Leukaemias can be acute or chronic.

Acute leukaemias tend to progress rapidly. Chronic leukaemias tend to progress slowly.

There are four main types of leukaemia:

• acute myeloblastic leukaemia (AML)
• acute lymphoblastic leukaemia (ALL)
• chronic myeloid leukaemia (CML)
• chronic lymphocytic leukaemia (CLL).

Each leukaemia is named after the type of white blood cell it affects. For example, chronic lymphocytic leukaemia affects cells called lymphocytes.