Specific immunotherapy to birch allergen does not enhance suppression of Th2 cells by CD4(+)CD25(+) regulatory T cells during pollen season.
BACKGROUND
The aim of this study was to investigate the suppressive capacity of CD25(+) regulatory T cells on birch allergen-induced T-cell responses during the first birch pollen season after initiation of specific immunotherapy (SIT).


METHODS
CD25(pos) and CD25(neg) T cells were purified from blood of birch-allergic SIT patients and birch-allergic controls, stimulated with birch pollen extract, and analyzed for T-cell proliferation and production of interferon gamma (IFN-gamma), interleukin (IL)-5 and IL-10.


RESULTS
We show that allergen-induced proliferation and IFN-gamma production were suppressed equally well by CD25(pos) T cells from SIT patients and controls, while the IL-5 production was not suppressed by either of the groups. IL-10 levels were higher in SIT patients relative to controls only when CD25(neg) and CD25(pos) were cultured together. Furthermore, neither FOXP3 levels nor proportions of CD25(high) T cells were enhanced in SIT patients compared to allergic controls.


CONCLUSIONS
These results suggest that the Th2-suppressive capacity of allergen-stimulated CD25(pos) Treg in vitro is not improved by SIT in spite of increased IL-10 production from T cells.
Grindebacke
Hanna
H
Department of Rheumatology and Inflammation Research, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. hanna.grindebacke@rheuma.gu.se
Larsson
Pia
P
Wing
Kajsa
K
Rak
Sabina
S
Rudin
Anna
A
D000293:Adolescent; D000328:Adult; D000485:Allergens; D029662:Betula / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology / Q000628:therapy*; D007167:Immunotherapy / Q000379:methods*; D007371:Interferon-gamma / Q000032:analysis; D016753:Interleukin-10 / Q000032:analysis; D015848:Interleukin-5 / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000008:administration & dosage / Q000627:therapeutic use; D011058:Pollen / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D018418:Th2 Cells / Q000166:cytology* / Q000276:immunology; D055815:Young Adult
D000485:Allergens; C521342:Alutard SQ allergen; D015848:Interleukin-5; D010936:Plant Extracts; D016753:Interleukin-10; D007371:Interferon-gamma