Narissara Suratannon

Component-resolved diagnostics for the evaluation of peanut allergy in a low-prevalence area.

Major allergenic components of peanut from distinct geographical regions are widely dispersed. Most of the diagnostic studies are from countries with a high prevalence. There have been only few reports of allergen component sensitizations from countries with a low prevalence of peanut allergy. We aimed to investigate roles of component‐resolved diagnostic (CRD) to differentiate peanut allergy and peanut tolerance in the Asian population from a country with low prevalence of peanut allergy.

The House Dust Mite Major Allergen Der p 23 Displays O-Glycan-Independent IgE Reactivities but No Chitin-Binding Activity.

Background: The in-depth characterization of the recently identified house dust mite (HDM) major allergen Der p 23 requires the production of its recombinant counterpart because the natural allergen is poorly extractable from fecal pellets. This study aimed to provide a detailed physico-chemical characterization of recombinant Der p 23 (rDer p 23) as well as to investigate its IgE reactivity in a cohort of HDM-allergic patients from Thailand. Methods: Purified rDer p 23, secreted from recombinant Pichia pastoris, was characterized by mass spectrometry and circular dichroism analyses as well as for its chitin-binding activity. The IgE-binding frequency and allergenicity of Der p 23 were determined by ELISA and RBL-SX38 degranulation assays, respectively. Results: Purified intact rDer p 23 carried O-mannosylation and mainly adopted a random coil structure. Polyclonal antibodies to rDer p 23 can detect the corresponding natural allergen (nDer p 23) in aqueous fecal pellet extracts, suggesting that both forms of Der p 23 share common B-cell epitopes. Despite its homologies with chitin-binding proteins, both natural Der p 23 and rDer p 23 were unable to interact in vitro with chitin matrices. Of 222 Thai HDM-allergic patients tested, 54% displayed Der p 23-specific IgE responses. Finally, the allergenicity of rDer p 23 was confirmed by the degranulation of rat basophil leukemia cells. Conclusion: Our findings highlighted important levels of Der p 23 sensitizations in Thailand. Our study clearly suggested that rDer p 23 is likely more appropriate for HDM allergy component-resolved diagnosis than HDM extracts.

Adaptive immune defects in a patient with leukocyte adhesion deficiency type III with a novel mutation in FERMT3

To the Editor, Leukocyte adhesion deficiency (LAD) is a rare primary immunodeficiency disease characterized by impairment of phagocyte adhesion (1–3). Three subtypes have been classified by distinct phases of the adhesion cascade. LAD-III is caused by defects in signaling pathways used for integrin activation in all hematopoietic cell types leading to recurrent infections with poor platelet aggregation resembling Glanzmann’s thrombasthenia (4). Mutations in FERMT3 have been identified to underlie LAD-III (4, 5). FERMT3 encodes kindlin-3, one of the focal adhesion proteins which contain a FERM domain located at the carboxyl terminus binding to b-integrin cytoplasmic tails. This molecule cooperates with the cytoskeletal protein talin leading to integrin activation. It also stabilizes active conformations of the integrin subunits and the ligand binding (5, 6). Evidently, integrins are widely expressed in many cell types including T and B lymphocytes. Defects in integrin function therefore could lead to both innate and adaptive immune dysfunctions. However, almost all reported cases of LAD-III only had innate immune defects. Here, we describe a female Thai patient who was diagnosed with LAD-III, yet presenting with a mild atypical phenotype in which a humoral immune defect was detected. Our patient was the second child of consanguineous parents who were first cousins. The pedigree of the family is shown in Fig. 1a. She presented with early-onset severe gram-negative infections, thrombasthenia, hepatosplenomegaly, and defective wound healing. Between three and 8 months old, she experienced four episodes of bacterial pneumonia with sepsis. Firstly, she had severe pneumonia and subsequently developed acute respiratory distress syndrome. Cultures of tracheal suction specimens revealed Acinetobacter baumannii. Salmonella spp. was also reported from stool samples when she was found to have diarrhea. In the second episode of pneumonia, A. baumannii was reported again from specimens obtained by tracheal suctioning. Pseudomonas aeruginosa was isolated from ear discharge. Thirdly, the patient had pneumonia with septic shock. Tracheal suction cultures revealed Streptococcus mitis and Escherichia coli. Finally, necrotizing pneumonia was reported. The patient’s blood culture was positive for P. aeruginosa. She had the ability to form pus, although minimal, and umbilical cord separation occurred at the age of 9 days. After prolonged courses of antibiotics, the patient had developed mucocutaneous candidiasis. She did not suffer from invasive fungal infections, as described in other patients with LAD-III (3, 7). Her bleeding symptoms were mild and appeared only during episodes of infections, while spontaneous intracranial bleeding and/or massive pulmonary hemorrhage have been reported in patients with typical LAD-III (3, 7). Initial investigations and immunologic assessment at the age of 5 months revealed persistent leukocytosis with neutrophilia, anemia, and thrombocytopenia. A complete blood count showed a hematocrit of 28% (29–42), white blood cell count of 45,430 cells/mm (6000–17,500), neutrophils of 25,440 cells/ mm (4000–12,000), lymphocytes of 10,903 cells/mm (2000– 17,000), and platelets of 109,000 cells/mm (300,000–700,000). Flow cytometric analysis of lymphocyte populations demonstrated normal numbers of total T cells (CD3+), CD4+ T cells, CD8+ T cells, B cells (CD19+), and NK cells (CD16+56+).

