Jasper Pruessmann, Wiebke Pruessmann, Maike M. Holtsche, Beke Linnemann, Christoph M. Hammers, Nina van Beek, Detlef Zillikens, Enno Schmidt, Christian D. Sadik
DOI: 10.2340/00015555-3771

Massive recruitment of eosinophils into the dermis is a hallmark of bullous pemphigoid pathogenesis. Identifying the chemoattractant(s) guiding eosinophils into the skin in bullous pemphigoid is a prerequisite to thera­peutic targeting of eosinophil recruitment. Galectin -9 is a potent chemoattractant for eosinophils, but its potential role in bullous pemphigoid is unknown. The aim of this study was to determine the expression levels of galectin-9 in serum and skin of patients with bullous pemphigoid. Galectin-9 levels were significantly elevated in serum of patients with bullous pemphigoid compared with age- and sex-matched controls, but did not correlate with disease activity assessed with the Bullous Pemphigoid Disease Area Index. Galectin-9 expression was also increased in lesional skin of patients with bullous pemphigoid, and was expressed predominantly in eosinophils, neutrophils and keratinocytes. In conclusion, these results support the notion that galectin-9 may play a role in the patho­genesis of bullous pemphigoid.

Eosinophils are major culprit cells in bullous pemphigoid, but the mechanism of their recruitment into the skin is unknown. This study identified galectin-9 as a potential driver of eosinophil recruitment in bullous pemphigoid. The results also show that galectin-9 is a potential serum biomarker in bullous pemphigoid. This finding could lead to the development of composite biomarkers for the diagnosis of bullous pemphigoid from serum samples.

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