In vitro lymphocyte proliferation as compared to patch test using gold, palladium and nickel.

BACKGROUND

A conventional lymphocyte transformation test (LTT) was compared to the commercially available MELISA (memory lymphocyte immunostimulation assay), a lymphoproliferative assay that has been suggested to be a valuable instrument for the diagnosis of metal allergy. Sensitivity and specificity of the two assays were calculated using a patch test as a reference method.

METHODS

34 patients were patch-tested for gold sodium thiosulfate, palladium chloride and nickel sulfate, and the lymphocyte proliferation to these metals was tested in vitro using mononuclear cells from peripheral blood.

RESULTS

No significant differences regarding sensitivity and specificity were found between MELISA and conventional LTT. The sensitivity varied between 55 and 95% and the specificity between 17 and 79%.

CONCLUSIONS

The low specificity of the two in vitro assays suggests that they are not useful for diagnosis of contact allergy to the metals gold, palladium and nickel, since a large number of false-positive results will be obtained.