Overview
Transient hypogammaglobulinemia of infancy (THI) describes a self-limited period of hypogammaglobulinemia in a pediatric patient.
Most infants have a period of hypogammaglobulinemia between 3 to 6 months of age. Prior to 3 months of age maternal immunoglobulin is present. After 6 months endogenous immunoglobulin production kicks in.
Clinical and laboratory features:
(1) prolongation of hypogammaglobulinemia beyond 6 months into early childhood
(2) serum IgG concentration more than 2 standard deviations below mean for age
(3) variable deficiencies in IgA and/or IgM
(4) normalization of immunoglobulin levels over time
(5) variable risk for recurrent infections, usually bacterial respiratory tract infections
(6) specific antibody responses are usually normal
Differential diagnosis:
(1) common variable immunodeficiency (CVID)
