Airway allergy and viral infection.

There are complex interactions between airway allergy and viral infection. Available evidence suggests that viral respiratory infection can initiate, maintain and activate exacerbation of allergic conditions in respiratory tract. Innate and inflammatory responses to acute viral infection play important roles in its relationship to allergic reactions. On the other hand, biased immune responses toward Th2 caused by an allergic reaction may make the immune response ineffective in combating viral infection. It was previously shown that allergy can increase the expression level of rhinovirus receptors on mucosal epithelial cells. This suggests that airway allergy may increase the risk of rhinovirus infection. We have recently shown that allergy may also increase the expression level of influenza virus receptors. This suggests that airway allergy and viral infection may have a reciprocal interaction. The effect of allergy on the risk and outcome of viral infection needs to be further confirmed in clinical studies and its potential implication for clinical practice should be considered.

Quantification of Der f 1 in houses of patients allergic to house dust mite, Dermatophagoides farinae, using a locally produced detection reagents.

Background: House dust mite (HDM) allergen quantification in house dust samples before and after the allergen elimination is one means of convincing the target population about the health benefits of allergen removal from their environment. Objective: To produce local reagents for quantification of Der f 1 (major allergen of Dermatophagoides farinae) in dust samples from houses of HDM allergic Thai patients. Methods: Recombinant Der f 1 was used for immunization of a BALB/c mouse for hybridoma production. Polyclonal antibody (PAb) to whole body extract of D. farinae was prepared from an immunized rabbit. A sandwich ELISA (MAb-allergen-PAb) was used, in comparison with the commercialized reagents (Indoor Biotechnology, UK), to quantify Der f 1 in dust samples. Results: Two hybridoma clones, Df1-1 and Df1-2, were established. Their secreted MAbs (MAbDf1-1 and MAbDf1-2, respectively) bound to the homologous antigen as well as native Der f 1 and a crude extract of D. farinae. Epitopes of MAbDf1-1 and MAbDf1-2 were located at amino acid residues 206NSQHYGISNYCQ217 and 283DYW---NSWD-WGDSG298 of Der f 1. MAbDf1-1 had higher affinity to Der f 1 than the MAbDf1-2. A sandwich ELISA (MAbDf1-1-allergen-PAb) and commercialized reagents (MAb1-allergen-MAb2 sandwich ELISA) were used in comparison for quantification of Der f 1 in 42 dust samples collected from bedrooms and living rooms of 21 houses of the HDM allergic patients. All of the 42 dust samples measured by both ELISAs had the Der f 1 levels higher than 2 mg per gram of fine dust which is the HDM allergy sensitizing level. In addition, Der f 1 levels in 41 samples (except 1 sample from a living room) measured by the MAbDf1-1-PAb and MAb1-MAb2 sandwich ELISAs were higher than 10 mg per g of dust which is the morbidity level of HDM allergen. The local sandwich ELISA showed a high coefficient correlation (r = 0.91) in measuring known amounts of recombinant and native Der f 1. The results indicate that the reagents produced in the present study can be used for measuring the environmental levels of HDM Der f 1. The assay can also be used for standardization of the HDM extract for monitoring patient's allergenic status or for immunotherapeutic purpose.

In-vivo allergenic potency of Siriraj Mite Allergen Vaccine (SMAV) comparing with standardized vaccine in mite-sensitive patients.

Background: The prevalence of allergic diseases, particularly asthma and allergic rhinitis, has increased tremendously in Thailand and worldwide. House dust mite (HDM) is the major IgE sensitizer among allergic children and adults. We have developed local standardized mite allergen extracts, Siriraj Mite Allergen Vaccine (SMAV) from Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df) from our source materials which were highly purified (99%). Objective: To compare in-vivo allergenic potency of both SMAV Dp and Df with commercial standardized mite allergen vaccine by using skin prick testing in mite-sensitive individuals. Methods: This was a double-blind, randomized, self controlled study comparing SMAV and commercial standardized mite allergen vaccine (Dp and Df) by using skin prick testing in mite-sensitive adult volunteers, 18 – 60 years of age. Results: The study was performed in 54 adult volunteers (19 males, mean age 26.6 + 5.5 years old) who had positive skin test to commercial Dp and Df. Seventeen of them had no allergic disease. The most common allergic disease among the volunteers was allergic rhinitis (21/37). Mean wheal diameter of SMAV Dp and commercial Dp at the concentration of 10,000 and 5, 000 AU/ml were equivalent but at the concentration of 2,500 AU/ml was inequivalent. Mean wheal diameter of SMAV Dp was significantly larger than commercial Dp at concentration of 2,500 AU/ml (p < 0.05). Mean wheal diameter of SMAV Df and commercial Df at all 3 concentrations were equivalent. There was no systemic side effect in all subjects. Conclusion: The study demonstrated that in mite-sensitive adults, SPT using SMAV Dp (10,000 AU) and Df (10,000 AU) had equivalent allergenic potency to the commercial comparator without any systemic side effect.

Nasal provocation test: how to maximize its clinical use.

In order to diagnose allergic rhinitis (AR), skin prick tests and serum specific IgE level are the most common used methods. But there are some conditions which the results of both methods do not correlate with the clinical presentation of AR. Nasal provocation test is the method of detecting local IgE at the shock organ. There are some variations of NPT in terms of dosage, allergen administration, evaluation and scoring system. This article summarized the usefulness of NPT, its indication and contraindication, dosage and instillation techniques for allergens and evaluation of outcome in the hope that if we can standardize the procedure and make it easier to perform, NPT will be applied more in clinical practice. In addition normal values among Asian ethnics are presented for appropriate interpretation of the test

Allergenicity of native/recombinant tropomyosin, per a 7, of American cockroach (CR), periplaneta Americana, among CR allergic Thais.

