This is a relatively new type of treatment. Antibodies are proteins that are part of the body's natural defence against infection. They recognise harmful cells and organisms and destroy them. Monoclonal antibodies have been designed to recognise certain proteins found on the surface of specific cancer cells.

A type of monoclonal antibody called alemtuzumab (MabCampath®) can be used to treat chronic lymphocytic leukaemia. It can be given either as an injection into the vein (intravenously) or as an injection just under the skin (subcutaneously). It may be given on its own or in combination with chemotherapy in people who have previously had chemotherapy.

Rituximab (Mabthera®) is another type of monoclonal antibody that may be used. Rituximab is given by intravenous infusion (drip). You may be able to have treatment as an outpatient or you may be asked to stay in hospital overnight.

Some people may have a high temperature, shaking, and low blood pressure when they are being given the drugs but this doesn’t usually last long. Other side effects may include feeling sick (nausea) and lowered resistance to infection. People may have very few side effects with these treatments.

Monoclonal antibody treatment can reduce the number of immune antibodies in the blood and so reduce resistance to infection. People taking monoclonal antibodies for more than six months usually need to take antibiotics and antiviral drugs to prevent infection.