Antibodies binding to citrullinated telopeptides of type I and type II collagens and to mutated citrullinated vimentin synergistically predict the development of seropositive rheumatoid arthritis.

OBJECTIVE: To assess whether antibodies binding to citrullinated carboxy-terminal telopeptides of type I and type II collagens (TELO-I and TELO-II, respectively), mutated citrullinated vimentin (MCV) and cyclic citrullinated peptides (CCP) predict the development of rheumatoid arthritis (RA). METHODS: A case-control study was nested within a Finnish cohort of 36 000 adults who had neither arthritis nor a history of arthritis at baseline examination in 1966-1972. Among them, 151 subjects developed seropositive (ie, positive for rheumatoid factor) RA, and 67 subjects developed seronegative RA by late 1989. One or two control subjects were chosen for every case. Preillness serum specimens were analysed for antibodies against synthetic TELO-I, TELO-II, MCV and CCP. RESULTS: The mean levels of anti-TELO-I, anti-TELO-II, anti-CCP and anti-MCV antibodies were higher in subjects who later developed seropositive or seronegative RA than in controls. In subjects who later developed seronegative RA, anti-TELO-I and anti-TELO-II antibodies were statistically significantly higher compared with controls (p=0.005 and p=0.013). In the highest tertiles of anti-MCVs and anti-TELO-I levels, the OR for rheumatoid-factor-positive RA were 2.66 (95% CI 1.48 to 4.77) or 2.51 (CI 1.48 - 4.28), respectively. The subjects ranked into the highest tertiles of both anti-TELO-I and anti-MCV antibodies had a 4.56 OR (95% CI 1.82 to 11.46) of developing seropositive RA compared with those in the lowest tertiles of these antibodies. For the co-occurrence for high anti-TELO-II and anti-MCV antibodies, the corresponding OR was 3.62 (95% CI 1.37 to 9.54). CONCLUSION: Antibodies to TELO-I or TELO-II and MCV exert a synergistic effect on the risk of developing seropositive RA.

Intradermal cytosine-phosphate-guanosine treatment reduces lung inflammation but induces IFN-γ-mediated airway hyperreactivity in a murine model of natural rubber latex allergy.

Asthma and other allergic diseases are continuously increasing, causing considerable economic and sociologic burden to society. The hygiene hypothesis proposes that lack of microbial T helper (Th) 1-like stimulation during early childhood leads to increased Th2-driven allergic disorders later in life. Immunostimulatory cytosine-phosphate-guanosine (CpG)-oligodeoxynucleotide motifs are candidate molecules for immunotherapeutic studies, as they have been shown to shift the Th2 response toward the Th1 direction and reduce allergic symptoms. Using natural rubber latex (NRL)-induced murine model of asthma, we demonstrated that intradermal CpG administration with allergen reduced pulmonary eosinophilia, mucus production, and Th2-type cytokines, but unexpectedly induced airway hyperreactivity (AHR) to inhaled methacholine, one of the hallmarks of asthma. We found that induction in AHR was dependent on STAT4, but independent of STAT6 signaling. CpG treatment increased production of IFN-γ in the airways and shifted the ratio of CD4(+):CD8(+) T cells toward CD8(+) dominance. By blocking soluble IFN-γ with neutralizing antibody, AHR diminished and the CD4(+):CD8(+) ratio returned to CD4(+) dominance. These results indicate that increased production of IFN-γ in the lungs may lead to severe side effects, such as enhancement of bronchial hyperreactivity to inhaled allergen. This finding should be taken into consideration when planning prophylaxis treatment of asthma with intradermal CpG injections.

Latex medical gloves: time for a reappraisal.

