Solid-phase red cell adherence versus gel column agglutination: Is there any difference for the detection of alloantibodies associated with the JK system?

Background: Detection of alloantibodies associated with the JK system may be tricky. They are nevertheless associated with transfusion reactions and their detection is crucial.

Study design and methods: Retrospectively and over a period of 7 years, we compared the results obtained using two different assays for antibody detection. We performed antibody detection testing with solid-phase red cell adherence (SPRCA). If positive, the antibody identification was carried out with the SPRCA and confirmed with the gel method in Coombs medium. In case of discrepant results occurring in recently transfused patients, we investigated these patients during the post-transfusion period.

Results: Fifty-five patients with anti-JK1 or anti-JK2 were identified out of which 41 were further analyzed. Both techniques clearly identified 10 alloantibodies. In 22 cases, the alloantibody identified by SPRCA was not observed with the gel method because of negative detection tests. In one case, none of the techniques identified the alloantibody and in 8 cases, the final result was inconclusive (1/41 with the SPRCA and 8/41 with the gel method). Two patients having a highly probable delayed hemolytic transfusion reaction (DHTR) were identified among the discrepant results. For both cases, anti-JK2 was clearly identified by the SPRCA but showed inconclusive reactions with the gel method.

Discussion: This study shows that in 29 out of 41 cases, the anti-JK1 or anti-JK2 identified with the SPRCA method were not with the gel method in Coombs medium. Eleven cases (11/29) were clinically significant and among them, 4 likely DHTRs and 2 highly probable DHTRs occurred.