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Case Reports in Dermatological Medicine
Volume 2014 (2014), Article ID 937513, 4 pages
Case Report

Expansion of Natural Killer Cells in Peripheral Blood in a Japanese Elderly with Human T-Cell Lymphotropic Virus Type 1-Related Skin Lesions

1Division of Hematology, Takasago Seibu Hospital, 1-10-41 Nakasuji, Takasago 676-0812, Japan
2Division of Internal Medicine, Takasago Seibu Hospital, Takasago 676-0812, Japan
3Department of Pathology, School of Medicine, Kurume University, Kurume 830-0011, Japan

Received 11 August 2014; Revised 16 October 2014; Accepted 20 October 2014; Published 9 November 2014

Academic Editor: Naoki Oiso

Copyright © 2014 Shinsaku Imashuku et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Natural killer (NK) cells were proposed to play an important role in the pathogenesis of human T-cell lymphotropic virus type 1- (HTLV-1-) associated neurologic disease. Our patient was a 77-year-old Japanese man, who had been treated for infective dermatitis associated with HTLV-1 for nearly 10 years. When referred to us, he had facial eczema/edema as well as extensive dermatitis at the neck/upper chest and nuchal area/upper back regions. Dermal lesions had CD3+CD4+ cells, but no NK cells. Flow cytometry of his peripheral blood showed a phenotype of CD2+ (97%), CD3+ (17%), CD4+ (12%), CD7+ (94%), CD8+ (6%), CD11c+ (70%), CD16+ (82%), CD19+ (0%), CD20+ (0%), CD56+ (67%), HLA-DR+ (68%), and NKp46+ (36%). Absolute numbers of CD56+NK cells in the peripheral blood were in a range of 986/μL–1,270/μL. The expanded NK cells in the peripheral blood are considered to be reactive, to maintain the confinement of the HTLV-1-positive CD4+ cells in the skin, and to prevent the progression of the disease.