Psoriasis is a chronic inflammatory proliferative
skin disease involving various types of
chemokines regulating immune cell migration, localization, and activation. Bath
psoralen plus UVA (PUVA) treatment is an established
phototherapy for
psoriasis, but its effects on
chemokine levels remain unknown. We investigated the levels of 22 serum
chemokines in 20 patients with
psoriasis first treated with bath
PUVA therapy between 2007 and 2011 in a single center and analyzed the associations between the
chemokines and disease severity (PASI) before and after
therapy to investigate the mechanisms of action of bath
PUVA therapy. Before bath
PUVA therapy, the PASI scores correlated with the serum levels of CCL17 (r = 0.581), CCL18 (r = 0.462), CCL19 (r = 0.477), and CXCL16 (r = 0.524). After bath PUVA, the serum levels of CCL17, CCL22, CXCL1, and CXCL9 were significantly decreased. Heatmap clustering and network analysis based on statistically significant Spearman correlations among the
chemokines showed distinctive changes in the
chemokine signature. Our findings revealed that the levels of several
chemokines correlated with the disease state of
psoriasis. Furthermore, bath
PUVA therapy reduced the secretion of
keratinocyte-derived chemokines that induce the migration of immune cells important for
psoriasis pathogenesis, partly revealing the mechanism of the therapeutic activity.