Performance of a commercially available plant allergen series in the assessment of suspected occupational contact dermatitis to plants in north Indian patients.

BACKGROUND: Parthenium hysterophorus is the leading cause of phytogenic allergic contact dermatitis in India. The Indian Standard Series currently supplied by Systopic Laboratories Ltd and manufactured by Chemotechnique Diagnostics ® contains parthenolide as the only allergen representing plant allergens. AIM: The study was conducted to assess the performance of the Chemotechnique plant series (PL-1000), consisting of 14 allergens, in patients with clinically suspected occupational contact dermatitis to plant allergens. METHODS: Ninety patients were patch tested with the Chemotechnique plant series from 2011 to 2013. Demographic details, clinical diagnosis and patch test results were recorded in the contact dermatitis clinic proforma. RESULTS: Of 90 patients, 24 (26.7%) showed positive reactions to one or more allergens in the plant series. Positive patch tests were elicited most commonly by sesquiterpene lactone mix in 19 (78.6%) patients, followed by parthenolide in 14 (57.1%), Achillea millefolium in 10 (42.9%) and others in decreasing order. CONCLUSION: The plant allergen series prepared by Chemotechnique Diagnostics is possibly not optimal for diagnosing suspected allergic contact dermatitis to plants in north Indians. Sesquiterpene lactone mix should replace parthenolide as the plant allergen in the Indian Standard Series until relevant native plant extracts are commercially available for patch testing.

Pediatric contact dermatitis.

Allergic contact dermatitis (ACD) in children, until recently, was considered rare. ACD was considered as a disorder of the adult population and children were thought to be spared due to a lack of exposure to potential allergens and an immature immune system. Prevalence of ACD to even the most common allergens in children, like poison ivy and parthenium, is relatively rare as compared to adults. However, there is now growing evidence of contact sensitization of the pediatric population, and it begins right from early childhood, including 1-week-old neonates. Vaccinations, piercing, topical medicaments and cosmetics in younger patients are potential exposures for sensitization. Nickel is the most common sensitizer in almost all studies pertaining to pediatric contact dermatitis. Other common allergens reported are cobalt, fragrance mix, rubber, lanolin, thiomersol, neomycin, gold, mercapto mix, balsum of Peru and colophony. Different factors like age, sex, atopy, social and cultural practices, habit of parents and caregivers and geographic changes affect the patterns of ACD and their variable clinical presentation. Patch testing should be considered not only in children with lesions of a morphology suggestive of ACD, but in any child with dermatitis that is difficult to control.

A study of allergen-specific IgE antibodies in Indian patients of atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a chronic, relapsing, pruritic dermatitis frequently associated with the hyperproduction of IgE to various allergens. Identification of these allergens is possible by various laboratory investigations. AIM: The present study was designed to assess these allergen-specific antibodies in the diagnosis of AD in the Indian context. METHODS: This prospective study comprised 50 patients of AD. The diagnosis was made clinically after satisfying Hanifin and Rajka's criteria. Serum IgE levels were estimated and specific IgE antibodies were measured for 20 food allergens and aeroallergens. RESULTS: Serum IgE was elevated in 88% of the patients. The highest elevation of mean IgE levels was seen in the 10-20 years age group. Sixty five percent of the children under the age of ten years were positive to one or more food allergens. Food allergens were more often positive in the < or = 10 years age group and specific antibodies to inhalants were seen more frequently in the older age groups. Specific antibodies to apples were found in all age groups. CONCLUSION: Antibodies against apples and hazelnuts were the more commonly seen specific antibodies in children. Incidence of positivity was much higher in children when compared to earlier studies. Identification of food allergens can be an important factor in the diagnosis of AD in children in India. Positivity to inhalant allergens in the older age groups was lower in this study. The allergen profile with regard to inhalants in Indian patients was similar to that of earlier studies.

Use of patch testing for identifying allergen causing chronic urticaria.

BACKGROUND AND AIMS: The aim of this present study was to evaluate the role of patch testing for the etiological diagnosis of chronic urticaria (CU) by using the Indian standard battery of patch test allergens approved by Contact and Occupational Dermatitis Forum of India (CODFI). METHODS: A total of 57 cases with chronic urticaria were tested with the Indian standard battery of allergens. All those cases that showed allergy to patch test allergens were advised to avoid contact with the allergen(s) to whom they had allergy; they were also advised to avoid/restrict allergens in the diet. This avoidance/restriction was advised for a period of six weeks. During this period, clinical improvement of each patient was evaluated and recorded at weekly intervals. RESULTS: Out of the 57 cases of CU, 11 patients showed positive reactions to one or more patch test allergens. Nine out of eleven showed complete disappearance of CU by 2-3 weeks on avoidance of the allergen and this improvement continued till the end of six weeks. The remaining two cases showed partial recovery from CU during the same period. CONCLUSION: Patch testing is a safe, simple and inexpensive alternative that can be used for the etiological diagnosis of chronic urticaria before undertaking expensive investigations.

Natural killer cell clones can efficiently process and present protein antigens.

NK cell clones obtained from three different donors were tested for their ability to present soluble proteins to Ag-specific T cell clones. All NK clones were CD2+CD3-CD56+, whereas the expression of CD16 varied from clone to clone. The NK cell clones were able to process and present tetanus toxoid (TT) to TT-specific T cell clones in a class II HLA restricted manner. The capacity of NK cell clones to function as APC was also observed using the house dust mite allergen Der p I and the Der p I-derived peptide Val89-Cys117. As with EBV-transformed B cell line, NK cell clones could present the peptide 3-13 derived from the 65-kDa heat shock protein of Mycobacterium leprae, but they were unable to present the whole M. leprae Ag. Freshly isolated NK cells, IL-2-activated NK cells, and NK cell lines expanded in vitro could also process and present TT. The ability of the different NK populations to act as accessory cells correlated with their levels of class II HLA expression. These data demonstrate that NK cell clones can efficiently function as APC, however they may be restricted in the types of Ag that they can process.