Abstracts/Presentation Description
Jason Chun Lao1,2, Yi Tong Vincent Aw3, Jamma Li2,3, Therese Boyle3, Richard Fulton1, Reina Zaragoza3, Suran Fernando1-3
1Immunology Laboratory, Royal North Shore Hospital/NSW Health Pathology, Sydney, Australia
2Northern Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
3Department of Clinical Immunology and Allergy, Royal North Shore Hospital, Sydney, Australia
2Northern Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
3Department of Clinical Immunology and Allergy, Royal North Shore Hospital, Sydney, Australia
Introduction: Severe cutaneous drug reactions (SCAR) are delayed hypersensitivity reactions to drugs that carry significant morbidity and mortality. It remains challenging to pinpoint the culprit drug when multiple drugs were given prior to onset of symptoms.
Method: A previously published1 XTT-based lymphocyte transformation test (LTT) was used. Peripheral blood mononuclear cells were isolated from heparinised blood and cultured for six days with antibiotics before being read with a XTT assay.
Results: We present three patients who experienced SCAR after exposure to multiple antibiotics and underwent XTT-LTT assay. One patient who developed drug reaction with eosinophilia and systemic symptoms (DRESS) after exposure to trimethoprim-sulfamethoxazole and amoxicillin-clavulanic acid passed direct drug provocation testing (DPT) to amoxicillin-clavulanic acid following negative XTT-LTT to same. Another patient had acute generalised exanthematous pustulosis (AGEP) after exposure to doxycycline, benzylpenicillin, azithromycin, amoxicillin-clavulanic acid and piperacillin-tazobactam, and tolerated amoxicillin-clavulanic acid and azithromycin DPT after negative XTT-LTT to both. A third patient developed Steven-Johnson’s Syndrome (SJS) following exposure to flucloxacillin, cefepime and piperacillin-tazobactam. XTT-LTT was positive to piperacillin-tazobactam, equivocal to flucloxacillin and negative to cefepime.
Method: A previously published1 XTT-based lymphocyte transformation test (LTT) was used. Peripheral blood mononuclear cells were isolated from heparinised blood and cultured for six days with antibiotics before being read with a XTT assay.
Results: We present three patients who experienced SCAR after exposure to multiple antibiotics and underwent XTT-LTT assay. One patient who developed drug reaction with eosinophilia and systemic symptoms (DRESS) after exposure to trimethoprim-sulfamethoxazole and amoxicillin-clavulanic acid passed direct drug provocation testing (DPT) to amoxicillin-clavulanic acid following negative XTT-LTT to same. Another patient had acute generalised exanthematous pustulosis (AGEP) after exposure to doxycycline, benzylpenicillin, azithromycin, amoxicillin-clavulanic acid and piperacillin-tazobactam, and tolerated amoxicillin-clavulanic acid and azithromycin DPT after negative XTT-LTT to both. A third patient developed Steven-Johnson’s Syndrome (SJS) following exposure to flucloxacillin, cefepime and piperacillin-tazobactam. XTT-LTT was positive to piperacillin-tazobactam, equivocal to flucloxacillin and negative to cefepime.
Conclusion: XTT-LTT assay is helpful for facilitating DPT to less likely drug culprits when there are many implicated. This will reduce unnecessary drug allergy.
Reference:
1. Weir C, Li J, Fulton R, Fernando SL. Development and initial validation of a modified lymphocyte transformation test (LTT) assay in patients with DRESS and AGEP. Allergy Asthma Clin Immunol. 2022 Oct 9;18(1):90.
Speaker/Presenting Authors
Authors
Submitting/Presenting Authors
Dr Jason Chun Lao - Royal North Shore Hospital/ NSW Health Pathology (NSW, Australia)