2014 Volume 60 Issue 6 Pages 585-591
Anti-human plasma proteins, especially anti-IgA and anti-haptoglobin, are reported to cause anaphylactic transfusion reactions. To detect anti-plasma proteins effectively, we designed and evaluated a sensitive and specific immunoassay using a Luminex system. Subjected samples were assayed with human plasma proteins (IgA, IgA1, IgA2, haptoglobin, α2-macroglobulin, ceruloplasmin, C4, C9, and albumin) coupled with microspheres and analyzed using the Luminex system. An absorption test was performed for sample serum which had been pre-incubated with pooled human plasma. In the sensitivity test using 2-fold serially diluted anti-IgA and anti-haptoglobin serum, the Luminex assay showed 64 times higher sensitivity than an ELISA. In screening of 242 serum samples derived from non-hemolytic transfusion reaction cases, multi-transfused patients, and healthy donors, 49 were found to be positive for at least one plasma protein using the Luminex assay. Only 2 of these were confirmed positive for anti-IgA2 and anti-haptoglobin using the absorption test. The other 47 sera were regarded as nonspecific reactions, since their reactivities were not absorbed by pooled human plasma. All 49 Luminex-positive sera were negative on ELISA. Although highly sensitive immunoassays often show nonspecific reactions, conducting a simultaneous absorption test could improve the specificity of the Luminex assay. Therefore, our newly developed Luminex assay is suitable for detecting anti-human plasma proteins in non-hemolytic transfusion reaction cases.
