White blood cells 1: non-malignant disorders Review Article

• Disorders of white cells are very common in clinical practice. • White-cell development and numbers are controlled by a mixture of external stimuli including cytokines, matrix proteins, and accessory cells. • Several different white-cell lineages are recognised; each has a role in host defence. • Both white-cell deficiency and overproduction can lead to disease. • Some forms of inherited white-cell deficiency are potentially treatable with gene therapy.