Altered immune parameters correlate with infection-related hospitalizations in children with Down syndrome

In addition to previously studied immunological variables, the relative expression of IFNGR2, IFNAR1, CD18, and CD275 (all encoded in chromosome 21) on circulating leucocytes and multifunctional T cells (evaluated by an intracellular cytokine/proliferation assay) were compared between children with Down syndrome (DS) and healthy controls (HC). As previously reported, numbers of lymphocytes, CD4⁺ T cells, Treg cells, B cells, and levels of serum IgM were decreased, and levels of IgG and IgA were increased in children with DS. Moreover, the relative expression of CD18 on T and B cells (previously and not previously reported, respectively) were elevated in DS children (p ⩽ 0.01). Age and numbers of B and Treg cells moderately correlated with retrospectively identified infection related hospitalizations (rho: 0.300–0.460, p ⩽ 0.003). Age and the numbers of Treg cells also correlated with prospectively identified infection related hospitalizations. Future studies are necessary to clarify the role of these parameters in the immunity of DS patients.