Page 139 - Essential Haematology

Chapter 8 White cells: Granulocytes and monocytes / 125

Enzyme replacement therapy with glucocerebro- Niemann – Pick d isease

sidase, imiglucerase (Cerezyme ® ), made by recom-
Niemann – Pick disease shows certain clinical and
binant technology and given intravenously once
’
pathological similarities to Gaucher s disease. It is

every 2 weeks is very effective in treating the disease
caused by a sphingomyelinase defi ciency. Th e
with shrinkage of spleen, rise in blood count and
majority of patients are infants who die in the fi rst
improved bone structure (Fig. 8.14 d,f). Two new
few years of life although occasional patients survive
recombinant enzymes, velaglucerase and taliglu-
to adult life. Massive hepatosplenomegaly occurs
cerase, are now available. An oral drug, miglustat, is
and there is usually lung and nervous system
useful in mild forms. It reduces the amount of sub-
involvement with retarded physical and mental
strate being produced in lysosomes and may be used
development. A ‘ cherry - red ’ spot is commonly seen
in combination with the intravenous enzyme.

in the retina of affected infants. Pancytopenia is a
Newer preparations are becoming available. Th e
regular feature and in marrow aspirates foam cells ’
‘
use of imiglucerase has virtually eliminated the need
of similar size to Gaucher cells are seen. Chemical
for splenectomy but it cannot reverse established
analysis of the tissues reveals that the disorder is
osteonecrosis, bone deformation, hepatic, splenic or
caused by an accumulation of sphingomyelin and

marrow fibrosis. Stem cell transplantation has been
cholesterol.
carried out successfully in severely aff ected patients,
usually with type II or III disease.

■ Granulocytes include neutrophils ■ Defects of function of neutrophils and

(polymorphs), eosinophils and basophils. monocytes may affect their chemotaxis,
They are made in the bone marrow under phagocytosis or killing.

the control of a variety of growth factors ■ Histiocytes are tissue macrophages SUMMARY
and have a short lifespan in the blood derived from circulation monocytes. They
stream before entering tissues. may form clonal diseases called
■ Phagocytes (neutrophils and monocytes) Langerhans ’ cell histiocytosis which affect

are the body ’ s main defence against single or multiple organs.

bacterial infection. Neutrophil leucocytosis ■ The haemophagocytic syndrome involves

occurs in bacterial infection and in other destruction of red cells, granulocytes and
types of infl ammation. Neutropenia, if platelets by tissue macrophages.
severe, predisposes to infections. It may ■ Lysosomal storage diseases are caused by

be caused by bone marrow failure, inherited defects in the enzymes
chemotherapy or radiotherapy drugs, responsible for breakdown of glycolipids.
immune mechanisms or occur congenitally. Gaucher ’ s disease is caused by
■ Eosinophilia is most frequently caused by glucocerebrosidase defi ciency and is

allergic diseases, including skin diseases, associated with accumulation of glycolipids
parasitic infections or drugs. It can be in the reticuloendothelial system with
caused by a clonal increase in eosinophils splenomegaly, pancytopenia and bone
termed chronic eosinophilic leukaemia or lesions causing the main clinical
an idiopathic condition, often associated manifestations.
with tissue damage.
Now visit www.wiley.com/go/essentialhaematology
to test yourself on this chapter.