In vitro study of the cross-sensitivity of hair dye using hapten-specific lymphocytes

Paraphenylenediamine (pPDA), which is used frequently in hair dyes, has a high sensitization potential and is also well-known to cross-react with chemicals of similar structure. pPDA-specific lymphocytes from sensitized inbred guinea pigs were prepared and the cross-reaction of pPDA was examined using cultured epidermal cells as the target. The cytolytic effect was observed to be highest with pPDA, followed by paraaminophenol, orthophenylenediamine, and metaphenylenediamine. Resorcinol and the control produced no cytolytic reaction. These results showed a good correlation between in vitro and in vivo tests. The recognizing ability of hapten-specific lymphocytes is suggested to vary according to the position of the functional group and its type.