Nasal immunotherapy in weed-induced allergic rhinitis

[Allergen immunotherapy for rare allergens]

Among allergies to aeroallergens, approximately 20% are allotted to the so-called rare allergens. These include ash pollen, weed pollen, storage mites, molds, and animal allergens. The prevalences of allergies to these allergens are lower, but affected patients also suffer considerably from their "rare" allergy. Hence, these allergies should neither be overseen nor completely forgotten in daily practice. Especially mold, mite, and animal allergens often induce asthma, so that the significance of allergen-specific immunotherapy (AIT) should not be neglected in causal therapy. This work summarizes the current state of knowledge on the groups of rare aeroallergens in terms of characteristics, prevalences, and data on AIT. It is based on a systematic literature search performed in the MEDLINE (PubMed®) and Google Scholar databases. AIT preparations for rare allergens are classified as individual formulations and are not subject to the German Therapy Allergen Ordinance. Due to the low case numbers, the levels of evidence for these formulations are not as high as those for dust mites, grass, or birch pollen, but exhibit good efficacy in practical experience.

LNIT-Local nasal immunotherapy in allergic rhinitis: revisited evidence and perspectives

PURPOSE OF REVIEW

Allergen immunotherapy (AIT) is a personalized treatment approach for the allergic airway disease. The most common routes of administration are subcutaneous and sublingual. Local nasal immunotherapy (LNIT) presents another alternative route for allergen desensitization. Nasal mucosa is the first entry site of pathogens and numerous lymphoid organs are located in this area, making LNIT a favorable method for triggering immune tolerance. LNIT has shown promising results in reducing symptoms and medication use in allergic rhinitis patients. Over time, difficulties in dosing adjustments have made this method less popular. Recent advances in intranasal drug delivery systems warrant re-examination of LNIT as a viable option for the treatment of the allergic airway disease.

RECENT FINDINGS

The scope of the review includes evidences of LNIT in human trials including comparison with placebo and conventional method of immunotherapy. Recent articles regarding the mechanism of LNIT and the challenges of intranasal drug delivery are reviewed. Advances in the LNIT delivery system which have overcome previous limitations demonstrate promising effects.

SUMMARY

LNIT presents a judicious alternative for noninjection AIT. The evidences from previous clinical trials and the novel improvement of drug delivery system will lead into the future allergen vaccine production.

Local nasal immunotherapy for allergic rhinitis: A systematic review and meta-analysis

INTRODUCTION

Local nasal immunotherapy (LNIT), an alternative noninjection immunotherapy method, is theoretically an efficient method for inducing immunotolerance directly in the affected organ. LNIT is more convenient and less invasive than injection immunotherapy, with fewer systemic reactions. The development of adjuvants to overcome LNIT's limitations raises the possibility of it being an alternative allergen immunotherapy.

OBJECTIVES

To evaluate the clinical and immunological efficacy and safety of LNIT for patients with allergic rhinitis.

METHODS

A systematic search for randomized controlled trials comparing LNIT and placebo was performed using OVID Medline and Embase. Outcomes were total nasal symptom score (TNSS), symptom-medication score (SMS), medication score, immunological assessment, and nasal provocation threshold. Data were pooled for meta-analysis.

RESULTS

A total of 20 studies with 698 participants were included. The LNIT group had greater posttreatment improvement in TNSS, SMS, and medication score than control (TNSS: standardized mean difference [SMD], -1.37 [95% confidence interval [CI], -2.04 to -0.69]; SMS: SMD, -1.55 [95% CI, -2.83 to -0.28]; and medication score: SMD, -1.09 [95% CI, -1.35 to -0.83]). Immunological assessments showed no significant differences in serum-specific IgE (mean difference [MD], 6.35; 95% CI, -4.62 to 17.31), nasal IgE (MD, -0.59; 95% CI, -1.99 to 0.81), or nasal eosinophil cationic protein (MD, 7.63; 95% CI, -18.65 to 33.91). Only serum IgG significantly increased with LNIT (MD, 0.45; 95% CI, 0.20, 0.70). Posttreatment, nasal provocation threshold was higher with LNIT (MD, 27.30; 95% CI, 10.13-44.46). No significant adverse events were reported.

CONCLUSIONS

LNIT is a safe alternative allergen immunotherapy route without significant adverse events. It improves clinical symptoms, reduces medication usage, and increases the nasal provocation threshold.

