Cross-reacting IgE and IgG antibodies to Pityrosporum ovale mannan and other yeasts in atopic dermatitis.

Atopic dermatitis (AD) patients often demonstrate positive skin prick test results and serum IgE antibodies to a range of different yeasts. This has been thought to be due to cross-reactivity. In this study, the cross-reactivity of IgE and IgG antibodies between mannan and crude antigens of Pityrosporum ovale, Candida albicans, and Saccharomyces cerevisiae and crude antigens of Cryptococcus albidus and Rhodotorula rubra was examined by RAST and ELISA inhibition with two serum pools of AD patients. We found cross-reacting IgE and IgG antibodies. In the IgE response, the main cross-reacting pattern was the mannan region, although inhibition could be achieved also with crude antigens of C. albicans, S. cerevisiae, and, to some extent, C. albidus. P. ovale was the most potent inhibitor of IgE-binding components, and against it the highest IgE antibody levels were detected in AD serum pools. In contrast, C. albicans was found to be the most important inducer of IgG antibodies, since the IgG level against P. ovale mannan in both AD serum pools was very low. Cross-reacting antibodies were also seen in ELISA inhibition with both crude and mannan antigens, but since the IgG antibody level of P. ovale mannan in AD serum pools was low, further studies are needed to confirm the IgG results.     

IgE autoantibodies in atopic dermatitis -occurrence of different antibodies against the CH3 and the CH4 epitopes of IgE

Levels of "free" anti-IgE autoantibodies and IgE/anti-IgE immune complexes were measured in the sera of patients with atopic dermatitis before and after treatment, psoriasis patients, and nonatopic controls. In this measurement, we used two monoclonal antibodies with distinct in vitro functions (LE 27, BSW 17), directed against the epsilon CH3 and CH4 domains of the IgE Fc-fragment, in a novel immunobinding assay. In patients with atopic dermatitis, elevated levels of "free" anti-IgE antibodies and IgE/anti-IgE immune complexes were detected in comparison to psoriasis patients and controls. In addition, there was a positive correlation between total IgE and the amount of IgE/anti-IgE complexes detected by LE 27 ( r =0.7; P < 0.001) or BSW 17 ( r = 0.64; P < 0.001) in patients with atopic dermatitis. In contrast, an inverse correlation was observed between total IgE and "free" anti-IgE antibodies ( r =−0.34; P < 0.05) in atopic dermatitis. However, serum levels of anti-IgE autoantibodies before and after therapy in patients with atopic dermatitis did not differ, and levels of anti-IgE antibodies did not correlate with clinical severity, as evaluated by an established clinical scoring system. Our data clearly indicate that significantly elevated amounts of anti-IgE antibodies could be observed in patients with atopic dermatitis, which are directed against different epitopes on the IgE molecule. It is tempting to speculate that these autoantibodies exert different effects on IgE-receptor-bearing effector cells and may play an important role in IgE regulation.     

The relevance of skin prick tests for Pityrosporum ovale in patients with head and neck dermatitis

BACKGROUND: Patients with atopic dermatitis often develop immunoglobulin E antibodies against the yeast Pityrosporum ovale. This organism may produce positive skin prick reactions in a higher rate in patients with atopic dermatitis of the head, scalp, and neck region. METHODS: We investigated whether positive prick tests to P. ovale were associated with a specific localization in the head and neck region. A total of 589 consecutive patients were prick tested with a P. ovale extract from ALK Abelló. RESULTS: Thirty-seven patients (6.3%) showed a positive reaction to the P. ovale extract. We could not find significant differences in the localizations of the dermatitis and the pattern of reaction to the tested intracutaneous allergens between the 37 patients positive to P. ovale and the control group of 55 subjects with negative reactions. In a subgroup, we found an elevated level of P. ovale-specific IgE in 100.0% of the patients with head and neck dermatitis, compared with 13.6% in the atopic dermatitis patients with lesions in any other localization. CONCLUSIONS: Our results clearly show that P. ovale-specific IgE is strongly related to the head and neck localization of atopic dermatitis, but RAST seems more sensitive than a prick test with the extract we used.     

