In vitro lymphocyte reactivity to gold compounds in the diagnosis of contact hypersensitivity

The use of the lymphocyte transformation test (LTT) in the diagnosis of contact hypersensitivity to gold was studied in 8 patients who had positive patch tests to gold salts, and in 8 control subjects who were negative to such patch tests. Gold sodium thiosulfate and gold chloride were added to cultures of lymphocytes, which were labeled by 3H-thymidine after 96 h. The lymphocyte stimulation index was calculated as the beta-counts in stimulated cultures divided by those in control cultures. The index was statistically significantly higher for the patient group (p=0.005-0.04) than for the control group. Levels of interferon-gamma (IFN-gamma) were determined for the supernatants of the lymphocyte cultures. An index IFN-gamma, which is defined as the level of IFN-gamma in stimulated cultures divided by that in control cultures, was statistically significantly higher for the patient group (p=0.01-0.006). The LTT stimulation index showed specificity and sensitivity between 67 and 80%, the respective values for Index IFN-gamma being between 73 and 100% when the patch test was used as a reference method. Evaluation of lymphocyte reactivity might be of future interest in the diagnosis of allergic reactions to gold if the sensitivity and specificity can be improved.