ICON: Diagnosis and management of allergic conjunctivitis

Ocular allergy (OA), interchangeably known as allergic conjunctivitis, is a common immunological hypersensitivity disorder affecting up to 40% of the population. Ocular allergy has been increasing in frequency, with symptoms of itching, redness, and swelling that significantly impacts an individual's quality of life (QOL). Ocular allergy is an often underdiagnosed and undertreated health problem, because only 10% of patients with OA symptoms seek medical attention, whereas most patients manage with over-the-counter medications and complementary nonpharmacological remedies. The clinical course, duration, severity, and co-morbidities are varied and depend, in part, on the specific ocular tissues that are affected and on immunologic mechanism(s) involved, both local and systemic. It is frequently associated with allergic rhinitis (commonly recognized as allergic rhino conjunctivitis), and with other allergic comorbidities. The predominance of self-management increases the risk of suboptimal therapy that leads to recurrent exacerbations and the potential for development of more chronic conditions that can lead to corneal complications and interference with the visual axis. Multiple, often co-existing causes are seen, and a broad differential diagnosis for OA, increasing the difficulty of arriving at the correct diagnosis(es). Ocular allergy commonly overlaps with other anterior ocular disease disorders, including infectious disorders and dry eye syndromes. Therefore, successful management includes overcoming the challenges of underdiagnosis and even misdiagnosis by a better understanding of the subtleties of an in-depth patient history, ophthalmologic examination techniques, and diagnostic procedures, which are of paramount importance in making an accurate diagnosis of OA. Appropriate cross-referral between specialists (allergists and eyecare specialists) would maximize patient care and outcomes. This would significantly improve OA management and overcome the unmet needs in global health.

Oralair®: sublingual immunotherapy for the treatment of grass pollen allergic rhinoconjunctivitis

Oralair(®) is a sublingual grass pollen immunotherapy tablet that was authorized for use in Europe on 26 November 2009 and is currently in Phase III clinical trials in the USA. It is indicated for the management of grass pollen allergic rhinitis with or without conjunctivitis in adults, adolescents and children (above the age of 5) with clinically relevant symptoms, confirmed by a positive cutaneous test and/or a positive titer of the specific IgE to the grass pollen. Treatment is composed of an initiation phase (3-day dose escalation: 100 IR [index of reactivity] on day 1, 200 IR on day 2 and 300 IR on day 3) and a continuation phase at a dosage of 300 IR/day. Treatment is scheduled to start approximately 4 months before the actual start of the pollen season and should be continued throughout the season. The treatment should be prescribed and initiated by an experienced allergy specialist.

Local nasal specific immunotherapy for allergic rhinitis

The possibility of producing local hyposensitization by administering allergens via mucosal routes was envisaged at the beginning of 1900, and local nasal immunotherapy has been extensively studied since the 1970s. Presently, there are 21 randomized controlled trials being conducted with the most common allergens, consistently showing the clinical efficacy of local nasal immunotherapy for rhinitis. Other advantages are that it has an optimal safety profile and can be self-administered at home by the patient. Moreover, there are several data from animal models and from humans that confirm the immunomodulatory effect of intranasally administered antigens. On the other hand, local nasal immunotherapy seems to be effective only on rhinitis symptoms and requires a particular technique of administration. For these reasons, its clinical use is progressively declining in favour of the sublingual route although nasal immunotherapy is validated in official documents and remains a viable alternative to injection.

Allergic diseases of the eye

The prevalence of ocular allergy is clearly underappreciated; it has been an underdiagnosed and undertreated area in primary care medicine. The ocular symptoms associated with the most common ocular allergy conditions,such as seasonal and perennial AC, are twice as likely to affect the allergy sufferer as nasal symptoms alone. The emergence of new medications for the specific treatment of ocular symptoms over the course of the past 15 years offers a new field for improved patient care by the primary and sub-specialty health care providers.

