The Cellular Immune System Comes of Age

• Published in: Journal of allergy and clinical immunology 2017-06, Vol.139 (6), p.1793-1794
• Main Authors: van Lier, René A.W, Kuijpers, Taco W
• Format: Article
• Language: English
• Subjects: Allergy and Immunology; Antigens; B cells; Blood; Blood cells; Bone marrow; CD4+ T cells; CD8+ T cells; Child; Child, Preschool; Children; Circulation; Colony-stimulating factor; Cytokines; Cytomegalovirus; Feeding; Genetics; Granulocyte colony-stimulating factor; Granulocytes; Growth factors; Homeostasis; Human subjects; Humans; Immune System; Infections; Inflammation; innate leukocytes; interindividual immunologic variance; Interleukin 17; Leukocytes (granulocytic); Longitudinal leukocyte dynamics; Lungs; Lymphocytes; Lymphocytes T; Neutrophils; nongenetic determinants; Peripheral blood; Phagocytes; Receptors, Antigen, T-Cell, gamma-delta - immunology; Skin; Studies; T cell receptors; T-cell receptor γδ+ T cells
• ISSN: 0091-6749; 1097-6825
• DOI: 10.1016/j.jaci.2017.02.023

[...]it has become evident that a subset of the initially activated pool of T cells takes up permanent residency in solid tissue, such as the gut, skin, and lung. Ideally, not only would one like to be able to gather information about the dynamics of the circulating and tissue-resident populations, but also novel techniques should be developed to assess these parameters in human subjects. [...]these data become available, it is difficult to determine how representative the peripheral blood cell count is for the actual number of immune cells in the body. For phagocytes, it is known that inflammatory cytokines, such as IL-17, and growth factors, such as granulocyte colony-stimulating factor, will boost the formation of granulocyte production in the bone marrow, leading to an increase in circulating cell counts.9 Still, in the absence of overt infection, granulocyte production and numbers in the circulation are kept at a certain steady-state level, and it is not understood how this process is regulated in human subjects. [...]the study indicates that apart from infection, factors other than genetics play a role in or at least correlate with shaping the cellular composition of the blood compartment, such as sex, breast-feeding, and type of infection (where the age at primary infection might be another critical factor to consider the early phase of immune determination), for better or worse. 1 D. van den Heuvel, M.A. Jansen, K. Nasserinejad, W.A. Dik, E.G. van Lochem, L.E. Bakker-Jonges, Effects of nongenetic factors on immune cell dynamics in early childhood: the...