IL10 Genetic Variants Are Associated With House Dust Mite-Allergy But Not Directly On Asthma In A Severe Asthma Case-Control Study

Abstract

RATIONALE: Cytomegalovirus (CMV) is a recognised cause of morbidity in immunocompromised individuals. CMV seropositivity has been associated with signs of immunosenescence and systemic inflammation in the elderly. We aimed to assess the presence of CMV DNA in the blood of elderly and non-elderly patients with bronchial asthma. METHODS: Eighty five elderly asthmatics (above 65 years of age) and 74 younger asthma patients (aged 30-50) were recruited and underwent clinical and laboratory evaluation. Control group consisted of 63 adults over 65 years old and 56 subjects aged 30-50 without chronic respiratory disease. Real-time PCR (RT-PCR) for quantitation of CMV DNA was performed with the commercial CMV detection kit (detection limit > 500 copies/ mL) and with an in-house assay targeting the UL55gene (detection limit >100 copies/mL). RESULTS: Commercial CMV assay was positive in 18% of elderly and 1,3% non-elderly asthma patients, but was negative in all control samples. Custom made RT-PCR assay detected low levels of CMV DNA in 42.1% of asthma patients and in 12.6%, of control subjects (p<.001). The test positivity was higher in elderly asthmatics than in younger patients (52.9% vs. 29.7%, p5.003), and higher in elderly control subjects than in younger controls (22.2% vs. 1.8%, p<.001). Presence of CMV DNA was associated with an increased risk of asthma: OR55.1 [(95% CI: 2.7-9.4, p<.001)] for the whole population tested and OR521.6 [(95%CI: 2.8-166.1); p<.001)] for non-elderly subjects. CONCLUSIONS: CMV replication at low level is highly prevalent in elderly asthmatics and is associated with risk of asthma.