Scientific Publications by FDA Staff

Transfusion 2004 Feb;44(2):170-2

Evidence that Hy- RBCs express weak Joa antigen.

Scofield TL, Miller JP, Storry JR, Rios M, Reid ME

Scofield TL, Amer Red Cross, N Cent Blood Serv, 100 S Robert St, St Paul, MN 55107 USA Amer Red Cross, N Cent Blood Serv, St Paul, MN 55107 USA US FDA, Ctr Biol Evaluat & Res, Bethesda, MD USA Univ Hosp, Skane Blood Ctr, Lund, Sweden New York Blood Ctr, Immunohematol Lab, New York, NY 10021 USA

BACKGROUND: RBCs of the Hy- phenotype have, in the past, been typed as Gy(a+w), Hy-, Jo(a-), and RBCs with the Jo(a-) phenotype type Gy(a+), Hy+w, and Jo(a-). Anti-Hy and anti-Joa are difficult to identify mainly because appropriate reagent RBCs are poorly characterized. Historically, anti-Joa has not reacted with RBCs with either phenotype. This report describes a case of an anti-Joa that shows Hy- RBCs express some Joa antigen, albeit weakly. CASE REPORT: Anti-Joa was identified in a serum sample of a 71-year-old woman. The antibody reacted 1+ to 2+ by the IAT with all untreated and ficin-treated panel RBCs and did not react with Gy(a-) RBCs and Jo(a-) RBCs. Unexpectedly, the serum sample reacted weakly with six of eight RBC samples with the Hy- phenotype. The anti-Joa was adsorbed onto and eluted from Hy- RBCs, indicating the presence of weak Joa antigen. The patient's RBCs typed Gy(a+), Hy+, Jo(a-). DNA studies using PCR-RFLP analysis showed the patient to be homozygous for the JO allele, which is consistent with the serologically determined Jo(a-) status. CONCLUSION: The DNA and serologic evidence of this case show that Hy- RBCs may express low levels of Joa antigen, which contradicts previously published data concerning the Joa type of Hy- RBCs.