Induced apoptosis of TH₂ lymphocytes in asthmatic children treated with Dermatophagoides pteronyssinus immunotherapy

Abstract

Allergen-specific immunotherapy (IT) has been effectively used for the treatment of asthma. Allergen specific IT induced immune tolerance with induction of TH2 cells anergy remain to be clarified. The aim of this study was to evaluate whether the mite allergen Dermatophagoides pteronyssinus (Dpt) specific IT serially decreased IL-4+/CD4+ (TH2) lymphocytes and induced apoptosis of TH2 lymphocytes in asthmatic children. Sixty Dpt-sensitive asthmatic children were randomly assigned to a received IT and an untreated group. Dermatophagoides pteronyssinus specific IT treated patients were examined at three time points: before IT, after 6 months of an increased dose phase and with maximum tolerated doses after 1 yr. Peripheral blood mononuclear cells (PBMC) were isolated and cultured for 48 h for cellular staining with CD4+, CD45RO cell phenotypes and interleukin (IL)-4 and interferon-gamma expression by fluorescence monoclonal antibodies. Apoptosis was measured using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) method. A simultaneous flow cytometric study using the same permeabilized cell was examined to determine whether apoptosis occurred preferentially in TH2 lymphocytes. The data demonstrated that Dpt specific IT decreased Dpt-specific IgE levels (p < 0.01) after 1 yr of treatment. In addition, decreased CD4+IL-4+ TH2 cells with increased CD4+IFN-gamma+ TH(1) cells were observed at 6 months and 1 yr after IT treatment (p < 0.05). At the same time, apoptosis of CD4+IL-4+ TH2 lymphocytes in the IT group had increased after 1 yr of treatment when compared with the results before treatment (p < 0.001) and after 6 months of treatment (p = 0.046). In addition, CD45RO cells apoptosis mainly occurred after 6 months of IT treatment and after 1-year period of IT treatment (p < 0.05). All of the data suggested that Dpt specific IT decreased Dpt specific IgE and CD4+IL-4+ TH2 lymphocytes with induction apoptosis of CD4+IL-4+ TH2 lymphocytes subsets serially.

TLR2 Agonists Enhance CD8+Foxp3+ Regulatory T Cells and Suppress Th2 Immune Responses during Allergen Immunotherapy

“…CD8 + Treg cells with regulatory function express transcription factor Foxp3 (11)(12)(13). Human CD8 + Treg cells are implicated in various infectious diseases (14-16) and autoimmune disorders, including multiple sclerosis (17) and inflammatory bowel disease (18) Allergen-specific immunotherapy (IT) by repeated s.c. administration of increased doses of allergen extracts has a long-lasting effect on immune tolerance to common environmental allergens (25)(26)(27). Recent studies suggested that the induction of CD4 + Treg cells might be associated with suppression of allergic responses in patients after successful IT (25).…”

“…Apoptosis of allergen-specific Th2 cells during IT represents a unique downregulatory mechanism that prevents the continuous activation of Th2 immune responses by allergen (26,27 …”

“…The patients received the maximum monthly tolerated dose, according to a previously described standardized protocol, and were followed for 1 y (27). Patients were instructed to record asthmatic scores (27), and pulmonary function forced expiratory volume in 1 s (FEV1) (Sensomedics, Yorba Linda, CA) was measured before and after IT. Fifty children with normal serum IgE levels and who were negative for skin-prick tests were selected as controls.…”

“…Cells were washed twice and stimulated with anti-human CD3 mAb (1 mg/ml; positive control) or Pam3CSK4 (5 mg/ml) for 5 d. For the CFSE-suppression assay (8) + T cells was obtained by flow cytometry after labeling DNA strand breaks using a TUNEL kit (Mebstain Kit, Immunotech, Luminy, France), as mentioned above (27). To confirm TUNEL data, we used an Annexin V-propidium iodide (PI)-labeling kit (BD Biosciences), followed by flow cytometry, to measure apoptosis.…”

Chinese Guideline on allergen immunotherapy for allergic rhinitis

“…The efficacy of AIT in asthma is measured using symptom scores, medication scores, as well as lung function test (55,134,(233)(234)(235). The symptom and medication scores are frequently used as primary endpoints in AIT trials.…”