Comparison of serum specific IgE antibodies to staphylococcal enterotoxins between atopic children with and without atopic dermatitis

BACKGROUND: The skin of patients with atopic dermatitis (AD) exhibits a striking susceptibility to colonization and infection by Staphylococcus aureus. The exotoxins secreted by S. aureus can act as superantigens and classic allergens, inducing the production of functionally relevant specific IgE antibodies. The aim of this study was to compare the levels and positive rates of serum staphylococcal enterotoxin A (SEA)- and staphylococcal enterotoxin B (SEB)-specific IgE between atopic children with and without AD. METHODS: Sixty children with AD, 55 children with respiratory allergy without AD, and 24 nonatopic healthy children were studied. The levels and positive rates of serum SEA- and SEB-specific IgE were compared among three groups. The correlation between the levels or positive rates of serum SEA/SEB-specific IgE and the severity of AD or the presence of previous skin infections was studied. RESULTS: The children with AD had significantly higher levels and positive rates of serum SEA- and SEB-specific IgE than the atopic children without AD (P < 0.001) and the nonatopic children (P < 0.001). There was no significant difference in the levels and positive rates of serum SEA- and SEB-specific IgE between the atopic children without AD and the nonatopic children. With or without adjustment for the potential confounding effect of total serum IgE levels, the levels and positive rates of serum SEA- and SEB-specific IgE were significantly correlated with severity of AD (P <0.005), but they were not significantly different between AD children with and without previous skin infections. CONCLUSIONS: SEA and SEB may contribute to chronic inflammation and exacerbation of AD through the IgE-mediated immune response.     

IgE and IgG antibodies to Malassezia spp. yeast extract in patients with atopic dermatitis

The presence of immunoglobulins to Malassezia spp. surface proteins in the sera from patients with atopic dermatitis and healthy subjects was studied. It was found that 28% of 25 examined patients with atopic dermatitis had IgE antibodies to Malassezia spp. surface protein preparation. All patients and 5 healthy subjects had IgG antibodies to this preparation. The presence and concentration of specific IgE antibodies in patients with atopic dermatitis correlated with reverse titers of IgG antibodies to this preparation (r=0.782). The medians of values reciprocal to IgG antibody titers in patients with atopic dermatitis with and without specific IgE antibodies to the preparation and in healthy subjects were 64, 1024, and 16, respectively. The preparation derived from Candida albicans (candidine) and previously derived preparation from Malassezia did not cross-react. According to immunoblotting data, the preparation contains allergens presented by proteins with molecular weights 15, 36, 52-56, and 78.4 kDa.     

IgE on Langerhans cells in the skin of patients with atopic dermatitis and birch allergy

Epidermal cell suspensions from the skin of seven patients with atopic dermatitis (AD) and seven healthy non-atopic controls were investigated for the presence of surface HLA-DR and CD1 antigen, and IgE using indirect and double-staining immunofluorescence techniques. Fifty-seven percent of all CDI + and 68% of all HLA-DR + cells from the patients demonstrated IgE on their surface, indicating that Langerhans cells (Lc) in AD may be a heterogeneous population with regard to surface characteristics. No IgE + cells were found in the epidermal cell suspensions from the healthy non-atopic controls. An attempt lo demonstrate birch pollen antigen on the surface of Lc from the same patients all strongly allergic to birch pollen, using indirect immunofluorescence techniques, was unsuccessful, also after in vitro incubation of the Lc with high concentration of the birch antigen.     

