Association between IL-10 systemic low level and highest pain score in patients during symptomatic SARS-CoV-2 infection

Abstract

Background: Despite the wide variety of Covid-19 symptoms, pain and the related mechanisms underlying unsettled nociceptive status are still under-prioritized. Understanding the complex network of Covid-19-related pain may result in new lines of study. It is unknown whether patient's immunological background influences pain in the acute phase of Covid-19, including musculoskeletal pain. Thus, we evaluated the blood levels of selected molecules that are upregulated in SARS-CoV-2 infection and analyzed a possible correlation with pain during Covid-19. Methods: A cohort of 20 hospitalized patients with confirmed diagnoses for Covid-19 were evaluated in the context of pain. Visual analogic scale (VAS) was applied to quantitate pain level. Blood tests were used to determine the systemic levels of cytokines (IL-10 and IL-1β), substance P, and leptin. The data were correlated when appropriate to determine the association between pain-related markers and assessed pain intensity. Results: Our findings show that systemic levels of IL-10 have strong negative correlation with pain intensity on Covid-19 patients. Additionally, we also show that leptin systemic levels were increased in Covid-19 patients with pain, however, with moderate positive correlation between these events. IL-1β and SP levels did not differ between Covid-19 patients with or without pain. Men reported less pain compared to women. No differences were found between genders in the levels of the molecules evaluated in patients with pain. Conclusion: IL-10 has been described over the years as an anti-inflammatory and analgesic cytokine. The present data support that low IL-10 levels might contribute to Covid-19-associated pain.