Eosinophilia in rheumatologic diseases: a prospective study of 1000 cases

The role of eosinophilia in connective tissue diseases and the relationship between symptoms of rheumatic disease and eosinophilia have not been clearly established. The purpose of the present study was to explore the prevalence of eosinophilia in rheumatologic disease and determine its relationship to the symptoms. One thousand patients who applied to our rheumatology outpatient clinic between 2001 and 2002 were prospectively studied. The upper limit of normal blood eosinophil numbers was determined as 500 cells/microl of blood. A detailed history was obtained from all patients and careful physical examination was done. A negative correlation was observed between eosinophilia and dryness of the mouth, vitiligo, and fatigue (P < 0.05). Nonsteroidal anti-inflammatory drug usage correlated positively with eosinophilia, which was also statistically meaningful (P < 0.05). Twenty-six of our patients with fibromyalgia (n = 293), three of our subjects with rheumatoid arthritis who were using methotrexate (n = 182), 15 of whom who were not on methotrexate therapy, and one of the 26 with vasculitis had eosinophilia, which was not statistically significant (P > 0.05). None of the patients with scleroderma (n = 12) had eosinophilia. Eleven of the patients with gout had eosinophilia, and only one of them was using allopurinol. We conclude that eosinophilia can be seen in various rheumatologic conditions but, as corticosteroids are one of the most common medications used in collagen tissue diseases, the eosinophil numbers found may be lower than expected and eosinophilia may be more frequent than reported.

Cytokine expression in allergic inflammation: systematic review of in vivo challenge studies

BACKGROUND

Allergic inflammatory responses are driven by cells of the immune system that rely on cytokines to regulate the activity of other immune and structural cells.

OBJECTIVE

To review published studies to (1) identify cytokines consistently increased after allergen challenge in atopic patients and (2) investigate temporal variation in cytokine expression.

METHODS

A PUBMED systematic search was used to extract data from studies involving analysis of cytokine expression in fluids or biopsies following in vivo allergen challenge in atopic patients.

RESULTS

Data were extracted from 82 studies. There were no consistent reports of cytokine protein increase in fluids of patients at 0-1 h after challenge. At 4-12 h, the chemokines eotaxin, macrophage inflammatory protein-1alpha, RANTES (regulated on activation normal T cell expressed and secreted) and interleukin (IL)-8 have all been consistently reported to be up-regulated. At 18-24 h after challenge, the lymphokines IL-4, IL-5 and IL-13, as well as the pro-inflammatory cytokines granulocyte-macrophage colony-stimulating factor, tumour necrosis factor-alpha and IL-6 are consistently increased when compared with the respective control value. There were no reports of up-regulation in interferon-gamma protein and mRNA and in IL-2 mRNA.

CONCLUSION

The expression of granulocyte-macrophage colony-stimulating factor is consistently increased in tissues at 4-12 h after challenge. The influence of this cytokine on antigen capture and presentation by dendritic cells should be further investigated. Additionally, allergen challenge studies are needed that investigate the expression of macrophage-derived chemokine and thymus-regulated and activation-regulated chemokine in tissues of atopic patients. Blocking the effects of these lymphocyte-specific chemokines might provide new therapeutic approaches for the control of allergic inflammation.

Expression of cysteinyl leukotriene synthetic and signalling proteins in inflammatory cells in active seasonal allergic rhinitis

BACKGROUND

Cysteinyl leukotrienes (CysLTs) are bioactive lipids that have been shown to contribute to allergic and inflammatory diseases. Eosinophils and mast cells have the capacity to produce large amounts of CysLTs after allergic or non-allergic stimulation. Molecular identification of both the synthetic and signalling proteins in the CysLT pathway allows the investigation of expression of the CysLT enzymes and receptors in active allergic rhinitis.

OBJECTIVE

We examined the expression of the proteins involved in the synthesis of CysLTs and the cysteinyl leukotriene-1 (CysLT1) and cysteinyl leukotriene-2 (CysLT2) receptors in inflammatory cells from patients with active seasonal allergic rhinitis.

METHODS

Nasal lavage samples were obtained from patients during active seasonal allergic rhinitis. Specific cellular immunocytochemical techniques were used to detect the cysteinyl leukotriene synthetic proteins, namely 5-lipoxygenase (5-LO), 5-lipoxygenase-activating protein (FLAP) and leukotriene C4 synthase (LTC4S). In situ hybridization and immunocytochemical techniques were used to identify the mRNA and proteins for the CysLT1 and CysLT2 receptors.

RESULTS

5-LO, FLAP and LTC4S, and the CysLT1 and CysLT2 receptors were expressed in the majority of eosinophils and in subsets of mast cells and mononuclear cells. 5-LO, FLAP and the CysLT1 receptor, but not LTC4S or the CysLT2 receptor, were expressed in a subset of nasal neutrophils.

