L22 - Immunodeficiency Diseases 1

• Immunodeficiency diseases

  Conditions where the defence mechanisms of the body are impaired
• Immunodeficiency diseases


  • Leads to repeated microbial infections
  • Sometimes enhanced susceptibility to malignancies
• Deficiencies of immune mechanisms may involve

  • Specific immune functions - humoral immunity or cell mediated immunity or both
  • Nonspecific mechanisms such as phagocytosis, NK cells & complement
• Primary immunodeficiency diseases


  May result from genetic abnormalities in one or more components of the immune system are called congenital (primary) immunodeficiencies
• Secondary immunodeficiency diseases


  May result from infections, nutritional abnormalities or treatments that cause loss inadequate functions of various components of immune system. This is also called acquired immunodeficiency diseases
• Congenital or Primary Immunodeficiencies

  • Humoral Immunodeficiencies (B-cell defects)
  • Cellular Immunodeficiencies (T cell defects)
  • Combined Immunodeficiencies (Both B & T cell defects)
  • Severe combined immunodeficiency diseases (SCID)
  • Complement deficiency
  • Disorder of Phagocytosis
• 1. X-Linked agammaglobulinemia

  Common clinical syndrome caused by blocking of B cell maturation. B cells in bone marrow fail to mature, so marked decrease or absence of mature B cells circulation. It is seen mostly in male infants.
• X-Linked agammaglobulinemia

  • The disease presents as recurrent serious infection with pyogenic bacteria particularly - Pneumococci, Streptococci, Meningococci, Pseudomonas and H. influenzae
  • Plasma cells & germinal centres are absent even antigenic stimulation, so antibody formation does not occur
  • All classes of immunoglobulins are grossly depleted
  • Cell mediated immunity is not affected
• Management of X-Linked agammaglobulinemia

  1. Initial administration of 300 mg of ɣ-globulin/kg body weight, followed by monthly injections of 100mg/kg body weight

  2. Whole plasma infusion can be used
• Transient hypogammaglobulinemia of Infancy

  Abnormal delay in the initiation of IgG synthesis in some infants. Spontaneous recovery occurs between 18 – 30 months of age.
• Transient hypogammaglobulinemia of Infancy

  • It may be found in infants of both sexes
  • Recurrent otitis media & respiratory infections are the common disease
• Late onset hypogammaglobulinemia


  Usually manifested only by 15 – 35 years of age. B cells are failure to differentiate into plasma cells & do not secrete immunoglobulins.
• Late onset hypogammaglobulinemia


  • It is characterized by recurrent pyogenic infection & increased incidence of autoimmune diseases
  • Malabsorption and giardiasis are common
• Selective immunoglobulin deficiencies


  Selective deficiency of one or more immunoglobulin classes due to chromosomal deletion at Ig heavy chain locus (149 32 ), while others remain normal.
• Selective IgA deficiency


  • Causes recurrent respiratory infection & steatorrhea (presence of excess fat in faeces)
• Selective IgM deficiency


  • Associated with septicemia
• Deficiencies of IgG subclasses


  • Associated with chronic progressive bronchiectasis (dilated thick-walled bronchi)
• Immunodeficiencies with hyper IgM

  Low IgA & IgG levels but IgM level is elevated
• Immunodeficiencies with hyper IgM


  • Enhanced susceptibility to infections & autoimmune processes - thrombocytopenia, neutropenia, haemolytic anemia and renal lesions
• Transcobalamin II deficiency


  Inherited as an autosomal recessive trait, Patient shows metabolic defects of vitamin B12 deficiency
• Transcobalamin II deficiency


  • Due to Vitamin B12 deficiency, the plasma cells are depleted, diminished immunoglobulin levels and impaired phagocytosis
• Management of Transcobalamin II deficiency

  Can be managed by vitamin B12 supplement