Activation of Human Dendritic Cells byp-Phenylenediamine

Abstract

Exposure to p-phenylenediamine (pPD), a primary intermediate in hair dye formulations, is often associated with the development of allergic contact dermatitis. Such reactions involve activation of the subject's immune system. The aim of these studies was to explore the relationship between pPD oxidation and functional maturation of human monocyte-derived dendritic cells in vitro. Dendritic cells were incubated with pPD and Bandrowski's base (BB) for 16 h, and expression of the costimulatory receptors CD40, CD80, CD83, CD86, and major histocompatability complex class II intracellular glutathione levels and cell viability were measured. In certain experiments, glutathione (1 mM) was added to culture medium. Liquid chromatography-mass spectrometry (LC-MS) analysis and exhaustive solvent extraction were used to monitor the rate of [ 14 C]pPD oxidation and the extent of pPD binding to cellular and serum protein, respectively. Proliferation of allogeneic lymphocytes was determined by incorporation of [ 3 H]thymidine. Exposure of dendritic cells to pPD (5-50 M), but not BB, was associated with an increase in CD40 and MHC class II expression and proliferation of allogeneic lymphocytes. Dendritic cell activation with pPD was not associated with apoptotic or necrotic cell death or depletion of glutathione. Neither pPD nor BB altered dendritic cell expression of CD80, CD83, or CD86. LC-MS analysis revealed pPD was rapidly oxidized in cell culture media to BB. Addition of glutathione inhibited BB formation but did not prevent covalent binding of pPD to dendritic cell protein or dendritic cell activation. Collectively, these studies show that pPD, but not BB, selectively activates human dendritic cells in vitro.

The Generation, Detection, and Effects of Reactive Drug Metabolites

“…Studies published 30 years ago reported that 50–100% of human volunteers treated with a topical solution of PPD became sensitized . Contact with PPD is known to cause T‐cell‐mediated severe allergic contact dermatitis leading to irritation, edema, and keratoconjuctivitis …”

“…This oxidation gives an electrophilic intermediate known as a quinonediimine, which is highly unstable and consequently is not available synthetically; nor has it ever been isolated or characterized. This intermediate can undergo a series of self‐conjugation reactions followed by a further oxidation event to yield the rearrangement trimer, Bandrowski's base (BB), shown in Figure . Previously published work suggests that the immune‐stimulatory responses observed in animal models are dependent on the oxidation of PPD to BB .…”

Oxidative transformation processes and products of para-phenylenediamine (PPD) and para-toluenediamine (PTD)—a review

“…Furthermore, the amines might undergo photolytic or photooxidative degradation when exposed to sunlight [20,21]. In properly composed oxidative hair dye formulations, the aryldiamines are efficiently converted into the desired permanent dye by reaction with the coupler component avoiding the formation of toxic byproducts, e.g., Bandrowski's Base [2,22]. Nevertheless, even under those conditions, the aryldiamines are not completely scavenged and consumed by the couplers so that a certain reactivity potential might persist.…”

The importance of hapten–protein complex formation in the development of drug allergy

“…These costimulatory or 'danger' signals are usually provided by infectious organisms, damaged cells and proinflammatory cytokines. The ways in which drugs or reactive metabolites provide danger signals are an active area of research [4][5][6][7].…”