![]() Meningitis and blood poisoning pose a constant threat. Some children develop a sharp, persistent cough with Pneumocystis pneumonia, blood disorders, or chronic hepatitis. Weakened by chronic diarrhea, the baby may stop growing and gaining weight. Usually by the time a baby is three months old, he or she (because many cases of SCID are X-linked, SCID is more common in boys than in girls) is likely to have persistent thrush or extensive diaper rash. Although the specifics vary from case to case, these children are vulnerable to serious infections caused by bacteria, as is typical with a B cell deficiency, and also by viruses and opportunistic germs, as is the case with a T cell deficiency. The child lacks almost all immune defenses, develops life-threatening infections, and needs major treatment to survive beyond infancy. Whatever the underlying problem that causes SCID, the consequences are nearly always the same. ![]() Without this B cell/ T cell communication, the immune defenses are compromised. Class II MHC molecules, which appear on many immune cells, allow B cells and other immune cells to recognize, interact with, and activate T cells. MHC molecules are specialized proteins found on the surface of body cells and play an important role in bone marrow transplantation. Yet another type of SCID is known as MHC class II deficiency or bare lymphocyte syndrome.Purine nucleoside phosphorylase (PNP) deficiency results from a similar enzyme problem, but B cells are less affected and the immunodeficiency is less severe, although affected patients may have other problems (neurologic).Without ADA, poisons build up and kill the lymphocytes. ADA deficiency results from the lack of an enzyme called adenosine deaminase (ADA) that helps cells, especially immune cells, to get rid of toxic byproducts.X-linked SCID, the most common type, a genetic flaw damages molecules that allow T cells and B cells to receive signals from crucial growth factors. ![]() Each is caused by a different genetic defect, and each develops along a different pathway: There are a number of different causes of SCID. The chances of a child being born with SCID are about one in 500,000 births. Severe combined immunodeficiency disease ( SCID) is rare. Severe combined immunodeficiency disease: A combined deficiency of the immune system in which its two major weapons, antibodies and T cells, are genetically missing or disabled. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |