Rituximab (Mabthera®) is is a monoclonal antibody directed against CD20 protein present on the surface of B‑lymphocytes

Binding of rituximab to CD20 causes death of B‑lymphocytes. In lymphoma and chronic lymphocytic leukaemia this is effective because  B-lymphocytes have become cancerous. In rheumatoid arthritis, B‑lymphocytes are involved in joint inflammation. In granulomatosis with polyangiitis (GPA or Wegener’s granulomatosis) and microscopic polyangiitis (MPA), destroying the B-lymphocytes lowers the production of antibodies thought to play an important role in attacking the blood vessels and causing inflammation.

Mechanism of action

Rituximab binds specifically to the transmembrane antigen, CD20, a non-glycosylated phosphoprotein, located on pre-B and mature B lymphocytes, both on normal and malignant cells. 

The Fab domain of rituximab binds to the CD20 antigen on B lymphocytes and the Fc domain can recruit immune effector functions to mediate B cell lysis. Possible mechanisms of effector-mediated cell lysis include complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity. Furthermore, rituximab binding to CD20 antigen on B lymphocytes also appears to induce cell death via apoptosis.  

Clinical use

In Europe, used to treat the following blood cancers and inflammatory conditions:

  • follicular lymphoma and diffuse large B cell non-Hodgkin’s lymphoma
  • chronic lymphocytic leukaemia 
  • severe rheumatoid arthritis
  • granulomatosis with polyangiitis (GPA or Wegener’s granulomatosis) and microscopic polyangiitis (MPA).

Depending on the condition it is used to treat, rituximab may be given on its own, or with chemotherapy, methotrexate or a corticosteroid. Consult CHMPs for details.

What can Sanquin do for you?

We have tests that:

  • can measure the levels of free drug in the serum; levels of therapeutic antibodies are assessed using validated ELISAs.
  • can measure the immunogenicity of rituximab; human anti-human antibodies are quantified using validated antigen-binding tests (radioimmunoassay or RIA).

As we have hands-on experience in these assays, we can provide you with accurate and reproducible test results. 

Send in samples

If you want to use our drug level or ADA testing services, fill out this form and send it to us along with 1 ml frozen serum sample per patient.