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

There was an association between recurrent wheezing and specific immunoglobulin G deficiencies. We suggest that intravenous immunoglobulin therapy significantly elevates specific immunoglobulin G levels though it lasts only for short term and might be associated with decreased respiratory symptoms. Therefore, low IgG4 levels among infants with recurrent wheezing may be indicative for intravenous immunoglobulin therapy.