Opioid therapy and immunosuppression: a review

Area of Science:

• Immunology
• Neuroscience
• Pharmacology

Background:

• The immunomodulatory effects of opioids have been recognized since the late 19th century.
• Exogenous opioids generally mediate immunosuppression, while endogenous opiates can have opposing actions.
• Opioid administration impacts various immune responses, including antibody production, natural killer cell activity, and cytokine expression.

Purpose of the Study:

• To explore the mechanisms by which opioids modulate the immune system.
• To investigate the role of opioid receptors in both the central nervous system and peripheral tissues.
• To understand the clinical implications of opioid-induced immunomodulation, particularly in chronic pain patients.

Main Methods:

• Review of historical and contemporary research on opioid-immune system interactions.
• Analysis of studies identifying opioid receptors on immune cells and peripheral nerves.
• Examination of proposed pathways involving the hypothalamic-pituitary-adrenal axis and autonomic nervous system.

Main Results:

• Opioids modulate immune responses similarly to cytokines, interacting with receptors in the central nervous system and periphery.
• Opioid receptors are present not only in the central nervous system but also in peripheral nerves and immune cells.
• Opioid-induced immunosuppression may contribute to increased infection rates in opioid users and influence HIV progression.

Conclusions:

• Opioid-induced immunosuppression involves both central and peripheral mechanisms, including opioid receptors on immune cells.
• The distinct effects of central versus intrathecal opioid administration suggest complex regulatory pathways.
• Understanding these mechanisms is crucial for managing patients on long-term opioid therapy for pain.