Relevance of allergenic sensitization to cynodon dactylon and Phragmites communis: cross-reactivity with pooideae grasses

Background and Objectives: The homologous group of sweet grasses belongs to the Pooideae subfamily, but grass pollen species from other subfamilies can also cause allergy, such as Cynodon dactylon (Chloridoideae) and Phragmites communi (Arundinoideae). C dactylon and P communis have not been included in the sweet grasses homologous group because of their low cross-reactivity with other grasses. The aims of this study were to investigate the profile of sensitization to C dactylon and P communis in patients sensitized to grasses and to analyze cross-reactivity between these 2 species and temperate grasses. Methods: Patients were skin prick tested with a grass mixture (GM). Specific IgE to GM, C dactylon, P communis, Cyn d 1, and Phl p 1 was measured by ImmunoCAP. A pool of sera was used for the immunoblot assays. Cross-reactivity was studied by ELISA and immunoblot inhibition. Results: Thirty patients had sIgE to GM. Twenty-four (80%) had positive results for C dactylon, 27 (90%) for P communis, 22 (73.3%) or nCyn d 1, and 92.9% for rPhl p 1. Bands were detected in the 3 extracts by immunoblot. Inhibition of GM was not observed with C dactylon or P communis by immunoblot or ELISA inhibition. When C dactylon or P communis were used in the solid phase, GM produced almost complete inhibition. Conclusions: Eighty percent of patients sensitized to grasses were also sensitized to C dactylon and 90% were sensitized to P communis. Sensitization to these species seems to be induced by allergens different to those in sweet grasses (AU)

Antecedentes y Objetivos: Desde un punto de vista taxonómico, el grupo homólogo de las gramíneas pertenece a la sub-familia Pooideae. Sin embargo, existen también otras especies de gramíneas alergénicas que pertenecen a sub-familias diferentes como son Cynodon dactylon (Chloridoideae) o Phragmites communis (Arundinoideae). C. dactylon y P. communis no están incluidas en este grupo homólogo debido a que la reactividad cruzada con otras gramíneas es limitada. Los objetivos del estudio fueron investigar el perfil de sensibilización a C. dactylon y P. communis en pacientes sensibilizados a gramíneas y analizar la reactividad cruzada entre estas dos especies y las gramíneas más comunes. Métodos: A los pacientes se les realizó una prueba cutánea con una mezcla de gramíneas (MG). Mediante ImmunoCAP se midió la IgE específica para MG, C. dactylon P. communis , Cyn d 1 y Phl p 1. Un pool de sueros se utilizó para ensayos de inmunoblot. La reactividad cruzada se estudió mediante ELISA e inmunoblot inhibición Resultados: Treinta pacientes tuvieron IgE específica para MG. Veinticuatro (80%) fueron positivos a C. dactylon, 27 (90%) a P. communis, 22 (73,3%) a nCyn d 1 y 92,9% fueron positivos a rPhl p 1. Se detectaron bandas en los tres extractos mediante inmunoblot. No se observó inhibición de MG con las otras dos especies mediante inmunoblot o ELISA inhibición. Cuando C. dactylon o P. communis se usaron en fase sólida, MG produjo una inhibición casi completa. Conclusiones: El 80% de los pacientes sensibilizados a gramíneas estaban también sensibilizados a C. dactylon y el 90% a P. communis. La sensibilización a estas especies parece estar inducida por diferentes alérgenos que en el caso de gramíneas (AU)

Respiratory allergy in immigrants to a highly industrialised area in Italy according to area of origin and time period

BACKGROUND: Migrants from developing to Western countries tend to become more sensitised to host than to origin country allergens, although substantial changes in migration patterns have occurred in recent decades. Methods We investigated adult immigrants with respiratory allergy, first tested for allergic sensitisation between 1985 and 2012 in a highly industrialised area in Italy. A comparison was made of the sensitisation pattern between immigrants and a random sample of native-born subjects affected by a respiratory allergy, and among immigrants according to macro-region of origin and time period. RESULTS: Between 1985 and 2012, 480 immigrants with respiratory allergy had a first positive allergy test. Immigrants were sensitised mainly to grass (67.1%), house dust mites (HDM) (38.5%) and birch (27.5%), with a pattern of sensitisation very similar to that observed in Italians (native-born). An increase in the proportion of subjects with asthma and of subjects with polysensitisation was observed from the first (1985-2002) to the middle (2003-2007) and the most recent period (2008-2012). In recent years, the proportion of subjects with polysensitisation in immigrants is higher than in Italians (native-born) (53.3% vs. 40.1%). Among immigrants, the risk of sensitisation to grass was higher in those from Sub-Saharan Africa (odds ratio, OR = 2.76) and Latin America (OR = 2.49), whereas risk of sensitisation to HDM was higher among immigrants from South Asia (OR = 2.71), compared to immigrants from Eastern Europe. CONCLUSIONS: Immigrants develop multiple sensitisations more frequently than native-born people, and are especially sensitised to local allergens; the country of origin seems to play a role

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A comparison of in vitro potency between European and Mexican allergen extracts and US (CBER/FDA) reference extracts

Background: The most important allergen manufacturers are based in Europe and in the US. In some countries local products are also sold. No comparison between European, US and local products has been made until now. Aim of the study: To determine total protein content and total specific IgE binding capacity or major allergen content of diagnostic extracts from European, US and Mexican origins relative to the CBER/FDA reference extracts for Dermatophagoides pteronyssinus (Dpt), Bermuda grass and cat (10,000 (B) AU/mL). Methods: Diagnostic extracts were purchased from various manufacturers, blinded and shipped to the analysing laboratory, where the following assays were conducted: total protein concentration (Bradford), specific IgE competition ELISA (Dpt and Bermuda grass) and determination of Fel d 1U/mL. When available, CBER/FDA recommended tests and reagents were used. Results: Total protein content of US reference extracts was higher than all other extracts. Relative potency of European and US-bought Dpt extracts 3,300–4,400 AU/mL, Bermuda grass 800–2,500 BAU/mL and cat 2.1–4.4 Fel d IU/mL (Ref. 19U/mL), with one exception. Locally produced Mexican products were almost all below 1,000 (B) AU/mL. Conclusions: Three diagnostic extracts from European manufacturers and from Mexican providers which obtain extracts in US have a <50% relative potency compared to 10,000 (B) AU/mL US extracts. Locally produced Mexican extracts have much lower total protein content and specific IgE binding capacity. These in vitro results must be complemented with other in vitro and in vivo skin prick tests to obtain a more complete picture of comparison of potency. Nevertheless results are quite consistent for the allergens tested here

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