Allergens of Pityrosporum ovale and Candida albicans

In atopic dermatitis (AD), a high prevalence has been reported of type I reactions and specific IgE to extracts of the commensal lipophilic skin yeast Pityrosporum ovale. In the present study, a highly significant correlation (r=0.77) was found between levels of anti- P , ovale IgE and of IgE reacting with extracts of Candida albicans , both measured by a sensitive ELISA method. In a series of 128 AD sera, 34 sera reacted positively with both yeast extracts, 38 reacted with P. ovale but not with C. albicans, and only one of the 56 anti-F. ovafe-negative sera showed a very weak reaction with C. albicans . The correlation was due to a marked cross-reactivity, as shown by inhibition ELISA. Eluid-phase preincubation of double-positive sera with either of the two yeast extracts resulted in a dose-dependent, and at high concentrations complete, inhibition of the IgE reactions with both coated P. ovale and C. albicans allergens. Mutual inhibition of IgE-binding could also be achieved with pools of glycoproteins and/or polysaccharides isolated from the crude extracts by Con A affinity chromatography. P. ovale allergens were, however, more potent fiuid-phase inhibitors than the corresponding C. albicans components. The apparently higher avidity for P. ovale allergens suggests that these antiyeast IgE antibodies in AD result from sensitization to P. ovale and cross-react with C albicans .     

Systemic ketoconazole is an effective treatment of atopic dermatitis with IgE-mediated hypersensitivity to yeasts

BACKGROUND: IgE-mediated hypersensitivity to yeasts is often seen in atopic dermatitis (AD) patients, especially when dermatitis is located in the head, neck, and shoulder regions. Two studies have shown the efficacy of ketoconazole in the treatment of this type of AD, in contrast to results of topical treatment. The objective was to assess the clinical efficacy of antifungal treatment in AD in a randomized, double-blind, placebo-controlled study with oral ketoconazole and yeast-specific IgE levels and saprophytic yeast growth monitored simultaneously. METHODS: Eighty patients with AD and positive P. ovale and/or C. albicans RAST/skin prick test results were randomized to receive ketoconazole or placebo for 30 days. The yeast growth of skin and pharynx; P. ovale, C. albicans, andS. cerevisiae RAST; serum total IgE; and the severity of the eczema (SCORAD) were assessed at day 0 and thereafter at 1 and 3 months. RESULTS: A significant improvement was seen in the SCORAD scale in the ketoconazole group at the second visit in comparison to the first visit (P<0.0005; n=36), but not in the placebo group (n=39). Of the individual determinants of the SCORAD, itching (P<0.005), the extent of dermatitis (area percentage), excoriation, lichenification (P<0.01), erythema, papulation, and dryness (P<0.05) improved significantly in the ketoconazole group. In the placebo group, only the extent of dermatitis (area percentage) decreased significantly (P<0.05). In the ketoconazole group, the number of positive P. ovale cultures decreased from 60% to 31% (n=35) compared to the placebo group (64% to 56%; n=39). The clinical response was most significant in female patients with positive yeast cultures. CONCLUSION: Saprophytic yeasts may be a source of allergens in AD. Thus, patients with AD, yeast growth, and elevated IgE levels to yeasts should be offered antifungal treatment.     

The severity of atopic dermatitis and the relation to the level of total IgE,onset of atopic dermatitis and family history about atopy

The aim of this study is the evaluation, if the level of total IgE, onset of atopic dermatitis (AD) and the family history are in the significant dependence to the severity of AD. The statistical evaluation of the dependence between the severity of AD and the the level of total IgE, family history and onset of AD was performed. 296 patients were examined. The level of total IgE above 200 IU/ml is recorded in 93 % of patients suffering from severe form and the positive data about atopy in family history are recorded in 66 % of patients with severe form of AD. The significant dependence was recorded between the severity of AD and parameters such as the level of total IgE, and family history about atopy. No dependence was recorded between the severity of AD and the onset of AD.     

IgE responses to exogenous and endogenous allergens in atopic dermatitis patients under long‐term systemic cyclosporine A treatment

Atopic dermatitis (AD) patients mount IgE antibody responses to a variety of environmental allergens and also to autoantigens. We analyzed serum samples from four AD patients who had received oral cyclosporine A (CyA) treatment for up to 17 months regarding IgE autoreactivity to nitrocellulose‐blotted human epithelial cell extracts and IgE levels to environmental allergens by quantitative ImmunoCap measurements. Skin inflammation was assessed by SCORAD. During full‐dose treatment, a strong reduction in T‐cell‐mediated skin symptoms was observed which reappeared when CyA treatment was reduced or stopped. The intensity of IgE autoreactivity seemed to follow skin inflammation as it was reduced during full‐dose treatment and increased upon inflammation. Interestingly, IgE levels to exogenous allergens were boosted by allergen exposure, declined thereafter, and seemed to be unaffected by CyA. Our data thus indicate that allergen‐specific IgE production is boosted by allergen contact and cannot be reduced by CyA‐mediated T‐cell suppression.     

