T lymphocyte dynamics in methylisothiazolinone-allergic patients

• Published in: Contact dermatitis Vol. 75; no. 1; pp. 1 - 13
• Main Authors: Popple, Amy, Williams, Jason, Maxwell, Gavin, Gellatly, Nichola, Dearman, Rebecca J., Kimber, Ian
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.07.2016; Wiley Subscription Services, Inc
• Subjects: allergic contact dermatitis; CAS no. 2682-20-4; Case-Control Studies; CD4-Positive T-Lymphocytes - drug effects; CD4-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - drug effects; CD8-Positive T-Lymphocytes - immunology; Cell Proliferation; Dermatitis, Allergic Contact - etiology; Dermatitis, Allergic Contact - immunology; Flow Cytometry; Humans; Ki-67 Antigen; Leukocytes, Mononuclear - drug effects; Leukocytes, Mononuclear - immunology; methylisothiazolinone; patch testing and skin sensitization; Preservatives, Pharmaceutical - adverse effects; Preservatives, Pharmaceutical - pharmacology; T lymphocytes; T-Lymphocytes - drug effects; T-Lymphocytes - immunology; Thiazoles - adverse effects; Thiazoles - pharmacology; Thymidine; Tritium; T lymphocytes; methylisothiazolinone; patch testing and skin sensitization; CAS no. 2682-20-4; allergic contact dermatitis
• ISSN: 0105-1873; 1600-0536
• DOI: 10.1111/cod.12600

Summary Background Methylisothiazolinone (MI), a preservative that is commonly used in personal care products, is now recognized as an important contact allergen in both cosmetic and occupational settings. Objectives To analyse T lymphocyte responses to MI, in order to provide important information regarding the relationship between the nature of such responses and skin sensitization potency. Methods Proliferative responses to free MI and to an MI–human serum albumin (HSA) conjugate were measured according to [3H]thymidine incorporation (n = 56 donors; patch test scores of + in 20, ++ in 29, and +++ in 7). Peripheral blood mononuclear cells were cultured in the presence of MI (0.001–1 µg/ml) or MI–HSA (0.001–100 µg/ml). Proliferating CD4+ and CD8+ T lymphocytes were identified by flow cytometry with the intracellular marker Ki‐67. Results For free MI, modest positive responses were recorded for 7 of 31 donors. In contrast, MI–HSA stimulated more marked responses in 17 of 31 donors. Characterization of positive proliferative responses showed variable patterns of proliferating CD4+ and CD8+ T lymphocytes from donors with the same patch test scores and similar maximal values. Conclusions MI–HSA is able to induce secondary responses in lymphocytes drawn from sensitized subjects, and provides a more effective source of antigen than free MI. Furthermore, individual donors show differential activity profiles with respect to T lymphocyte subsets.