Mite-specific induction of interleukin-2 receptor on T lymphocytes from children with mite-sensitive asthma: modified immune response with immunotherapy

A review of allergen-specific immunotherapy in human and veterinary medicine

This article reviews allergen-specific immunotherapy in human and veterinary medicine. Current hypotheses of possible mechanisms of actions are outlined. Indications, success rates, adverse effects and factors influencing outcome of therapy are discussed in humans, dogs, cats and horses.

Two year follow-up of immunological response in mite-allergic children treated with sublingual immunotherapy. Comparison with subcutaneous administration

Although the efficacy of allergen-specific sublingual immunotherapy (SLIT) is now accepted, the underlying mechanisms remain elusive. Such mechanisms are better documented in the case of subcutaneous immunotherapy (SCIT). In order to understand the T-lymphocyte response in patients receiving SLIT, we compared children with respiratory disease monosensitized to Dermatophagoides pteronyssinus receiving SLIT or SCIT over a 2-yr period. Peripheral blood was obtained before beginning immunotherapy, and after 3 months, 1 yr and 2 yr. Total IgE, specific IgE and IgG4 to D. pteronyssinus were determined in serum. T-cell markers (CD3, CD4, CD8, CD25) and intracellular cytokine production (TNF-alpha, IL-2, IL-4 and IFN-gamma) were determined in peripheral blood mononuclear cells (PBMC) by flow cytometry. No differences between SCIT and SLIT were detected in the clinical variables or in the subjective evaluation. Although an increase in specific IgE and IgG4 was only detected in SCIT, a significant decrease in the specific IgE/IgG4 ratio was found in both groups. SCIT and SLIT experienced an increase in the CD4/CD8 ratio over time, but an increase in the CD4(+)CD25(+) and a decrease in the CD8(+)CD25(+) subsets were only found with SCIT. A slight shift from a Th2 to a Th1 pattern, measured by the IFN-gamma/IL-4 ratio, was only detected in the CD4 T cells with SCIT. A decrease in both groups was found in TNF-alpha and IL-2 production over time. Children with respiratory allergic diseases receiving SCIT or SLIT had a different immunologic response in peripheral blood during treatment, though the clinical improvement was similar. Whether SLIT induces a mucosal protective response should be studied.

Cell-surface expression of CD25, CD26, and CD30 by allergen-specific T cells is intrinsically different in cow's milk allergy

BACKGROUND

The release of T(H)2 cytokines by food-specific T cells is thought to be important in the etiology of food allergy. It has been suggested that the activation state of food-specific T cells also plays a significant role, but this has not yet been studied at the single-cell level.

OBJECTIVE

Differences in the expression of cell-surface markers by cow's milk protein (CMP)-specific T cells between infants with and without cow's milk allergy (CMA) were evaluated at the clonal level. In addition, expression after the spontaneous development of tolerance of cow's milk in infants with CMA was analyzed.

METHODS

We established CMP-specific T-cell clones (TCCs) from blood of infants with CMA and atopic dermatitis, from atopic controls with atopic dermatitis but without CMA, and from nonatopic controls. In addition, we established TCCs from infants with CMA after they had spontaneously developed tolerance to cow's milk. Expression levels of CD25, CD26, and CD30 by each TCC were analyzed by use of flow cytometry.

RESULTS

Cow's milk protein-specific T cells from infants with CMA expressed much higher levels of CD25 and CD30 than CMP-specific T cells from infants without CMA. Expression of CD26 was much lower than in normal controls. After development of tolerance for cow's milk, expression of CD25 and CD30 was decreased, whereas the expression of CD26 was increased to normal levels.

CONCLUSION

Antigen-specific T cells from patients with food allergy display an increased expression of cell-surface markers of activation compared with cells of patients without food allergy. This suggests an intrinsically stronger food-specific T-cell response in food-allergic patients, and points to the key role of food-specific T cells in the pathogenesis of food allergy.

T-cell cytokine pattern at three time points during specific immunotherapy for mite-sensitive asthma

BACKGROUND

Several lines of evidence indicate that specific immunotherapy may act by modifying the patterns of cytokines produced by helper T cells. However, different protocols have been used and different results obtained.

OBJECTIVES

To quantify the effect of specific immunotherapy on the TH1/TH2 T-cell cytokine pattern at the single cell level.