Blood eosinophils and serum IgE as predictors for prognosis of interferongamma therapy in atopic dermatitis

Background Interferon-gamma (IFN-γ) therapy has been reported to be effective in atopic dermatitis. However, IFN-γ therapy in atopic dermatitis has not yet been well established, ln this study, immunologic variables were evaluated as predictors for the prognosis of IFN-γ therapy in atopic dermatitis
Methods Sixty-eight atopic dermatitis patients were each treated 18 times with 2 X 10⁶ units/m² IFN-γ. Blood IgE level, eosinophil percentage, eosinophil count, and levels of IFN-γ, interIeukin-4 (IL-4), IL-5, and IL-10 were investigated. According to clinical responses, patients were classified into three groups: patients with improved clinical severity scores of over 20% were included in group A; those with improved scores of 20% or less in group B; and those with no improvement in group C.
Results Serum IgE levels and blood eosinophil percentages were the lowest n group A. Most atopic dermatitis patients with an eosinophil percentage over 9% and IgE level over 1500 lU/ml did not respond to IFN-γ therapy. Initial IL-10 levels were the highest in group A. IL-4 levels in group A, and IL-5 and IL-10 levels in all groups were significantly decreased by IFN-γ therapy.
Conciusions WN-y therapy may be recommended for atopic dermatitis patients with blood eosinophil percentages less than 9% and serum IgE levels less than 1500 lU/ml.     

Determination of Blomia tropicalis-specific IgE and IgG subclasses in atopic dermatitis patients

BACKGROUND: To verify the importance of Blomia tropicalis in atopic dermatitis (AD), we determined the cutaneous reactivity and the serum level of B. tropicalis-specific IgE and IgG subclasses in AD patients. METHODS: B. tropicalis-specific IgE and IgG subclasses were determined in AD patients and compared with bronchial asthma (BA) patients and a control group (CG) of nonatopic subjects. Specific IgE was obtained by skin prick test and RAST. B. tropicalis-specific IgG subclasses were determined by ELISA. The data were statistically analyzed by chi-square test (Mantel-Haenszel) and odds ratio (OR). RESULTS: We detected positive skin prick tests in 61.76% of AD and 83.33% of BA patients, and in 12.5% of the CG. RAST was positive in 44.12% of AD and in 61.90% of BA patients, but not in the CG. B. tropicalis-specific IgG1 and IgG2 subclasses showed no significant differences between the three groups. IgG3 subclass positivity was statistically significant in AD patients (41.17%) when compared to BA patients (14.29%) and the CG (16.67%). The determination of B. tropicalis-specific IgG4 was positive in 32.35% of AD patients, 21.43% of BA patients, and 8.33% of the CG. CONCLUSIONS: These results confirm that the storage mite B. tropicalis is an important allergen in AD. It is possible that IgG3 activates the complement in AD patients, releasing vasoactive amines that further amplify the allergic reaction. The positive results of the B. tropicalis-specific IgG4 found in AD and BA were probably due to chronic exposure to this storage mite in the home environment.     

Increased urinary excretion of 1.4-methyl-imidazoleacetic acid in patients with atopic dermatitis

To investigate whether the overall histamine turnover is increased in patients with atopic dermatitis, without respiratory disease, the urinary excretion of the main histamine metabolite 1,4-methyl-imidazoleacetic acid (MIAA) was examined in 23 patients and in 23 age- and sex-matched non-atopic controls. The patients excreted significantly more MIAA than the controls. One third of the patients however, showed MIAA excretion within or below normal range. The MIAA excretion was neither correlated to the severity of the eczema nor to the total serum IgE. It was concluded that histamine does not play a significant role in the pathophysiology of atopic dermatitis, and that the great variation in MIAA excretion, and hence the histamine turnover, reflected the spectrum of histamine releasability in the patients.     