Many hospitals have implemented policies to restrict or ban the use of devices made of natural rubber latex (NRL) in healthcare as precautionary measures against the perceived risk of NRL allergy. Changes in glove technology, progress in measuring the specific allergenic potential of gloves and a dramatic decrease in the prevalence of NRL allergies after interventions and education prompted us to revisit the basis for justifiable glove selection policies. The published Anglophone literature from 1990 to 2010 was reviewed for original articles and reviews dealing with the barrier and performance properties of NRL and synthetic gloves and the role of glove powder. The review shows that NRL medical gloves, when compared with synthetic gloves, tend to be stronger, more flexible and better accepted by clinicians. The introduction of powder-free gloves has been associated with reductions in protein content and associated allergies. Recently, new methods to quantify clinically relevant NRL allergens have enabled the identification of gloves with low allergenic potential. The use of low-protein, low-allergenic, powder-free gloves is associated with a significant decrease in the prevalence of type I allergic reactions to NRL among healthcare workers. Given the excellent barrier properties and operating characteristics, dramatically reduced incidences of allergic reactions, availability of specific tests for selection of low-allergen gloves, competitive costs and low environmental impact, the use of NRL gloves within the hospital environment warrants reappraisal.

Sensitization to turnip rape and oilseed rape in children with atopic dermatitis: a case-control study.

Turnip rape and oilseed rape 2S albumins are new allergens in children with atopic dermatitis suspected for food allergy. We recently found that 11% (206/1887) of these children had a positive skin prick test to seeds of oilseed rape (Brassica napus) and/or turnip rape (Brassica rapa). In the present case-control study we examined how the children with atopic dermatitis sensitized to turnip rape and oilseed rape had been breast-fed and whether they had some common sensitization pattern to certain foods or pollens. A total of 64 children with atopic dermatitis and a positive skin prick test to turnip rape and/or oilseed rape (>or=5 mm) were examined. Sixty-four age- and sex-matched children with atopic dermatitis but negative skin prick tests to turnip rape and oilseed rape served as case controls. The turnip rape and/or oilseed rape sensitized children with atopic dermatitis had significantly more often positive skin prick tests reactions and IgE antibodies to various foods (cow's milk, egg, wheat, mustard; p < 0.01) and pollens (birch, timothy, mugwort; p < 0.01) than the control children. They had been exclusively breast-fed for a longer period (median 4 months; p < 0.05) and had more often associated asthma (36%) and allergic rhinitis (44%). Children with atopic dermatitis sensitized to oilseed rape and turnip rape had high frequency of associated sensitizations to all foods and pollens tested showing that oilseed plant sensitization affects especially atopic children who have been sensitized to multiple allergens.

Cutaneous, but not airway, latex exposure induces allergic lung inflammation and airway hyperreactivity in mice.

As respiratory symptoms are common in addition to skin reactions in natural rubber latex allergy, we investigated the significance of different allergen exposure routes in the development of lung inflammation and airway hyperreactivity (AHR). Both intracutaneous (IC) and intraperitoneal (IP) exposure followed by airway challenge with latex proteins induced an influx of mononuclear cells and eosinophils to the lungs. AHR and lung mucus production increased significantly after IC and IP but not after intranasal (IN) exposure. Infiltration of inflammatory cells was associated with the induction of T-helper type 2 (Th2) cytokines and several CC chemokines. Only a marginal induction of these mediators was found after IN exposure. On the contrary, increased levels of transforming growth factor-beta1 and forkhead box 3 mRNA, markers of regulatory activities, were found in the lungs after IN but not after IC exposure. Finally, IC and IP, but not IN, latex exposure induced a striking increase in specific immunoglobulin E (IgE) levels. Cutaneous latex exposure in the absence of adjuvant followed by airway challenge induces a local Th2-dominated lung inflammation and a systemic IgE response. Cutaneous exposure to proteins eluting from latex products may therefore profoundly contribute to the development of asthma in latex allergy.

Synergistic effect of persistent Chlamydia pneumoniae infection, autoimmunity, and inflammation on coronary risk.

