Enhanced frequency of CD18- and CD49b-expressing T cells in peripheral blood of asthmatic patients correlates with disease severity.
BACKGROUND
Results from a transcriptome analysis of human CD4+ T regulatory type 1 (Tr1) clones have indicated that transcripts for the integrins CD18 and CD49b are overexpressed in these cells. The aim of this study was to investigate whether the presence of T cells concomitantly expressing these molecules could be detected in asthmatic patients and represent Tr1 cells.


METHODS
Expression of CD18 and CD49b was analyzed by flow cytometry on peripheral blood mononuclear cells from asthmatic patients of various severity and healthy subjects. The cytokine production profile of purified CD4+ CD18(high) CD49b+ T cells was analyzed by ELISA. The effect of glucocorticoid treatment on the expression of CD18 and CD49b was determined.


RESULTS
The frequency of peripheral blood CD18(high) CD49b+ T cells was significantly elevated in severe asthmatic patients, as compared with both mild asthmatic and healthy donors, and was diminished in asthmatic patients with a controlled status of the disease. Neither short-course oral glucocorticoid treatment of asthmatic patients ex vivo, nor culture of their peripheral blood mononuclear cells with dexamethasone in vitro, increased the frequency of CD18(high) CD49b+ T cells, indicating that their presence seems to be independent from recent anti-inflammatory treatment. However, purified CD4+ CD18(high) CD49b+ T cells from these patients, in contrast to those from healthy donors, lacked the production of the immunosuppressive cytokine interleukin-10.


CONCLUSIONS
In contrast to healthy donors, peripheral blood CD18(high) CD49b+ T cells of asthmatic patients do not fulfill the phenotypic criteria of Tr1 cells. Nevertheless, the presence of elevated numbers of peripheral blood CD18(high) CD49b+ T cells is characteristic for patients with severe and uncontrolled asthma.
Rahmoun
Massilva
M
INSERM U454, CHU de Montpellier, Montpellier, France.
Foussat
Arnaud
A
Groux
Hervé
H
Pène
Jérôme
J
Yssel
Hans
H
Chanez
Pascal
P
D000328:Adult; D000368:Aged; D001249:Asthma / Q000097:blood* / Q000188:drug therapy / Q000276:immunology*; D018821:CD18 Antigens / Q000096:biosynthesis / Q000276:immunology*; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D005434:Flow Cytometry; D005541:Forced Expiratory Volume; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D016130:Immunophenotyping; D039421:Integrin alpha2 / Q000096:biosynthesis / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D018821:CD18 Antigens; D005938:Glucocorticoids; D039421:Integrin alpha2; D003907:Dexamethasone