Absence of specific IgE antibodies in allergic contact sensitivity to formaldehyde

Immunologic reactions are customarily divided into two broad categories, cell-mediated and antibody-mediated. An interplay between these two pathogenetic principles is indicated by reactions such as cutaneous basophil hypersensitivity, late-phase reaction, and cutaneous lesions indistinguishable from regular allergic contact dermatitis lesions after sensitization with IgE antibodies against certain haptens. In the present study, 23 patients with a history of a positive epicutaneous test to formaldehyde participated. On retest, 15 showed a positive reaction. Eight patients were Phadiatop® positive, indicating an atopic diathesis, and eight had a history of or ongoing atopic dermatitis. On RAST test®, only two, nonatopic patients had specific IgE antibodies to formaldehyde. In the cellular infiltrates of biopsies from epicutaneous test sites, cells reactive with monoclonal antibodies against IgE were found in positive and negative formalin tests, both in atopies and nonatopics, as well as in control biopsies from nonlesional skin. Double immunofluorescence staining experiments showed that IgE occurred on Langerhans' cells. The proportion of IgE-positive cells correlated to the level of serum IgE, but not to atopy. These cells were also found both in the epidermis and in the dermis in nonatopic patients. ICAM-1 occurred on keratinocytes in all patient groups. This study does not support the hypothesis that specific IgE antibodies are active in the pathogenesis of contact sensitivity to formaldehyde either in atopic or in nonatopic patients.     

Bronchial and cutaneous responses in atopic dermatitis patients after allergen inhalation challenge

Background Atopic dermatitis (AD) is often associated with allergic asthma (AA). Inhalation of allergens influences the activity of AA but the effect on the skin in AD is unclear. Objectives We evaluated the degree of bronchial hyperresponsiveness to methacholine in eight AD patients with AA (AD⁺) and eight AD patients without AA (AD^–) and studied bronchial and cutaneous responses after allergen inhalation challenge. Methods All patients were treated in hospital for their eczema with tar ointment (pix liquida) and orally administered antihistamines (mean hospital stay 37 days). After clearing of the skin lesions allergen inhalation challenge was performed. Cutaneous responses were studied by measuring the‘Costa’ score before and 24 h after allergen inhalation challenge. Results The median value of the provocative concentration of methacholine causing a 20% fall (PC₂₀ Mch) in forced expiratory volume in 1 second (FEV₁) was significantly higher in the AD^– group compared to the AD⁺ group with median values of 10.70 and 0.60mg/mL, respectively. These values did not change significantly in both groups during hospital stay. After challenge all AD⁺ patients showed early and late asthmatic responses whereas only four AD^– patients showed early asthmatic responses (mean values of the maximal fall in FEV_l during the EAR 37%/16% and in PEF during the LAR 27%/4% for AD⁺ and AD^–patients, respectively). The‘Costa’ score increased in both groups (mean score before 19.1/ 24.4 and after challenge 26.8/26.9 for AD⁺ and AD⁺ patients, respectively). The increase in the AD^– group was significantly higher compared with the AD^– group (P= 0.016). Conclusion We conclude that allergen inhalation challenge causes a flare up of the skin lesions in atopic dermatitis patients. This was more prominent in atopic dermatitis patients who already suffered from an IgE-mediated allergic inflammation in the lung.     

Functional characterization of skin-infiltrating lymphocytes in atopic dermatitis.

Skin-infiltrating lymphocytes (SIL) were isolated from skin biopsies of patients with hyperimmunoglobulin E (IgE) atopic dermatitis (AD) and expanded in vitro in the presence of IL-2 in combination with IL-4. Phenotypic analysis of skin-derived cells revealed the predominance of CD4+ T helper/inducer phenotype in SIL populations. In 3H-thymidine incorporation assays, SIL showed proliferation in response to IL-2, IL-3, IL-4, ionomycin (Io) + 12-o-tetradecanoyl-phorbol-13-acetate (TPA) and OKT3 + TPA. OKT4 with and without TPA did not induce proliferation. Tumour necrosis factor alpha (TNF-alpha) did not block proliferative responses of SIL to IL-2 and IL-4. Cultured SIL showed no cytotoxic activity against K562 and Jurkat target cells. Expanded skin-derived T cells were tested for their capacity to secrete several cytokines in vitro. SIL secreted significant amounts of IL-4, GM-CSF and TNF-alpha upon stimulation with mitogens but failed to secrete IFN-gamma. Io in combination with phorbol-ester induced the secretion of larger amounts of IL-4, GM-CSF, TNF-alpha and low amounts of IFN-gamma. The data indicate that SIL derived from AD lesions were defective in their capacity to secrete IFN-gamma but were enriched in T cells capable of producing IL-4 upon stimulation. The results support the possibility of a predominant 'TH2-like' cell-mediated immune response in lesional skin of AD patients.     

