Diagnostic value of specific T cell reactivity to drugs in 95 cases of drug induced liver injury

Background—Diagnosis of drug induced liver injury is usually based on a temporal relation between drug intake and clinical picture as well as on the exclusion of alternative causes. More precise diagnosis has been attempted by using in vitro specific T cell reactivity to drugs but the test has never reached general acceptability because of frequent negative results which could be explained, in part, by prostaglandin producing suppressor cells (PPSC). Aim—To analyse the diagnostic value of a modified test where lymphocyte responses to drugs are detected in the presence of a prostaglandin inhibitor. Patients—Ninety five patients with a clinical diagnosis of drug induced liver injury, 106 healthy controls, 35 individuals with recent exposure to the same drugs without adverse effects, and 15 patients with liver disease unrelated to drugs. Methods—Peripheral blood mononuclear cells (PBMC) were cultured in the presence of drugs alone and in the presence of drugs and a prostaglandin inhibitor. Responses were assessed by3H-thymidine incorporation in lymphocytes. Results were expressed as counts per minute and as stimulation indexes (SI). Results—When PBMC were stimulated with drugs alone, lymphocyte sensitisation to drugs (SI>2) was detected in 26% of the cases. This was noticeably increased (56%) when a prostaglandin inhibitor was added to the cultures. No reactivity was found in controls. In patients with possible sensitivity to several drugs, lymphocyte reactivity was detected to only one drug. The severity of the lesions, as assessed by aminotransferase concentrations and disease duration, was lower in patients with evidence of PPSC. Conclusions—This new approach is useful for the diagnosis of drug induced liver injury, particularly in patients exposed to more than one drug; furthermore, the presence of putative PPSC is associated with less severe forms of drug induced hepatitis.