Biomedical subjects

F Carballada

Publications and source records attributed to F Carballada.

4 recordsLinked to original sources

PubMed2002

Assessment of profilin as an allergen for latex-sensitized patients.

BACKGROUND: The presence of the actin-binding protein, profilin, has been demonstrated in natural latex extracts; but the clinical significance of this molecule as an allergen for latex-allergic patients is not clear. We studied the allergenic relevance of isolated latex natural and recombinant profilin, by in vivo and in vitro techniques, in two populations of spina bifida children (SB) and adults allergic to latex (AL). METHODS: Profilin is present in small amounts in latex extracts obtained from low ammoniated (LA) natural latex. Its purification by affinity chromatography resulted difficult due to Heb v 1 unspecific binding. Therefore a method was developed to obtain natural profilin from natural latex, combining affinity chromatography (PLP, poly-L-proline Sepharose column) and previous ammonium sulfate fractionation. Alternatively, latex c-serum containing a low amount of Hev b 1 and a relatively higher profilin content could be used. Recombinant latex profilin isoform (rHev b 8) was cloned by PCR amplification. The entire coding region of Hev b 8 was subcloned into the expression vector pKN172 and a non-fusion form of Hev b 8 was expressed in Escherichia coli BL21 (DE3). Purified recombinant protein was obtained after a single passage through PLP-Sepharose column. RESULTS: Natural and recombinant purified Hev b 8 were tested cutaneously by intradermoreaction (ID) in 17 SB and 14 AL patients. They were positive in 15 SB and 14 AL patients. No wheals were produced when tested in nonatopic control patients. Only 42% of sera from latex-allergic patients revealed specific IgE titers of class 1 or higher by enzyme immunoassay and only 39% of them exhibited IgE binding by SDS-PAGE immunoblotting with any natural or recombinant Hev b 8 forms. CONCLUSION: It seems that profilin is a relevant allergen for both groups of patients from a frequency point of view, but with scarce presence in natural latex extracts and raw sources, with a subsequent low IgE induction capacity.

Adult↗

PubMedDate not supplied

[Childhood asthma and viral infection: interactions and therapeutic possibilities].

Rhinovirus infections are the main cause of wheezing in children and adults. Studies carried out with experimental infections report that at least in certain conditions, this infection may spread to the lower respiratory tract as the virus acts on the respiratory epithelium. In vitro experiments with cells from the immune system and lower respiratory tract suggest that the mechanisms of action are directly linked to the production of pro-inflammatory cytokines. Both in vivo and in vitro evidence shows that rhinoviruses may stimulate bronchial epithelial cells to produce cytokines and pro-inflammatory chemokines. They may also stimulate the cholinergic and non-cholinergic nervous system, increasing the production of ICAM-1 and may give rise to a T-lymphocyte non-specific response or to T-lymphocyte replication in direct relation with viral infection. In addition, greater production of cysteinyl leukotrienes has been observed in the secretions of patients with bronchospasm. Experimental infection with Rhinovirus increases clinical symptomatology and bronchial hyperreactivity. The latter is associated with increased eosinophils and cationic proteins in sputum. The above findings suggest that multiple cellular pathways are involved in the induction of exacerbations of asthma induced by the virus. In addition, the possible stimulating role of exposure to allergens in sensitized patients would also increase allergic inflammation. Because of the limited therapeutic efficacy of steroids in reducing exacerbations, new treatment strategies based on greater insight into the physiopathology of the role of viruses in asthma are needed.

Adult↗

PubMedDate not supplied

[Preventive immunotherapy].

