LYMPHOCYTE IMMUNOSUPPRESSION AND DYSFUNCTION CONTRIBUTING TO PERSISTENT INFLAMMATION, IMMUNOSUPPRESSION, AND CATABOLISM SYNDROME (PICS) - Review focuses on PICS immunosuppression mechanisms

Q: Which lymphocyte populations are discussed as contributing to post-traumatic and septic immunosuppression?

The review discusses regulatory T cells (Tregs), innate lymphoid cells, natural killer T cells (NKT cells), TCR-α CD4− CD8− double-negative T cells (DN T cells), and B cells as contributors to immunosuppression after trauma and sepsis.

Sep 28, 2026

Uploaded by Hazel

Persistent Inflammation, Immune Suppression, and Catabolism Syndrome (PICS) describes a disease state in patients who experience prolonged recovery after a major inflammatory insult such as trauma or sepsis. The review emphasizes immunosuppression and cellular dysfunction, highlighting that innate and adaptive immune cells have been linked to immunosuppressive functions, yet their clinical role in sustained immunosuppression remains poorly defined. Regulatory T cells, innate lymphoid cells, NKT cells, double-negative T cells, and B cells may drive post-traumatic and septic immune dysfunction. The article outlines diagnostic and therapeutic strategies now under investigation to counter detrimental immunosuppression.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages41

Reading Time1 h 43 min

AccessFree to download

Definition of PICS

Immunosuppression and immune cell dysfunction in PICS

Lymphocyte contributions to PICS (Tregs, innate lymphoid cells, NKT cells, DN T cells, B cells)

Author Manuscr ipt Author Manuscr ipt Author Manuscr ipt Author Manuscript | | HHS Public Access
Author manuscript
Shock. Author manuscript; available in PMC 2025 December 31. | | --- | --- | Published in final edited form as: Shock. 2021 June 01; 55(6): 723–741. doi:10.1097/SHK.0000000000001675 . LYMPHOCYTE IMMUNOSUPPRESSION AND DYSFUNCTION CONTRIBUTING TO PERSISTENT INFLAMMATION, IMMUNOSUPPRESSION, AND CATABOLISM SYNDROME (PICS) Christian B. Bergmann* , Nadine Beckmann* , Christen E. Salyer* , Peter A. Crisologo†, Vanessa Nomellini *,‡, Charles C. Caldwell *,§ * Division of Research, Department of Surgery, College of Medicine, University of Cincinnati, Cincinnati, Ohio †Division of Podiatric Medicine and Surgery, Critical Care, and Acute Care Surgery, Department of Surgery, College of Medicine, University of Cincinnati, Cincinnati, Ohio ‡Division of Trauma, Critical Care, and Acute Care Surgery, Department of Surgery, University of Cincinnati, Cincinnati, Ohio § Division of Research, Shriners Hospital for Children, Cincinnati, Ohio Abstract Persistent Inflammation, Immune Suppression, and Catabolism Syndrome (PICS) is a disease state affecting patients who have a prolonged recovery after the acute phase of a large inflammatory insult. Trauma and sepsis are two pathologies after which such an insult evolves. In this review, we will focus on the key clinical determinants of PICS: Immunosuppression and cellular dysfunction. Currently, relevant immunosuppressive functions have been attributed to both innate and adaptive immune cells. However, there are significant gaps in our knowledge, as for trauma and sepsis the immunosuppressive functions of these cells have mostly been described in acute phase of inflammation so far, and their clinical relevance for the development of prolonged immunosuppression is mostly unknown. It is suggested that the initial immune imbalance determines the development of PCIS. Additionally, it remains unclear what distinguishes the onset of immune dysfunction in trauma and sepsis and how this drives immunosuppression in these cells. In this review, we will discuss how regulatory T cells (Tregs), innate lymphoid cells, natural killer T cells (NKT cells), TCR-a CD4 − CD8 − double-negative T cells (DN T cells), and B cells can contribute to the development of post-traumatic and septic immunosuppression. Altogether, we seek to fill a gap in the understanding of the contribution of lymphocyte immunosuppression and dysfunction to the development of chronic immune disbalance. Further, we will provide an overview of promising diagnostic and therapeutic interventions, whose potential to overcome the detrimental immunosuppression after trauma and sepsis is currently being tested. All figures contain adapted graphics from Les Laboratoirs Servier-Medical Art under the terms of the Creative Commons Attribution License (CC BY) for noncommercial use. The use, distribution, or reproduction in other forums is permitted: [https://](https://)[ ](https://)[creativecommons.org/licenses/by/3.0/legalcode](creativecommons.org/licenses/by/3.0/legalcode), last access April 30, 2020. Address reprint requests to Charles C. Caldwell, PhD, Division of Research, Department of Surgery, College of Medicine, University of Cincinnati, MSB SRU G479, 231 Albert Sabin Way, Cincinnati, [OH 45267. charles.caldwell@uc.edu](OH 45267. charles.caldwell@uc.edu). The authors report no conflicts of interest. Author Manuscr ipt Author Manuscr ipt Author Manuscr ipt Author Manuscript Bergmann et al. Page 2 Keywords B cells; double-negative T cells; immunosuppression; innate lymphoid cells; natural killer T cells; regulatory T cells DEFINITION OF PICS Many septic and severe trauma patients require treatment in the intensive care unit (ICU). Due to improved clinical care in recent years, however, acute mortality rates have decreased in these patients (1). Nevertheless, death rates are still unacceptab

FAQs

What does PICS stand for and when does it occur?

PICS stands for Persistent Inflammation, Immune Suppression and Catabolism Syndrome. It occurs in patients with prolonged recovery after an acute large inflammatory insult such as trauma or sepsis.

How is PICS clinically defined according to the review?

The review cites criteria including prolonged hospitalization (>14 days), elevated inflammation markers (C-reactive protein >150 μg/dL), immune suppression (lymphocyte count <800/mm3), and weight loss despite adequate nutrition.

Which lymphocyte populations are discussed as contributing to post-traumatic and septic immunosuppression?

The review discusses regulatory T cells (Tregs), innate lymphoid cells, natural killer T cells (NKT cells), TCR-α CD4− CD8− double-negative T cells (DN T cells), and B cells as contributors to immunosuppression after trauma and sepsis.

Sep 28, 2026

Uploaded by Hazel