Severe Combined Immunodeficiency (bubble boy disease) Presented By SUBASH SAPKOTA
CONTENTSIntroductionTypes of SCIDSymptoms and diagnosis of SCIDTreatment for SCIDTransplant for SCIDReferences
Introduction Severe combined immunodeficiency (SCID), is a genetic disorder in which both "arms" (B cells and T cells) of the adaptive immune system are impaired due to a defect in one of several possible genes. SCID is a severe form of heritable immunodeficiency. It is also known as the bubble boy disease because its victims are extremely vulnerable to infectious diseases and some of them, such as David Vetter, become famous for living in a sterile environment. SCID is the result of an immune system so highly compromised that it is considered almost absent.
Types of SCID X-linked severe combined immunodeficiency Adenosine deaminase deficiency Omenn syndrome Bare lymphocyte syndrome JAK3 Artemis/DCLRE1C
Symptoms and diagnosis of SCID Children with SCID are at risk for life-threatening infections. From their first months of life, they have infections that may be frequent, severe, long-lasting or hard to treat. Infections may occur in the lungs (pneumonia), around the brain and spinal cord (meningitis) or in the blood stream. Several US states are performing pilot studies to diagnose SCID in newborns through the use of T- cell recombinant excision circles. The delay in detection is because newborns carry their mothers antibodies for the first few weeks of life and SCID babies look normal.
Treatment for SCID Preventing infections Enzyme therapy for ADA deficiency SCID The standard treatment for ADA deficiency SCID is treatment with a form of the ADA enzyme called PEG-ADA. Treatment with PEG- ADA is effective in about 90% of children. However, despite PEG- ADA therapy, some children continue to require IVIG treatments. Gene therapy A treatment option being studied in clinical trials is gene therapy. Gene therapy has shown promising results for some patients with ADA deficiency SCID. At first, gene therapy also appeared to be a promising treatment for X-linked SCID, but some children treated with gene therapy developed leukemia. New trials of gene therapy are in progress. But despite some promising results, gene therapy remains an experimental treatment for SCID.
Transplant for SCID The most common treatment for SCID is bone marrow transplantation, which has been successful using either a matched related or unrelated donor, or a half-matched donor, who would be either parent. The half-matched type of transplant is called haploidentical and was perfected by Memorial Sloan Kettering Cancer Center in New York and also Duke University Medical Center which currently does the highest number of these transplants of any center in the world. Haploidentical bone marrow transplants require the donor marrow to be depleted of all mature T cells to avoid the occurrence of graft- versus-host disease (GVHD). Consequently, a functional immune system takes longer to develop in a patient who receives a haploidentical bone marrow transplant compared to a patient receiving a matched transplant. David Vetter, the original "bubble boy", had one of the first transplantations but eventually died because of an unscreened virus, Epstein-Barr (tests were not available at the time), in his newly transplanted bone marrow from his sister.
Referenceshttp://www.cga.ct.gov/2008/rpt/2008-R-0564.htm"Severe combined immunodeficiency: A nationalsurveillance study“"Jak3, severe combined immunodeficiency, and a new classof immunosuppressive drugs“Fischer A, Hacein-Bey S, Cavazzana-Calvo M (2002). "Genetherapy of severe combined immunodeficiencies". Nat RevImmunol 2 (8): 615-621.Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L.(2007). Dermatology: 2-Volume Set. St. Louis: Mosby.ISBN 1-4160-2999-0