CONCLUSIONS

Our study demonstrates the presence of CysLT pathway proteins in key allergic and inflammatory cells from the upper airway of patients with active seasonal allergic rhinitis. Our expression data highlight the potential of CysLT-modifying agents to treat both upper and lower airway symptoms in patients suffering from allergic rhinitis and asthma.

Measurement of changes in mRNA for IL-5 in noninvasive scrapings of nasal epithelium taken from patients undergoing nasal allergen challenge

Nasal allergen challenge of patients with allergic rhinitis results in increased numbers of inflammatory cells and increased production of pro-inflammatory cytokines including interleukin 5 (IL-5). We report a sensitive, noninvasive method to measure changes in the amount of mRNA for IL-5 in nasal epithelium and have used this method to detect alterations of IL-5 mRNA from patients undergoing a nasal allergen challenge. Ten grass or ragweed allergic adults were challenged out of season with appropriate pollen extracts at sufficient dose to give a rhinitis total symptom score of 5 on a scale of 12. After allergen exposure, symptoms were recorded hourly. At 0, 3, and 6 h after allergen exposure, secreted proteins were collected on filter paper strips and two superficial scrapings of nasal epithelium were obtained. The scrapings of epithelium were immediately immersed in 100 microl of RNAlater (Ambion, Austin, TX) and stored at 4 degrees C for up to 1 month without loss of RNA quality. Total RNA was isolated and RT-PCR was performed. cDNA for IL-5 was then measured by real-time fluorescence quantitative PCR with Pre-Developed TaqMan Assay Reagents (PE Biosystems, Foster City, CA). Sufficient RNA was isolated from eight subjects to measure IL-5 mRNA. Data were normalized for content of ribosomal RNA. The relative amount of cDNA for IL-5 was calculated by comparison with internal standards prepared from phytohemagluttinin-stimulated peripheral blood mononuclear cells. Messenger RNA for IL-5 was increased 8.7+/-2.7-fold at 3 h (p<0.01) and 39.5+/-20.9-fold at 6 h (p<0.01). Increased IL-5 mRNA levels at 6 h closely correlate with total symptom scores at 6 h (r=0.88; p=0.007). IL-5 protein was measured by ELISA in eluates from the filter papers. At 6 h, there was increased IL-5 protein (7.7+/-2.8 ng/ml) compared with time zero (1.8+/-0.5 ng/ml) (p=0.02). The levels of IL-5 protein did not correlate significantly with the symptoms score or with changes in the levels of IL-5 protein with IL-5 mRNA. These data show that changes in IL-5 mRNA in patients with allergic rhinitis undergoing an allergen challenge correlate with total symptom scores better than changes in IL-5 protein eluted from filter paper. Furthermore, these changes can be measured quantitatively in very small amounts of tissue.

Current opinion of immunotherapy for ocular allergy

PURPOSE OF REVIEW

Allergic conjunctivitis is common and may be the most prominent or the only feature of allergies. Immunotherapy has been used as a primary treatment for allergies since the early 1900s. Currently the use of immunotherapy for allergic rhinoconjunctivitis is well established and has been shown to decrease the development of bronchial hyperreactivity and asthma. However, the role of immunotherapy for primary treatment of allergic conjunctivitis is unclear. We reviewed the studies where immunotherapy was used with particular attention to the affects on ocular allergies.

RECENT FINDINGS

There are many schedules and methods of delivering immunotherapy. Recent studies have started to assess ocular symptoms as one of the parameters to monitor efficacy of therapy. They follow the affects of immunotherapy on conjunctival provocation tests, ocular symptoms, or the use of eye drops. The literature suggests that using the various immunotherapy modalities at different schedules, ocular symptoms improved even when immunotherapy was used on a rush schedule.

SUMMARY

The initiation of immunotherapy for allergic rhinoconjunctivitis has been shown to switch the immune response to T helper 1 and thus avoid the progression of other atopic conditions. Current literature shows that using many allergens with different forms of immunotherapy appear to have a significant improvement in ocular allergy symptoms and this can be achieved rapidly and safely in most patients. Whether using immunotherapy early in allergic conjunctivitis will alter the progression of other atopic conditions remains to be investigated.

