Genetic polymorphisms and asthma: findings from a case - control study in the Madeira island population

BACKGROUND: Asthma is a complex disease influenced by multiple genetic and environmental factors. While Madeira has the highest prevalence of asthma in Portugal (14.6%), the effect of both genetic and environmental factors in this population has never been assessed. We categorized 98 asthma patients according to the Global Initiative for Asthma (GINA) guidelines, established their sensitization profile, and measured their forced expiratory volume in 1second (FEV1) and forced vital capacity (FVC) indexes. Selected single nucleotide polymorphisms (SNPs) were analysed as potential markers for asthma susceptibility and severity in the interleukin 4 (IL4), interleukin 13 (IL13), beta-2-adrenergic receptor (ADRB2), a disintegrin and metalloprotease 33 (ADAM33), gasdermin-like (GSDML) and the signal transducer and activator of transcription 6 (STAT6) genes comparatively to a population reference set. RESULTS: Although mites are the major source of allergic sensitization, no significant difference was found amongst asthma severity categories. IL4-590*CT/TT and IL4-RP2*253183/183183 were found to predict the risk (2-fold) and severity (3 to 4-fold) of asthma and were associated with a lower FEV1 index. ADRB2-c.16*AG is a risk factor (3.5-fold), while genotype GSDML-236*TT was protective (4-fold) for moderate-severe asthma. ADAM33-V4*C was associated to asthma and mild asthma by the transmission disequilibrium test (TDT). Finally, ADAM33-V4*CC and STAT6-21*TT were associated with higher sensitization (mean wheal size ≥10mm) to house dust (1.4-fold) and storage mite (7.8-fold). CONCLUSION: In Madeira, IL4-590C/T, IL4-RP2 253/183, GSDML-236C/T and ADAM33-V4C/G SNPs are important risk factors for asthma susceptibility and severity, with implications for asthma healthcare management.

Clinical and Immunological Responses in Ocular Demodecosis

The purpose of this study was to investigate clinical and immunological responses to Demodex on the ocular surface. Thirteen eyes in 10 patients with Demodex blepharitis and chronic ocular surface disorders were included in this study and treated by lid scrubbing with tea tree oil for the eradication of Demodex. We evaluated ocular surface manifestations and Demodex counts, and analyzed IL-1beta, IL-5, IL-7, IL-12, IL-13, IL-17, granulocyte colony-stimulating factor, and macrophage inflammatory protein-1beta in tear samples before and after the treatment. All patients exhibited ocular surface manifestations including corneal nodular opacity, peripheral corneal vascularization, refractory corneal erosion and infiltration, or chronic conjunctival inflammatory signs before treatment. After treatment, Demodex was nearly eradicated, tear concentrations of IL-1beta and IL-17 were significantly reduced and substantial clinical improvement was observed in all patients. In conclusion, we believe that Demodex plays an aggravating role in inflammatory ocular surface disorders.

Interleukin-13 and Its Receptors in Idiopathic Interstitial Pneumonia: Clinical Implications for Lung Function

Idiopathic interstitial pneumonia (IIP) is characterized by varying degrees of interstitial fibrosis. IL-13 and IL-4 are strong inducers of tissue fibrosis, whereas IFN-gamma has antifibrotic potential. However, the roles of these substances in IIP remain unknown. IL-13, IL-4, and IFN-gamma were measured in the BAL fluid of 16 idiopathic pulmonary fibrosis (IPF) patients, 10 nonspecific interstitial pneumonia (NSIP) patients, and 8 normal controls. The expression of IL-13 and IL-13Ralpha1/alpha2 in lung tissues was analyzed using ELISA and immunohistochemistry. IL-13 levels were significantly higher in IPF patients than the others (P<0.05). IL-4 levels were higher in both IPF and NSIP patients than in normal controls (P<0.05), and IFN-gamma levels were lower in NSIP patients than in normal controls (P=0.047). IL-13 levels correlated inversely with FVC% (r=-0.47, P=0.043) and DLCO% (r=-0.58, P=0.014) in IPF and NSIP patients. IL-13 was strongly expressed in the smooth muscle, bronchial epithelium, alveolar macrophages and endothelium of IPF patients. IL-13Ralpha1, rather than IL-13Ralpha2, was strongly expressed in the smooth muscle, bronchial epithelium, and endothelium of IPF patients. IL-13 and its receptors may contribute to the pathogenesis of fibrosis in IIP and appear to be related to the severity of the disease.

Expression of cytokines and monosaccharide transporters in the duodenal mucosa of patients with gastrointestinal symptoms in rural Thailand.

Levels of cytokines and GLUT family monosaccharide transporters in the duodenal mucosa were examined in patients from Nong Khai, Thailand, who had underwent gastroscopy because of gastrointestinal problems. Duodenal biopsy specimens were collected from a total of 33 patients (24 males and 9 females, 45.0 +/- 13.5 years old). Ten patients had present or recent intestinal helminth infections, including strongyloidiasis, taeniasis or ascariasis (group A), 7 were urease-test positive, indicating Helicobacter pylori infection (group B), and 16 had neither helminth infections nor urea-test positivity (group C). Total RNA was extracted from the biopsied specimens and a semi-quantitative RT-PCR was performed. The positivities for IL-13, IL-5 and IFN-gamma mRNA expressions in the patients were 24.2, 60.6 and 100%, respectively, with the highest IL-13 and IL-5 positivities in group A, followed by group C and B. The IL-5 positive rate was significantly higher among patients with high peripheral blood eosinophil counts (> 4%) than in patients with low peripheral blood eosinophil counts. GLUT-1 and GLUT-5 were detectable in all the patients. Although GLUT-1 expressions did not differ among groups A, B and C. GLUT-5 expressions were significantly lower in group B than in group C. These results indicate that helminth and H. pylori infections result in different immunopathological responses in the duodenal mucosa, lower expressions of type 2 cytokines and monosaccharide transporters in H. pylori infections than in helminth infections.