Neutrophils in autoimmunity: when the hero becomes the villain

Abstract

SUMMARY Neutrophils were long considered to be a short-lived homogenous cell population, limited to their role as first responders in anti-bacterial and -fungal immunity. While it is true that neutrophils are first to infiltrate the site of infection to eliminate pathogens, growing evidence suggests their functions could extend beyond those of basic innate immune cells. Along with their well-established role in pathogen elimination, utilizing effector functions such as phagocytosis, degranulation and the deployment of neutrophil extracellular traps (NETs), neutrophils have recently been shown to possess antigen-presenting capabilities. Moreover, the identification of different subtypes of neutrophils points to a multifactorial heterogeneous cell population with great plasticity in which some subsets have enhanced pro-inflammatory characteristics, while others seem to behave as immunosuppressors. Interestingly, the aberrant presence of activated neutrophils with a pro-inflammatory profile in several systemic and organ-specific autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), multiple sclerosis (MS), and type 1 diabetes (T1D) could potentially be exploited in novel therapeutic strategies. The full extent of the involvement of neutrophils, and more specifically that of their various subtypes, in the pathophysiology of autoimmune diseases is yet to be elucidated.

Added diagnostic value of routinely measured hematology variables in diagnosing immune checkpoint inhibitor mediated toxicity in the emergency department

“… 6 Neutrophil depolarization is a feature of neutrophil activation, which has also been associated with auto‐immunity, but this has not been studied extensively. 23 We found the red blood cell distribution width (rdw) to be negatively associated with irAE. Increased rdw is known to be associated with infections, which are arguably the most likely alternative diagnosis when considering irAE.…”

“…Eosinophiles are thought to play a pathogenic role in auto‐immune disorders and are known to be associated with irAE 6 . Neutrophil depolarization is a feature of neutrophil activation, which has also been associated with auto‐immunity, but this has not been studied extensively 23 . We found the red blood cell distribution width (rdw) to be negatively associated with irAE.…”

Hematological Studies of an Ayurvedic Medicine “Vata Gajendra Singha” Used in Rheumatoid Arthritis After Chronic Administration to Male Sprague-Dawley Rats

“…Low MCV or MCH levels can be due to lead poisoning, microcytic anemia or hemoglobinopathy. 30 Microcytic anemia is usually caused by an iron deficiency. Hemoglobinopathies are genetic disorders such as sickle cell anemia that result in abnormally shaped hemoglobin, making it unable to efficiently carry oxygen through the blood.…”

Footprint of pancreas infiltrating and circulating immune cells throughout type 1 diabetes development

“…Neutrophils, as active patrollers of the circulation, have been described in the natural history of T1D over the last years (20, 21). Contradictory evidence exists however on peripheral neutrophil counts and functions like neutrophil extracellular trap (NET) formation during different disease stages (reviewed in (22)), but our group recently demonstrated with high-throughput live-cell imaging that peripheral NETosis was not aberrant in children and adults at various stages of T1D development (23). Still, neutrophils and NET-associated proteins have been shown to accumulate locally in the human pancreas, more specifically in the exocrine part, during the pre-symptomatic stages of T1D and persisted afterwards (5,24).…”