Age-Related Changes in Humoral and Cell- Mediated Immunity in Down Syndrome Children Living at Home

Abstract

ABSTRACT. Abnormalities of humoral and cell-mediated TC, T cells immunity have been described in Down syndrome but HC, helper cells reported findings have been inconsistent. Confounding fac-SC, suppressor cells tors have included age, institutional versus home life, hepatitis B antigenemia, and zinc deficiency. To clarify this problem, we studied 64 children with Down syndrome (DS) compared with an age-matched control group. All children had always lived at home. All the DS children were negative for hepatitis B surface antigen. Serum zinc concentration in the DS group was on average 12 pg/dl lower than age-matched control children. They also had significantly lower levels of immunoglobulin M, total lymphocyte count, T and B lymphocytes, and T helper and suppressor cells. In vitro lymphocyte response to phytohemagglutinin and concanavalin A was significantly reduced at all ages in the DS group. Lymphocyte response to pokeweed mitogen increased with age in control children but decreased in the DS children. By 18 yr, the mean response for DS was 60000 cpm lower than controls. The DS group had significantly higher concentrations of immunoglobulins A and G than controls and the difference increased with age. Complement fractions C3 and C4 were also higher in the DS group at all ages. The number of HNK-1 positive cells was higher in the DS group than controls at all ages. When hepatitis and institutionalization are excluded a s confounding factors, DS children still differ in both humoral and cell-mediated immunity from an age-matched control group. (Pediatr Res 22: 536-540, 1987)

Decreased Thymic Output Accounts for Decreased Naive T Cell Numbers in Children with Down Syndrome

“…Studies on the adaptive immune system of DS have shown that total lymphocyte numbers are decreased in this population (8)(9)(10)(11)(12)(13)(14). This holds true for the CD4 + and CD8 + T cell subsets, especially in the first 2 y of life, but becomes less pronounced with increasing age and eventually normalizes around the age of 16 y. Subdivision of T cells into naive and memory cells showed that in fact only the naive subsets are smaller compared with healthy controls (8,9,(11)(12)(13).…”

“…This holds true for the CD4 + and CD8 + T cell subsets, especially in the first 2 y of life, but becomes less pronounced with increasing age and eventually normalizes around the age of 16 y. Subdivision of T cells into naive and memory cells showed that in fact only the naive subsets are smaller compared with healthy controls (8,9,(11)(12)(13). In contrast, the fraction of CD8 + T cells within the T cell compartment is increased, and the fraction of CD4 + T cells decreased (9).…”

“…In addition, several studies have described low numbers of T cells, decreased cytokine production upon antigenic stimulation, and diminished Ab-dependent T cellmediated cytotoxicity in DS (10,13,41). It was suggested that thymic insufficiency causes peripheral T cell dysfunction in DS and that decreased thymic output is a causative factor for the low numbers of naive T cells in these children.…”

Antibody response to pneumococcal capsular polysaccharide vaccine in Down syndrome patients

“…Different aspects of the immune system have been studied in DS to obtain a better understanding of the increased risk of infection observed in affected individuals (4). Abnormalities in humoral and cell-mediated immunities and in phagocytic function have been reported (3)(4)(5)(6)(7).…”

Genetic Syndromes with Evidence of Immune Deficiency

“…388,390 Increased IgG and decreased IgM levels may occur during late childhood and adolescence. 391 The thymus may be small, with marked thymocyte depletion and an increased number of Hassall's corpuscles.…”