Rituximab (Rituxan)

Abstract

Rituximab is a monoclonal antibody that was first approved by the FDA as an antineoplastic agent designed to treat B-cell malignancies. This article will review the mechanism of action and clinical role of this anti-B-cell agent.

Fig 1.

Schematic illustration of the mechanism of action of rituximab. The antibody labels B lymphocytes, which have the CD20 cell marker. These cells are then killed by 1 of 3 mechanisms: antibody-dependent cytotoxicity, complement-dependent cytotoxicity, or stimulation of apoptosis. Illustration by Priya A. Rajdev.

Fig 2.

A 68-year-old woman presented with clumsiness, dropping things from her right hand, difficulty speaking, and right facial droop. A, T2-weighted axial FSE image of the brain shows patchy areas of increased T2-signal-intensity edema surrounding a low T2-signal-intensity lesion at the left temporal and frontal parietal lobes. B, T1-weighted postcontrast axial spin-echo image of the brain shows irregular and patchy enhancement of the lesion. Surrounding edema is seen as a low T1 signal intensity. A biopsy of the mass was performed, and CD20-positive B-cell lymphoma was diagnosed.

Fig 3.

The patient was admitted and received chemotherapy with methotrexate, vincristine, and rituximab. Follow-up MR imaging was performed 2 cycles into her chemotherapy. A, T2-weighted axial FSE image shows only residual edema as high T2 signal intensity in the deep white matter of the left frontal parietal lobes. B, Enhanced T1-weighted axial spin-echo image shows resolution of the enhancing mass.