In vitro allergen-induced mRNA expression of signaling lymphocytic activation molecule by PBMC of patients with allergic rhinitis is increased during specific pollen immunotherapy.
BACKGROUND
Specific immunotherapy (SIT) acts by inducing a shift from T(H)2 to T(H)1 cell response on mucous membranes, reducing allergic inflammation. New genes expressed primarily in T(H)1-type cells have been found. Of these genes, signaling lymphocytic activation molecule (SLAM) promotes T-cell proliferation and IFN-gamma production. Nothing is known about its role in T(H)2-T(H)1 switch during SIT.


OBJECTIVE
We sought to analyze the mRNA expression of SLAM and other T(H)1-associated genes, interleukin-12 receptor beta2 (IL-12Rbeta2) and T-box expressed in T cells (T-bet), and compare them with the clinical outcome of the therapy.


METHODS
PBMC from 30 patients allergic to pollen undergoing SIT were collected during the therapy. Control PBMC were collected from 10 patients with allergic rhinitis not participating in SIT and from 10 nonallergic subjects. Cells were stimulated in vitro with pollen allergen extracts. SLAM, IL-12Rbeta2, and T-bet mRNA expressions were studied by real-time quantitative RT-PCR technique (Taqman). Symptom scoring and medication scoring were registered before commencement of SIT and after 1 year of the therapy.


RESULTS
Before the treatment, in vitro allergen-induced SLAM mRNA expression in PBMC was significantly lower in the patients with allergic rhinitis than in the healthy control subjects. After 1 year of the treatment, SLAM mRNA expression was increased in the patients undergoing SIT and was associated with IFN-gamma mRNA expression and inversely associated with the symptom improvement. At the maintenance dose, an increase in SLAM mRNA expression was associated with the clinical symptom improvement at 1 year. No changes were seen in IL-12Rbeta(2) or T-bet mRNA expressions.


CONCLUSIONS
SLAM mRNA expression in PBMC is modulated during the course of SIT, and an early and transient increase of SLAM mRNA expression is associated with clinical symptom improvement.
Laaksonen
Kirsi
K
Department of Pulmonary Disease and Clinical Allergology, University of Turku, Turku, Finland.
Junikka
Miia
M
Lahesmaa
Riitta
R
Terho
Erkki O
EO
Savolainen
Johannes
J
D000328:Adult; D000485:Allergens / Q000008:administration & dosage / Q000276:immunology*; D015703:Antigens, CD; D029662:Betula / Q000276:immunology*; D003888:Desensitization, Immunologic; D005260:Female; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics / Q000378:metabolism*; D007963:Leukocytes, Mononuclear; D008213:Lymphocyte Activation; D008297:Male; D031784:Phleum / Q000276:immunology*; D010936:Plant Extracts / Q000008:administration & dosage / Q000276:immunology; D011058:Pollen / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface; D018123:Receptors, Interleukin / Q000235:genetics / Q000378:metabolism; D053707:Receptors, Interleukin-12; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1; D020825:T-Box Domain Proteins; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016896:Treatment Outcome; D000098815:T-bet Transcription Factor
D000485:Allergens; D015703:Antigens, CD; D006023:Glycoproteins; C508439:IL12RB2 protein, human; D007136:Immunoglobulins; D010936:Plant Extracts; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D018123:Receptors, Interleukin; D053707:Receptors, Interleukin-12; D020825:T-Box Domain Proteins; D000098815:T-bet Transcription Factor; D014157:Transcription Factors; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1