A 29-year-old man developed allergy during treatment with rituximab for B-cell lymphoblastic lymphoma (LBL). The man, who was diagnosed with B-cell LBL and secondary haemophagocytic lymphohistiocytosis in 2013, started receiving rituximab 100mg infusion [frequency not stated] along with modified CHOP regimen comprising cyclophosphamide, epirubicin [epirubicin hydrochloride], vindesine [vindesine sulphate] and prednisone on 25 October 2013. Thereafter, he developed allergy to rituximab. The man's rituximab therapy was discontinued on day 1 of chemotherapy. He received 2 additional courses of CHOP regimen on 6 November 2013 and 28 November 2013, and 1 course of high-dose methotrexate, pegaspargase and vindesine on 19 December 2013. Thereafter, he achieved a complete remission of disease. However, 4 months after the initial diagnosis, he had disease relapse manifested as acute lymphocytic leukemia. He was administered CHOP regimen, but he died due to disease relapse [outcome of allergy not stated]. Author comment: "Rituximab (100 mg infusion) was ceased on day 1 due to an allergy".