Up-regulation of chemokine C–C ligand 2 (CCL2) and C-X-C chemokine 8 (CXCL8) expression by monocytes in chronic idiopathic urticaria

Summary The disturbed cytokine-chemokine network could play an important role in the onset of diseases with inflammatory processes such as chronic idiopathic urticaria (CIU). Our main objectives were to evaluate the relation between proinflammatory chemokine serum levels from CIU patients and their response to autologous skin test (ASST) and basophil histamine release (BHR). We also aimed to assess the chemokine secretion by peripheral blood mononuclear cells (PBMC) upon polyclonal stimulus and to evaluate chemokine C-C ligand 2/C-X-C chemokine 8 (CCL2/CXCL8) and Toll-like receptor-4 (TLR-4) expression in monocytes. We observed significantly higher serum levels of the CXCL8, CXCL9, CXCL10 and CCL2 in CIU patients compared to the healthy group, regardless of the BHR or ASST response. The basal secretion of CCL2 by PBMC or induced by Staphylo- coccus aureus enterotoxin A (SEA) was higher in CIU patients than in the control group, as well as for CXCL8 and CCL5 secretions upon phyto- haemagglutinin stimulation. Also, up-regulation of CCL2 and CXCL8 mRNA expression was found in monocytes of patients upon SEA stimula- tion. The findings showed a high responsiveness of monocytes through CCL2/CXCL8 expression, contributing to the creation of a proinflammatory environment in CIU.