Regulation of Immune Function by the Lymphatic System in Lymphedema

Front Immunol. 2019 Mar 18;10:470. doi: 10.3389/fimmu.2019.00470. eCollection 2019.

Abstract

The lymphatic vasculature has traditionally been thought to play a passive role in the regulation of immune responses by transporting antigen presenting cells and soluble antigens to regional lymph nodes. However, more recent studies have shown that lymphatic endothelial cells regulate immune responses more directly by modulating entry of immune cells into lymphatic capillaries, presenting antigens on major histocompatibility complex proteins, and modulating antigen presenting cells. Secondary lymphedema is a disease that develops when the lymphatic system is injured during surgical treatment of cancers or is damaged by infections. We have used mouse models of lymphedema in order to understand the effects of chronic lymphatic injury on immune responses and have shown that lymphedema results in a mixed T helper cell and T regulatory cell (Treg) inflammatory response. Prolonged T helper 2 biased immune responses in lymphedema regulate the pathology of this disease by promoting tissue fibrosis, inhibiting formation of collateral lymphatics, decreasing lymphatic vessel pumping capacity, and increasing lymphatic leakiness. Treg infiltration following lymphatic injury results from proliferation of natural Tregs and suppresses innate and adaptive immune responses. These studies have broad clinical relevance since understanding how lymphatic injury in lymphedema can modulate immune responses may provide a template with which we can study more subtle forms of lymphatic injury that may occur in physiologic conditions such as aging, obesity, metabolic tumors, and in the tumor microenvironment.

Keywords: Th2 type T cells; fibrosis; immune function; inflammation; lymphatic vessels.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Alarmins / biosynthesis
  • Alarmins / genetics
  • Alarmins / immunology
  • Animals
  • Cell Movement
  • Dendritic Cells / physiology
  • Disease Models, Animal
  • Fibrosis
  • Humans
  • Inflammation
  • Lymph Node Excision / adverse effects
  • Lymph Nodes / immunology
  • Lymphatic Metastasis
  • Lymphatic System / immunology*
  • Lymphatic Vessels / immunology
  • Lymphatic Vessels / physiopathology
  • Lymphedema / epidemiology
  • Lymphedema / etiology
  • Lymphedema / immunology*
  • Lymphocyte Activation
  • Macrophage Activation
  • Mice
  • Postoperative Complications / etiology
  • Postoperative Complications / immunology
  • Receptors, Pattern Recognition / immunology
  • T-Lymphocyte Subsets / immunology*
  • T-Lymphocytes, Helper-Inducer / immunology
  • T-Lymphocytes, Regulatory / immunology

Substances

  • Alarmins
  • Receptors, Pattern Recognition