The immune system is made up of cells that identify and eliminate foreign bacteria, viruses and fungi. A properly functioning immune system is essential for life. A number of conditions that can affect infants and young children are inherited immune system defects. Many of these conditions are serious and require bone marrow transplants. AIDS is also a growing concern as it can also cause disease in childhood.
Transient Hypogammaglobulinemia of Childhood
Of all the immune disorders, transient hypogammaglobulinemia is the mildest. While growing in the uterus, the fetus can receive antibodies from the mother. This provides some protection for the infant in the first 6 months of life. Infants begin making their own antibodies at about 3 months. In some infants, this process is delayed for unknown reasons. After they reach 6 months, they become susceptible to infections. These infants may need immunotherapy for until they are 1 to 3 years old. Eventually, their immune systems becomes activated, and they completely recover.
Bruton's Agammaglobulinemia
Bruton's agammaglobulinemia is disorder in which infants cannot make antibodies. This disorder is X-linked and therefore only affects boys. The missing protein is Bruton tyrosine kinase, or Btk. Infants and toddlers with the disease manifest with frequent and increasingly severe infections, which start after about the 6 months old. Bacterial infections are most common and affect the respiratory tract, skin and gastrointestinal tract. These toddlers should be treated with regular antibiotics and immunotherapy to provide missing antibodies to these children.
Wiskott Aldrich Syndrome
Wiskott Aldirch Syndrome is characterized by increased susceptibility to infections, bleeding manifestations and eczema. Like Bruton's agammaglobulinemia, this condition is X-linked and only occurs in boys. Because the condition also results in decreased platelets, bleeding is more common. Patients with this condition require regular platelet transfusions and immunotherapy. A cure for the condition may be achieved with bone marrow transplant.
Severe Combined Immunodeficiency
Severe combined immunodeficiency, or SCID, is a disorder in which both "wings" of the immune system, the T and B-cells, are completely defective. Many defective genes are found in this condition. This most common gene defect is in IL-2RG, which is needed for immune cell communication. The defect results in an extreme susceptibility to bacterial, fungal and viral infections. SCID is a pediatric emergency. The only known cure of SCID is bone marrow transplant. However, some trials with gene therapy have found success in these children as well.
AIDS in Toddlers
Infection with the human immunodeficiency virus, or HIV, can occur in utero, during delivery or through breast milk. Symptoms of HIV infection may include enlarged lymph nodes, failure to gain weight, recurrent diarrhea and pneumonia and oral fungal infections. Some infants may only have chronic diarrhea and malnutrition. As with adults, infants with AIDS should be treated with highly active antiretroviral therapy, or HAART.
References
- "Nelson Textbook of Pediatrics"; Dr. Robert M. Kliegman, et al.; 2008
- PubMed Health: Agammaglobulinemia; May 16, 2010
- Marrow.org: Wiskott Aldrich Syndrome
- Marrow.org: Severe Combined Immunodeficiency
