be identified early to prevent graft failure. In addition, some test is needed for patients who are weaned off immunosuppression (IS) to forewarn of weaning failure. The usual measures of function—such as serum creatinine levels—are not sensitive enough to detect rejection in a timely manner.
Methods: A study was carried out on 72 patients who received living-donor kidney transplants with clonal deletion protocol (total lymphoid irradiation or bortezomib), and followed with reduced doses of maintenance IS. Every month or every 2 months, a test was performed for donor-specific antibodies (DSA) using Luminex mixed and/or single antigen beads.
Results: After transplantation, DSA developed in 17% of the patients at 6 months, 41% at 1 year, and 57% at 2 years, with 95% confidence limits of 10%, 28%; 30%, 55%; and 44%, 71%, respectively. Fifty-three percent of patients weaned IS to less than 10 mg prednisone daily experienced DSA within 3 months. Furthermore, prednisone dose (per 2.5 mg) and years after transplantation were inversely associated with DSA production (risk ratio 0.92 [95% confidence limits: 0.85, 0.99], and 0.70 [0.49, 1.00]).
Conclusions: DSA monitoring is highly effective for detecting escape from tolerance and reemergence of the immune response in weaned patients. DSA appearance was inversely proportional to the level of maintenance drugs in the weaning process. Measurement of DSA on a monthly basis is adequate for detection of the change in immune reactivity.

Anti-Human Leukocyte Antigen Immunization After Early Allograft Nephrectomy

Anti-Human Leukocyte Antigen Immunization After Early Allograft Nephrectomy: Introduction: The occurrence of de novo anti-human leukocyte antigen (HLA) antibodies and donor-specific antibodies (DSAs) after early graft loss is not well known. The aims of this single-center study were to evaluate the incidence of de novo DSAs and non-DSA anti-HLA antibodies after allograft nephrectomy for early graft loss and to seek the predictive factors for the development of DSAs.
Materials and Methods: Thirty-two patients, who experienced an early graft loss (<3 months after transplantation) and required an allograft nephrectomy, and who were considered for retransplantation, were included in the study. Anti-HLA antibodies were assessed, using the Luminex assay, before transplantation, on day 15 and at months 1, 3, 6, and 9 after the nephrectomy, and then every 3 to 6 months until the last follow-up.
Results: The median time between transplantation and allograft nephrectomy was 2.5 (0–81) days. The median follow-up was 335 (30–1441) days. At month 9, postallograft nephrectomy, the incidence of DSAs was 56.6% (17/30). Anti-HLA class I and class II DSAs were detected, respectively, in 33.3% (10/30) and 30% (9/30) of patients. The incidence of de novo non-DSA anti-HLA antibodies was 64% (19/30): of these, 83.3% reacted to the donors’ epitopes. Induction therapy (type and dose) and the time between transplantation and allograft nephrectomy did not influence the incidence of DSAs. No independent predictive factor for the development of DSAs was identified.
Conclusion: Even after a short transplantation period, DSAs and non-DSA anti-HLA antibodies may develop in more than 50% of patients whose immunosuppression has been stopped after an allograft nephrectomy.

A New Diagnostic Algorithm for Antibody-Mediated Microcirculation Inflammation in Kidney Transplants

A New Diagnostic Algorithm for Antibody-Mediated Microcirculation Inflammation in Kidney Transplants:

We studied the significance of microcirculation inflammation in kidney transplants, including 329 indication biopsies from 251 renal allograft recipients, who were mostly nonpresensitized (crossmatch negative). Glomerulitis (g) and peritubular capillaritis (ptc) were often associated with antibody-mediated rejection (65% and 75%, respectively), but were also found in other diseases in the absence of donor-specific antibody (DSA): T-cell-mediated rejection (ptc, g), glomerulonephritis (g) and acute tubular necrosis (ptc). To develop rules for reducing the nonspecificity of microcirculation inflammation and defining the best grading thresholds associated with DSA, we built and validated a decision tree to predict DSA.

Terminal Complement Inhibition Decreases Antibody-Mediated Rejection in Sensitized Renal Transplant Recipients

Terminal Complement Inhibition Decreases Antibody-Mediated Rejection in Sensitized Renal Transplant Recipients:

Sensitized renal transplant recipients with high levels of donor-specific alloantibody (DSA) commonly develop antibody-mediated rejection (AMR), which may cause acute graft loss or shorten allograft survival. We examined the efficacy of terminal complement inhibition with the humanized anti-C5 antibody, eculizumab, in the prevention AMR in renal transplant recipients with a positive crossmatch against their living donor.

Posttransplant Donor-Specific Anti-HLA Antibodies Negatively Impact Pancreas Transplantation Outcome

Posttransplant Donor-Specific Anti-HLA Antibodies Negatively Impact Pancreas Transplantation Outcome:

During a 9-year follow-up, 167 consecutive pancreas transplant recipients (152 simultaneous pancreas-kidney [SPK]) were followed for the detection of posttransplant anti-HLA antibodies. Forty patients (24%) developed anti-HLA antibodies, 26 (65%) had donor-specific antibodies (DSA; 61% anticlass 2) and 14 (35%) non-DSA (78.6% anticlass 1).

Long-term follow up for anti-HLA donor specific antibodies postrenal transplantation: high immunogenicity of HLA class II graft molecules

Long-term follow up for anti-HLA donor specific antibodies postrenal transplantation: high immunogenicity of HLA class II graft molecules:

Summary

Τhe clinical significance of de novo post-transplant anti-HLA donor-specific antibodies (DSA) was evaluated using 4241 serum samples collected between 2000 and 2007 from 597 renal transplant recipients. Patients transplanted before December 1996 (n = 77) were included in the historic group and those transplanted thereafter (n = 520) were included in the study group.