The immune system--multiple sites but one system

Toxicologic Pathology Forum: Considerations Regarding Determination of Adversity for Immunopathology Findings in Nonclinical Toxicology Studies with Immune-Modulating Therapeutics

The evaluation of changes in the immune system serves to determine the efficacy and potential immunotoxicologic effects of new products under development. Toxicologic pathologists play critical roles in identifying immune system changes that drive the immunosafety determination. Standard pathology evaluations of therapies and chemicals remain similar; however, biopharmaceutical therapies have moved from simply affecting the immune system to being specifically developed to modify the immune system, which can impact interpretation. Recent explosive growth in immunomodulatory therapies presents a challenge to the toxicologic pathologist, toxicologist, and regulatory reviewer in terms of evaluating the clinical relevance and potential adversity of immune system changes. Beyond the recognition of such changes, there is an increasing expectation to evaluate, describe, and interpret how therapies affect complex immune system pathways for both immunomodulatory therapies and non-immunomodulatory drugs with off-target immunotoxic effects. In this opinion piece, considerations regarding immune system evaluation, the current landscape of immunomodulatory therapies, a brief description of immunotoxicologic (and immunopathologic) endpoints, the importance of integrating such immunosafety data, and relevance to adversity determination are discussed. Importantly, we describe how the current paradigm of determining adversity for immune system changes may be challenging or insufficient and propose a harmonized and flexible approach for assessing adversity.

Pain and stress in a systems perspective: reciprocal neural, endocrine, and immune interactions

This paper advances a psychophysiological systems view of pain in which physical injury, or wounding, generates a complex stress response that extends beyond the nervous system and contributes to the experience of pain. Through a common chemical language comprising neurotransmitters, peptides, endocannabinoids, cytokines, and hormones, an ensemble of interdependent nervous, endocrine, and immune processes operates in concert to cope with the injury. These processes act as a single agent and comprise a supersystem. Acute pain in its multiple dimensions, and the related symptoms that commonly occur with it, are products of the supersystem. Chronic pain can develop as a result of unusual stress. Social stressors can compound the stress resulting from a wound or act alone to dysregulate the supersystem. When the supersystem suffers dysregulation, health, function, and sense of well-being suffer. Some chronic pain conditions are the product of supersystem dysregulation. Individuals vary and are vulnerable to dysregulation and dysfunction in particular organ systems due to the unique interactions of genetic, epigenetic and environmental factors, as well as the past experiences that characterize each person.

PERSPECTIVE

Acute tissue injury activates an ensemble of interdependent nervous, endocrine, and immune processes that operate in concert and comprise a supersystem. Some chronic pain conditions result from supersystem dysregulation. Individuals vary and are vulnerable to dysregulation due to the unique interactions of genetic, epigenetic, and environmental factors and past experiences that characterize each person. This perspective can potentially assist clinicians in assessing and managing chronic pain patients.