Neutrophils of healthy subjects with a history of reactive arthritis show enhanced responsiveness, as defined by CD11b expression in adherent and non-adherent whole blood cultures.
OBJECTIVE
To study innate immune responsiveness of HLA-B27 positive subjects recovered from Yersinia-triggered reactive arthritis (B27 + ReA+).


METHODS
Whole blood samples from 15 B27 + ReA+, 15 B27 + ReA- and 15 B27 - ReA- subjects were heparinized, aliquoted and (i) kept at 0 degree C to preserve constitutive cell surface marker status, or (ii) cultured with or without bacterial lipopolysaccharide (LPS) supplement, in adherent and non-adherent conditions at 37 degrees C for 4 h. Neutrophil surface expression of CD11b, CD14 and CD16 was quantified flow cytometrically, and compared between the subject groups using Jonckheere-Terpstra test.


RESULTS
The B27 + ReA+ group showed significantly higher CD11b levels than the B27 - ReA- group on non-adherent neutrophils cultured with LPS as 100 pg/ml (P = 0.027), 10 ng/ml (P = 0.048) or 1 microg/ml (P = 0.024), or on adherent neutrophils without LPS supplement (P = 0.040). CD14 and CD16 expression on cultured neutrophils and constitutive expression of all three markers were comparable between the groups.


CONCLUSIONS
Enhanced neutrophil reactivity observed may exacerbate innate immune inflammation in HLA-B27 positive ReA patients.
Kuuliala
K
K
Haartman Institute, Department of Bacteriology and Immunology, University of Helsinki, Finland. krista.anttonen@helsinki.fi
Orpana
A
A
Leirisalo-Repo
M
M
Repo
H
H
D016918:Arthritis, Reactive / Q000276:immunology*; D039481:CD11b Antigen / Q000097:blood*; D002448:Cell Adhesion / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D015796:HLA-B27 Antigen / Q000097:blood; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000097:blood; D008070:Lipopolysaccharides / Q000276:immunology; D009504:Neutrophils / Q000276:immunology*; D000091402:Prohibitins; D017452:Receptors, IgG / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D039481:CD11b Antigen; D015796:HLA-B27 Antigen; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; C000717331:PHB2 protein, human; D000091402:Prohibitins; D017452:Receptors, IgG; D014409:Tumor Necrosis Factor-alpha