BACKGROUND: Given the role of chronic infections, autoimmunity, and inflammation in atherosclerosis, we studied the joint effect of chronic Chlamydia pneumoniae infection, persistently elevated human heat-shock protein 60 (hHsp60) antibodies, and C-reactive protein (CRP) on coronary risk. METHODS AND RESULTS: The participants for this prospective nested case-control study were obtained from the Helsinki Heart Study, during which 241 nonfatal myocardial infarctions or coronary deaths occurred among 4081 dyslipidemic middle-aged men. Serum samples taken at baseline and 3 to 6 months before the coronary events that occurred during the 8.5-year period were analyzed for antibodies to C pneumoniae and hHsp60 and the CRP concentration. Compared with persistently low levels, the risk of coronary events was 2-fold for persistently elevated immunocomplex (IC)-bound and/or serum IgA antibodies to C pneumoniae (OR, 1.96; 95% CI, 1.14 to 3.36) and also for serum IgA antibodies to hHsp60 (OR, 2.11; 95% CI, 1.08 to 4.13). The risks associated with elevated antibodies were much higher when CRP was also elevated. Compared with low or transiently elevated levels, the risk of coronary events, with adjustment for age and smoking, was 4.5-fold for persistently elevated CRP and C pneumoniae IC/IgA antibodies together (OR, 4.47; 95% CI, 1.84 to 10.83) and was similar for CRP and hHsp60 IgA antibodies together (OR, 4.36; 95% CI, 1.53 to 12.39). CONCLUSIONS: Persistently but not transiently elevated C pneumoniae IC/IgA and hHsp60 IgA antibodies, especially when present together with an elevated CRP level, predicted coronary events.

Antibodies to periodontal pathogens are associated with coronary heart disease.

OBJECTIVE: We analyzed the association of coronary heart disease (CHD) and serology of periodontitis in a random sample (n=1163) of men (aged 45 to 74 years) by determining serum IgG-antibodies to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. METHODS AND RESULTS: CHD (n=159) was more prevalent among edentulous than dentate subjects (19.8% and 12.1%, P=0.003). In the dentate population, CHD was more common among subjects seropositive for P. gingivalis compared with those seronegative (14.0% and 9.7%, P=0.029). Accordingly, CHD was more prevalent in subjects with a high combined antibody response than those with a low response (17.4% and 11.1%, P=0.026). When adjusted for age and several CHD risk factors, the subjects with a high combined antibody response had an odds ratio of 1.5 (95% CI, 0.95 to 2.50, P=0.077) for prevalent CHD. In a linear regression model, the combined antibody response was directly associated with prevalent CHD (P=0.046) and inversely with serum HDL cholesterol concentration (P=0.050). CONCLUSIONS: In conclusion, edentulousness and serum antibodies to major periodontal pathogens were associated with CHD. This suggests that periodontal infection or response of the host against the infection may play a role in the pathogenesis of CHD.

Autoimmunity to human heat shock protein 60, Chlamydia pneumoniae infection, and inflammation in predicting coronary risk.

Heat shock protein 60 (Hsp60) and Chlamydia pneumoniae infection have both been associated with cardiovascular diseases. Our aim was to study the role of Hsp60 antibodies as coronary risk predictors and their association with C pneumoniae infection and inflammation. This was a prospective, nested, case-control study. The cases consisted of 239 middle-aged Finnish men who developed myocardial infarction or coronary death during the follow-up. Baseline levels of IgA and IgG antibodies to human-specific and C pneumoniae-specific Hsp60 were measured by enzyme immunoassay. Human Hsp60 IgA, but not IgG or C pneumoniae Hsp60, antibodies were a significant risk factor for coronary events (odds ratio 2.0, 95% CI 1.1 to 3.6, when the fourth and first quartiles are compared). When an elevated human Hsp60 IgA antibody level (above the second quartile) was present simultaneously with a high C pneumoniae IgA antibody level (the third quartile) and an elevated C-reactive protein level (the second quartile), compared with all factors at low levels, the risk was 7.0 (95% CI 2.6 to 19.1) without adjustment and 5.0 (95% CI 1.8 to 14.2) when adjustment was made for age and smoking. In conclusion, an elevated human Hsp60 IgA antibody level was a risk factor for coronary events, especially when it was present together with C pneumoniae infection and inflammation.

Severe periodontitis enhances macrophage activation via increased serum lipopolysaccharide.

