title: Rituximab efficiently depletes B cells in lung tumors and normal lung tissue.
abstract: Rituximab is a monoclonal antibody that targets the CD20 B-cell-specific antigen and is widely used as therapy for B-cell lymphoma. Since rituximab depletes both malignant and normal B cells, it is increasingly being used to treat various conditions in which normal B cells have a pathogenic role, such as rheumatoid arthritis and multiple sclerosis. It is well-established that rituximab efficiently eliminates B cells in blood, lymph nodes, and spleen. In contrast, the effect of rituximab in non-lymphoid tissues remains poorly documented and is debated. Here, we report a rheumatoid arthritis patient who was treated with rituximab before receiving thoracic surgery for non-small cell lung cancer. Using flow cytometry and immunohistochemistry, we show that rituximab efficiently depleted CD20-positive B cells in a primary lung tumor, in lung-associated lymph nodes, and in normal lung tissue. We conclude that rituximab may be very efficient at depleting normal B cells in the lungs. This property of rituximab may potentially be exploited for the treatment of conditions in which pathogenic B cells reside in the lungs. On the other hand, the clearance of lung B cells may provide an explanation for the rare cases of severe non-infectious pulmonary toxicity of rituximab.
authors.affiliation: Tumor Immunology group, Department of Pathology, Oslo University Hospital, Oslo, Norway; Centre for Immune Regulation, University of Oslo, Oslo, Norway.
authors.forename: Albane
authors.initials: A
authors.lastname: Joly-Battaglini
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.
authors.forename: Clara
authors.initials: C
authors.lastname: Hammarström
authors.affiliation: Tumor Immunology group, Department of Pathology, Oslo University Hospital, Oslo, Norway; Centre for Immune Regulation, University of Oslo, Oslo, Norway.
authors.forename: Branislava
authors.initials: B
authors.lastname: Stankovic
authors.affiliation: Tumor Immunology group, Department of Pathology, Oslo University Hospital, Oslo, Norway; Centre for Immune Regulation, University of Oslo, Oslo, Norway; Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway.
authors.forename: Henrik
authors.initials: H
authors.lastname: Aamodt
authors.affiliation: Betanien Hospital, Skien, Norway.
authors.forename: Johan
authors.initials: J
authors.lastname: Stjärne
authors.affiliation: Department of Oncology, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
authors.forename: Odd Terje
authors.initials: OT
authors.lastname: Brustugun
authors.affiliation: Department of Oncology, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway; Department of Cancer Genetics, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
authors.forename: Åslaug
authors.initials: Å
authors.lastname: Helland
authors.affiliation: Tumor Immunology group, Department of Pathology, Oslo University Hospital, Oslo, Norway; Centre for Immune Regulation, University of Oslo, Oslo, Norway.
authors.forename: Inger
authors.initials: I
authors.lastname: Øynebråten
authors.affiliation: Tumor Immunology group, Department of Pathology, Oslo University Hospital, Oslo, Norway; Centre for Immune Regulation, University of Oslo, Oslo, Norway; Department of Biosciences, University of Oslo, Oslo, Norway.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Corthay
keywords: B cells; depletion; lungs; lymph node; monoclonal antibody; non-small cell lung cancer; rituximab; tumor