Clinico-immunologic evaluation of allergy to Himalayan tree pollen in atopic subjects in India--a new record.

Exposure to local pollen allergens has a direct bearing on the prevalence of allergic symptoms among the inhabiting atopic population. The populations in the Himalayas and around it are exposed to a variety of pollen grains from trees growing in the region, but the pollen-population interaction has not been clinically investigated. Himalayan tree pollen from five different taxa, i.e. Alnus nitida (AN), Betula utilis (BU), Cedrus deodara (CD), Mallotus phillipensis (MP) and Quercus incana (QI) were evaluated for their allergenicity in the Indian population by in vivo (skin prick test) and in vitro (ELISA) clinico-immunological methods. The presence of specific IgE against these tree pollen in the sera of skin test positive patients was taken as evidence for sensitization to these pollen. The average skin positivity in atopic populations recorded at different allergy centers in India varied from 2.2% against AN, to 4.7% against MP pollen. Significantly raised specific IgE against these pollen were observed in the sera of hypersensitive patients. The sensitization pattern to Himalayan tree pollen in these atopic populations varied. It was concluded that skin prick test positivity and raised IgE antibodies specific to AN, BU, CD, MP and QI established Himalayan tree pollen as important sensitizers in the atopic populations of India. A high incidence of skin sensitivity was observed to pollen antigens of Cedrus deodara, Mallotus phillipensis and Quercus incana in patients of Chandigarh residing in the hills and foothills of the Himalayas while Alnus nitida, Betula utilis and Cedrus deodara were important sensitizers in Delhi patients. The skin sensitization pattern against these pollen was in accordance with the level of exposure to these pollen of the subjects residing in that part of the country.

Common environmental allergens causing respiratory allergy in India.

Respiratory allergy affects all age groups but the children are the worst affected by the respiratory allergy. Bioparticles from different biological sources are the main cause of allergy. Pollen grains, fungal spores, insect and other materials of biological origin form the most important allergen load in the air. For the efficient diagnosis of the allergy and its effective treatment it is very important to know about the prevalence, seasonal and annual variations of aeroallergens of the area. India being the climatically diversed country, there is diversity in the flora and fauna of different parts of the country. Atmospheric surveys carried out in different parts of India reveal that, Alanus nitida, Amarantus spinosus, Argemone mexicana Cocos nucifera, Betula utilis, Borasus flabellifer, Caraica papaya, Cedrus deodara, Cassia fistula, Parthenium, Chenopodium album, Dodonaea viscosa, Malotus phillipensis, Plantago ovata, Prosopis juliflora, Ricinus communis, Holoptelea intergifolia are the allergenically important pollens of the country. Among the fungal aeroallergens, Alternaria, Candida aibieans, Aspergillus versicolor, Aspergillus terreus, Aspergillus japonicus, Cladosporium cladosporoides, Fusarium roseum, Ganoderma lucidum,Neurospora sitophila Helminthosporium, Ustilago trtici, Uromyses are important allergens. Dust mites D. farinae, D.pteronyssinus are also important source of inhalant allergens particularly in the coastal areas of the country. Cockroaches, beetles, weevils, mosquitoes, house flies also contribute towards the aeroallergen load and are allergenically implicated. Avoidance of the indoor and outdoor aeroallergens is recommended for better management of respiratory allergy.

Fomes pectinatis: an aeroallergen in India.

