Page 366 - Textbook of Pathology, 6th Edition

350 diameter. It possesses a large, central, oval, notched or 7. Haematopoietic diseases e.g. CML, polycythaemia vera,
indented or horseshoe-shaped nucleus which has pernicious anaemia, Hodgkin’s disease, following
characteristically fine reticulated chromatin network. The splenectomy.
cytoplasm is abundant, pale blue and contains many fine 8. Malignant diseases with metastases.
dust-like granules and vacuoles. 9. Irradiation.
The main functions of monocytes are as under: 10. Miscellaneous disorders e.g. polyarteritis nodosa, rheuma-
1. Phagocytosis of antigenic material or microorganisms. toid arthritis, sarcoidosis.
2. Immunologic function as antigen-presenting cells and Eosinopenia. Adrenal steroids and ACTH induce eosino-
present the antigen to lymphocytes to deal with further. penia in man.
3. As mediator of inflammation, they are involved in release
of prostaglandins, stimulation of the liver to secrete acute Basophils
phase reactants.
Tissue macrophages of different types included in RE MORPHOLOGY. Basophils resemble the other mature
system are derived from blood monocytes (Chapter 4). granulocytes but are distinguished by coarse, intensely
basophilic granules which usually fill the cytoplasm and
PATHOLOGIC VARIATIONS. A rise in the blood mono- often overlie and obscure the nucleus.
cytes above 800/μl is termed monocytosis. Some common The granules of circulating basophils (as well as their
causes of monocytosis are as follows: tissue counterparts as mast cells) contain heparin, histamine
1. Certain bacterial infections e.g. tuberculosis, subacute and 5-HT. Mast cells or basophils on degranulation are
bacterial endocarditis, syphilis.
SECTION II
associated with histamine release.
2. Viral infections.
3. Protozoal and rickettsial infections e.g. malaria, typhus, PATHOLOGIC VARIATIONS. Basophil leucocytosis or
trypanosomiasis, kala-azar. basophilia refers to an increase in the number of basophilic
leucocytes above 100/μl. Basophilia is unusual and is found
4. Convalescence from acute infection.
5. Haematopoietic disorders e.g. monocytic leukaemia, in the following conditions:
lymphomas, myeloproliferative disorders, multiple 1. Chronic myeloid leukaemia
myeloma, lipid storage disease. 2. Polycythaemia vera
6. Malignancies e.g. cancer of the ovary, stomach, breast. 3. Myelosclerosis
7. Granulomatous diseases e.g. sarcoidosis, inflammatory 4. Myxoedema
bowel disease. 5. Ulcerative colitis
8. Collagen-vascular diseases. 6. Following splenectomy
7. Hodgkin’s disease
Eosinophils
8. Urticaria pigmentosa.
MORPHOLOGY. Eosinophils are similar to segmented
neutrophils in size (12-15 μm in diameter), and have coarse, INFECTIOUS MONONUCLEOSIS
deep red staining granules in the cytoplasm and have usually
two nuclear lobes. Granules in eosinophils contain basic Infectious mononucleosis (IM) or glandular fever is a benign,
protein and stain more intensely for peroxidase than granules self-limiting lymphoproliferative disease caused by Epstein-
in the neutrophils. In addition, eosinophils also contain cell Barr virus (EBV), one of the herpesviruses. Infection may
adhesion molecules, cytokines (IL-3, IL-5), and a protein that occur from childhood to old age but the classical acute
Haematology and Lymphoreticular Tissues
precipitates Charcot-Leyden crystals in lung tissues in infection is more common in teenagers and young adults.
asthmatic patients. The infection is transmitted by person-to-person contact such
Eosinophils are involved in reactions to foreign proteins as by kissing with transfer of virally-contaminated saliva.
and to antigen-antibody reactions. Groups of cases occur particularly in young people living
together in boarding schools, colleges, camps and military
PATHOLOGIC VARIATIONS. An increase in the number institutions. Primary infection in childhood is generally
of eosinophilic leucocytes above 400/μl is referred to as asymptomatic, while 50% of adults develop clinical
eosinophilia and below 40/μl is termed as eosinopenia. manifestations. The condition is so common that by the age
Eosinophilia. The causes are as under: of 40, most people have been infected and developed
1. Allergic disorders e.g. bronchial asthma, urticaria, antibodies. It may be mentioned here that EBV is oncogenic
angioneurotic oedema, hay fever, drug hypersensitivity. as well and is strongly implicated in the African (endemic)
2. Parasitic infestations e.g. trichinosis, echinococcosis, Burkitt’s lymphoma and nasopharyngeal carcinoma as
intestinal parasitism. discussed in Chapter 8.
3. Skin diseases e.g. pemphigus, dermatitis herpetiformis,
erythema multiforme. Pathogenesis
4. Löeffler’s syndrome. EBV, the etiologic agent for IM, is a B lymphotropic
5. Pulmonary infiltration with eosinophilia (PIE) syndrome. herpesvirus. The disease is characterised by fever, genera-
6. Tropical eosinophilia. lised lymphadenopathy, hepatosplenomegaly, sore throat,