Allogeneic red cell transfusion and its influence on relevant humoral and cellular immunological parameters: A prospective observational trial.

Background: It is assumed that transfusion of allogeneic red cells is associated with increased peri-operative mortality and morbidity. Also assumed is the theory of transfusion-related immunomodulation.

Objective: The aim of this study was to investigate the hypothesis that red cell transfusion specifically leads to an immunological response in surgical patients.

Design: Prospective observational study.

Setting: Departments of Orthopedic Surgery and Anaesthesia, University Hospital, Thailand.

Patients: Low-risk, noncancer patients, aged 18 to 75 years undergoing elective major spine surgery, with and without red cell transfusion therapy.

Interventions: Blood specimens were withdrawn four times (prior to surgery and on days 1, 3 and 5).

Main Outcome Measures: Assessment of immunocompetent cells and cytokines in transfused and nontransfused patients using flow cytometry and multiplex ELISA.

Results: From a total of 78 patients, 61 met the requirements and were analysed in three groups: 19 with no transfusion and 26 and 16 transfused intra-operatively and on day 1 or 2, respectively. No patient experienced peri-operative haemorrhage. Postoperative infection or thrombosis occurred in 5.5% of nontransfused patients and 16.6% of transfused patients; the difference was not significant. There was no significant immunomodulatory effect of red cell transfusion: of 45 immunological parameters, only five little-relevant cytokines were significantly affected, although slightly and nonspecifically.

Conclusion: Our data indicate that red cell transfusion alone does not create an immunological response in otherwise healthy surgical patients. Our findings do not generally contradict the transfusion-related immunomodulation phenomenon, which has, however, primarily been observed in patients with an already weakened or procedure-deteriorated immune system, such as from malignant disease, significant comorbidity, extensive abdominal/thoracic surgery and cardiopulmonary bypass.

Trial Registration: The study was registered on 15 May 2014, before enrolment of the first patient, at www.ClinicalTrials.gov, NCT02140216.