tailieunhanh - Chapter 061. Disorders of Granulocytes and Monocytes (Part 10)

Disorders of the Mononuclear Phagocyte System Many disorders of neutrophils extend to mononuclear phagocytes. Thus, drugs that suppress neutrophil production in the bone marrow can cause monocytopenia. Transient monocytopenia occurs after stress or glucocorticoid administration. Monocytosis is associated with tuberculosis, brucellosis, subacute bacterial endocarditis, Rocky Mountain spotted fever, malaria, and visceral leishmaniasis (kala azar). Monocytosis also occurs with malignancies, leukemias, myeloproliferative syndromes, hemolytic anemias, chronic idiopathic neutropenias, and granulomatous diseases such as sarcoidosis, regional enteritis, and some collagen vascular diseases. Patients with LAD, hyperimmunoglobulin E–recurrent infection (Job's) syndrome, CHS, and CGD all have defects in the mononuclear phagocyte system. . | Chapter 061. Disorders of Granulocytes and Monocytes Part 10 Disorders of the Mononuclear Phagocyte System Many disorders of neutrophils extend to mononuclear phagocytes. Thus drugs that suppress neutrophil production in the bone marrow can cause monocytopenia. Transient monocytopenia occurs after stress or glucocorticoid administration. Monocytosis is associated with tuberculosis brucellosis subacute bacterial endocarditis Rocky Mountain spotted fever malaria and visceral leishmaniasis kala azar . Monocytosis also occurs with malignancies leukemias myeloproliferative syndromes hemolytic anemias chronic idiopathic neutropenias and granulomatous diseases such as sarcoidosis regional enteritis and some collagen vascular diseases. Patients with LAD hyperimmunoglobulin E-recurrent infection Job s syndrome CHS and CGD all have defects in the mononuclear phagocyte system. Monocyte cytokine production or response is impaired in some patients with disseminated nontuberculous mycobacterial infection who are not infected with HIV. Genetic defects in the pathways regulated by IFN-y and IL-12 lead to impaired killing of intracellular bacteria mycobacteria salmonellae and certain viruses Fig. 61-10 . Figure 61-10 Lymphocyte-macrophage interactions underlying resistance to mycobacteria and other intracellular parasites such as Salmonella. Mycobacteria infect macrophages leading to the production of IL-12 which activates T or NK cells through its receptor leading to production of IL-2 and IFN-y. IFN-y acts through its receptor on macrophages to upregulate TNF-a and IL-12 and kill intracellular parasites. Mutant forms of the cytokines and receptors shown in large type have been found in severe cases of nontuberculous mycobacterial infection and salmonellosis. Certain viral infections impair mononuclear phagocyte function. For example influenza virus infection causes abnormal monocyte chemotaxis. Mononuclear phagocytes can be infected by HIV using CCR5 the chemokine receptor that .