Human leukocyte antigen immunization in transfusion-dependent Moroccan patients with beta-thalassemia major: prevalence and risk factors

INTRODUCTION

Beta-thalassemia major patients need a regular blood transfusion to have an initial normal growth. However, these patients have an increased risk of developing alloantibodies. Our main goal was to study HLA alloimmunization in Moroccan Beta-thalassemia patients by confronting it with transfusion and demographic criteria, exploring the involvement of HLA typing profile in the development of HLA antibodies and in turn determining risk factors for their development.

METHODS

The study consisted of 53 Moroccan pediatric patients with Beta-thalassemia major. Screening for HLA alloantibodies was performed using Luminex technology Whereas HLA genotyping was done with sequence-specific primers (PCR-SSP).

RESULTS

In this study, 50.9% of patients have been identified as positive for HLA antibodies, with 59.3% having both HLA Class I and Class II antibodies. A significant increase frequency of DRB1*11 allele was revealed in non-immunized patients (34.6% vs. 0%, p = 0.001). Our results also revealed that the majority of our HLA immunized patients were women (72.4% vs. 27.6%, p = 0.001), and transfused with more than 300 units of RBC units (66.7% vs. 33.3%, p = 0.02). There were statistically significant differences when comparing these frequencies.

CONCLUSIONS

This paper revealed that the transfusion dependent Beta-thalassemia major patients are exposed to risk of developing HLA antibodies following transfusions with leukoreduced RBC units. The HLA DRB1*11 was a protective factor against HLA alloimmunization in our beta-thalassemia major patients.

[Husband to wife renal transplantatation and pretransplant HLA immunization: about two cases]

La transplantation rénale est la meilleure thérapeutique pour l'insuffisance rénale terminale. Cette transplantation est possible grâce au don de rein à partir d'un donneur vivant ou d'un donneur en état de mort encéphalique (EME). L'immunisation des receveurs est une vraie problématique de la greffe car elle est responsable de difficultés particulières de choix d'un donneur et surtout expose au risque de rejet de greffon. Nous allons présenter deux observations de greffe rénale entre époux, ou les deux receveurs avaient des taux faibles d'anticorps dirigés contre des antigènes HLA du donneur mais dont l'issue en post-greffe immédiat était différente selon le sexe du receveur. En effet l'immunisation anti-HLA des femmes suite aux grossesses est un vrai obstacle à leur greffe par le rein de leur époux. Malgré la faible compatibilité HLA qui caractérise la transplantation rénale entre les époux, car le donneur est ici non apparenté, cette transplantation offre une bonne alternative aux greffes de reins à partir de donneurs en EME, qui font cruellement défaut au Maroc.