Rituximab is a drug whose essence is an antibody against CD20 protein on the surface of B lymphocytes which create antibodies for example against viruses and bacteria. It is used primarily in the treatment of some blood cancers and autoimmune disorders. However, it has the potential to become a drug with a significant positive impact on patients with inflammatory cardiomyopathy

The immune system consists of two big parts – so-called cellular immunity (white blood cells) and antibody immunity.

Cellular immunity is comprised of many cell types which are divided into several groups based on their CD marks. These marks are used as a “mark” for proteins in the membrane of white blood cells. Each one of these proteins is unique for one certain type of white blood cells. Thanks to that it is possible to identify them.

One of these cells are B lymphocytes with CD20 protein. They have a value in the development and correct function of B lymphocytes. However, these white blood cells may also play a significant role in diseases like non-Hodgkin lymphoma, chronic lymphatic leukaemia (both cancer of the blood), vasculitis (inflammatory diseases of vessels) and autoimmune disorders (rheumatoid arthritis). Their role in the process of damage to the heart muscle has also been described. This type of B lymphocytes may also contribute to the rejection of transplanted organs.

In the case of these diseases, it is sometimes possible to administer Rituximab which binds on CD20 protein. It is prescribed with very good results, often together with chemotherapy, in the treatment of above-mentioned blood cancers. It has been used with success even in a study of patients with myocarditis emerge in association with an autoimmune disease called SLE (systemic lupus erythematosus) and in a study of patients with the rejection of transplanted heart including those where the indication for the transplant was giant cell myocarditis.

There is an interesting discovery by a German study that B lymphocytes with CD20 protein are present in more than 60 % of patients with inflammatory cardiomyopathy non-responding to the immunosuppressive therapy which does not affect B lymphocytes with CD20 protein. Not only in these patients the treatment with Rituximab could lead to the general improvement of the state of health. In the case of heart diseases (including myocarditis and inflammatory cardiomyopathy) this drug is still a subject of research and thus not a part of standard therapy. However, it would still be suitable only for certain groups of patients because not all patients respond to the therapy or it is not suitable for them (for example when CD20 B lymphocytes are not in such extent involved in the development of the disease). As soon as the research results will be published, you can read about them on myocarditis.eu.

The side-effects of Rituximab include shivers, headache, increased temperature, malaise, increased blood pressure. These symptoms often disappear as the therapy continues. It should not be administered in patients with acute infections and increased caution is needed also in patients with chronic infections.

Author of the opening picture: Simon Caulton