This work is focused on the aerobiology and allergenicity of Fomes pectinatis in India. The atmospheric concentration of Fomes basidiospores was recorded and the antigens were prepared from spore (FSE) and whole body (FWBE) materials. The intradermal (ID) and prick (PT) skin tests were conducted on 172 patients having respiratory allergy. The period from July to October has been recorded as having a higher concentration of Fomes spores. The maximum counts (67 spores/m3) were observed from the North Delhi site in the month of July, 1989, compared with 550 spores/m3 in the South Delhi site. Marked skin positivity (2+ and above) varied from 9.8% to FSE to 22% to FWBE. Nine out of twelve ID positive patients (2+ to 3+) to FSE also gave PT positive response. For FWBE, similar ID and PT response was obtained in 80% of cases. The soluble protein content of FSE was 0.37 mg/ml, whereas, for FWBE it was 0.70 mg/ml. It was observed through ELISA that almost all patients had significantly raised FP specific IgE levels in their sera. The current study, therefore, indicates that Fomes pectinatis may be a prevalent aeroallergen in India.

Sensitization to different species of Aspergillus in bakery workers and general atopic population.

Six species of Aspergillus predominant in the bakery environment--Aspergillus flavus, A. fumigatus, A. nidulans, A. ochraceous, A. sydowi and A. versicolor--were studied for their role in causing Type 1 hypersensitivity among bakery workers and atopic patients from the general population (PGP). Antigenic extracts from the above species were prepared for in vivo and in vitro studies. The IEF, SDS-PAGE, skin test, ELISA and immunoblot techniques were performed to detect the biochemical- and clinico-immunological characteristics of these species. Among those tested, the important fungal sensitizers among the bakery workers and patients from the general population were A. sydowi, A. fumigatus, A. nidulans and A. ochraceous. The protein fractions of different species were in the acidic region (pI 3.0-6.5) and in the molecular weight range of 13.0-91.0 kDa. The protein fraction of 44.0 kDA of A. flavus and 20.0 and 70.0 kDa for A. fumigatus showed IgE binding in the sera of bakery workers only. Significantly, raised IgG antibodies to different species were recorded among the bakery workers as compared to the PGP group. The study showed that different species of Aspergillus are of potential allergenic significance in bakery workers and the general atopic population.

Survey of airborne culturable and non-culturable fungi at different sites in Delhi metropolis.

A two year aerobiological survey for culturable and non-culturable fungi was conducted at human height at five different sites in Delhi metropolis. Burkard Personal Volumetric Sampler for petriplates and slide exposures were used for sampling the air. With simultaneous petriplate and slide exposure a total of 98 fungal forms were recorded. Cladosporium contributed for 25-40% of total airborne fungi followed by Ustilago (smuts) (24%) Aspergillus flavus (10-13%), Alternaria (11%) and A. niger (8%). Basidiomycetes contributed 7-13% at different sites. The frequency of occurrence of these types varied from 50-98%. In general fungal concentration was high from July to April with low counts in winter (January) and dry and hot summer (May-June). Quantitative variations in the spore counts were found to be statistically significant within the same urban locality.

Biological standardization of pollen allergens from India.

Standardization of allergens are achieved by in vitro and in vivo methods. Some of the allergens from Western countries are standardized using biological potency of the extracts but no attempt has been made till now to standardize any of the pollen extracts from India based on biological units. Therefore, we have attempted to standardize two important pollen allergens Ricinus communis and Holoptelea integrifolia by biological methods. Broadly the methods adopted by Dreborg and Grimmer (1983) was followed. Skin prick tests were carried out with the extracts of R. communis and H. integrifolia on 15 allergic patients in five three fold log dilutions starting with 1:10, in 50% glycerinated buffer. Glycerinated buffer (50%) and histamine dihydrochloride (1 mg/ml) were used as negative and positive controls, respectively. The mean wheal diameter obtained with different concentrations showed a gradual systematic fall with increase in dilution. The mean relative diameter (% of histamine reaction) varied from 124.1 +/- 8.9 to 33.7 +/- 6.1 and 78.9 +/- 5.5 to 21.4 +/- 3.8 with the highest and lowest concentrations of R. communis and H. integrifolia pollen antigens, respectively. The histamine equivalent concentration of antigen 1,000 Biological Units (BU) obtained for crude pollen extracts of R. communis and H. integrifolia was 1:17 and 1:22 respectively.