OBJECTIVE: In periodontitis, overgrowth of Gram-negative bacteria and access of lipopolysaccharide (LPS) to circulation may activate macrophages leading to foam cell formation. We investigated whether periodontal treatment affects proatherogenic properties of low-density lipoprotein (LDL) and, thus, macrophage activation. METHODS AND RESULTS: LDL was isolated and characterized before and after treatment from 30 systemically healthy patients with periodontitis. Production of cytokines and LDL cholesteryl ester (LDL-CE) uptake by macrophages (RAW 264.7) was determined. Baseline periodontal variables correlated positively with serum LPS and C-reactive protein concentrations, as well as macrophage cytokine production and LDL-CE uptake. LPS concentration correlated positively with serum concentration of oxidized LDL and cytokine production. Higher cytokine production and LDL-CE uptake were induced by LDL isolated from patients with elevated number of affected teeth before treatment. Patients with serum LPS concentrations above the median (0.87 ng/mL) at baseline had higher serum high-density lipoprotein (HDL) cholesterol (baseline versus after treatment, 1.30+/-0.19 versus 1.48+/-0.28 mmol/L; P=0.002) and HDL/LDL ratio (0.31+/-0.01 versus 0.34+/-0.10; P=0.048), but lower serum LPS concentration (1.70+/-0.49 versus 0.98+/-0.50 ng/mL; P=0.004) and autoantibodies to beta2-glycoprotein I (0.11+/-0.06 versus 0.09+/-0.04 ELISA units; P=0.022) after treatment. CONCLUSIONS: Our results suggest that in systemically healthy patients, the infected/inflamed area in periodontitis is associated with macrophage activation via increased serum LPS concentration.

Serum tryptase levels in acute coronary syndromes.

BACKGROUND: Mast cell accumulation and activation have been demonstrated in the vulnerable shoulder regions of atherosclerotic plaques and at the actual sites of plaque erosion and rupture. When activated and degranulated, mast cells release tryptase, a neutral protease, capable of activating matrix metalloproteinases and predisposing to plaque rupture. We tested the hypothesis that in acute coronary syndromes the levels of serum tryptase would reflect mast cell activation. METHODS AND RESULTS: The study population consisted of 183 patients admitted to the emergency room of 3 general hospitals because of acute chest pain of ischemic origin. Of these patients, 64 suffered from exertional angina presenting with acute chest pain, 60 had unstable angina, and 59 had acute myocardial infarction. Serum tryptase levels were analyzed from samples drawn, on average at 7 h, and also at 24 h after the onset of the chest pain. As controls served 41 patients admitted for surgical treatment of inguinal hernia or varicose veins. Serum tryptase levels remained stable within the observation period, and no differences were detected between the patient groups and controls. On the other hand, the differences in C-reactive protein levels reflected the extent of myocardial injury. CONCLUSIONS: In ACS, serum tryptase levels are normal and remain stable. Our results do not exclude the possibility of local activation of coronary mast cells, but suggest that the excess quantity of tryptase acutely released from mast cells in ACS, if any, is not sufficient to be detected by measuring tryptase concentration in the systemic circulation.

Epicutaneous natural rubber latex sensitization induces T helper 2-type dermatitis and strong prohevein-specific IgE response.

