Prolonged elevation of serum granulysin in drug-induced hypersensitivity syndrome

Funding sources: none. Conflicts of interest: none declared. Madam, Drug‐induced hypersensitivity syndrome (DIHS),1 also known as drug rash with eosinophilia and systemic symptoms (DRESS),2 has been established as a clinical entity in severe cutaneous adverse drug reactions. DIHS is characterized by the limited number of causative drugs, late onset, clinical similarity to infectious mononucleosis‐like syndrome and prolonged clinical course due to relapse.1 Granulysin is a cytotoxic molecule produced against virus‐infected cells, tumour cells, transplant cells, bacteria, fungi and parasites.3 It plays an important role in the host defence against pathogens. A recent paper reported that granulysin is highly expressed in blisters of two other severe cutaneous adverse drug reactions: Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).4 In addition, we found that serum granulysin is more elevated in patients with early‐stage SJS/TEN than in those with ordinary drug‐induced skin reactions (ODSRs).5 This paper investigates the serum granulysin level of patients with DIHS. We assembled serum samples of patients with DIHS and analysed the correlation between granulysin concentrations with clinical manifestations and disease courses.