The haemoglobinopathy survey: The reality of transfusion practice in sickle cell disease and thalassaemia in England

Red Blood Cell Alloimmunizations in Thalassaemia Patients With Regular Transfusion in China: a Systematic Review and Meta-Analysis

OBJECTIVE

The development of red blood cell alloimmunization intensifies transfusion complication in thalassaemia patients. The purpose of this paper is to evaluate the existing evidence on the prevalence of erythrocyte alloimmunization in China by meta-analysis. We systematically searched cross-sectional studies regarding the alloimmunization of thalassaemia patients with regular blood transfusion in China from year 2000 to May 2021 in the Cochrane library, PubMed, EMBASE, Web of Science, and Chinese databases including CNKI, Wanfang Data, Vip and CBM. Data extraction and quality evaluation of the included studies were performed. Meta-analysis was performed using the DerSimonian and Laird random-effects models with inverse variance weighting. The presence of publication bias was tested by Egger's test, and the methodological quality of each included article was evaluated by the criteria specific to prevalence studies.

RESULTS

A total of 1874 patients and 263 alloantibodies from 11 studies were identified and included in the meta-analysis. The proportion of alloantibodies against antigens belonging to the Rh, MNSs and Kidd systems were as high as 70.3%, 17.9%, and 6.5%, respectively. Meta-analysis showed that the overall prevalence of alloimmunization among transfusion-dependent thalassaemia patients in China is 11.4% (95%CI: 7.2%∼16.3%).

CONCLUSIONS

The characteristics of red blood cell alloimmunization among thalassaemia patients with regular transfusion in China differ greatly from those in other countries. Therefore, transfusion strategies shall be actively adapted in line with thalassaemia patients in China to minimize the risk of alloimmunization.

Towards manufactured red blood cells for the treatment of inherited anemia

Patients with inherited anemia and hemoglobinopathies (such as sickle cell disease and β-thalassemia) are treated with red blood cell (RBC) transfusions to alleviate their symptoms. Some of these patients may have rare blood group types or go on to develop alloimmune reactions, which can make it difficult to source compatible blood in the donor population. Laboratory-grown RBC represent a particularly attractive alternative which could satisfy an unmet clinical need. The challenge, however, is to produce - from a limited number of stem cells - the 2x1012 RBC required for a standard adult therapeutic dose. Encouraging progress has been made in RBC production from adult stem cells under good manufacturing practice. In 2011, the Douay group conducted a successful proof-of-principle mini-transfusion of autologous manufactured RBC in a single volunteer. In the UK, a trial is planned to assess whether manufactured RBC are equivalent to RBC produced naturally in donors, by testing an allogeneic mini-dose of laboratory-grown manufactured RBC in multiple volunteers. This review discusses recent progress in the erythroid culture field as well as opportunities for further scaling up of manufactured RBC production for transfusion practice.