D2.56 - Diagnostic value of the lymphocyte transformation test for the investigation of drug-induced enterocolitis syndrome (DIES)

DIES is a rare drug hypersensitivity characterized by isolated severe gastrointestinal symptoms that can lead to hypovolemic shock. DIES pathophysiology is poorly documented, but is thought to involve a LT lymphocytic reaction infiltrating the digestive tract. Antibiotics, including amoxicillin (AMX), are frequently implicated. DIES is diagnosed on the basis of clinical criteria. As skins tests (ST) are not contributive in cases of DIES, the oral provocation test (OPT) remains the gold standard for diagnosis, at the risk of triggering a severe reaction. An in vitro test such as the lymphocyte transformation test (LTT) could facilitate and render more secure the diagnostic process.

Our aim was to describe the use of LTTs as a complementary tool for diagnosis of DIES.

We report the case of a 22-year-old woman referred to the Allergy Department after two reactions evocative of DIES following the intake of AMX. The AMX prick test (20 mg/mL) and intradermal tests (2mg/mL and 20 mg/mL) were negative at 20 minutes and 24 hours. Progressive OPT with AMX up to a cumulative dose of 55 mg induced vomiting, diarrhea, abdominal pain, hypotension and loss of consciousness after 1.5 hour, requiring vascular filling and transfer to intensive care. The percritical tryptase was normal. The clinical criteria induced by TPO led to the diagnosis of DIES with AMX. This was confirmed by the positive LTT for 1000µg/L AMX, concluding that circulating lymphocytes were proliferating by AMX-specific induction.

In the absence of relevance of skin tests, the LTT could be a useful and secure diagnostic tool in cases of strong suspicion of DIES. Further studies are needed to assess the role of this test as a diagnostic biomarker in the management of DIES with the aim of preventing severe reactions following new exposure.