Thymosin ß4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial.

PURPOSE: Standard therapies for severe dry eye are limited and fail to resolve the problem. The purpose of this study was to evaluate the safety and efficacy of Thymosin ß4 eye drops (RGN-259) as a novel therapy for severe dry eye disease (including that associated with graft vs. host disease). METHODS: A small, multicenter, randomized, double-masked, placebo-controlled 56-day phase 2 clinical trial including a 28-day follow-up at 2 US sites. Nine patients with severe dry eye were treated with either RGN-259 (0.1%) or vehicle control 6 times daily over a period of 28 days. Dry eye sign and symptom assessments, such as ocular discomfort (using the OSDI questionnaire) and corneal fluorescein staining (using the NEI workshop grading system), were evaluated at various time points. RESULTS: Statistically significant differences in both symptom and sign assessments, were seen at various time points throughout the study. Of particular note at day 56, the RGN-259-treated group (12 eyes) had 35.1% reduction of ocular discomfort compared with vehicle control (6 eyes) (P = 0.0141), and 59.1% reduction of total corneal fluorescein staining compared with vehicle control (P = 0.0108). Other improvements seen in the RGN-259-treated patients included tear film breakup time and increased tear volume production. CONCLUSIONS: In this small trial, RGN-259 eye drops were safe and well tolerated and met key efficacy objectives with statistically significant symptom and sign improvements, compared with vehicle control, at various time intervals, including 28-days posttreatment. CLINICAL TRIAL REGISTRATION--URL: http://www.clinicaltrials.gov. Unique identifier: NCT01393132.

Recombinant birch allergens (Bet v 1 and Bet v 2) and the oral allergy syndrome in patients allergic to birch pollen.

BACKGROUND: IgE cross-reactivity between pollen and food allergens represents the molecular basis for oral allergy syndrome (OAS). OBJECTIVE: To evaluate specific IgE for Bet v 1 and Bet v 2 in the serum of patients sensitized to birch pollen and to identify whether IgE antibodies to Bet v 1 and Bet v 2 were predictors of OAS. METHODS: Thirty-three patients with skin prick test results and radioallergosorbent assay test results positive to birch pollen, 12 (36%) of whom had OAS symptoms, were enrolled in the study. Serum levels of specific IgE were determined by the fluoroenzyme immunoassay technique. RESULTS: The t test revealed significantly higher serum IgE levels against Bet v 1, Bet v 2, and birch pollen in the 12 symptomatic patients with respect to those without OAS (32.4 vs 12.4 kU/L, 7.6 vs 1.3 kU/L, and 42.3 vs 17.3 kU/L, respectively). Attempts to establish a threshold value of serum IgE antibirch pollen and the appearance of OAS revealed that a level of 20 kU/L or more yields an efficiency of the test equal to 70%. CONCLUSIONS: In our study, quantitative birch specific IgE level proved useful in predicting clinical allergy symptoms with birch exposure.

[Cross-reactivity between fruit and vegetables]. / Reactividad cruzada en frutas y vegetales.

Vegetable foods are the most frequent cause of food allergy after the age of 5 years. The most commonly implicated foods are fruit and dried fruits, followed in Spain by legumes and fresh garden produce. In patients allergic to fruit and garden produce, multiple sensitizations to other vegetable products, whether from the same family or taxonomically unrelated, are frequent, although they do not always share the same clinical expression. Furthermore, more than 75 % of these patients are allergic to pollen, the type of pollen varying in relation to the aerobiology of the area. The basis of these associations among vegetable foods and with pollens lies in the existence of IgE antibodies against "panallergens", which determines cross-reactivity. Panallergens are proteins that are spread throughout the vegetable kingdom and are implicated in important biological functions (generally defense) and consequently their sequences and structures are highly conserved. The three best-known groups are allergens homologous to Bet v 1, profilins, and lipid transfer proteins (LTP). Allergens homologous to Bet v 1 (major birch pollen allergen) constitute a group of defense proteins (PR-10), with a molecular weight of 17 kDa, which behave as major allergens in patients from northern and central Europe with allergy to vegetables associated with birch pollen allergy. In these patients, the primary sensitization seems to be produced through the inhalation route on exposure to birch pollen. The symptomatology characteristically associated with sensitization to this family of allergens is oral allergy syndrome (OAS). Profilins are highly conserved proteins in all eukaryotic organisms and are present in pollen and a wide variety of vegetable foods. They have a molecular weight of 14 kDa and present a high degree of structural homology as well as marked cross-reactivity among one another. The presence of anti-profilin IgE broadens the spectrum of sensitizations to vegetable foods detected through skin tests and/or in vitro tests but whether it correlates with the clinical expression of food allergy is unclear.LTPs are the most commonly implicated allergens in allergy to Rosaceae fruits in patients from the Mediterranean area without birch pollen sensitization. LTPs are a family of 9kDA polypeptides, widely found in the vegetable kingdom and implicated in cuticle formation and defense against pathogens (PR-14). They are thermostable and resistant to pepsin digestion, which makes them potent food allergens and explains the frequent development of systemic symptoms (urticaria, anaphylaxis) in patients allergic to Rosaceae fruits in Spain. LTPs have also been identified in other vegetable foods and in pollens and a marked degree of cross-reactivity among them has been demonstrated, which may explain (together with profilin) the frequency of individuals sensitized to vegetable foods in the Mediterranean area.