In this study, native tropomyosin (Per a 7) of American cockroach (CR), Periplaneta americana, caught in Thailand was purified. Also, gene sequence encoding full length tropomyosin of the CR was PCR ampli-fied by using degenerate primers designed from gene sequences coding for P. americana tropomyosin of the data-base (Per a 7.0101 and Per a 7.0102; accession no.Y14854 and AF106961, respectively). Amino acid sequence deduced from the nucleotide sequence encoding P. americana tropomyosin of this study (GenBank accession no. FJ976895) had 98.59% identity with the sequences of Per a 7.0101 and Per a 7.0102 and was 97.18% identical to the Bla g 7 sequence of German cockroach, Blatella germanica (accession no. AF260897). The native and recom-binant tropomyosins (~34 kDa) were used as antigens in sandwich ELISA for detecting specific IgE in serum sam-ples of 14 consented allergic patients who were positive by skin test to crude CR extract in comparison to 5 indi-viduals who were skin test negative. It was found that 8 (57%) and 6 (43%) of the CR allergic patients gave positive IgE binding results to the native and the recombinant proteins, respectively, while none of the non-allergic counter-parts was positive. Results of immunoblotting conformed to the ELISA results. Tropomyosin extracted from the P. americana caught in Thailand has potential as standard P. americana allergen in clinical monitoring of the allergic Thai patients.

The accuracy of limited CT in the evaluation of chronic rhinosinusitis and for endoscopic sinus surgery: a multicenter study.

Objective: To compare the accuracy of Limited CT with the Full CT as the standard evaluation for inflammatory disease of PNS and the identification of anatomical variations. Methods: From Full CT of PNS, Limited CT were retrieved. Computerized tomographic scans were performed for the preoperative planning of endoscopic sinus surgery (ESS) in 3 tertiary care university hospitals in Thailand. The two types of examinations were reviewed independently and in random order by two experienced radiologists. Using Full CT as the standard, the accuracy of Limited CT were evaluated for 1) the radiologic staging of rhinosinusitis (Lund-Mckay scoring system) and 2) the anatomic variations which are an important landmark for surgical operations in rhinosinusitis. Results: Totally 132 patients were included. Two hundred and sixty four half-faces were reviewed. Lund-McKay radiographic sinus staging system showed 97-99% specificity except for the ostiomeatal complex region. Regarding anatomic variation, Limited CT was able to yield accurate results for the frontal cell type II-IV, Haller cell, Agger nasi cell, paradoxical middle turbinate, concha bullosa and the protrusion of the optic nerve. Conclusion: Limited CT can be used as a surgical roadmap for the cases with the anterior group of sinus involvement. It may be utilized for surgical planning of chronic CRS involving the anterior group of sinuses. For the posterior group of sinuses, it may not yield enough accuracy and the standard Full CT should be requested to prevent erroneous estimation.

Nasopharyngeal hamartoma: A case report and literature review.

Hamartoma is a non-neoplastic tumoral lesion resulting from a developmental anomaly and is characterized by the existence of cells and mature tissues common to the place of origin. Although hamartoma is common in the lung, kidney, and intestines, it is rare in the nasal cavity, the paranasal sinuses and particularly in the nasopharynx. Within the nasal cavity, the most common site of occurrence is the posterior aspect of the nasal septum. We reported a case of 15-year-old Thai male who presented with chronic rhinitis and left eustachian tube dysfunction for several months. Nasal telescopy revealed one smooth pink mass which originated from the left eustachian tube opening and another mass originated from the roof of the nasopharynx near the posterior part of nasal septum. Tumor removal was performed by endoscopic approach, and left myringotomy and a pressure equalization tube placement was done. No postoperative complications were found. Pathological diagnosis is consistent with hamartoma. After a 3 -month follow-up period, the patient still had a small residual mass in the left eustachian tube without any symptoms. Endoscopic approach enables the satisfactory role in the treatment of this rare condition.

A surveillance study of bacteriologic profile in rhinosinusitis.

Objective: To review the types of bacteria found in rhinosinusitis and the prevalence of a beta-lactamase producing organism in a tertiary care hospital during the year 2004 and compared with our previous reports. Methods: Charts of patients who underwent endoscopic sinus surgery or maxillary antral puncture or endoscopic-guided culture at the Rhinology & Allergy Division, Department of Otolaryngology and the Department of Microbiology, Siriraj Hospital from January 2004 to December 2004 were reviewed. Information regarding the patient’s age, site of specimens, culture and sensitivity results were obtained. Results: There were 162 specimens and 29 bacterial species isolated. There were 50.4% positive aerobic cultures, gram-negative bacteria were more common than gram-positive bacteria (68.5% vs 31.5%). Common aerobes were Pseudomonas aeruginosa (16.2%), non-fermentative gram negative rod: NF-GNR (10.8%), Coagulase- negative Staphylococcus aureus :CNS (9.9%) and Klebsiella pneumoniae (9.9%).The most common anaerobes were Peptostreptococcus sp., Bacteroides fragilis and Fusobacterium sp. Conclusion: Contrary to our previous studies, gram negative organisms play a more important role than gram positive organisms. The causative pathogens of rhinosinusitis should be studied continuously because rapid progress in the development of new antimicrobial agents has a significant impact on their bacteriologic profile.