Organ-specific local cytokine release syndrome after anti-CD19 CAR-T therapy with salivary gland involvement: a case report, literature review, and a diagnostic alert for tocilizumab-associated cervical swelling.

Background. Cytokine release syndrome (CRS) is the most frequent toxicity after chimeric antigen receptor T-cell (CAR-T) therapy and typically presents as a systemic inflammatory syndrome. In recent years, a localized form of CRS (L-CRS), most commonly involving the craniocervical region, has been increasingly recognized. L-CRS may occur with or without overt local tumor involvement and can progress to airway impairment, requiring prompt recognition and treatment. Case presentation. We report two cases of patients with refractory diffuse large B-cell lymphoma (DLBCL) treated with anti-CD19 CAR-T therapy who developed abrupt, painful bilateral parotid and/or submandibular gland swelling (left predominance) early after infusion, following systemic CRS treated with tocilizumab. Infectious, obstructive, and autoimmune causes were excluded; ultrasound findings were compatible with inflammatory glandular changes. Given rapid progression and concern for airway patency, corticosteroids were administered with prompt clinical resolution. Literature review and diagnostic alert. We provide an overview of published L-CRS with craniocervical presentations (Table 1). Similar acute swelling temporally related to tocilizumab has been reported in other settings. In such cases, differential diagnostics of L-CRS vs. a tocilizumab-associated infusion-related/hypersensitivity reaction needs to be carried out. Conclusion. L-CRS is a clinically relevant and potentially severe complication of CAR-T therapy that may involve salivary glands even without cervical tumor burden. Clinicians should also consider drug-related reactions, particularly when cervical swelling occurs shortly after tocilizumab administration.