Mey-Fann Lee

Hypersensitivity to Forcipomyia taiwana (biting midge): clinical analysis and identification of major For t 1, For t 2 and For t 3 allergens.

Background:  Forcipomyia taiwana is a tiny, blood‐sucking midge that cause intense pruritis and swelling in sensitive individuals. It is distributed island‐wide in rural Taiwan and Southern China.

Immunologic characterization of a recombinant American cockroach (Periplaneta americana) Per a 1 (Cr‐PII) allergen

Background: Previously, we have identified several Per a 1 (Cr‐PII) allergens from a λgt22A cDNA library of Periplaneta americana. This study aimed to sequence clone C42 and determine its molecular and antigenic properties.

Identification of Hevamine and Hev b 1 as Major Latex Allergens in Taiwan

Background: Proteins from latex gloves have been documented to trigger occupational latex allergy among health care workers. Allergen characterization of latex glove extract has never been studied in Taiwan. This study aimed to identify allergenic proteins from latex gloves. Methods: Crude extracts of latex gloves were prepared with phosphate-buffered saline and 20 medical workers with a history of latex allergy were enrolled in this study. The specific IgE antibody was determined by the Pharmacia CAP system and in-house enzyme-linked immunoassay and immunoblotting. The target proteins were excised from two-dimensional PAGE and analyzed by electrospray ionization tandem mass spectrometry. Results: Immunoblotting of glove extracts revealed three IgE-binding proteins at a molecular mass of 45, 30 and 14 kDa. Peptide mass fingerprinting revealed that the protein at 45 kDa, which was recognized by 10% (2/20) of atopic sera tested, was an allergenic lipolytic esterase from Hevea brasiliensis (Hev b 13). The 30- and 14-kDa proteins, which were recognized by 55% (11/20) and 85% (17/20) of patients’ sera, were found to be hevamine and rubber elongation factor (Hev b 1), respectively. Conclusions: Our results indicated that hevamine and Hev b 1 are the major allergens from latex gloves in Taiwan, which differs from the reports in Western countries.

IgE-binding epitopes of the American cockroach Per a 3 allergen

Background: The Per a 3 is a species‐specific allergen of the American cockroach (Periplaneta americana) related to insect hemolymph proteins and includes four known isoallergens. This study aimed to identify Per a 3 linear IgE‐binding epitopes.

Expression of the American cockroach Per a 1 allergen in mammalian cells

Background: Cockroach allergens are one of the major etiologic risk factors for developing IgE‐mediated allergic respiratory illness throughout the world. Per a 1 is a cross‐reactive allergen of American and German cockroaches. This study aimed to investigate the expression of a recombinant American cockroach (Periplaneta americana) Per a 1, C42, allergen in mammalian COS‐1 cells.

Allergenic components of Indian jujube (Zizyphus mauritiana) show IgE cross-reactivity with latex allergen.

Background: ‘Latex-fruit syndrome’ has been well documented. A prevalence of latex allergy among medical workers of 6.8–8.6% had been reported in Taiwan. However, there has been no study to determine the importance and type of fruit hypersensitivity in latex-allergic patients in Taiwan. This study aimed to identify the allergenic components of Indian jujube (Zizyphus mauritiana) and characterize the cross-reactivity of specific IgE antibodies to latex allergen. Methods: Crude extracts were prepared from Indian jujube and from ammoniated natural rubber latex, and six medical workers and one patient with a history of fruit allergy underwent skin testing with routine allergens, latex, Indian jujube and other fruits. Sera from two Indian jujube skin test-positive latex-allergic subjects were used for allergen-specific IgE, immunoblotting, immunoblot inhibition and enzyme-linked immunosorbent assay (ELISA) inhibition studies. Results: Both patients had positive skin test responses and specific IgE assays to Indian jujube and latex extracts. Immunoblotting revealed that IgE from both subjects bound to a 42-kD latex protein and a 42-kD Indian jujube protein. In addition, IgE from one subject bound to a 30-kD Indian jujube protein. Preincubation of atopic sera with Indian jujube or latex extract demonstrated absent and/or marked inhibition of IgE binding. Moreover, anti-Indian jujube protein antibody-based ELISA was able to detect latex extracts. Conclusions: Our results add to findings regarding the ‘latex-fruit syndrome’ described in the literature, and further study of the cross-reacting allergens identified in Indian jujube may help to elucidate the mechanisms underlying this syndrome.

IgE-Binding Epitope Mapping and Tissue Localization of the Major American Cockroach Allergen Per a 2.

