How Rituxan Is Thought to Work

ANCAs are produced by plasma cells, which develop from B-cells

Antibodies are produced by the immune system. Their job is to fight germs. But in GPA and MPA, something goes wrong. Harmful antibodies called autoantibodies (pronounced aw-toh-AN-ti-bod-ees) are produced. The autoantibody often involved in GPA and MPA is known as ANCA. ANCAs attack healthy tissue and cells. 

ANCAs are produced by B-cells. They target a certain type of white blood cell called neutrophils (pronounced NOO-truh-fils). ANCAs cause the neutrophils to stick and clump to the walls of small blood vessels in different tissues and organs of the body. This process leads to inflammation. 

Rituxan® (rituximab) decreases the number of B-cells by targeting those that have a specific marker on their cell surface called CD20. It is thought that interfering with B-cell function can disrupt ANCA production.

Rituxan targets B-cells and is thought to reduce their lifespan in the body

Rituxan targeting B-cells diagram Rituxan targeting B-cells diagram

It is believed that B-cells, a type of white blood cell that is found in the immune system, may play a role in Granulomatosis with Polyangiitis (GPA) and Microscopic Polyangiitis (MPA). Rituxan targets only certain B-cells.

Because it is thought to interfere with B-cell function and disrupt ANCA production, Rituxan works differently from other medications used to treat GPA and MPA.

What are the most common side effects during treatment with Rituxan?

  • infusion-related reactions 
  • infections (may include fever, chills) 
  • body aches 
  • tiredness 
  • nausea

In patients with GPA or MPA, the most common side effects of Rituxan also include:

  • low white and red blood cells 
  • swelling 
  • diarrhea 
  • muscle spasms

Other side effects include:

  • aching joints during or within hours of receiving an infusion 
  • more frequent upper respiratory tract infections

Please see below and the Rituxan Prescribing Information and Medication Guide for additional Important Side Effect Information, including Most Serious Side Effects.


Call 1-877-317-5179 to talk about your Rituxan treatment.