T cell subsets and their soluble products regulate eosinophilia in allergic and nonallergic asthma.
Lymphokines derived from activated T cells regulate the proliferation and postmitotic differentiation of eosinophils in vitro. We investigated whether peripheral blood eosinophilia, which is a characteristic feature of both allergic and nonallergic asthma, correlates with T cell activation and lymphokine production in asthmatic patients. Flow cytometric analysis of T cell activation markers revealed that asthmatic individuals are characterized by increased numbers of IL-2R (CD25)-bearing T cell subsets. The absolute number of IL-2R+ T cells correlated with the eosinophilia observed in the asthmatic patients. Purified CD4+ and CD8+ T cells from allergic and nonallergic asthmatic individuals spontaneously secreted factors that extend the lifespan of eosinophils in vitro. T cells from normal donors displayed this effect only after polyclonal stimulation with anti-CD3 antibody. The eosinophil lifespan-extending factors were also found in sera of asthmatic patients. Identification of these factors was performed by using neutralizing antibodies against IL-3, IL-5, and granulocyte-macrophage CSF. In sera, mainly IL-5 and granulocyte-macrophage CSF were responsible for prolonged eosinophil survival, whereas granulocyte-macrophage CSF was dominant in T cell supernatants. These results indicate that T cells and secretion of lymphokines play an important regulatory function toward eosinophils, which are thought to represent major proinflammatory effector cells in certain types of asthma.
Walker
C
C
Swiss Institute of Allergy and Asthma Research, Davos.
Virchow
J C
JC
Bruijnzeel
P L
PL
Blaser
K
K
D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000502:physiology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology; D001249:Asthma / Q000097:blood / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D016827:CD8 Antigens; D003470:Culture Media; D016207:Cytokines / Q000096:biosynthesis / Q000502:physiology; D004802:Eosinophilia / Q000276:immunology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D015375:Receptors, Interleukin-2 / Q000032:analysis; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D016827:CD8 Antigens; D003470:Culture Media; D016207:Cytokines; D015375:Receptors, Interleukin-2