The minor house dust mite allergen Der p 13 is a fatty acid‐binding protein and an activator of a TLR2‐mediated innate immune response

The house dust mite (HDM) allergen Der p 13 could be a lipid‐binding protein able to activate key innate signaling pathways in the initiation of the allergic response. We investigated the IgE reactivity of recombinant Der p 13 (rDer p 13), its lipid‐binding activities, and its capacity to stimulate airway epithelium cells.

Dust mite infestation in cooking flour: experimental observations and practical recommendations

BACKGROUND The first documented case of oral mite anaphylaxis has recently been reported in Thailand, with mites possibly originating from cooking flour. OBJECTIVE Our study was designed to assess the effects of cooking flours enhancement and storage conditions on mite proliferation and to provide practical recommendations to prevent mite anaphylaxis. METHODS In a factorial experiment, six commercial brands of cooking flours were selected and either inoculated or set free of mites and stored in one of the four containers chosen for the study: original package, plastic bag, plastic box and glass bottle. The resulting experimental units where then stored at either room temperature or in a refrigerator (+4C). In order to determine levels of Der f 1 allergen, 0.1 gram of flour was sampled from each experimental unit and tested by ELISA. Sampling was carried out immediately after inoculation and subsequently at week 2, 4, 6, 8, 10, 12, 16 and 20. RESULTS Levels of Der f 1 allergen in the inoculated samples increased significantly in all conditions 6 weeks after inoculation (p <0.001) and reached the highest levels at week 8. While experimental units left at room temperature showed higher levels of mite growth (p <0.001), no statistical differences were found among types of containers. The highest amount of Der f 1 was observed for Gogi, followed by Gold Label, tempura flour, corn flour, wheat flour and tapioca starch, respectively (p <0.01). CONCLUSIONS In the context of our experiment, mites preferably grew in cooking flours containing high amounts of wheat at room temperature, particularly after 8 week of storage. According to our results, we thus advise to keep household cooking flour refrigerated and while the type of container does not matter, storage should not exceed 20 weeks.

Assessing the reactogenicity of Tdap vaccine administered during pregnancy and antibodies to Bordetella pertussis antigens in maternal and cord sera of Thai women

INTRODUCTION Pregnant Thai women have low antibody titers against B. pertussis antigens, which coincide with an increasing incidence of pertussis among Thai infants. Thus, there exists a potential benefit of a booster dose of tetanus- diphtheria-acellular pertussis (Tdap) vaccine administered during pregnancy. Here, we report the vaccine reactogenicity profile and birth outcomes in Tdap-vaccinated pregnant women who have or have not had prior immunization with tetanus vaccine, and the IgG levels to B. pertussis antigens in maternal and cord sera at delivery. MATERIALS AND METHODS Pregnant women (N = 370) aged 18-40 years were administered the Tdap vaccine (Boostrix®, GlaxoSmithKline, Rixensart, Belgium) at 26-36 weeks gestation. Adverse events following vaccination were identified by follow-up telephone call and medical record review. IgG against pertussis toxin (anti-PT), filamentous hemagglutinin (anti-FHA) and pertactin (anti-PRN) in both maternal and umbilical cord blood obtained at delivery were quantitatively evaluated using enzyme-linked immunosorbent assay (EUROIMMUN®, Lübeck, Germany). RESULTS There was no reported increase in the severity or duration of adverse events associated with the administration of an extra tetanus-containing vaccine within the previous five years (N = 181) or multiple doses of tetanus-containing vaccines during the current pregnancy (N = 98). Vaccination at least eight weeks prior to delivery resulted in high antibody titers to all B. pertussis antigens studied. CONCLUSIONS The reactogenicity of Tdap vaccine administered during pregnancy was not affected by prior tetanus toxoid immunization. High transplacental antibody against B. pertussis antigens in the cord blood provides evidence of antibody transfer and should thus help to protect newborns from pertussis during early life.

Detecting Allergens From Black Tiger Shrimp Penaeus monodon That Can Bind and Cross-link IgE by ELISA, Western Blot, and a Humanized Rat Basophilic Leukemia Reporter Cell Line RS-ATL8

Background Black tiger shrimp Penaeus monodon is one of the common causes of shellfish allergy that is increasing worldwide. One of the important problems in the management of shellfish allergy is the lack of accurate diagnostic assay because the biological and immunological properties of allergens in black tiger shrimp have not been well characterized. This study aims to detect proteins with the ability to bind and cross-link immunoglobulin E (IgE) from black tiger shrimp by enzyme-linked immunosorbent assay (ELISA), Western blot, and a humanized rat basophilic leukemia reporter cell line RS-ATL8. Methods Sera from shrimp allergic subjects were subjected to ELISA and Western blots using raw or cooked shrimp extract as antigens. Pooled sera were used to sensitize the RS-ATL8 reporter cell line and cells were activated by shrimp extract. Eluted protein extracts separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were tested on the RS-ATL8 cell line and subjected to mass spectrometry to identify potential candidate allergens. Results Allergic sera reacted stronger to raw shrimp extract than cooked shrimp extract (P=0.009). Western blot demonstrated that major IgE reactivity protein bands were at 32–39 kDa and 91–230 kDa in both raw and cooked shrimp extracts. The eluted protein bands at the molecular weight of 38 and 115 kDa from raw shrimp extract induced IgE cross-linking as assayed by the RS-ATL8 cell line. These protein bands were subjected to mass spectrometry for analysis. Ubiquitin-activating enzyme and crustacyanin were identified as potential candidate novel shrimp allergens. Conclusions The RS-ATL8 reporter cell line can be used to identify potential new shrimp allergens that can functionally cross-link IgE and induce mast cell degranulation.