Rituximab-induced interstitial pneumonitis in patient with non-Hodgkin lymphoma: a clinical case

Rituximab is a chimeric monoclonal antibody against CD20+ lymphocytes used to treat non-Hodgkin lymphoma, hematological and autoimmune diseases – rheumatoid arthritis, systemic lupus erythematosus, thrombocytopenic purpura, hemolytic anemia, multiple sclerosis. The safety of the drug is critical to the choice of treatment. Rituximab-associated interstitial lung disease is rare.

Objective. To describe a case of interstitial pneumonitis induced by rituximab in monotherapy at the end of maintenance therapy.

Materials and methods. We describe a case of a 37-year-old patient with stage IIB non-Hodgkin lymphoma involving palatine tonsils and cervical and submandibular lymph nodes on both sides. Histologically, this tumor was a diffuse large B-cell lymphoma.

Results. A patient received six R-CHOP courses of chemotherapy and immunotherapy for stage IIB diffuse large B-cell lymphoma. After the therapy, a complete clinical and metabolic response was achieved. Rituximab maintenance therapy was administered at a dose of 375 mg/m² every 2 months for 2 years. At this treatment stage, combined positron emission tomography and 18F-fluorodeoxyglucose computed tomography (PET/CT with 18F-FDG) was performed at 4–5 months intervals. No radiological signs of pulmonary diseases were detected. Seven weeks after the last dose of rituximab (24 months), another PET/CT with 18F-FDG showed radiological changes that were considered to be interstitial pneumonitis, with no respiratory signs of the disease. No signs of tumor progression were found.

Conclusion. Rituximab may contribute to late pulmonary toxicity presented as interstitial pneumonitis in non-Hodgkin lymphoma patients at a young age after maintenance therapy for 24 months. PET/CT with 18F-FDG is the primary method of diagnosing pulmonary toxicity.