title: Reversible disruption of thymic function by steroid treatment.
abstract: The effect of steroid treatment on the thymic output of T cells was examined in an avian model. Recent thymic emigrants in chickens transiently express the chicken T cell Ag 1 thymocyte marker, and thymic function can be monitored indirectly by measuring the levels of TCR gene rearrangement excision circles in peripheral T cells. Both parameters were used to show that intensive steroid treatment induces thymic involution and a profound reduction in the supply of naive T cells to the periphery. Conversely, resident T cells in the peripheral lymphocyte pool were relatively spared. Thymopoiesis immediately recovered following cessation of steroid treatment, concurrent with restoration of the thymic output of newly formed T cells. Repopulation of the peripheral T cell pool recapitulated the ontogenetic pattern of gamma delta T cell replenishment before alpha beta T cell reseeding, thereby indicating the complete recovery of thymic function after a course of steroid treatment.
authors.affiliation: Division of Developmental and Clinical Immunology, Department of Microbiology, University of Alabama, Birmingham, AL 35294, USA.
authors.forename: Fan-Kun
authors.initials: FK
authors.lastname: Kong
authors.forename: Chen-lo H
authors.initials: CL
authors.lastname: Chen
authors.forename: Max D
authors.initials: MD
authors.lastname: Cooper
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage; D002454:Cell Differentiation / Q000187:drug effects / Q000276:immunology; D002645:Chickens; D003907:Dexamethasone / Q000008:administration & dosage*; D004351:Drug Resistance / Q000276:immunology; D007166:Immunosuppressive Agents / Q000008:administration & dosage; D007273:Injections, Intramuscular; D007399:Interphase / Q000187:drug effects / Q000276:immunology; D008231:Lymphopenia / Q000139:chemically induced / Q000276:immunology; D010865:Pilot Projects; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000473:pathology; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects* / Q000276:immunology* / Q000473:pathology
chemical_list: D000893:Anti-Inflammatory Agents; D007166:Immunosuppressive Agents; D003907:Dexamethasone