In medicine neutrophil to lymphocyte ratio (NLR) is used to show there is inflammation in the body. It is calculated by dividing the number of neutrophils by number of lymphocytes, usually from peripheral blood sample,[1] but sometimes also from cells that infiltrate tissue, such as tumor.[2] Recently Lymphocyte Monocyte ratio (LMR) has also been studied as a marker of inflammation including tuberculosis and various cancers.
Neutrophil to Lymphocyte ratio was first demonstrated as useful parameter after a correlation of a relationship between the neutrophil lymphocyte ratio to reactions of the immune response was noted. A study in 2001 was conducted by the Department of Anaesthesiology and Intensive Care Medicine, St. Elizabeth Cancer Institute in Bratislava by Zahorec which suggested the routine used of the ratio as a stress factor in clinical ICU practice in intervals of 6-12 and 24 hours.[12]
The first study to demonstrate that pre-therapeutic NLR can be used as a predictor of chemotherapy sensitivity to thoracic esophageal cancer was demonstrated by Hiroshi Sato, Yasuhiro Tsubosa, and Tatsuyuki Kawano in a 2012 study published in World Journal of Surgery journal.[13]
^ abWang X (Mar 2014). "Neutrophil to lymphocyte ratio in relation to risk of all-cause mortality and cardiovascular events among patients undergoing angiography or cardiac revascularization : A meta-analysis of observational studies". Atherosclerosis. 234 (1): 206–213. doi:10.1016/j.atherosclerosis.2014.03.003. PMID24681815.
^Wang Y, Peng C, Cheng Z, Wang X, Wu L, Li J, Huang C, Guo Q, Cai H (July 2018). "The prognostic significance of preoperative neutrophil-lymphocyte ratio in patients with hepatocellular carcinoma receiving hepatectomy: A systematic review and meta-analysis". Int J Surg. 55: 73–80. doi:10.1016/j.ijsu.2018.05.022. PMID29787804. S2CID44102006.
^Zahorec, R. (2001). "Ratio of neutrophil to lymphocyte counts--rapid and simple parameter of systemic inflammation and stress in critically ill". Bratislavske Lekarske Listy. 102 (1). Bratisl Lek Listy: 5–14. PMID11723675.
^Sato, Hiroshi; Tsubosa, Yasuhiro; Kawano, Tatsuyuki (March 2012). "Correlation Between the Pretherapeutic Neutrophil to Lymphocyte Ratio and the Pathologic Response to Neoadjuvant Chemotherapy in Patients With Advanced Esophageal Cancer". World Journal of Surgery. 36 (3): 617–622. doi:10.1007/s00268-011-1411-1. PMID22223293. S2CID13393640.
Tang, Xingxing; Du, Peng; Yang, Yong (27 July 2017). "The clinical use of neutrophil-to-lymphocyte ratio in bladder cancer patients: a systematic review and meta-analysis". International Journal of Clinical Oncology. 22 (5): 817–825. doi:10.1007/s10147-017-1171-5. PMID28752351. S2CID4910519.