Lymphocyte transformation test in pediatric drug hypersensitivity: case series report from a tertiary care hospital.

BACKGROUND

Diagnosing adverse drug reactions (ADRs) in children is challenging due to coexisting infections. Reliable in vitro methods are critically needed.

OBJECTIVES

To evaluate the lymphocyte transformation test (LTT) in supporting the Spanish Pharmacovigilance System (SPS) causality algorithm for identifying culprit drugs in pediatric ADRs, and to estimate the diagnostic accuracy of the SPS algorithm, LTT, skin tests, and drug provocation testing (DPT).

METHODS

Retrospective case-series (2018-2024) at a tertiary hospital. Children with adjudicated ADRs were identified through pharmacovigilance programs and clinical referrals. Tolerance upon re-exposure served as the reference standard to estimate sensitivity, specificity, and predictive values.

RESULTS

We analyzed 81 children (mean age 9.2 ± 5.9 years; 46.9% female). Most had no prior drug allergies (88.9%). The ADR spectrum was primarily cutaneous and hepatic (rash 19.5%, urticaria 13.0%, liver injury 11.9%). Frequent culprit drugs included amoxicillin (8.4%), paracetamol (7.9%), amoxicillin/clavulanic acid (6.9%), and ibuprofen (6.4%). Using re-exposure as the reference standard, LTT demonstrated 100% sensitivity (95% CI: 51.0-100%) and 100% NPV (95% CI: 89.3-100%), with 78% specificity (95% CI: 12.6-57.6%). Significant associations were found between LTT positivity and SPS scores ≥4 (p<0.001), and between LTT and DPT outcomes (p=0.008).

CONCLUSION

LTT positivity correlates significantly with high causality scores and DPT outcomes in children. LTT is a valuable, non-invasive tool for evaluating T-cell-mediated reactions, particularly when DPT is risky or contraindicated.