Low immunoglobulin G4 subclass level is associated with recurrent wheezing in young children

Human bocavirus respiratory infection: Tracing the path from viral replication and virus-cell interactions to diagnostic methods

Human bocaviruses were first described between 2005 and 2010, identified in respiratory and enteric tract samples of children. Screening studies have shown worldwide distribution. Based on phylogenetic analysis, they were classified into four genotypes (HBoV1-4). From a clinical perspective, human bocavirus 1 (HBoV1) is considered the most relevant, since it can cause upper and lower acute respiratory tract infection, mainly in infants, including common cold, bronchiolitis, and pneumonia, as well as wheezing in susceptible patients. However, the specific processes leading to structural, biochemical, and functional changes resulting in the different clinical presentations have not been elucidated yet. This review surveys the interactions between the virus and target cells that can potentially explain disease-causing mechanisms. It also summarises the clinical phenotype of cases, stressing the role of HBoV1 as an aetiological agent of lower acute respiratory infection in infants, together with laboratory tests for detection and diagnosis. By exploring the current knowledge on the epidemiology of HBoV1, insights into the complex scenario of paediatric respiratory infections are presented, as well as the potential effects that changes in the circulation can have on the dynamics of respiratory agents, spotlighting the benefits of comprehensively increase insights into incidence, interrelationships with co-circulating agents and potential control of HBoV1.

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

Transient low IgG4 levels cause recurrent wheezing requiring multiple hospitalizations in infancy

OBJECTIVES

To investigate whether the immunoglobulin G (IgG4) subclass is associated with recurrent wheezing and/or asthma in infants.

SUBJECTS AND METHODS

From April 2015 to March 2016, 77 infants under 3 years old who attended our hospital were enrolled in four groups (Group 1, controls; Group 2, infants with recurrent wheezing and multiple hospitalizations despite starting inhaled corticosteroids [ICS]; Group 3, infants with recurrent wheezing and without hospitalization after starting ICS; Group 4, allergic infants without wheezing). The relationship between IgG subclasses, especially IgG4, and recurrent wheezing resistant to ICS and requiring multiple hospitalizations in infants was examined.

RESULTS

The serum IgG, IgM, IgA, IgG1, IgG2, and IgG3 levels did not differ significantly among the four groups. The IgG4 level in Group 2 infants (3.1 ± 0.2 mg/dl) was significantly lower than in Groups 1, 3, and 4 (9.9 ± 8.0, 8.4 ± 6.1, and 23.4 ± 18.0 mg/dl). Of the 16 infants in Group 2, 10 could be followed to age 6 years. Nine of them had no recurrent wheezing at 6 years without medication. In addition, their IgG4 levels at age 6 years (16.1 ± 7.1 mg/dl) were significantly increased from those in infancy (3.0 ± 0.1 mg/dl).

CONCLUSION

A transient low IgG4 level in infancy might cause recurrent wheezing and/or asthmatic symptoms in infants, and it may be one of the types of early transient wheezing.