Immunoglobulin E-binding reactivities of natural pollen grain extracts from selected grass species in the Philippines

BACKGROUND: Pollen grains have been reported to be present in the Philippine atmosphere but studies regarding their allergenicity are limited. OBJECTIVE: The present study aimed to profile the sensitization of allergic individuals to selected grass pollen species and to characterize the pollen proteins that may be responsible for this allergenic response. METHODS: The protein profile of the grass pollen extracts from Cynodon dactylon, Saccharum spontaneum, Sporobulus indicus, Chloris barbata, Oryza sativa, Imperata cylindrica, and Zea mays was analyzed by Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis. The specific-IgE profile of the allergic individuals and the allergenic potential of the pollen extracts were evaluated through Enzyme-linked Immunosorbent Assay and IgE immunoblotting. RESULTS: Sensitization of the allergic individuals to the pollen extracts was detected with I. cylindrica and O. sativa to be the most frequently recognized with more that 92% reactivity, whereas for C. dactylon and Z. mays, were found to have less than 25% reactivity. CONCLUSION: Multiple IgE-binding proteins from S. indicus, S. spontaneum and C. barbata that were detected may be responsible for the allergic reactions among Filipino subjects.

IgE cross-reactivity between house dust mite allergens and Ascaris lumbricoides antigens

BACKGROUND: Common antigens between intestinal parasites and environmental allergens may play a role in the modulation of allergic immune responses. There is a growing interest in investigating cross-reactivity between common helminths and dust mites affecting humans, particularly in the tropics. OBJECTIVE: This study examined the cross-reactivity between the human roundworm Ascaris lumbricoides (Al) and three house dust mite (HDM) species. METHODS: Specific serum IgE levels to HDM species Blomia tropicalis (Bt), Dermatophagoides pteronyssinus (Dp), and Dermatophagoides farinae (Df ); and Al extracts among allergic (n=100) and ascariasis (n=60) subjects were measured through enzyme-linked immunosorbent assay (ELISA). IgE-reactive components of HDM and Al extracts were detected through Western-Blot Analysis. Cross-reactivity between HDMs and Al was determined by ELISA inhibition using HDM and Al-specific sera from allergic (n=15) and ascariasis (n=15) subjects. The IgE-binding capacity of a recombinant paramyosin peptide (Blo t 11-fD) to allergic (n=50) and ascariasis (n=50) subjects' sera were likewise determined. RESULTS: Among allergic subjects, 70% exhibited Al-specific positive IgE-reactivity, while 20-28% of ascariasis subjects demonstrated HDM-specific positive IgE-reactivity. Multiple IgE-reactive components of HDM allergens (14-240 kDa) and Al antigens (15-250 kDa) were detected, indicating multi-allergen sensitization among the subjects tested. Al antigens can inhibit up to 92% of HDM-specific IgE-reactivity among allergic subjects, while up to 54% of Al-specific IgE-reactivity among ascariasis subjects was inhibited by HDM allergens. Positive rBlo t 11-fD-specific IgE reactivity was observed in 80% of the allergic subjects and 46% of the ascariasis subjects. CONCLUSIONS: This study showed the presence of multiple cross-reactive antigens in HDM and Al extracts. Identification of these molecules may provide basis for designing novel diagnostic and therapeutic strategies. The potential role of paramyosin as a specific cross-reactive allergen present in HDMs and Al has been shown.

Association of house dust mite-specific IgE with asthma control, medications and household pets

BACKGROUND: Evidence is conflicting regarding the effectiveness of creating a low-allergen environment or reducing allergen exposure to control asthma exacerbations. OBJECTIVE: This study determined the association of house dust mite (HDM)-specific IgE levels with asthma symptom control, selected medications, family history of allergic disease, and exposure to second-hand smoke and household pets. METHODS: Serum samples from 102 doctor-diagnosed allergic asthma patients and 100 non-atopic controls were subjected to enzyme-linked immunosorbent assay using the HDM species Dermatophagoides pteronyssinus (Dp), Dermatophagoides farinae (Df), and Blomia tropicalis (Bt) allergens. Point-biserial correlation coefficient, Pearson R correlation, and logistic regression analyses were used to determine association of HDM-specific IgE levels with the abovementioned variables. RESULTS: Of the 102 cases, 38.24%, 47.06%, and 33.33% were sensitized to Bt, Df, and Dp, respectively. Sensitized patients showed greater probability [Bt (OR = 1.21), Df (OR = 1.14), and Dp (OR = 1.35)] to manifest symptoms than those who were not. Obtained p-values [Bt (p = 0.73), Df (p = 0.83), and Dp (p = 0.59)], however, proved that HDM-specific IgE levels had no significant contribution in predicting or explaining occurrence of asthma symptoms. Bt- and Df-specific IgEs showed moderately weak but significant relationship with bambuterol HCl and expectorant, respectively. Patients currently on said medications registered higher HDM-specific IgE levels than those who were not. No significant correlation between IgE levels and family history of allergic disease or with exposure to second-hand smoke was seen. Dp-specific IgE levels of patients exposed to household pets were significantly lower compared to those without exposure. CONCLUSION: This study proves that sensitization to Bt, Df, and Dp allergens is not significantly associated with asthma symptoms and control. Although cases were shown to be sensitized to HDMs, their current medications were at least effective in controlling their asthma symptoms.