In addition to immediate type I allergy symptoms, natural rubber latex allergy may manifest as protein contact dermatitis on the hands of health-care workers and other natural rubber latex glove users. We examined whether repeated application of natural rubber latex on mouse skin causes sensitization to natural rubber latex and dermatitis. Epicutaneous sensitization with natural rubber latex produced a significant influx of mononuclear cells, CD4+ CD3+ cells, and eosinophils to the sensitized skin sites. The number of degranulated mast cells in natural rubber latex-sensitized skin sites was significantly higher compared with control sites treated with phosphate-buffered saline. The expression of interleukin-1beta and interleukin-4 mRNA was markedly increased in natural rubber latex-sensitized skin sites. Moreover, significant increases in the mRNA expression of chemokines CCL2 (monocyte chemoattractant protein-1), CCL11 (eotaxin-1), CCL3 (macrophage inflammatory protein-1alpha), and CCL4 (macrophage inflammatory protein-1beta) were found. In addition to the cutaneous inflammatory response, epicutaneous sensitization with natural rubber latex induced a striking increase in the total and specific immunoglobulin E levels but not in the immunoglobulin G2a levels. Intraperitoneal immunization with natural rubber latex induced a strong natural rubber latex-specific immunoglobulin G2a response, but only a weak immunoglobulin E response. We also studied the role of two major natural rubber latex allergens, the highly hydrophilic prohevein and the hydrophobic rubber elongation factor. Cutaneous application of natural rubber latex elicited a strong immunoglobulin E response against prohevein, but not against rubber elongation factor. On the contrary, intraperitoneal immunization with natural rubber latex elicited strong immunoglobulin G2a production to rubber elongation factor but not to prohevein. These results demonstrate that epicutaneous sensitization with natural rubber latex induces T helper 2-dominated dermal inflammation and strong immunoglobulin E response in this murine model of natural rubber latex induced protein contact dermatitis. Epicutaneous sensitization to natural rubber latex proteins eluting from latex gloves may therefore contribute to the development of hand dermatitis and also natural rubber latex-specific immunoglobulin E antibodies.

Prognostic usefulness of plasma monocyte/macrophage and T-lymphocyte activation markers in patients with acute coronary syndromes.

Macrophages and T lymphocytes accumulate and are activated in atherosclerotic plaques. We tested the hypothesis that plasma levels of the monocyte/macrophage and T-lymphocyte activation markers, monocyte chemoattractant protein-1 (MCP-1) and soluble interleukin-2 receptor (sIL-2r), respectively, can be used in acute coronary syndrome classification and risk prediction. Blood samples were collected at hospital admissions of 183 patients who had ischemic chest pain. Of these, 59 had acute myocardial infarction, 60 had unstable angina, and 64 had angina pectoris. No significant differences in the levels or proportions of subjects with increased levels of MCP-1 or sIL-2r were found across groups. During a mean follow-up of 13 months, 117 patients (64%) had a study end point (i.e., cardiac death, recurrent myocardial infarction, unstable angina, or revascularization). Increased levels (above median) of MCP-1 and sIL-2r were associated with increased risk, with odds ratios of 1.85 (95% confidence interval 0.92 to 3.73, p = 0.08) and 2.34 (95% confidence interval 1.16 to 4.71, p <0.02), respectively. In summary, in this unselected patient population with a very high rate of coronary events during follow-up, increased plasma levels of MCP-1 and sIL-2r were helpful for predicting new coronary events.

Recent developments in latex allergy.

PURPOSE OF REVIEW: Immediate allergic reactions to natural rubber latex continue to be an important medical and occupational health problem. In this review we focus on progress made in understanding the significance of occupational exposure and epidemiology, risk groups, diagnosis and prevention of natural rubber latex allergy. We also discuss methods aimed at quantification of clinically relevant natural rubber latex allergens and studies on B-cell epitopes of major natural rubber latex allergens. RECENT FINDINGS: Prospective studies have been published focusing on the prevention of natural rubber latex allergy. Efforts to identify and characterize new natural rubber latex allergens were continued in several research groups. The use of purified allergens or proteins produced by recombinant DNA technology was assessed in studies aimed at improving the diagnosis of natural rubber latex allergy as well as in developing quantitative methods for the measurement of specific natural rubber latex allergens. For the first time, conformational immunoglobulin E epitopes were identified in a major natural rubber latex allergen, hevein, using a novel chimera-based allergen epitope mapping strategy. SUMMARY: Measures taken in health care to reduce exposure to natural rubber latex products seem to be effective in reducing the number of new sensitizations. A few new minor natural rubber latex allergens, probably important in allergen cross reactions, were identified, and some nonmedical natural rubber latex products were found to be potentially dangerous to natural rubber latex-allergic patients. Sensitive and specific immunoassays for quantification of clinically relevant natural rubber latex allergens in manufactured products were developed in some laboratories. These assays may eventually replace the nonspecific total protein measurement, currently advocated by health authorities in the indirect estimation of allergen amounts in natural rubber latex products. Knowledge about conformational immunoglobulin-binding B-cell epitopes of major allergens is expected to be helpful in designing optimal reagents to specific immunotherapy.

