The relationship between erythrocyte transfusion in very preterm infants and inflammatory cytokines and morbidities: a prospective observational study

It is essential to assess not only the hematologic outcomes but also the immunologic and inflammatory consequences of RBC transfusion in preterm infants. This study aimed to evaluate changes in serum cytokine levels following red blood cell (RBC) transfusion in preterm infants born at ≤ 32 weeks of gestation and to assess their potential proinflammatory effects and associations with neonatal morbidities. This prospective, single-center observational study included preterm infants born at ≤ 32 weeks of gestation, aged > 7 days, who received RBC transfusion. Serum interleukin (IL)-1, IL-6, tumor necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF), and melatonin were measured before and at 2 and 24 h after transfusion. Insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) were analyzed at 1, 2, and 3 weeks post-transfusion. Thirty-three infants met the inclusion criteria. The mean gestational age was 27.4 ± 2.7 weeks, and the mean birth weight was 1016 ± 356 g. Following transfusion, the hematocrit increased from 28.3 ± 3.1% to 35.0 ± 3.8%. No significant post-transfusion changes were observed in IL-1, IL-6, TNF-α, melatonin, or IGF-1 levels. However, VEGF increased ( p = 0.045) and IGFBP-3 decreased ( p = 0.022) significantly. During follow-up, clinical sepsis was observed in 7 (21.2%), 4 (12.1%), and 1 (3.0%) infants at weeks 1, 2, and 3, respectively ( p = 0.007). Respiratory support requirements decreased over time, particularly for non-invasive synchronized intermittent mandatory ventilation ( p = 0.029). In this single-arm observational cohort, RBC transfusion was followed by increased VEGF and decreased IGFBP-3 levels, without significant changes in major proinflammatory cytokines. During follow-up, respiratory support requirements decreased and clinical sepsis was observed in a subset of infants. However, because no non-transfused control group was included, these clinical findings should be interpreted as descriptive and exploratory temporal observations rather than evidence of causality.