Purpose Cockroaches are the second leading allergen in Taiwan. Sensitization to Per a 2, the major American cockroach allergen, correlates with clinical severity among patients with airway allergy, but there is limited information on IgE epitopes and tissue localization of Per a 2. This study aimed to identify Per a 2 linear IgE-binding epitopes and its distribution in the body of a cockroach. Methods The cDNA of Per a 2 was used as a template and combined with oligonucleotide primers specific to the target areas with appropriate restriction enzyme sites. Eleven overlapping fragments of Per a 2 covering the whole allergen molecule, except 20 residues of signal peptide, were generated by PCR. Mature Per a 2 and overlapping deletion mutants were affinity-purified and assayed for IgE reactivity by immunoblotting. Three synthetic peptides comprising the B cell epitopes were evaluated by direct binding ELISA. Rabbit anti-Per a 2 antibody was used for immunohistochemistry. Results Human linear IgE-binding epitopes of Per a 2 were located at the amino acid sequences 57-86, 200-211, and 299-309. There was positive IgE binding to 10 tested Per a 2-allergic sera in 3 synthetic peptides, but none in the controls. Immunostaining revealed that Per a 2 was localized partly in the mouth and midgut of the cockroach, with the most intense staining observed in the hindgut, suggesting that the Per a 2 allergen might be excreted through the feces. Conclusions Information on the IgE-binding epitope of Per a 2 may be used for designing more specific diagnostic and therapeutic approaches to cockroach allergy.

Specific IgE and IgG Responses and Cytokine Profile in Subjects with Allergic Reactions to Biting Midge Forcipomyia taiwana

Background:Forcipomyia taiwana is a tiny blood-sucking midge whose habitat covers large parts of Taiwan and southern China. Female midges bite during the day, causing intense pruritis and swelling in allergic individuals. In this study, we investigated the immune responses of different allergic reactions to midge bites. Methods:F. taiwana (midge)-specific IgE, -IgG and -IgG subclasses were examined by ELISA in 62 human subjects. Peripheral blood mononuclear cells (PBMC) from 6 subjects with solely delayed reactions (SDR) to midge bites and 6 nonallergic controls (NAC) were cultured with midge extract at various time points and assayed. Proliferation of PBMC was measured by MTT assay. Expression of cytokine mRNA was measured by real-time PCR and protein levels by cytometric bead immunoassay or ELISA. Protease activity in midge extract was determined by the Azocoll method. Results: Midge-specific IgE among subjects with an immediate reaction were significantly elevated compared to SDR and NAC subjects. There were no differences in the level of midge-specific-IgG, -IgG1, -IgG2, -IgG3 and -IgG4 among subjects with different biting reactions. Midge extract elicited significantly more PBMC proliferation, higher expression of IFN-γ, IL-10, IL-6 and TNF-α in SDR subjects than in NAC. Protease activity was detected in midge extract. Protease inhibitors E64 and pepstatin suppressed midge-extract-induced IL-8 production. Conclusions: Our results suggest that an immediate reaction to midge bites is IgE-mediated. IFN-γ, IL-6 and TNF-α are involved in delayed reactions to midge bites. A protease-activated pathway may also be involved in the intense, itchy reactions to midge bites.

For t 2 DNA vaccine prevents Forcipomyia taiwana (biting midge) allergy in a mouse model.

Forcipomyia taiwana (biting midge) is the most prevalent allergenic biting insect in Taiwan, and 60% of the exposed subjects develop allergic reactions. Subjects with insect allergy frequently limit their outdoor activities to avoid the annoyingly intense itchy allergic reactions, leading to significant worsening of their quality of life. Allergen‐specific immunotherapy is the only known therapy that provides long‐term host immune tolerance to the allergen, but is time‐consuming and cumbersome. This study tested whether the For t 2 DNA vaccine can prevent allergic symptoms in For t 2‐sensitized mice.

Molecular cloning and immunologic characterization of For t 2: a major allergen from the biting midge Forcipomyia taiwana

megaly to think about drug-induced hypersensitivity syndrome and as the reaction was already remitting, laboratory tests were not performed. The patient refused a challenge test to determine tolerance to alternative betalactams such as cephalosporins and refused any further studies. Allergic reactions to betalactams are the most common cause of adverse drug reactions mediated by specific immunological mechanisms. The diagnosis of betalactam allergy is well established and can be determined using the standardised diagnostic procedures of the European Network for Drug Allergy (ENDA) (2). Urticaria and rarely anaphylaxis (even fatal anaphylactic shock) are known to have occurred after IDT, in particular with drugs (3, 4). These unwanted side-effects occur in IgEmediated immediate hypersensitivity reactions. Systemic reactions after skin testing for nonimmediate drug eruptions seem to be rare, although a few cases have been reported (5, 6). This case illustrates the need for individual risk evaluation when undertaking drug allergy testing. Although in this case the clinical history was suggestive of a desquamative nonimmediate reaction to amoxicillin/clavulanic acid, which is a contraindication for performing a challenge test with the suspected drug, the positivity of skin tests is useful to confirm the clinical suspicion and to find alternative options. IDT should always be performed cautiously, as severe local reactions or systemic side-effect may occur. The possibility of performing patch tests prior to IDT or the use of higher dilutions should be assessed, not only in patients who have suffered severe skin reactions (e.g. TEN, severe bullous exanthema, AGEP, SJS) or systemic reaction (e.g. DRESS), but also in patients who have presented a less severe but desquamative eruption, even though the sensitivity of these tests would be lower.