Interleukin-31 is overexpressed in skin and serum in cutaneous T-cell lymphomas but does not correlate to pruritus

INTRODUCTION: Cutaneous T-cell lymphomas (CTCL) are malignant lymphoproliferative disorders accompanied by persistent pruritus. Pruritogenic role of interleukin-31 (IL-31) has been studied extensively and was proven in atopic dermatitis (AD), while its role in CTCL is still rather vague. AIM: To investigate IL-31 serum level along with IL-31, IL-31 receptor α (IL-31RA) and oncostatin M receptor β (OSMR) skin expression in CTCL and compare it to controls: AD and healthy volunteers. MATERIAL AND METHODS: The level of IL-31 in serum was measured using ELISA, while IL-31 and receptors’ expression in the skin were measured using immunohistochemistry and correlated with the stage of disease and pruritus severity. RESULTS: Expression of IL-31 and IL-31 receptor in serum and skin were significantly higher in CTCL and AD in comparison to healthy controls. No significant correlation between the IL-31 serum level and pruritus severity in CTCL patients was found. There was also no correlation between IL-31/IL-31RA/OSMR expression in the skin and CTCL pruritus, while IL-31 and IL-31RA in CTCL skin negatively correlated with the stage of disease. CONCLUSIONS: Our data indicate that IL-31 does not play a crucial role in pruritus in CTCL but it is rather involved in the pathogenesis of the disease. It seems that IL-31 plays an essential role in the pruritus pathomechanism that is unique to AD.