ROS generated by mitochondrial respiration are needed for optimal proinflammatory cytokine production in healthy cells, and are elevated in cells from patients with an autoinflammatory disorder.

Interleukin-17A (IL-17A) and IL-17F are 2 of several cytokines produced by T helper 17 cells (Th17), which are able to indirectly induce the recruitment of neutrophils. Recently, human Th17 cells have been phenotypically characterized and shown to express discrete chemokine receptors, including CCR2 and CCR6. Herein, we show that highly purified neutrophils cultured with interferon-␥ plus lipopolysaccharide produce the CCL2 and CCL20 chemokines, the known ligands of CCR2 and CCR6, respectively. Accordingly, supernatants from activated neutrophils induced chemotaxis of Th17 cells, which was greatly suppressed by anti-CCL20 and anti-CCL2 antibodies. We also discovered that activated Th17 cells could directly chemoattract neutrophils via the release of biologically active CXCL8. Consistent with this reciprocal recruitment, neutrophils and Th17 cells were found in gut tissue from Crohn disease and synovial fluid from rheumatoid arthritis patients. Finally, we report that, although human Th17 cells can directly interact with freshly isolated or preactivated neutrophils via granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-␣, and interferon-␥ release, these latter cells cannot be activated by IL-17A and IL-17F, because of their lack of IL-17RC expression. Collectively, our results reveal a novel chemokine-dependent reciprocal cross-talk between neutrophils and Th17 cells, which may represent a useful target for the treatment of chronic inflammatory diseases. (Blood. 2010;115:335-343)

Background Evidence suggests a role for excessive inflammation in COVID-19 complications. Colchicine is an oral anti-inflammatory medication beneficial in gout, pericarditis, and coronary disease. We aimed to investigate the effect of colchicine on the composite of COVID-19-related death or hospital admission.Methods The present study is a phase 3, randomised, double-blind, adaptive, placebo-controlled, multicentre trial. The study was done in Brazil, Canada, Greece, South Africa, Spain, and the USA, and was led by the Montreal Heart Institute. Patients with COVID-19 diagnosed by PCR testing or clinical criteria who were not being treated in hospital were eligible if they were at least 40 years old and had at least one high-risk characteristic. The randomisation list was computer-generated by an unmasked biostatistician, and masked randomisation was centralised and done electronically through an automated interactive web-response system. The allocation sequence was unstratified and used a 1:1 ratio with a blocking schema and block sizes of six. Patients were randomly assigned to receive orally administered colchicine (0•5 mg twice per day for 3 days and then once per day for 27 days thereafter) or matching placebo. The primary efficacy endpoint was the composite of death or hospital admission for COVID-19. Vital status at the end of the study was available for 97•9% of patients. The analyses were done according to the intention-to-treat principle. The COLCORONA trial is registered with ClinicalTrials.gov (NCT04322682) and is now closed to new participants. FindingsTrial enrolment began in March 23, 2020, and was completed in Dec 22, 2020. A total of 4488 patients (53•9% women; median age 54•0 years, IQR 47•0-61•0) were enrolled and 2235 patients were randomly assigned to colchicine and 2253 to placebo. The primary endpoint occurred in 104 (4•7%) of 2235 patients in the colchicine group and 131 (5•8%) of 2253 patients in the placebo group (odds ratio [OR] 0•79, 95•1% CI 0•61-1•03; p=0•081). Among the 4159 patients with PCR-confirmed COVID-19, the primary endpoint occurred in 96 (4•6%) of 2075 patients in the colchicine group and 126 (6•0%) of 2084 patients in the placebo group (OR 0•75, 0•57-0•99; p=0•042). Serious adverse events were reported in 108 (4•9%) of 2195 patients in the colchicine group and 139 (6•3%) of 2217 patients in the placebo group (p=0•051); pneumonia occurred in 63 (2•9%) of 2195 patients in the colchicine group and 92 (4•1%) of 2217 patients in the placebo group (p=0•021). Diarrhoea was reported in 300 (13•7%) of 2195 patients in the colchicine group and 161 (7•3%) of 2217 patients in the placebo group (p<0•0001).Interpretation In community-treated patients including those without a mandatory diagnostic test, the effect of colchicine on COVID-19-related clinical events was not statistically significant. Among patients with PCR-confirmed COVID-19, colchicine led to a lower rate of the composite of death or hospital admission than placebo. Given the absence of orally administered therapies to pr...