METHODS

We examined the interferon-gamma/interleukin-4 ratio in peripheral blood CD4+ and CD8+ T cells from 12 subjects with house dust mite-sensitive asthma using a flow cytometric method of intracellular cytokine detection. Cytokine production was determined following stimulation with phorbol myristate acetate/ionomycin, a policlonal activator. Subjects were examined at three occasions: before specific immunotherapy, after the 3-months dose increase phase and after 1 year of treatment. During the treatment year patients kept a diary in which they recorded: (a) symptoms of asthma according to a 0-3 grading (0 = absent, 1 = mild, 2 = moderate, 3 = severe); (b) number of puffs (100 microg) per day of salbutamol required to control symptoms; and (c) peak expiratory flow.

RESULTS

Specific immunotherapy improved clinical indices of disease activity including symptom scores and medication use during the treatment year, and had a marked effect in increasing the interferon-gamma/interleukin-4 ratio in peripheral blood CD4+ T cells already after the dose increase phase (5.47 +/- 1.5 vs 4.07 +/- 1.49%, P = 0.03) with and a further rise after 1 year's treatment (16.12 +/- 2.8 vs 4.07 +/- 1.49 and 16.12 +/- 2.8 vs 5.47 +/- 1.5%, P = 0.001 and P = 0.002, respectively). There were no significant changes in the interferon-gamma/interleukin-4 ratio in peripheral blood CD8+ T cells at the three times of the study.

CONCLUSIONS

These data add to view that the efficacy of specific immunotherapy may be attributed to a modified cytokine secretion of CD4+ T cells.

Activation of telomerase is induced by a natural antigen in allergen-specific memory T lymphocytes in bronchial asthma

The function of the immune system is known to be dependent on the cellular differentiation and clonal expansion of allergen-specific lymphocytes. Telomerase, a ribonucleoprotein enzyme, is believed to be essential for the indefinite proliferation of human cells. To clarify whether telomerase is involved in the pathogenesis of immune diseases as well as of malignancies, we investigated the upregulation of telomerase activity in allergen-specific T lymphocytes. Upregulation of telomerase in allergen-sensitized lymphocytes was induced not only by artificial mitogenic stimulations but also by the natural antigen, house dust mite, which causes allergic diseases. Moreover, the upregulation of telomerase activity in memory T cells activated during allergen-specific immune responses might be associated with the enduring allergen-specific atopic propensity in asthmatics.

Comparison between the in vitro cytokine production of mononuclear cells of young asthmatics with and without immunotherapy (IT)

BACKGROUND

The underlying mechanisms of immunotherapy (IT) are still unknown but may be related to modifications of cytokine production of T lymphocytes.

OBJECTIVE

In this study we determined the in vitro allergen-induced production of IL-2, IL-4, IL-5, IL-12 and IFNgamma of peripheral blood mononuclear cells (PBMC) of eight young asthmatics, aged 15+/-2 years, receiving IT (IT group) and of eight comparable asthmatics, aged 13+/-3.5 years, who never received IT (non-IT group).

METHODS

All patients suffered from perennial asthma and were allergic to house dust mite (HDM). They were selected if they showed a positive stimulation index (SI) of PBMC after in vitro incubation with HDM (i.e. SI > 2). Cells were incubated with and without HDM (10 microg/mL) during 24 h, 48 h and 7 days. Cytokines were determined in the supernatant at the three time points and are expressed as median values in pg/mL.

RESULTS

In the IT group the secretion of IL-2 was lower compared with the non-IT group after 7 days incubation of PBMC with HDM (0 vs 33.2, P = 0.008). In both groups maximal secretion of IL-2 was observed after 48 h. In the non-IT group a high value of IL-2 persisted after 7 days, whereas in the IT group a significant decline of IL-2 occurred after 7 days. Although IL-4 secretion was low in all subjects, more patients of the non-IT group showed detectable IL-4 in the HDM cultures after 24 h and 48 h, although the difference was not statistically significant (P = 0.08 and P = 0.28, respectively). Furthermore, IL-4 secretion was lower in the HDM cultures after 24 h in the IT group (1.75 vs 4.1, P = 0.011) and 48 h (2.2 vs 4.1, P=0.035). IL-5 secretion was lower in the HDM cultures after 24h (12.4 vs 47.6, P = 0.035) and 48 h (26.8 vs 135, P = 0.046) in the IT group than in the non-IT group. After 7 days of incubation with HDM there was no difference between the groups. There was no difference between both groups in secretion of IFNgamma and IL-12.

CONCLUSIONS

These results show a difference in vitro cytokine secretion of PBMC of asthmatics receiving IT compared with asthmatics who never received IT. PBMC of patients receiving IT secrete less IL-2 and IL-5 after in vitro incubation with HDM and show a tendency to secrete less IL-4. The efficacy of IT may be attributed to a modified cytokine secretion of PBMC.