RT Journal Article
SR Electronic
T1 Pneumococcal Infections in Humans Are Associated with Increased Apoptosis and Trafficking of Type 1 Cytokine-Producing T Cells
JF Infection and Immunity
JO Infect. Immun.
FD American Society for Microbiology
SP 5019
OP 5025
DO 10.1128/IAI.70.9.5019-5025.2002
VO 70
IS 9
A1 Kemp, Kåre
A1 Bruunsgaard, Helle
A1 Skinhøj, Peter
A1 Klarlund Pedersen, Bente
YR 2002
UL http://iai.asm.org/content/70/9/5019.abstract
AB Streptococcus pneumoniae infections are associated with considerable morbidity and mortality throughout the world. The immunopathology is characterized by an intense inflammatory reaction, including a strong acute-phase response and increased numbers of neutrophils in the circulation. However, little is known regarding the T-cell response during in vivo infections in humans. The purpose of this study was to test the hypothesis that activated T cells producing type 1 cytokines were engaged in the host response to pneumococcal infections. The phenotype and function of T cells were studied in 22 patients at admission to a department of infectious diseases and after antibiotic treatment for 1 week compared with an age-matched, healthy control group. Pneumococcal infections induced lymphopenia in the circulation due to the disappearance of activated T lymphocytes with a type 1 cytokine profile. In contrast, the numbers of naive T cells and interleukin-4-producing T cells did not change. Activated type 1 cytokine-producing cells reappeared in the circulation in relation to the treatment and clinical improvement. The underlying mechanisms during infection may include sequestration in the peripheral tissues and/or apoptosis. In fact, increased activation-induced apoptosis in the remaining peripheral lymphocytes and elevated levels of soluble Fas ligand were detected at admission to the hospital. In conclusion, these data suggest that activated T lymphocytes with a type 1 cytokine profile are highly engaged in the in vivo immune response to S. pneumoniae.