USMLE

IL-12 Receptor Deficiency

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Immunodeficiencies
  1. Selective IgA Deficiency
  2. Chediak-Higashi Syndrome
  3. DiGeorge Syndrome
  4. Bruton (X-linked) Agammaglobulinemia
  5. Hyper-IgM Syndrome
  6. IPEX
  7. Leukocyte Adhesion Deficiency (LAD)
  8. Chronic Granulomatous Disease (CGD)
  9. IL-12 Receptor Deficiency
  10. Wiskott-Aldrich Syndrome

Summary

Interleukin-12 Receptor (IL-12R) Deficiency is an autosomal recessive immunodeficiency disorder characterized by a mutation in the gene encoding receptors for Interleukin-12 (IL-12) on T-cells.  Since IL-12 signalling is required for naive Helper T-cells to differentiate into the Th1 effector cell line, these patients have a decreased Th1 response. This decreased Th1 response reduces interferon-gamma signalling, which impairs the activation of macrophages. Decreased Th1 response also impairs downstream Cytotoxic T-cell and Natural Killer (NK) cell responses against intracellular pathogens. Ultimately, patients with IL-12 receptor deficiency are susceptible to infections by intracellular organisms, including mycobacteria (tuberculosis) and salmonella.

Key Points