Which of the following statement about rituximab is FALSE:
**Core Concept**
Rituximab is a monoclonal antibody that targets the CD20 antigen on B cells, leading to their depletion and subsequent immunosuppression. This principle is crucial in the treatment of various autoimmune diseases and certain types of cancer.
**Why the Correct Answer is Right**
Rituximab works by binding to the CD20 antigen on the surface of B cells, marking them for destruction by the immune system. This results in a decrease in B cell count and subsequent reduction in antibody production. The mechanism of action of rituximab involves antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). The CD20 antigen is expressed on the surface of B cells from the early stages of development until maturity, making it an ideal target for rituximab.
**Why Each Wrong Option is Incorrect**
* **Option A:** This statement is true as rituximab is indeed used to treat autoimmune diseases such as rheumatoid arthritis and lupus nephritis.
* **Option B:** This statement is true as rituximab can cause infusion reactions, which can range from mild to severe.
* **Option C:** This statement is false as rituximab is not primarily used to treat hypertension. While it may be used in patients with hypertension who have autoimmune diseases, it is not a treatment for hypertension itself.
**Clinical Pearl / High-Yield Fact**
Rituximab can cause a reactivation of hepatitis B virus (HBV) in patients who are chronic carriers, making it essential to screen patients for HBV before initiating treatment.
**Correct Answer: C. Rituximab is not primarily used to treat hypertension.**