Recently, a crucial role of Th2 responses in
nickel allergic contact dermatitis (ACD) was demonstrated. As
palladium allergy is an issue of growing interest, the diagnostic potential of Th2 parameters for
palladium sensitization was investigated.
Palladium (Na(2) [
PdCl(4)])-induced lymphocyte proliferation (LPT), Th1 and Th2
cytokine production were correlated with skin test (ST) reactivity in 16 positive and 21 negative controls. Furthermore, the diagnostic potential of these assays was evaluated using receiver operating characteristics (ROC) analysis. For comparison, same experiments were carried out for
nickel (NiSO(4)). Correlation coefficients between
palladium ST reactivity and IFN-γ, LPT,
IL-5, and
IL-13 were 0.34, 0.51, 0.69, and 0.78, and overall test accuracies were 68%, 81%, 89%, and 95%, respectively. Both
palladium- and
nickel-mediated Th2 responses tightly correlate with ST reactivity, supporting recent findings on the crucial role of Th2 involvement in ACD. Therefore, these assays may have great potential as diagnostic tools for future in vitro sensitization testing.