Differences in chemokine receptors and chemokines in erythroderma and Sézary syndrome

Erythroderma can be caused by inflammatory dermatoses or cutaneous T-cell lymphoma. However, even if chemokines and their receptors are involved in the skin-selective lymphocyte recruitment, their role in inflammatory erythroderma is yet unclear.

Flow cytometry was carried out on both circulating and skin-infiltrating T lymphocytes, and serum chemokine levels were evaluated using ELISA techniques. CCR4, CCR5 and CXCR3 were expressed on about 40% of peripheral blood lymphocytes and on the majority of skin-infiltrating lymphocytes in the inflammatory erythroderma patients, whereas the leukemic CD4+CD26- subpopulation in Sézary syndrome was characterized by a high CCR4 expression without a concurrent increase in CCR5 or CXCR3. TARC, MDC and IP-10 serum levels were significantly increased in both erythrodermic and Sézary syndrome patients.

The results confirm that Sézary syndrome is a Th2 disorder with a selective expression of CCR4, whereas inflammatory erythroderma shares an overexpression of both Th1- and Th2-related chemokine receptors, suggesting an activation of different pathways driving reactive lymphocytes to the skin.