Blood, Marrow, And an Introduction to Leukaemia

What is Blood?

Blood is a mixture of plasma and cells. Plasma is largely composed of water with dissolved proteins (albumin), hormones, minerals (iron), vitamins and antibodies. Cells include red blood cells, white blood cells and platelets. White blood cells are neutrophils, monocytes, eosinophils, basophils and lymphocytes.

Red cells are the oxygen carrying cells in the body making up half the volume of blood. Platelets stop bleeding from an injured site by clumping together and forming a clot at the injured site. They are one tenth the size of red blood cells.

Neutrophils and monocytes are phagocytes (eating cells) which leave the blood stream to the tissues to ingest bacteria or fungi and cure an infection. Eosinophils and basophils are involved in allergic responses. Lymphocytes are mostly in the lymph nodes, spleen and lymphatic channels but also in the blood. Lymphocytes are T-cells, B-cells and NK cells.

It’s a spongy tissue where blood is formed. It occupies the central cavity of bones. The bones of hand, feet, arms and legs is no longer functional by young adulthood. In adults, bone marrow of the vertebrae, hipbones, shoulder bones, ribs, breast bones and skull is actively making blood cells and the passing blood picks up the formed blood cells for circulation.

What is Leukaemia?

Comes from the Greek word “leukos” meaning “white” and “haima” meaning “blood”. There are 4 types of leukaemia, myelogenous and lymphocytic, each having an acute and chronic form.

Acute leukaemia affects the primitive cells which are not yet fully developed or differentiated. Hence acute leukaemia are rapidly progressive diseases. Chronic leukaemia on the contrary permit the growth of more developed cells and hence progress slowly.

A fast proliferation of abnormal cells (blasts) displacing the other normal cells in the bone marrow is what happens in leukaemia. This leads to suppression of Red blood cells and platelets and normal white blood cells. Hence the child has a deficiency of red blood cells (anaemia), platelets (thrombocytopenia), and normal white blood cells (neutropenia).

Acute lymphoblastic leukaemia is more common in children than Acute myeloid leukaemia. B Acute lymphoblastic leukaemia has a better prognosis than T-cell Acute lymphoblastic leukaemia. 15% childhood leukaemia are Acute myeloid leukaemia and are treated differently from acute lymphoblastic leukaemia.

The next part of this article will include details of individual leukaemia.