CD4(+) IL-17A(+) T cells counts and serum IL-17 levels in conjunction with augmented FeNO levels are systemic markers of childhood asthma, using these markers, prediction and potential therapeutics for persistent asthmatics may be developed.

Pam3CSK4, a synthetic TLR2 ligand, has been shown to expand CD4+ regulatory T cells (Treg cells). Less is known about the function of CD8+ Treg cells than about the function of CD4+ Treg cells generated during allergen-specific immunotherapy (IT). This study investigated whether Dermatophagoides pteronyssinus-specific IT could expand the CD8+CD25+Foxp3+ Treg population and whether Pam3CSK4 could enhance the Treg population. PBMCs were isolated from healthy control subjects and from mite-sensitive asthmatic patients during IT at three specific times: before IT and 6 mo and 1 y after the maximum-tolerated dose. This study was performed without a placebo-controlled group. D. pteronyssinus-specific IT induced a significant increase in CD8+Foxp3+ Treg cells expressing intracellular IL-10 and granzyme B. Costimulation of PBMCs with Pam3CSK4 and D. pteronyssinus 2 expanded the CD8+CD25+Foxp3+ Treg population and inhibited D. pteronyssinus 2-induced IL-4 production. Pam3CSK4-treated CD8+CD25+ Treg cells directly suppressed CD4+ T cell proliferation by cell-contact inhibition. TUNEL revealed that CD8+CD25+ Treg cells, but not CD4+CD25+ Treg cells, directly induced CD4+CD45ROhi+ apoptosis. Our results provide direct evidence that Pam3CSK4 induces an immunomodulatory effect by inducing CD8+ Treg cells; therefore, it may be a good adjuvant for the treatment of mite allergies.

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.