Assay for detecting IgE and IgG antibodies against Candida albicans cell-wall mannan

In the present study, we assayed mannan-specific IgE and IgG antibodies in samples of serum isolated from blood collected from adult patients with bronchial asthma, using a liquid-phase method with a polysaccharide, mannan (Mn), purified from Candida albicans (C. alb), and investigated the relationships of allergenicity among a crude extract of C alb. purified Mn. and acid protease (AP). The correlations between the titers of anti-Mn A and anti-Mn B IgE and IgG were very strong, and the levels of inhibition of anti-Mn A IgE and IgG reactions by Mn A and Mn B were almost identical. Although no common allergenicity was observed between Mn A and AP because there was no correlation between the titers of anti-Mn A and anti-AP IgE, and no inhibition of the anti-Mn A IgE reaction by AP, both antigens were found to exist in crude C alb. The level of inhibition of anti-crude C. alb IgG reaction by Mn A or Mn B was about 60%. Approximately 70% inhibition of the anti-Mn A IgE reaction was observed for eight different fungal allergen extracts, but no inhibition was observed for 11 of the other fungal allergen extracts tested. The above results indicate that common antigenicity was observed between Mn A and Mn B in the human IgE and IgG antibody production system, and the cross-allergenicity observed among some fungi was considered to be the result of the common antigenicity of Mn isoforms.     

Pityrosporum and Candida specific and non-specific humoral, cellular and cytokine responses in atopic dermatitis patients

BACKGROUND: Recent cytokine (RT-PCR, ELISA) analyses of inflammation in atopic dermatitis (AD) have suggested a role for IL-4, IL-5 and IFNgamma. Pityrosporum ovale and Candida albicans are important allergens in some patients with AD of the seborrhoic head, neck and shoulder region. In AD patients, the saprophytic yeasts induce IgE responses while they usually induce TH1 type responses. The cytokine responses induced by yeasts in AD are sparsely investigated. OBJECTIVE: To characterize the P. ovale- and C. albicans-specific and non-specific humoral, lymphoproliferative and cytokine (IL-2, 4, 5 and IFNgamma) responses in AD. METHODS: Fifteen AD patients and seven healthy controls (HC) were included. Ficoll-isolated PBMC were stimulated by PHA and laboratory-generated extracts of P. ovale and C. albicans. Lymphocyte proliferation was measured by 3H-thymidine incorporation and cytokine production by sandwich-ELISAs. The antigen-specific IgG and IgE antibodies were analysed by ELISA and nitrocellulose RAST. RESULTS: Pityrosporum ovale- and C. albicans-specific IgE (both P < 0.001) and P. ovale-induced PBMC proliferation (P < 0.02) were elevated in AD. In general, the IL-4/IFNgamma ratio induced by P. ovale was higher than that induced by C. albicans (P < 0.01). The PHA-induced IL-2 (P < 0.05) and IL-4 responses (P < 0.005), and the C. albicans-induced IL-5 response (P < 0.02) and IFNgamma response (P < 0.01), were elevated in AD. A network of correlations was seen between serum total and the yeast-specific IgE, P. ovale-specific lymphoproliferation, PHA-induced IL-2, IL-4 and IL-5, and C. albicans-induced IL-5. CONCLUSION: The cytokine profiles found in this study support the role of TH0 or TH1 cells by the side of TH2 cells in the pathogenesis of atopic dermatitis. Pityrosporum ovale appears to be associated more with IL-4 responses and C. albicans with IFNgamma responses.