Latex allergy and skin.

PURPOSE OF REVIEW: In this review we address the prevalence and outcome of latex allergy in health care workers (HCWs). Recent findings in natural rubber latex (NRL) allergens and trials of specific immunotherapy (SIT) are also of interest. RECENT FINDINGS: A study involving skin prick test (SPT) screening in HCWs in Russia and adjacent countries found a prevalence of latex allergy of 1.9%. Questionnaire studies performed in Wales and in the USA identified prevalence rates of about 0.6%. An intervention undertaken at the Mayo Clinic, in which only gloves with low or undetectable allergen levels were allowed, reduced markedly the incidence of NRL allergy. Two studies, one from Finland and another from Ohio, showed that outcomes in latex-allergic HCWs are generally good. A study involving SPT screening showed that 6% of construction workers had latex allergy. A questionnaire study among allergists practicing in the USA showed that 62% performed latex SPT and 6% reported anaphylaxis, which mostly occurred while using a homemade SPT solution. Hev b 2, Hev b 5, Hev b 6.01 and Hev b 13 produced positive SPT reactions in over 60% of latex-allergic individuals. Topical application of NRL in a murine model of protein contact dermatitis caused a striking increase in prohevein-specific (Hev b 6.01) immunoglobulin E levels, together with a T-helper-2 type dermatitis. A placebo-controlled SIT trial with NRL extract alleviated cutaneous symptoms but caused some systemic reactions in latex-allergic patients. SUMMARY: Low prevalence rates suggest that the peak of the latex allergy epidemic has already passed in HCWs. Hospital-wide interventions requiring use of low-allergen gloves reduce sensitization and changing gloves to nonlatex ones, or even using low-allergen latex gloves, in the affected individuals appears to confer adequate secondary prevention. In the USA there is an urgent need for standardized latex SPT reagent. Hev b 5 and Hev b 6.01 are major in vivo NRL allergens. Findings in mice suggest that NRL proteins eluting from latex gloves may also cause hand eczema in humans. SIT with NRL extract must still be considered an experimental treatment.

Effect of treating periodontitis on C-reactive protein levels: a pilot study.

BACKGROUND: Periodontitis is associated with elevated levels of C-reactive protein and fibrinogen and it may be a coronary heart disease risk factor. We wanted to study if treatment of periodontitis can decrease the levels of these inflammatory markers. METHODS: C-reactive protein and fibrinogen levels were measured in 35 patients (21 M, 14 F, mean age 50 years) with adult periodontitis, before and after treatment. RESULTS: The median baseline C-reactive protein level in the patients was 1.05 mg/l and it decreased to 0.7 mg/l (p = 0.05) after periodontal treatment. Of the 30 patients who could be included in the analyses, 24 patients had a baseline level below 2 mg/l (the 95th percentile limit in Finland); 6 patients had levels higher than this. Elevation of the baseline C-reactive protein level or the magnitude of its decrease were not associated with severe form of periodontitis. The decrease in C-reactive protein levels was at least 50 % in 4/6 of those with elevated baseline levels, as compared with 3/24 of the rest of the patients (p = 0.016). No corresponding effect was observed in fibrinogen levels. CONCLUSIONS: Periodontitis seems to increase C-reactive protein only in some individuals, presumably the ones reacting to it with a systemic inflammatory reaction. Periodontal treatment decreases C-reactive protein levels in these individuals and it may thus decrease their risk of coronary heart disease.

Autoantibodies binding to citrullinated telopeptide of type II collagen and to cyclic citrullinated peptides predict synergistically the development of seropositive rheumatoid arthritis.

