1. ¹Department of Pharmacology, The University of Liverpool, Liverpool, UK
2. ²Division of Infection, Inflammation and Repair, School of Medicine, University of Southampton, Southampton, UK
3. ³SEAC Toxicology Laboratory, Unilever Research, Colworth House, Bedfordshire, UK
4. ⁴Department of Dermatology, The University of Liverpool, Liverpool, UK

Correspondence: Dean J. Naisbitt, Department of Pharmacology, Sherrington Building, Ashton Street, The University of Liverpool, Liverpool L69 3GE, UK. E-mail: dnes@liv.ac.uk

Received 2 April 2007; Revised 5 July 2007; Accepted 24 July 2007; Published online 4 October 2007.

Abstract

Allergic contact dermatitis is commonly associated with exposure to p-phenylenediamine. The aim of this study was to determine whether p-phenylenediamine (PPD) and/or Bandrowski's base (BB) stimulate T cells from allergic patients and volunteers, and to explore the relationship between T-cell immunogenicity and allergy. Lymphocytes from allergic patients proliferated with PPD and BB (n=8). Lymphocytes from 14/16 non-allergic individuals also proliferated following stimulation, but only with BB; cord blood lymphocytes failed to respond (n=6). Glutathione, which prevented BB formation, but not binding of PPD to cells and serum, did not prevent p-phenylenediamine-specific stimulation of patient lymphocytes. T-cell clones generated from allergic patients were stimulated separately with PPD and BB, while clones from volunteers proliferated with BB alone. Patient and volunteer clones secreted IL-4, IL-5, IL-13, TNF-, MIP-1, MIP-1, and RANTES. These data show that activation of T lymphocytes from allergic individuals alone with PPD represents an important discrimination between allergic and non-allergic groups. BB-specific T cells are found in both allergic patients and volunteers, but not in cord blood. Their presence seems to reflect an acquired immune response, which is not translated into an allergic reaction.