IgE reactivity to profilin in pollen-sensitized subjects with adverse reactions to banana and pineapple.

BACKGROUND: The so-called 'latex-fruit syndrome' is a well-documented phenomenon in cross-reactive allergies. By contrast, there is a lack of information about allergy to exotic fruits in patients with a predominant pollen sensitization. Since the ubiquitous protein profilin has been identified as an allergen in natural rubber latex as well as in pollen-related foods, the aim of this study was to investigate the role of profilin in allergy to certain exotic fruits. METHODS: Recombinant profilins from banana and pineapple were cloned by a PCR technique after isolation of total RNA using degenerated profilin-specific primers. The unknown 5' ends of copy DNA (cDNA) were identified by rapid amplification of 5'cDNA ends (5'-RACE) and expression in Escherichia coli BL21(DE3) cells. The recombinant profilins were purified by affinity chromatography using poly-(L)-proline as the solid phase. IgE-binding capabilities were characterized by means of immunoblot and Enzyme Allergosorbent Test (EAST). The cross-reactivity to birch pollen profilin and latex profilin was studied by EAST as well as by immunoblot inhibition experiments. RESULTS: Both banana and pineapple profilin were found to consist of 131 amino acid residues with high amino acid sequence identity to known allergenic pollen and food profilins (71-84%). IgE binding to the recombinant profilins was observed in 7/16 sera from subjects with suspected banana allergy (44%) and in 8/19 sera from subjects with suspected pineapple allergy (42%). Inhibition experiments indicated similar IgE reactivity of natural and recombinant allergens. In addition, high cross-reactivity to birch pollen profilin Bet v 2 and latex profilin Hev b 8 was demonstrated by immunoblot inhibition as well as EAST inhibition experiments. CONCLUSIONS: Since a high IgE-binding prevalence of about 40% was obtained in both banana and pineapple allergy, we conclude that profilin is an important mediator of IgE cross-reactivity between pollen and exotic fruits.

Cross-reactivities between date palm (Phoenix dactylifera L.) polypeptides and foods implicated in the oral allergy syndrome.

BACKGROUND: Date fruit and pollen antigens share a number of cross-reactive epitopes. Date pollen has been shown to cross-react with antigens from Artemisia, cultivated rye (Secale cereale), Timothy grass (Phleum pratense), Sydney golden wattle (Acacia longifolia) and Bermuda grass (Cynodon dactylon) pollen. The present study was carried out to examine any cross-reactivities between date palm polypeptides and antigens of some common foods and vegetables that have been implicated in the oral allergy syndrome (OAS). Because most of such cross-reactivities in other allergens are attributable to the presence of carbohydrate chains and profilin, their role was also investigated. METHODS: Fresh extracts of 20 common fruits and vegetables were prepared. Putative date profilins were isolated by affinity chromatography using a poly L-proline column. Date fruit extracts were digested by various endoglycosidases and the immunoglobulin (Ig)E binding of the postdigest products was assessed in immunoblots. Rabbit antisera to whole date fruit extracts, Timothy grass profilin and putative date profilins, as well as human sera from date sensitive individuals were used in immunoblotting, ELISA and in inhibition experiments. RESULTS: IgG, ELISA and immunoblot results with the different rabbit antisera and date-sensitive atopic sera showed several antigenic cross-reactivities and similar cross-reactivities were seen with birch, date and timothy grass profilins. IgE, ELISA and immunoblot experiments with pooled date sensitive human sera showed a range of cross-reactivities with some food extracts. A number of the IgE cross-reactivities could be inhibited after preabsorption of pooled sera with date extracts. Sixty-six percent of individual date hypersensitive human sera bound IgE in putative date fruit profilin and their pooled sera bound IgE in birch pollen profilin. IgE-binding of the endoglycosidase digested date fruit extracts to atopic serum pool was restricted to only a very low molecular weight band of 6.5-8 kDa. CONCLUSION: These results indicate that date palm polypeptides share cross-reactive IgG and IgE epitopes with a number of foods implicated in the oral allergy syndrome, bind to birch and Timothy grass profilins and bind IgE through glycosyl residues. The clinical relevance of these cross-reactivities needs to be further elucidated.

