A quality control program for crossmatching procedures for solid organ transplantation. The participating laboratories of the Australasian and South Asian Tissue Typing Association

In vivo heat inactivation of serum can distinguish false positive cross matches in renal transplants

INTRODUCTION

Renal transplants have traditionally been performed despite positive cross match if results are presumptively due to IgM antibodies. False positives have been distinguishable from true positives by dithiothreitol or dithioerythritol treatment to inactivate IgM antibodies. Heat inactivation, which renders the antibodies inactive, is an alternative to chemical amelioration.

METHODS

We retrospectively evaluated clinical outcomes of patients who had positive cross matches presumed to be falsely positive as determined by treatment with heat inactivation compared to controls with negative cross matches over a six-year period. A total of 414 transplanted patients had available cross match data: 355 with a negative cross match and 59 with a positive cross match rendered negative after heat inactivation. Serum creatinine was reviewed at 6, 12 and 24 months posttransplant.

RESULTS

Graft function was considered stable at 12 and 24 months post-transplant if the change in creatinine compared to the 6-month value was >0.5 mg/dL. Repeated and nonrepeated measures analysis showed equivalence in the change in sCr from 6 to 12 (p = 0.525) and from 6 to 24 months (p = 0.752). Kaplan-Meier curves to evaluate graft survival demonstrated no significant difference in function over 24 months. Curves were censored for patient death, treated as death with functioning (p = 0.48) and nonfunctioning (p = 0.64) grafts.

DISCUSSIONS

We have demonstrated comparable long-term function and survival for living donor renal transplants using heat inactivation to detect false positive cross matches. This simple and cost-effective method can be used to safely evaluate histocompatibility for living donor renal transplant recipients.

Delayed and acute hemolytic transfusion reactions resulting from red cell antibodies and red cell-reactive HLA antibodies

BACKGROUND

It has been controversial whether HLA antibodies cause hemolytic transfusion reactions (HTR) or shortened red blood cell (RBC) survival. A patient is reported who had two episodes of HTR, the latter of which was likely due to RBC-reactive HLA antibodies.

CASE REPORT

A 77-year-old woman, admitted for gastric varix rupture, had no RBC-irregular antibodies detected before transfusion. On Hospital Day 12, after transfusion of 2 units of RBCs and 2 units of fresh-frozen plasma, the first delayed hemolytic episode occurred and anti-E, anti-c, anti-Jk(a), and unidentified RBC-reactive antibodies were detected in a serum sample from Day 14. Two additional units of matched RBCs were transfused with a leukoreduction filter on Days 19 and 22. After 4 hours of starting a transfusion on Day 22, the patient had fever, and a second hemolytic episode was recorded. Multireactive HLA antibodies (reactive against 20 of 20 donor panel lymphocytes) were detected in serum samples from Day 15 to Day 21. These HLA antibodies reacted strongly with HLA-A2 and HLA-B7 antigens, corresponding to Bg(c) and Bg(a) antigens on RBCs, respectively. RBCs transfused on Day 22 were found to be HLA-A2 by genotyping.

CONCLUSION

Strong HLA alloantibodies in this recipient appear to have caused a HTR. It is suggested that HLA antibodies be considered in patients with unexplained HTRs.

The Italian quality control scheme for crossmatching procedures and HLA sera screening: the 2002 pilot study

CONTEXT

The first national quality control (QC) program of histocompatibility serum testing was performed in Italy in 2002.

OBJECTIVE

To monitor the performance of HLA typing laboratories while meeting the accreditation requirements of the European Federation for Immunogenetics (EFI), which require HLA typing laboratories to participate in external QC of their crossmatch and antibody analyses.

DESIGN

The Turin Transplant Immunology Service was asked to organize a QC survey of 17 HLA typing laboratories in Italy. Each laboratory received 12 serum specimens and 6 blood samples and was required to perform 36 crossmatches and 12 serum antibody specificity determinations.

SETTINGS

Data of participating centers were compared to establish whether EFI requirements were satisfied.

RESULTS

In crossmatch analysis, the results of 32 of 36 crossmatches reached the 75% consensus target, with all the participating laboratories meeting the standards of the EFI. In antibody analysis, only 7 of 17 laboratories met the EFI standards.

CONCLUSION

The first Italian QC program shows that the participating laboratories obtained consistent results in crossmatching, whereas the results were less satisfactory in the determination of serum antibody specificity, where consensus was reached only with monospecific sera and antibody-negative samples.