Plasma P2X7 receptor correlation with plasma C-reactive protein in infectious diseases

Adenosine triphosphate (ATP) is an extracellular signalling mediator that stimulates P2 receptors and is found to accumulate at sites of tissue injury and inflammation. P2X7 receptor (P2X7R) is expressed by virtually all cells of innate and adaptive immunity and seems to be the P2 receptor most involved in inflammation and immunity regulation [1]. P2X7R activation by ATP is one of the most potent stimuli for NLRP3 inflammasome activation thus leading to the production of interleukin-1β (IL-1β) [2] which is recognized as one of the earliest and most potent pro-inflammatory agents synthesized and released in response to infectious agents and injuries, and therefore central to both septic and sterile inflammation. P2X7R is known to be expressed on cell membrane but a soluble form has not been investigated yet. Increased P2X7R expression of peripheral blood monocytes was shown to be associated with high serum CRP, TNF-α, and IL-1β levels [3]. The present study aimed to assess the presence of P2X7R in blood, and the possible relationship between blood levels of P2X7R and CRP in healthy and unhealthy subjects. P2X7R was measured by ELISA in sera of healthy control subjects and subjects with known CRP whose samples were taken randomly from our laboratory. Results showed significant correlation between serum levels of P2X7R and CRP. Serum P2X7R was higher in patients with infectious diseases compared to patients with other types of diseases and healthy subjects. These findings indicate that P2X7R in blood may be involved in the pathological changes of patients with inflammatory disease, and might be considered as a novel marker for inflammation. 1. Surprenant A, Rassendren F, Kawashima E, North RA, Buell G (1996) The cytolytic P2Z receptor for extracellular ATP identified as a P2X receptor (P2X7). Science 272:735-738. 2.Giuliani AL, Dal Ben D, Sarti AC, Falzoni S, Di Virgilio F (2017) The P2X7 receptor-interleukin-1 liaison. Front Pharmacol 8:1-10. 3. Wu H, Nie Y, Xiong H, Liu S, Li G, Huang A, Guo L, Wang S, Xue Y, Wu B, Peng L, Song M, Li G, Liang S (2015) P2X7 Receptor Expression in Peripheral Blood Monocytes Is Correlated With Plasma C-Reactive Protein and Cytokine Levels in Patients With Type 2 Diabetes Mellitus: a Preliminary Report. Inflamm 38:2076-2081.