Comparison of Viral Load in Individuals with and without Asthma during Infections with Rhinovirus

Abstract

Rationale: Most virus-induced attacks of asthma are caused by rhinoviruses (RVs).Objectives: To determine whether people with asthma are susceptible to an increased viral load during RV infection.Methods: Seventy-four children (4-18 yr old) were enrolled; 28 with wheezing, 32 with acute rhinitis, and 14 without respiratory tract symptoms. Nasal washes were evaluated using quantitative polymerase chain reaction for RV to judge viral load along with gene sequencing to identify strains of RV. Soluble intercellular adhesion molecule-1, IFN-l 1 , and eosinophil cationic protein in nasal washes, along with blood eosinophil counts and total and allergen-specific IgE in sera, were also evaluated. Similar assessments were done in 24 young adults (16 with asthma, 8 without) who participated in an experimental challenge with RV (serotype 16).Measurements and Main Results: Fifty-seven percent of wheezing children and 56% with acute rhinitis had nasal washes testing positive for RV. The geometric mean of viral loads by quantitative polymerase chain reaction in washes from wheezing children was 2.8-fold lower, but did not differ significantly from children with rhinitis (7,718 and 21,612 copies of viral RNA per microliter nasal wash, respectively; P = 0.48). The odds for wheezing were increased if children who tested positive for RV were sensitized to one or more allergens (odds ratio, 3.9; P = 0.02). Similarly, neither peak nor cumulative viral loads differed significantly in washes from adults with asthma compared with those without asthma during the experimental RV challenge.Conclusions: During acute symptoms, children infected with RV enrolled for wheezing or acute rhinitis had similar viral loads in their nasal washes, as did adults with and without asthma infected with RV-16 experimentally.

IL-33–Dependent Type 2 Inflammation during Rhinovirus-induced Asthma Exacerbations In Vivo

“…Increased rhinovirus replication in asthmatic BECs has previously been observed ex vivo and related to delayed and impaired production of antiviral IFNs (34,35), but to date increased viral load in vivo in asthma has not been observed (36,37). The earlier and greater peak in viral load in asthma demonstrated in the present study is consistent with these ex vivo reports and suggests an impaired antiviral immune response in some patients with asthma.…”

Rhinovirus Detection in Symptomatic and Asymptomatic Children: Value of Host Transcriptome Analysis

“…Even higher asymptomatic RV detection rates were recently reported in a study conducted in the context of a pneumococcal vaccine trial where RVs were detected in 31-50% of asymptomatic children (39). Thus, high detection rates in asymptomatic subjects, together with common codetection with other respiratory viruses and the reported lack of clear correlation between RV loads and disease severity (40), have raised questions about the causality of RV detection in clinical illness.…”

Understanding the Association of Human Rhinovirus with Asthma

“…For example, studies of RSV using genetic variance and direction of causation models in twins demonstrated that wheezing illness may reflect genetic susceptibilities of the host (45). Elevated total IgE level (46) and sensitization to dust mites (47) or other allergens (48) have been shown to influence the likelihood of wheezing with rhinovirus, adding evidence that allergic individuals may have a different response to infection.…”