الفهرس 
Classifiation of phylum ArthropodaOnly 14 pages are availabe for public view
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Abstract
House Dust Mites (HDM) are free living arthropods belonging to class Arachnid that also includes ticks, the role of HDM allergens was established since long times.(Voorhorst,1969).
Different allergens of the clinically important principal mite species Dermatophagotes Pteronyssinus and Dermatophagotes Farinae have been described. It has been observed that the majority of these allergens possesses enzymatic activity, also it has been suggested that they are associated with the digestive processes of these arthropods, because they have been found in both the bodies and the faeces of these mites. (Jorge et al, 1999).
The relation of HDM to Man health is confirmed to their ability to release potent allergic substance which may trigger atopic reactions. (Fukuda et al,1995).
Among these atopic reactions the bronchial asthma, atopic dermatitis and allergic rhinitis are well settled. (Smith et al,1983) .
Allergic rhinitis is an IgE-mediated hypersensitivity disease of the mucous membranes of the nasal airways characterized by sneezing, itching, watery nasal discharge and a sensation of nasal obstruction. (Durham,1993).
The role of house dust mites in bronchial asthma and allergic rhinitis is well recognized, but its role in non allergic nasal diseases is unclear.
Similarly Gammrah et al 2002 could found highly significant HDM enzymes in broncho-alveolar lavage fluid and tissue homogenates of non atopic chronic bronchitis patients more than asthmatics and healthy