OBJECTIVES: To find out whether autoantibodies to citrullinated telopeptides of type I and II collagens and to cyclic citrullinated peptides (CCPs) predict the development of rheumatoid arthritis (RA). METHODS: A case-control study (matched for sex, age and municipality) was nested within a Finnish cohort of 19072 adults who had neither arthritis nor a history of it at the baseline examination during 1973-7. 124 subjects developed RA by late 1989, and of these, 89 were positive for rheumatoid factor (RF). Preillness serum specimens were analysed for autoantibodies against arginine (A)- or citrulline (C)-containing synthetic telopeptides using a chemiluminescence method and for anti-CCPs Mark2 with an enzyme-linked immunosorbent assay method. RESULTS: The mean levels of autoantibodies to citrulline-containing telopeptides and the C/A ratios of type I and II collagens and to CCP were higher in subjects who later developed RF-positive RA. In the highest tertiles of C/A (I), C/A (II) ratios and anti-CCPs levels, the relative risk of RF-positive RA was significantly increased. In the multifactorial model, only anti-CCPs retained its statistical significance. However, the interaction term of C/A (II) ratio and anti-CCPs proved to be statistically significant (p = 0.02). The subjects ranked into the highest tertiles of both C/A (II) ratio and anti-CCPs had an odds ratio of 20.06 (95% confidence interval, 4.37 to 92.06) of developing RF-positive RA compared with those in the lowest tertiles of these antibodies. None of the autoantibodies predicted RF-negative RA. CONCLUSION: Autoantibodies to citrullinated telopeptides of type I and II collagen and to CCPs exert a synergistic effect on the risk of seropositive RA.

Murine model of food allergy after epicutaneous sensitization: role of mucosal mast cell protease-1.

OBJECTIVE: Studies of the pathological mechanisms of food allergy have been impeded by the lack of relevant animal models. The purpose of this study was to develop a physiological model of food allergy that was not dependent on immunostimulatory adjuvants. MATERIAL AND METHODS: Balb/c mice were epicutaneously sensitized four times at varying intervals over a 22-day period, and challenged orally from day 40, 6 times every 1-3 days with either saline or ovalbumin. RESULTS: After sensitization (day 35) but before the oral challenges, the ovalbumin-sensitized groups showed increased specific IgE and IgG1 production when compared with the sham-sensitized groups. Mucosal mast cell protease-1 (MMCP-1) was undetectable in serum before the intragastric challenge. MMCP-1 concentrations were increased after the first ovalbumin dose, solely in the ovalbumin-sensitized and -challenged group. After the challenge period, the mean serum MMCP-1 concentration increased from an undetectable level in controls to an over 44-fold level in the ovalbumin-sensitized and -challenged mice. In this group, MMCP-1-positive cells were present in the small intestine and expressions of IFN-gamma and CXCL-9 mRNA were decreased in the ileum, suggesting an impaired Th-1-type response. Within one hour of the last ovalbumin challenge, 5 out of 6 mice developed diarrhea in the ovalbumin-sensitized and -challenged group, but there was no diarrhea in the other groups. CONCLUSIONS: A murine model of food allergy based on sensitization via epicutaneous exposure to allergen without immunostimulatory adjuvants was developed. Effective production of MMCP-1 together with specific IgE and IgG1 suggests a breakdown in oral tolerance to the allergen. Intragastric challenges were accompanied by mast cell-dependent immunopathological changes and diarrhea.

Napins, 2S albumins, are major allergens in oilseed rape and turnip rape.

