Rituximab (Mabthera) is a new type of drug that is being used in several different types of lymphoma and leukaemia.

It is a special type of antibody, called a monoclonal antibody.

Whenever any of us has an infection the white blood cells in our body are able to detect foreign proteins, called antigens, on the bacteria or virus causing the infection. Our blood cells then make another protein, called antibody, which will lock on to, and react with, the foreign antigen, leading to the destruction of the bacteria or virus.

In the mid 1970s it became possible to produce antibodies in the laboratory. These artificially produced antibodies were called monoclonal antibodies.

With this new technology researchers wondered if they could use monoclonal antibodies to help treat cancer. To do this they would need to find antigens on the surface of cancer cells, and then produce monoclonal antibodies to those antigens.

The theory was that these monoclonal antibodies could then recognise the antigen on the cancer cells and lock on to it (like a key in a lock). This might then trigger the body's immune system to attack the cancer cells or even cause the cancer cells to destroy themselves.

Rituximab is one of the first monoclonal antibodies to be developed for cancer treatment. It is directed against an antigen called CD20 that is on the surface of malignant (cancerous) B lymphocytes (a type of white blood cell found in some types of leukaemia and lymphoma. When it is given it attaches to the surface of the B cells and activates the immune system to attack the cell.

Rituximab is given intravenously as a weekly infusion through a drip. It is given for up to 4 weeks depending on the response to treatment. It is usually given as an outpatient, although the first infusion may be done in hospital. It may also be given in combination with other chemotherapy drugs.

Unlike many types of chemotherapy, Rituximab does not cause hair loss and causes only very slight nausea and has little or no effect on the blood count. There are some side-effects, however, these include fever, chills, nausea, wheezing, a drop in blood pressure and shivers which may occur while the infusion is being given. Giving tablets and medicines before the infusion begins can help to prevent these side-effects. Side-effects are most likely with the first one or two infusions and then tend to disappear.

The chances of getting a benefit from treatment with Rituximab depend very much on the particular type of leukaemia or lymphoma and so your uncle would need to talk to his doctors to see if it might be helpful in his condition.