A Review of the Role of Lymphocytes in Chronic Neuropathic Pain: A Clinical Perspective

Chronic neuropathic pain is one of the most common morbidities in the developed world. It has a lifetime incidence of 80% with females being affected more than males. Chronic neuropathic pain pathogenesis and its associated “sickness syndrome” has been poorly understood but recent research has shown a neuroimmune basis. Many studies performed to date have been pre-clinical or animal-based with a lack of human studies in chronic neuropathic pain. Background: We performed a review of literature with emphasis on clinical and human studies. The numbers of such studies are low due to limitations with ethical approval, recruitment and heterogeneity of humans. We aimed to investigate the most recent studies as well as important seminal research in this area. Methods: Literature search was performed using Stella search engine, Pubmed and National Library of Medicine search engines. Pre-clinical, animal and human studies were included. Conclusion: The immune system, in particular the adaptive immune system, regulates the initiation, progression and resolution of chronic neuropathic pain in humans. The exact “switch” which mediates initiation, upregulation and downregulation of the components of the immune system is not known. Further research in this area is needed but the challenge of recruiting patients for CNP studies remains. Study sample sizes tend to be small. However, clinically relevant findings although small can offer important information to further our understanding of CNP.