Infants colonized with enterotoxin-producing staphylococci at 3 months display a decreased frequency of interferon-gamma-producing CD45RO lymphocytes upon stimulation with staphylococcal enterotoxin A at birth but not at 6 months of age.
The aim of the study was to elucidate the relationship between the cytokine response to staphylococcal enterotoxin A (SEA) at birth and subsequent staphylococcal colonization in the first months of life. In a cohort of 45 newborns, cord blood lymphocytes were stimulated with SEA (10 ng/ml) in vitro, re-stimulated with PMA (phorbol myristate acetate) and ionomycin at day 3 and assessed for CD45RO expression and cytokine generation by flow cytometry. The infants were classified into three groups according to nasal staphylococcal colonization and enterotoxin generation at 3 months: There were 16 infants with either no colonization or non-enterotoxin-producing staphylococci, 16 infants with enterotoxins B, C, D and E, and 13 infants colonized with SEA-producing staphylococci. At birth, the group without subsequent colonization displayed a significantly higher frequency of CD45RO-positive interferon-gamma-producing cells (1.7%; range 0.0-9.3%) in comparison to the SEA-positive group (0.1%; range 0.0-0.4%) and also to the group positive for other enterotoxins (0.50%; range 0.0-2.5%). Comparable but less pronounced results were found for interleukin-5 but not for interleukins 2 and 4. At 6 months, no differences in cytokine generation were detected between the three groups. The results provide evidence that a non-specific immunologic immaturity at birth is a risk factor for early bacterial colonization. Furthermore, it is remarkable that this immaturity is similar to that seen in infants destined to be atopic with respect to disequilibrium of interferon-gamma to interleukin-4 generation. Thus the link between early staphylococcal colonization and subsequent atopy requires further investigation.
Schauer
U
U
Klinik für Kinder- und Jugendmedizin der Ruhr Universität im St Josef Hospital Bochum, Germany.
Thurau
A
A
Seitz
M
M
Nowak
L
L
Petri
H
H
Leinhaas
C
C
Rieger
C
C
D000367:Age Factors; D004768:Enterotoxins / Q000276:immunology*; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D006801:Humans; D066298:In Vitro Techniques; D007223:Infant; D007231:Infant, Newborn; D007371:Interferon-gamma / Q000096:biosynthesis*; D015847:Interleukin-4 / Q000096:biosynthesis; D015848:Interleukin-5 / Q000096:biosynthesis; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D009666:Nose / Q000382:microbiology; D013203:Staphylococcal Infections / Q000209:etiology / Q000276:immunology* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000276:immunology / Q000302:isolation & purification / Q000472:pathogenicity; D016176:T-Lymphocyte Subsets / Q000276:immunology*
D004768:Enterotoxins; D015848:Interleukin-5; D015847:Interleukin-4; C026066:enterotoxin A, Staphylococcal; D007371:Interferon-gamma; D017493:Leukocyte Common Antigens