Recombinant allergen molecules: tools to study effector cell activation.

The IgE antibody-mediated activation of allergic effector cells is the key pathomechanism underlying the immediate symptoms of Type I allergy, a genetically determined hypersensitivity disease affecting 25% of the population. In recent years important environmental allergens and their epitopes have become available as structurally defined recombinant molecules. In addition, corresponding human monoclonal IgE and IgG antibodies have been isolated. This review summarizes data obtained regarding the three-dimensional structure of allergens, their IgE epitopes and the recognition of allergens by IgE and IgG antibodies. In particular, we discuss results of recent in vitro and in vivo studies with defined allergen molecules, their epitopes and the corresponding antibodies which support the hypothesis that the density and geometrical arrangement of IgE epitopes on a particular allergen molecule may profoundly affect effector cell activation. If the structural requirements for effector cell activation can be delineated, it may be envisaged that, based on this knowledge, allergens can be converted into hypoallergenic immunogens by reorientation of IgE epitopes. Such allergen derivatives may be used for allergen-specific immunotherapy with reduced risk of inducing anaphylactic side effects.

[Incidence of sensitization to profilin in a population allergic to pollen: responsibility of profilin in pollen polysensitizations in patients with a normal level of total IgE]. / Incidence de la sensibilisation á profiline dans une population allergique aux pollens: responsabilité de la profiline dans des polysensibilisations polliniques chez des patients á taux normal d'IgE totales.

UNLABELLED: The study had the aim of establishing the incidence of sensitization to profilin (a panallergen found in pollens and foods of vegetal origin) in pollen-allergic patients. We evaluated the consequences of such sensitizations on the results of specific IgE, the positivity of skin tests and clinical signs. METHODS: 94 consenting patients, allergic to pollens (trees and/or grasses and/or weeds) replied to a questionnaire and had skin tests to purified profilin and measurement of serum anti-profilin IgE. RESULTS: Two groups were defined: one group was sensitized to profilin (GSP), with positive skin test and anti profilin IgE of 31 patients, and a group non-sensitive to profilin (GNSP) (negative skin test and anti-profilin IgE) of 41 patients. Discordant results were found in 22 patients. Taking in account the two groups, sensitization to profilin was 43%. The two groups were homogenous for age, sex, ethnics and clinical signs. Food allergy was more frequent but not statistically different (p = 0.09) in the group GSP (51.6%) than the GNSP (31.7%), in particular allergy to fruits of the Rosaceae family. Pollen polysensitization (to three species, trees, weeds and grasses) was more frequent in the GSP group (64.5%) than the GNSP (12.5). Polysensitization to pollens and foods was also more frequent in the sensitized group (65.5%) than in the non-sensitized group (12.5%). In a sub-group with normal levels of total IgE pollen polysensitization was more frequent in patients who were sensitive to profilin. On biological investigation, sensitization to profilin influenced the result of anti-latex IgE and also the IgE to many vegetal allergens. These results show the value of seeking a sensitization to profilin in patients with pollinoses.

Anaphylactic reaction to lychee fruit: evidence for sensitization to profilin.

BACKGROUND AND OBJECTIVE: Due to the increasing popularity of exotic fruits in the Western diet, allergologists are confronted with allergic reactions to substances in these plants. The present report describes an anaphylactic reaction after the consumption of lychee fruit (Litchi sinensis). The atopic patient also suffers from rhinoconjunctivitis due to a sensitization against pollen of the Compositae family, as well as from dyspnoea after eating sunflower seeds. Our goals were to determine crossreactivity between antibodies against lychee fruit and other plants and to characterize the allergen. METHODS AND RESULTS: Specific IgE against lychee fruits were detected by an EAST assay. The allergen was characterized by immunoblot, immunoblot inhibition and EAST inhibition assays. Broad crossreactivity between lychee fruit and other plants was found and profilin identified as the protein responsible for the patient's complex allergy syndrome. CONCLUSION: Lychee fruit contains a significant amount of profilin. Consumption of this exotic fruit can cause severe anaphylactic reactions in patients being sensitized against the plant pan-allergen profilin.