Background: Erythrocyte transfusion is the cornerstone of clinical practice, playing a vital role in treating various conditions such as severe blood loss, anemia, and certain hematological disorders. However, worries regarding the possible elevated hazard of transfusion-related immunomodulation (TRIM) persist. Purpose: We attempt to identify TRIM-associated erythrocyte characteristics and evaluate their genetic influence on TRIM based on a Mendelian randomization (MR) study. Method: A multivariate MR method was used to screen out the potential exposure factors. Gene variants related to the 12 erythrocyte characteristics were acquired from a genome-wide association study of hematologic characteristics, and these variants were utilized in the UK Biobank. Univariate MR methods were employed for sensitivity analyses. Hemoglobin was identified to be a significant erythrocyte trait in the context of TRIM. Based on the inverse variance-weighted (IVW) method, hemoglobin predicted by genetics was found to be favorably correlated with TRIM. MR-Egger, weighted median, and MR pleiotropy residual sum and outlier tests also provided robust estimation. Results: When incorporating all available gene variants for the erythrocyte characteristics, the exposure factor most associated with TRIM, based on marginal inclusion probability (MIP), was hemoglobin (MIP = 0.90), while all other erythrocyte characteristics had an MIP < 0.24. This indicates that hemoglobin stands out prominently among the various erythrocyte characteristics in its association with TRIM. The high MIP value for hemoglobin strongly suggests that it is a key determinant in the development of TRIM, while the much lower MIP values for other traits imply their relatively minor roles in this context. Sensitivity analyses showed that even when eliminating the highly correlated hematocrit, hemoglobin was still chosen with the greatest MIP. Additionally, univariate MR using IVW validated that hemoglobin was uniformly favorably correlated with TRIM. Conclusion: Hemoglobin is the key erythrocyte characteristic underlying TRIM, which shows that increasing hemoglobin via blood transfusion increases the risk of TRIM. Hence, the benefits of blood transfusion that raise hemoglobin need to be weighed against the side effects.
Zhu et al. (Mon,) studied this question.