title: Impairment of helper T-cell function following severe head injury.
abstract: Major infections, such as sepsis and pneumonia, occur in 50-75% of patients following isolated severe head injury. Previous studies have demonstrated that this high incidence of infection following severe head injury may be related to a decrease in helper T-cell activation and function. The present study was designed to investigate the effect of severe head injury on specific subgroups of helper T cells known to enhance or suppress cellular immune function. Specifically, peripheral blood lymphocytes (PBLs) from 10 head-injured patients and 10 matched controls were evaluated following in vitro stimulation with the T-cell mitogen, phytohemagglutinin (PHA). Subsets of helper T cells evaluated included activated helper (CD4+/CD25+) T cells; helper/inducer (CD4+/CDw29+) T cells, which enhance cellular immune activity; and suppressor/inducer (CD4+/CD45R+) T-cells, which induce suppressor (CD8+) T-cells. In addition, the effect of intraventricular fluid (IVF) on PHA-stimulated in vitro CD4 and CD25 expression was investigated to determine whether severe head injury results in the production of mediators within the central nervous system capable of affecting T-cell activation. The results of this study indicate that isolated severe head injury selectively reduces the ability of PHA-stimulated PBLs to express the helper/inducer (CD4+/CDw29+) T-cell (p = 0.023) and activated helper (CD4+/CD25+) T-cell (P = 0.041) phenotypes. There was no significant change in PHA-stimulated CD4 or CD25 expression following incubation of PBLs with intraventricular fluid (IVF) from head-injured patients. The relationship between these changes in specific helper T-cell subpopulations and the infectious complications of severe head injury are discussed.
authors.affiliation: Department of Neurosurgery, University of California, Davis.
authors.forename: K B
authors.initials: KB
authors.lastname: Quattrocchi
authors.forename: B W
authors.initials: BW
authors.lastname: Issel
authors.forename: C H
authors.initials: CH
authors.lastname: Miller
authors.forename: E H
authors.initials: EH
authors.lastname: Frank
authors.forename: F C
authors.initials: FC
authors.lastname: Wagner
mesh_terms: D000293:Adolescent; D000328:Adult; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000276:immunology; D001424:Bacterial Infections / Q000276:immunology; D015704:CD4 Antigens / Q000276:immunology; D006259:Craniocerebral Trauma / Q000150:complications / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D010835:Phytohemagglutinins; D013194:Staining and Labeling; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D015704:CD4 Antigens; D010835:Phytohemagglutinins