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

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

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.

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).

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.