BACKGROUND: Children with IgE-mediated allergy to foods frequently react to seeds of oilseed rape (Brassica napus ssp. oleifera) and turnip rape (Brassica rapa ssp. oleifera) in skin prick tests (SPTs). Sensitization pathways are not known. OBJECTIVE: We identified possible major allergens in oilseed rape and turnip rape using sera from 72 atopic children (mean age, 3.3 years) with positive SPT responses to oilseed rape and turnip rape. METHODS: Allergens from oilseed rape and turnip rape seed extracts were purified by using gel filtration and cation exchange chromatography and characterized by means of reversed-phase chromatography, N-terminal amino acid sequencing, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. IgE binding of sera from 72 children with positive SPT reactions to oilseed rape and turnip rape and 72 age- and sex-matched atopic control subjects with negative SPT responses were analyzed by means of IgE ELISA and immunoblotting. In vivo reactivity of the purified allergens was tested with SPTs in 6 children. RESULTS: In IgE immunoblotting and IgE ELISA major reactivity was to a group of homologous, approximately 9.5- to 14.5-kd proteins. These allergens were identified as 2S albumins, also known as napins, by means of N-terminal amino acid sequencing. In ELISA approximately 80% of the patients had IgE to purified napins from both plants. In SPTs purified napins caused positive reactions in all 6 children tested. CONCLUSIONS: This study shows that 2S albumins in oilseed rape and turnip rape are new potential food allergens. Further studies are needed to clarify the routes of exposure and mechanisms of sensitization.

Isolated hevein-like domains, but not 31-kd endochitinases, are responsible for IgE-mediated in vitro and in vivo reactions in latex-fruit syndrome.

BACKGROUND: Individuals with natural rubber latex allergy often have immediate reactions to plant-derived foods and fresh fruits, such as avocado and banana. IgE of these patients has been shown to bind endochitinases containing an N-terminal hevein-like domain (HLD). However, evidence on 31-kd endochitinase-induced reactions in vivo is lacking. OBJECTIVE: We sought to assess the clinical significance of 31-kd endochitinases and isolated HLDs in latex-fruit syndrome. METHODS: The 31-kd endochitinases and corresponding HLDs were purified or produced from avocado, banana, latex, and wheat germ. Skin prick test reactivities against purified proteins were examined in 15 patients with natural rubber latex allergy. The binding efficiency of IgE to purified proteins was studied by using an inhibition ELISA. Experimentally resolved or modeled structures of the proteins were compared to clarify the molecular basis of clinical reactions. RESULTS: Eleven (73%) patients had skin prick test reactions to isolated HLDs of avocado and banana, but only 1 (7%) patient reacted to their corresponding 31-kd endochitinases. HLDs from avocado and banana inhibited binding of IgE to prohevein (Hev b 6.01) in 59% and 38% of patients, respectively, whereas corresponding percentages for 31-kd endochitinases were 17% and 20%, respectively. Isolated HLDs of wheat germ agglutinin and 18-kd wheat germ agglutinin did not significantly inhibit IgE binding to hevein. CONCLUSION: The isolated HLD molecules alone, but not when linked to endochitinases, seem to be responsible for IgE-mediated clinical reactions in latex-fruit syndrome. Careful selection of relevant allergens in their proper molecular form is therefore crucial in forming a reliable diagnosis of latex-fruit syndrome.

Quantitation of latex allergens.

Minimizing allergen concentration in latex goods to prevent sensitization to natural rubber latex (NRL) and thereby the development of clinical allergy is acknowledged as of mutual interest for rubber manufacturers and regulatory health authorities. However, measuring total protein, the principal currently available method, cannot be deemed a satisfactory regulatory measure to control allergen content. Specific methods based on human IgE-containing reagents, such as radioallergosorbent test (RAST) inhibition, have been available in certain laboratories for demonstrating NRL allergens in rubber products but the methods lack standardization. Currently, one commercial test has become available for measuring individual NRL allergens by capture ELISA-based assays using monoclonal antibodies and purified or recombinant allergens. Such methods are specific, they can be properly standardized, and they are of sufficient sensitivity and reproducibility. Results from medical gloves collected in two national market surveys in Finland in 1995 and 1999, respectively, show that Hev b 6.02 and Hev b 5, the two major allergens for NRL-allergic adults, are the most abundant allergens regularly detectable in high- and moderate-allergen gloves. In addition, Hev b 3 and Hev b 1, the two major allergens for children with spina bifida, are also commonly found. In general, when the sum of the four allergens exceeded 1 microg/g, most NRL-allergic patients showed positive skin prick test reactions against them. Using these new methods assessment of threshold levels that could in due course become guidelines for the rubber industry and regulatory health authorities is becoming possible. Eventually, this progress is expected to lead to a declining incidence of latex allergy.