Biomarkers of Perioperative Immune Suppression

Abstract

Perioperative immune suppression is a multifactorial phenomenon with significant implications for postoperative recovery, morbidity, and mortality among surgical patients. The identification and validation of biomarkers for perioperative immune suppression have enabled clinicians to stratify risk, personalize perioperative management, and potentially improve outcomes. This review synthesizes current evidence on the epidemiology, pathophysiology, risk factors, clinical features, diagnostic modalities, management strategies, emerging therapies, and guideline-based recommendations relating to biomarkers of perioperative immune suppression, offering a comprehensive resource for clinicians and researchers dedicated to optimizing perioperative care.

Introduction

Immune suppression occurring in the perioperative period is increasingly recognized as a critical determinant of surgical outcomes, including infection, delayed wound healing, and tumor recurrence. The perioperative period is characterized by complex physiological responses involving the neuroendocrine, metabolic, and immunological systems. Biomarkers have emerged as essential tools in quantifying and monitoring immune function, allowing for early identification of at-risk individuals and guiding therapeutic interventions. This article provides an in-depth review of key biomarkers, their clinical relevance, and practical approaches to their application in perioperative medicine.

Epidemiology / Disease Burden

Perioperative immune suppression affects a substantial proportion of surgical patients, particularly those undergoing major procedures such as cardiac, oncologic, and emergency abdominal surgeries. The incidence of significant immune suppression varies by patient population, surgical type, and pre-existing comorbidities but can range from 20% to over 50% in high-risk cohorts. The burden is evidenced by increased rates of nosocomial infections, sepsis, and poor wound healing, contributing to prolonged hospital stays, increased healthcare costs, and elevated postoperative mortality. In oncologic surgery, perioperative immune suppression may facilitate micrometastasis and tumor recurrence, underscoring its clinical importance.

Pathophysiology

The pathophysiology of perioperative immune suppression involves both innate and adaptive immune pathways. Surgical trauma triggers the hypothalamic-pituitary-adrenal axis and sympathetic nervous system, leading to the release of glucocorticoids and catecholamines. These mediators suppress pro-inflammatory cytokine production and impair the function of key immune cells, including neutrophils, natural killer (NK) cells, dendritic cells, and T lymphocytes. The resultant shift toward an anti-inflammatory profile, with increased interleukin-10 (IL-10) and transforming growth factor-beta (TGF-β), dampens immune surveillance and host defense mechanisms. Additionally, factors such as blood transfusion, anesthesia, and perioperative hypothermia further modulate immune responses, magnifying the risk of clinical immune suppression.

Risk Factors

Multiple patient- and procedure-related risk factors predispose individuals to perioperative immune suppression. Advanced age, malnutrition, diabetes mellitus, malignancy, chronic corticosteroid use, and pre-existing immunodeficiency are well-established patient-related risk factors. Procedural variables, including the magnitude of surgical trauma, duration of surgery, emergency versus elective status, and intraoperative blood transfusion, have also been implicated. Identification of these risk factors enables targeted perioperative assessment and intervention, improving patient stratification and care planning.

Clinical Features

Clinically, perioperative immune suppression often manifests as increased susceptibility to infections, delayed wound healing, and poor response to standard antimicrobial therapies. Subtle features may include persistent low-grade fever, atypical infection presentations, or unexplained postoperative complications. In oncologic patients, immune suppression may contribute to early recurrence or metastasis due to impaired immune surveillance. Recognizing these clinical manifestations is essential for prompt diagnosis and management.

Diagnosis

The diagnosis of perioperative immune suppression relies heavily on biomarker assessment. Key biomarkers include monocyte human leukocyte antigen-DR (mHLA-DR) expression, neutrophil-to-lymphocyte ratio (NLR), lymphocyte counts, serum cytokine profiles (IL-6, IL-10, TNF-α), and the presence of myeloid-derived suppressor cells (MDSCs). Reduced mHLA-DR expression is a sensitive marker of immunoparalysis and correlates with poor clinical outcomes. Elevated NLR and persistent lymphopenia are associated with increased infection risk. Serial measurement of these biomarkers allows dynamic assessment of immune status, facilitating timely intervention.

Treatment & Management

Management strategies for perioperative immune suppression focus on risk mitigation, early detection, and targeted intervention. Optimization of nutritional status, glycemic control, and minimization of unnecessary blood transfusions are foundational. Immunomodulatory therapies, including granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon-gamma, have shown promise in restoring immune function in selected patients. Enhanced recovery protocols and minimally invasive surgical techniques may reduce the magnitude of immune suppression. Close monitoring with serial biomarker assessment is recommended in high-risk individuals to guide the need for prophylactic or therapeutic interventions.

Recent Advances / Emerging Therapies

Recent advances have focused on refining biomarker panels and developing novel immunotherapeutic agents. High-throughput multi-omics approaches, including transcriptomics and proteomics, are being leveraged to identify new biomarkers with greater sensitivity and specificity. The use of checkpoint inhibitors and adoptive cellular therapies in the perioperative setting is under investigation, particularly in oncologic surgery. Point-of-care testing for immune biomarkers is also being developed, with the goal of real-time risk stratification and tailored immunomodulation. Ongoing clinical trials are evaluating the efficacy and safety of these emerging therapies.

Guideline Recommendations

Current guidelines from societies such as the European Society of Anaesthesiology and Intensive Care (ESAIC) and the American Society of Anesthesiologists (ASA) underscore the importance of perioperative immune assessment in high-risk populations. Recommendations include routine evaluation of risk factors, judicious use of blood transfusions, maintenance of normothermia, and consideration of immunomodulatory therapies in selected patients. The integration of validated biomarkers into perioperative protocols is encouraged to enhance personalized care and improve outcomes. Continued research and consensus-building are needed to standardize biomarker use and management strategies.

Conclusion

Biomarkers of perioperative immune suppression offer valuable insights into the complex interplay of host factors and surgical stress, enabling clinicians to identify, monitor, and manage at-risk patients more effectively. Advances in biomarker discovery and immunotherapeutic interventions hold promise for improving surgical outcomes and reducing perioperative morbidity. Ongoing research and the integration of evidence-based guidelines into clinical practice are essential for optimizing perioperative immune health and enhancing patient care.