Infections and immunodeficiency in Down syndrome

Area of Science:

• Immunology
• Genetics
• Pediatrics

Background:

• Down syndrome (DS), the most common genetic disorder, is associated with cognitive impairment and various physical abnormalities.
• DS individuals exhibit a higher frequency and severity of infections, particularly respiratory tract infections, linked to immune system dysfunction.

Purpose of the Study:

• To review the immunological and non-immunological factors contributing to increased infection susceptibility in Down syndrome.
• To highlight the need for further investigation into the molecular mechanisms underlying immune defects in DS.

Main Methods:

• Literature review of studies on immune system abnormalities in Down syndrome.
• Analysis of genetic factors (e.g., trisomy 21, gene over-expression) and non-immunological factors (e.g., anatomical, reflux) impacting infection risk.

Main Results:

• DS is characterized by T and B cell lymphopenia, impaired T cell proliferation, reduced antibody response, and neutrophil chemotaxis defects.
• Potential contributing factors include over-expression of genes like SOD1 and RCAN1, zinc deficiency, and anatomical issues like tracheomalacia.

Conclusions:

• Immune system defects and non-immunological factors contribute significantly to the high infection rates in Down syndrome.
• Targeting both immunological and non-immunological pathways may be crucial for reducing infection susceptibility in DS patients.