Clinical significance of CCR4 expression in adult T-cell leukemia/lymphoma: its close association with skin involvement and unfavorable outcome.

Adult T-cell leukemia/lymphoma (ATLL) is a distinct clinical entity among mature T-cell neoplasms, and its causative agent has been confirmed to be long-term infection by human T-lymphotropic virus type 1. A recent study demonstrated frequent expression of a chemokine receptor, CC chemokine receptor (CCR)4, which is known as a Th2 marker but not CXC chemokine receptor (CXCR)3, which is known as a Th1 marker, among both ATLL- and human T-lymphotropic virus type 1-immortalized T cells. In this study, immunostaining analysis for CCR4 and CXCR3 expression in ATLL cells obtained from 103 patients with ATLL was performed, and the clinical parameters and overall survival of the CCR4-positive and -negative cases were compared. Ninety-one (88.3%) of the 103 cases were positive for CCR4 staining, whereas only 5 (4.9%) were positive for CXCR3 staining. Positivity for CCR4 was significantly associated with skin involvement (P < 0.05), although there were no significant differences in clinical characteristics between the CCR4-positive and -negative cases at the time of initial diagnosis. CCR4(+) ATLL cells may accumulate in the skin because of the expression of a CCR4 ligand, thymus and activation-regulated chemokine (TARC), on normal and inflamed cutaneous endothelia. As for survival analysis, positivity for CCR4 expression was extracted as an unfavorable prognostic factor as well as other factors, including the presence of B symptoms and extranodal involvement of more than one site. Multivariate analysis confirmed that CCR4 expression was an independent and significant prognostic factor (P < 0.05). Thus, our finding may provide a novel insight into not only the biological but also the clinical features of ATLL.