This 2021 review subject was recent history and uses of the neutrophils-to-lymphocytes ratio parameter to indicate systemic inflammation and stress:

“NLR is widely used across almost all medical disciplines as a reliable and easily available marker of immune response to various infectious and non-infectious stimuli. NLR reflects dynamic relationships between innate (neutrophils) and adaptive (lymphocytes) cellular immune response during illness and various pathological states.

A normal range of NLR is between 1–2, and values higher than 3.0 and below 0.7 in adults are pathological. NLR between 2.3–3.0 may serve as an early warning of cancer, atherosclerosis, infection, inflammation, psychiatric disorders, and stress.

Neutrophils play a pivotal role in innate immune response including phagocytosis, and release of a variety of cytokines and molecule mediators. Lymphocytopenia is a hallmark of stress while inflammation is due to demargination, redistribution, and accelerated apoptosis.

Opposite changes in neutrophil and lymphocyte counts are a multifactorial dynamic process depending on regulation of various immunologic, neuroendocrine, humoral, and biologic processes such as margination / demargination, mobilization / redistribution, accelerated / delayed apoptosis, influence of stress hormones, and sympathetic / parasympathetic nervous system imbalance. NLR is the best expression of a tight functional relation between two fundamental immunocompetent leukocyte populations.”

https://doi.org/10.4149/bll_2021_078 “Neutrophil-to-lymphocyte ratio, past, present and future perspectives”

The fourth study of Uses of the lymphocytes-to-monocytes ratio also commented on NLR.

Sunday morning stroll