Allergen specific immunotherapy has been shown to be effective in rigorous double-blind placebo-controlled clinical trials in both children and adults A recent WHO position paper stated that immunotherapy is an effective treatment for patients with allergic rhinitis/conjunctivitis, allergic asthma and allergic reactions from stinging insects and is thought to be more effective in children than in adults. When speaking about children there are several questions that are important regarding the natural course of the disease. One of the most important is whether immunotherapy can prevent asthma, either by preventing sensitisation to allergens related to the development of asthma or by preventing the inflammation in the lungs caused by allergen exposure. Another point could be to establish the differences in the long term outcome of those patients treated with immunotherapy and medication during childhood, compared to the long term outcome of those with comparable asthma features who received only antiasthmatic medication The PAT study is a European multi-center study. The end-point is to show in what capacity allergen specific subcutaneous immunotherapy can prevent the development of asthma in children who only have rhinoconjunctivitis secondary to grass or birch pollen sensitisation. Two hundred and ten children aged from 5 to 13 years were included in the study. Children were randomised to the active treatment group receiving allergen specific immunotherapy with birch and/or timothy pollen allergen extract or to the control group receiving only pharmacotherapy. It is important to highlight that the main criteria to be included was that the children should never have had any asthmatic symptom. Immunotherapy has been effective in terms of decreasing significantly the amount of symptoms in the active group compared to the control one. It was safe with no serious adverse reactions and reduced the risk of the onset of asthma. After two years of treatment more children in the control group developed clinical asthma than in the active group: p = 0.004. Des Roches et al reported the results of a prospective non randomised trial of immunotherapy with Dermatophagoides pteronyssinus in 44 asthmatic children younger than six years of age who were sensitive only to dust mites. The purpose of the study was to assess whether immunotherapy could reduce the development of new sensitisation during a period of three years of follow up. Specific immunotherapy was given with only D. Pteronyssinus extract. All 22 children in the control group developed new sensitivities as determined by skin testing and in vitro tests, while 10 (45%) of 22 children who received mite immunotherapy did not develop additional sensitivities. The findings of this study suggests that immunotherapy may alter the natural course of the allergic sensitisation reducing the risk of developing new sensitisation in mono sensitive children. A limited number of studies have examined the long terms effects of immunotherapy on the clinical presentation of asthma and rhinoconjunctivitis, and have shown a long lasting efficacy decreasing the amount of symptoms 6-10 years after termination. In a retrospective study of children treated with immunotherapy during childhood for at least three years, that were re-evaluated in early adulthood, the control patients who were treated with medication and no immunotherapy suffered almost 3.5 times more symptoms than the active group treated with immunotherapy. The current findings suggest that immunotherapy should be considered earlier in the course of allergic disease to prevent progression or to prevent the development of new sensitisation. Further studies with long term follow up particularly in children could address this possibility.

Adolescent↗

PubMedDate not supplied

Factors influencing the clinical picture and the differential sensitization to house dust mites and storage mites.

Sensitization to house dust mites and storage mites has been studied in a number of papers, but several environmental factors and clinical conditions that differently affect sensitization to these mites are still controversial. The purpose of this study was to determine the influence of climatic conditions, occupation and patient age in the differential sensitization to house dust and storage mites, and also to search for possible different symptoms caused by each group of mites. Eighty patients sensitized to mites but not to other inhalant allergens were studied by case history and by skin prick test and serum IgE to Dermatophagoides pteronyssinus. Dermatophagoides farinae, Lepidoglyphus destructor and Tyrophagus putrescentiae. Home conditions, including content of the allergens Der p 1, Der f 1, Lep d 2 and Tp, were determined for all patients. Human activities, such as farming or similar occupations, and humidity are conditions for preferential sensitization to storage mites, while we found no difference between living in rural or urban areas. Mean age for the onset of sensitization was 6.7 years for house dust mites and 18.7 years for storage mites. Conjunctivitis was more frequent in patients allergic to storage mites, whereas perioral syndrome (itching of the tongue and swelling of the lips) was only seen in patients sensitized to T. putrescentiae. We concluded that climatic and damp conditions and human activity, but not urban or rural living environments, influence the differential sensitization to house dust mites and storage mites.

Adolescent↗