Ocular allergy guidelines: a practical treatment algorithm

The treatment of ocular allergy requires a better understanding of the spectrum of clinical disorders involving various components of the immune system, and of interactions at the conjunctival surface. The immune response focuses primarily on the different levels of activity of Th2 lymphocytes and various other immune cells associated with allergic disorders, including mast cells, eosinophils, fibroblasts, and epithelial and endothelial cells. Ocular allergic disorders include seasonal allergic conjunctivitis (SAC), perennial allergic conjunctivitis (PAC), vernal keratoconjunctivitis (VKC), giant papillary conjunctivitis (GPC) and atopic keratoconjunctivitis (AKC), which, through immunopathological and molecular immunological techniques, can all be better appreciated as being part of a larger spectrum of an atopic disease state. In SAC, pathological changes, such as increased mast-cell activation, the presence of migratory inflammatory cells, and early signs of cellular activation at the molecular level, are minimal. In PAC, these changes are more pronounced in line with the increased duration of allergenic stimulation. In more chronic forms of allergic conjunctivitis, such as VKC in children and AKC in adults, the following changes are evident: a persistent state of mast cell, eosinophil and lymphocyte activation; noted switching from connective-tissue to mucosal-type mast cells; increased involvement of corneal pathology; and follicular development and fibrosis. The treatment of acute and more chronic forms of allergic conjunctivitis has focused in the past on symptomatic relief of symptoms, but with a better understanding of the mechanisms involved we can now provide interventional therapeutic strategies and symptomatic relief. Our advances in the basic understanding of these conditions are providing the foundation for guidelines that improve the ocular health of patients with ocular allergies.

Role of IL-10 in allergen-specific immunotherapy and normal response to allergens

Induction of specific unresponsiveness (tolerance/anergy) in peripheral T cells by interleukin-10 (IL-10) and recovery by cytokines from the tissue microenvironment represent two key steps in specific immunotherapy of allergy and in natural exposure to allergens in healthy individuals. IL-10 elicits anergy in T cells by selective inhibition of the CD28 costimulatory pathway and controls suppression and development of antigen-specific immunity.

Mechanisms of interleukin-10-mediated immune suppression

Specific immune suppression and induction of anergy are essential processes in the regulation and circumvention of immune defence. Interleukin-10 (IL-10), a suppressor cytokine of T-cell proliferative and cytokine responses, plays a key regulatory role in tolerizing exogenous antigens during specific immunotherapy (SIT) of allergy and natural exposure to antigens. Specific T-cell tolerance is directed against the T-cell epitopes of an antigen and characterized by suppressed proliferative and T helper type 1 (Th1) and type 2 (Th2) cytokine responses. IL-10 elicits tolerance in T cells by selective inhibition of the CD28 co-stimulatory pathway and thereby controls suppression and development of antigen-specific immunity. IL-10 only inhibits T cells stimulated by low numbers of triggered T-cell receptors and which therefore depend on CD28 co-stimulation. T cells receiving a strong signal from the T-cell receptor alone, and thus not requiring CD28 co-stimulation, are not affected by IL-10. IL-10 inhibits CD28 tyrosine phosphorylation, the initial step of the CD28 signalling pathway, and consequently the phosphatidylinositol 3-kinase p85 binding to CD28. Together these results demonstrate that IL-10-induced selective inhibition of the CD28 co-stimulatory pathway acts as a decisive mechanism in determining whether a T cell will contribute to an immune response or become anergic.

Decreased serum IgE level, decreased IFN-gamma and IL-5 but increased IL-10 production, and suppressed cyclooxygenase 2 mRNA expression in patients with perennial allergic rhinitis after treatment with a new mixed formula of Chinese herbs

