Prediction of JENU-Negative Phenotype by Genotyping among Thai Patients with Multiple Transfusions.

BACKGROUND

The MNS7 (Mi) is a low-prevalence antigen associated with GP.Mur hybrid glycophorin, which is high in Thai populations. Consequently, anti-Mi, particularly anti-Mur caused by alloimmunisation is involved in transfusion medicine. In Thailand, before the first transfusion of transfusion-dependent patients with thalassemia, typing of Mi and Rh antigens is minimally required to provide phenotype-matched donors. A patient with Mi-positive phenotype encoded by homozygote (do not express GPB, JENU-negative) receiving either Mi-negative or Mi-positive phenotype can produce anti-JENU, leading to difficulty in locating compatible donors. Genotyping for hybrid alleles to predict the JENU-negative phenotype is alternatively implemented. This study aimed to predict the JENU-negative phenotype in multitransfused Thai patients using PCR-based coupled DNA sequencing.

METHODS

Blood samples from 861 multitransfused Thai patients were included. Mi antigen testing was performed using serology and PCR-sequence-specific primer. () hybrid alleles were analyzed using Sanger DNA sequencing. Only 5 of 68 patients receiving more than 40 red cell units developed alloantibodies. The sequence analysis revealed that 60 of 68 patients carried the allele, including / heterozygotes (86.76%) and the / homozygote (1.47%). The remaining 8 patients were / heterozygotes (10.29%) and / heterozygotes (1.47%). The , , and alleles were not observed. One female patient with JENU-negative phenotype received 24 red cell transfusions within 1 year without alloantibody production, which might be due to the number of red blood cell (RBC) units or her disease status.

CONCLUSIONS

Concerning this study, multiple transfusions can induce alloantibody production. Therefore, phenotype-match transfusions are beneficial among patients with long-term transfusion therapy, and further investigation of the JENU-negative phenotype is suggested.