Rituximab-induced nonspecific interstitial pneumonia like reaction in a patient with idiopathic thrombocytopenic purpura

Rituximab, a chimeric anti-CD20 IgG1 monoclonal antibody, is an effective treatment for haematological autoimmune diseases such as idiopathic thrombocytopenic purpura (ITP). A 72-year-old man was diagnosed with idiopathic thrombocytopenic purpura (ITP). After receiving 4 cycles of rituximab in one month complete response was achieved. However, three weeks after the last infusion he presented to the haematology department with fever, productive cough and dyspnea and severe hypoxemia. HRCT of the thorax revealed patchy areas of ground glass opacities throughout both lungs and small peripheral consolidations were seen. Transbronchial biopsy showed interstitial thickening and type II pneumocyte activation with interstitial pneumonia. Bronchoalveolar lavage showed increased eosinophils. The patient was treated with three pulses of 1 gr iv methylprednisolone and then gradually switched to 15mg of prednisolone for 3 months. The dyspnea and tachypnea gradually improved, in addition to blood oxygenation and a follow up HRCT 3 months later showed a significant resolution of lesions.

Severe lung toxicity like acute respiratory distress syndrome, cryptogenic organizing pneumonia, pneumonitis, and interstitial lung disease are very rare, with most of the knowledge coming from case reports. Rituximab-induced interstitial lung disease (R-ILD) is a rare complication. To the best of our knowledge, 23 cases of R-ILD have been reported in the literature; 22 of them were treated with R-CHOP for NHL and only one was receiving rituximab for ITP. We report the second case to develop this complication for a non-malignant disorder.