A new mixed formula of Chinese herbs containing Shin-yi-san + Xiao-qing-long-tang + Xiang-sha-liu-jun-zi-tang by the weight of 9 + 3 + 3 g/day was prescribed for the treatment of patients with perennial allergic rhinitis for 3 months (the composition of each herb is shown in the tables of the article). We classified the patients into high (H-IgE) and low IgE (L-IgE) groups according to the titer of serum total IgE (> 200 KIU/l in H-IgE vs. < 200 KIU/l in L-IgE) and the presence of house dust mite-specific IgE. The nasal symptomatic score in the high IgE group was significantly improved from 7.19 +/- 0.18 before treatment to 2.67 +/- 0.37 after treatment. In addition, the serum total and house dust mite-specific IgE level were also decreased after treatment. For elucidating the working mechanism of the mixed formula, the Th1 (IFN-gamma) and Th2 (IL-4, IL-5, IL-10 and IL-13) cytokine production by phytohemagglutinin (PHA)-stimulated mononuclear cells (2 x 10(6) cells/ml) and cyclooxygenase type 2 (COX-2) mRNA expression in LPS or IL-13-stimulated PMN were compared before and after 3 months of treatment. We found that the mixed formula treatment significantly enhanced IL-10 but decreased IFN-gamma and IL-5 production by PHA-stimulated mononuclear cells. The IL-5 production was also decreased by PHA-stimulated lymphocyte. In addition, the COX-2 mRNA expression in stimulated PMN was significantly suppressed after treatment. These results suggest that the new mixed formula treatment is beneficial to the patients with perennial allergic rhinitis via modulating the function of lymphocytes and neutrophils.

Specific immunotherapy prevents increased levels of allergen-specific IL-4- and IL-13-producing cells during pollen season

BACKGROUND

Specific allergen immunotherapy (SIT) is effective for treatment of IgE-mediated diseases: however, the mechanisms of action still remain unclear. Earlier, we showed that IL-4 and IL-13 are produced in response to specific allergens. The aim of this study was to investigate whether these cytokine responses were affected by allergen SIT, and, furthermore, to evaluate the effect of SIT on allergen-specific IgE and IgG4 levels.

METHODS

Blood samples from pollen-sensitized individuals were collected before the pollen season (before treatment) and during the pollen season (after SIT or placebo treatment). Peripheral blood mononuclear cells were activated in vitro with allergens and the numbers of IL-4-, IL-13-, IL-10-, and IFN-gamma-producing cells were determined by ELISPOT. Serum levels of allergen-specific IgE and IgG4 were measured by RAST and ELISA, respectively.

RESULTS

The numbers of IL-4- and IL-13-producing cells were shown to be increased in the placebo group during the pollen season, an increment which was absent in patients receiving allergen SIT. We found an increase in allergen-specific IgG4 in the SIT-treated individuals, but not in the placebo group. Both groups displayed elevated specific IgE levels during the pollen season.

CONCLUSIONS

Taken together, our data show a downregulation of IL-4- and IL-13-producing cells in peripheral blood after SIT, suggesting induction of nonresponsiveness/tolerance or a redistribution of these cells. Furthermore, we demonstrate that SIT acts on antibody production by increasing the specific IgG4 levels.

Atopic diseases and upper respiratory infections

This article reviews information on the topics of asthma, allergic rhinitis, atopic dermatitis, food allergy, and upper respiratory infections. The asthma section includes a review of inhaled steroids and their potential side effects. New findings on the pathogenesis, triggers, and therapies of atopic dermatitis and new insights into food hypersensitivity reactions are presented. Recent publications in the areas of allergic rhinoconjunctivitis and upper respiratory infections are also reviewed.

IL-10-induced anergy in peripheral T cell and reactivation by microenvironmental cytokines: two key steps in specific immunotherapy

Specific immunotherapy (SIT) is widely used for treatment of allergic diseases and could potentially be applied in other immunological disorders. Induction of specific unresponsiveness (anergy) in peripheral T cells and recovery by cytokines from the tissue microenvironment represent two key steps in SIT with whole allergen or antigenic T cell peptides (PIT). The anergy is directed against the T cell epitopes of the respective antigen and characterized by suppressed proliferative and cytokine responses. It is initiated by autocrine action of IL-10, which is increasingly produced by the antigen-specific T cells. Later in therapy, B cells and monocytes also produce IL-10. The anergic T cells can be reactivated by different cytokines. Whereas IL-15 and IL-2 generate Th1 cytokine profile and an IgG4 antibody response, IL-4 reactivates a Th2 cytokine pattern and IgE antibodies. Increased IL-10 suppresses IgE and enhances IgG4 synthesis, resulting in a decreased antigen-specific IgE:IgG4 ratio, as observed normally in patients after SIT or PIT. The same state of anergy against the major bee venom allergen, phospholipase A2, can be observed in subjects naturally anergized after multiple bee stings. Together, these data demonstrate the pivotal role of autocrine IL-10 in induction of specific T cell anergy and the important participation of the cytokine microenvironment in SIT. Furthermore, knowledge of the mechanisms explaining reasons for success or failure of SIT may enable possible predictive measures of the treatment.