Comparison of NiSO4 and NiCl2 as Sensitizers in the Guinea Pig

Abstract

Nickel sulfate (NiSO₄) and nickel chloride (NiCl₂) were evaluated as sensitizers in the Guinea Pig Maximization Test (GPMT). The highest concentrations of NiSO₄ or NiCl₂ used as an intradermal challenge (0.25 and 0.5%) yielded responses that were significantly different (p < 0.05) between exposed and control guinea pigs at 24 h, and the highest concentration (0.5%) yielded significant differences (p < 0.05) at 48 h. The responses at the 0.125% NiSO₄ challenge site were significantly greater (p < 0.05) than for controls at both 24 and 48 h. Using the lymphocyte transformation test (LTT), the stimulation indices for the NiSO₄- and NiCl₂-exposed guinea pigs were nearly identical; however, the difference between exposed and control groups was greater for NiSO₄ than for NiCl₂. The results of both intradermal skin challenge and lymphocyte transformation indicated that NiSO₄ may be preferable to NiCl₂ in the GPMT. Because the skin test yielded statistically significant results while LTT did not, the skin test may be of more value when using these sensitizers in the GPMT.