MicroRNAs predict early complications of autologous hematopoietic stem cell transplantation

Autologous hematopoietic stem cell transplantation (AHSCT) remains the most prevalent type of stem cell transplantation. In our study, we investigated the changes in circulating miRNAs in AHSCT recipients and their potential to predict early procedure-related complications. We collected serum samples from 77 patients, including 54 with multiple myeloma, at four key time points: before AHSCT, on the day of transplantation (day 0), and at days + 7 and + 14 post-transplantation. Through serum miRNA-seq analysis, we identified altered expression patterns and miRNAs associated with the AHSCT procedure. Validation using qPCR confirmed deviations in the levels of miRNAs at the beginning of the procedure in patients who subsequently developed bacteremia: hsa-miR-223-3p and hsa-miR-15b-5p exhibited decreased expression, while hsa-miR-126-5p had increased level. Then, a neural network model was constructed to use miRNA levels for the prediction of bacteremia. The model achieved an accuracy of 93.33% (95%CI: 68.05-99.83%), with a sensitivity of 100% (95%CI: 67.81-100.00%) and specificity of 90.91% (95%CI: 58.72-99.77%) in predicting bacteremia with mean of 6.5 ± 3.2 days before occurrence. In addition, we showed unique patterns of miRNA expression in patients experiencing platelet engraftment delay which involved the downregulation of hsa-let-7f-5p and upregulation of hsa-miR-96-5p; and neutrophil engraftment delay which was associated with decreased levels of hsa-miR-125a-5p and hsa-miR-15b-5p. Our findings highlight the significant alterations in serum miRNA levels during AHSCT and suggest the clinical utility of miRNA expression patterns as potential biomarkers that could be harnessed to improve patient outcomes, particularly by predicting the risk of bacteremia during AHSCT.