CCL26

CCL26, also known as eotaxin-3, is a CC chemokine produced by humans that functions as a chemoattractant for eosinophils. It belongs to the eotaxin subfamily, which also includes CCL11 (eotaxin-1) and CCL24 (eotaxin-2), and signals primarily through the CCR3 receptor on eosinophils and related cells.

Expression and regulation of CCL26 occur in tissues prone to eosinophilic inflammation. It is expressed by airway epithelial cells, bronchial smooth muscle cells, and endothelial cells, and its production is upregulated by Th2-type cytokines such as interleukin-4 and interleukin-13, as well as by other proinflammatory stimuli. This regulation links CCL26 to allergic and parasitic responses where eosinophil recruitment is prominent.

Functionally, CCL26 directs eosinophil migration to sites of inflammation and can promote eosinophil activation. The chemokine’s activity contributes to the tissue infiltration of eosinophils observed in several conditions characterized by eosinophilia, including asthma and other allergic diseases. Elevated levels of CCL26 have been reported in respiratory samples and skin lesions from atopic individuals, correlating with eosinophilic inflammation in some studies.

Clinical relevance and research continue to explore CCL26 as a biomarker of eosinophilic activity and as a potential therapeutic target. Because eosinophil recruitment is central to certain inflammatory diseases, antagonists or inhibitors targeting the CCL26–CCR3 axis have been investigated in preclinical and early clinical contexts, though no CCL26-targeted therapies are approved to date.