Typical Blood Disorders

Anaemia: Leukopenia: low number of white blood cells

Thrombopenia: platelet deficiency

Immunocytopenia: reduction in the number of blood cells)

Immune thrombocytopenia (ITP): reduction in the number of platelets due to an autoimmune reaction

Autoimmune haemolysis (AIHA): caused by the formation of antibodies that destroy red blood cells

Unlike acute leukaemias, chronic leukaemias tend to develop slowly and insidiously. A distinction is made between:

• Chronic lymphocytic leukaemia (CLL): CLL is a malignant disease of the lymphatic system. Mature B lymphocytes multiply uncontrollably in lymphatic organs such as the lymph nodes, spleen, liver and bone marrow. They are also regularly found in the blood.
• Chronic myeloid leukaemia (CML): in CML, cancer cells develop from immature blood cell precursors. The maturation of white blood cells is particularly impaired, but the development of platelets is usually also affected. This leads to uncontrolled division of the abnormal cells (leukaemia cells). White blood cells at different stages of maturation are then found in increased numbers in the bone marrow and blood.

Myeloproliferative diseases (myelo = bone marrow, proliferative = multiplying) are a group of malignant diseases of the blood system that develop in the bone marrow. The haematopoietic cells in the bone marrow (progenitor cells) grow and multiply abnormally. These diseases usually affect the production of red blood cells, white blood cells and platelets.

Myelodysplastic syndrome (myelo = bone marrow, dysplastic = malformed) is a collective term for a group of acquired diseases of the bone marrow stem cells, which give rise to the different blood cells through cell division. In these related diseases, altered haematopoietic cells develop in the bone marrow. These cells disrupt the formation of normal blood cells and, over time, leukaemia can develop.

 In this type of tumour, cells in the lymphatic system degenerate. A distinction is made between:

• Hodgkin's lymphoma (Hodgkin's disease, Hodgkin's disease) This disease is characterised by the presence of Hodgkin's and Reed-Sternberg cells (HRS cells). It is named after Thomas Hodgkin, who first described the disease in the 19th century.
• Non-Hodgkin's lymphomas (NHL): these are further subdivided into more malignant (aggressive) NHL and less malignant (indolent) NHL. The latter includes chronic lymphocytic leukaemia (CLL), for example. Non-Hodgkin's lymphomas are characterised by a large number of lymphoma cells.

MGUS is a condition in which a very large amount of a specific protein (monoclonal immunoglobulin, M protein) is found. MGUS is often found by chance. It is not a malignant condition, but MGUS is associated with an increased risk of certain malignant blood disorders, particularly multiple myeloma.

• Aplastic anaemia: disorder of bone marrow function associated with a reduction in bone marrow cells and reduced formation of all blood cells.
• Paroxysmal nocturnal haemoglobinuria (PNH): an alteration in the stem cells of the bone marrow that leads to the production of red blood cells that lack certain proteins on their surface and are therefore recognised as foreign, ultimately leading to their destruction.
• Haemophagocytic lymphohistiocytosis (HLH): the targeting and control of natural killer cells and T cells is defective. Excessive activation of immune cells consequently leads to healthy blood cells and tissue being attacked.