What causes IFNGR deficiency?IFNGR deficiency is caused by an inherited mutation in a gene. The affected gene is found on cells called granulocytes. These granulocytes have protein receptors on their surfaces that reject interferon gamma, a chemical needed to fight off tuberculosis and other infections caused by mycobacteria as well as salmonella infections.
What are the symptoms of IFNGR deficiency?Mycobacteria cause the most serious problems for people with IFNGR deficiency. Infections may involve the lungs, lymph nodes, blood and bone marrow. People with complete IFNGR deficiency have more serious infections than those with partial IFNGR deficiency. The disease occurs early in infancy in those with complete IFNGR deficiency. Those with partial deficiency are more likely to develop illness later in childhood.
How is IFNGR deficiency diagnosed?A doctor suspects IFNGR deficiency in a patient with a history of severe or repeated mycobacterial infections. Sophisticated laboratory tests measure the amount of interferon gamma in the blood and show the patient's white blood cells respond poorly, or not at all, to interferon gamma. Depending on whether the patient has complete or partial IFNGR deficiency, the blood will have either very high or very low levels of interferon gamma. Genetic testing can determine whether the patient has one of four mutations that cause either partial or complete IFNGR deficiency.
How is IFNGR deficiency treated?Patients with complete INFGR deficiency have a poorer outlook than those with partial INFGR deficiency. They need aggressive and long-term treatment with antibiotics. Patients with partial INFGR deficiency have milder disease that is easier to treat with antibiotics. Bone marrow transplantation has cured a small number of patients.
NIAID scientists are developing methods to add a corrective gene to bone marrow cells that will become granulocytes. They are also working to improve the multi-drug treatment that is the mainstay for IFNGR-deficient patients. Patients with complete IFNGR deficiency may especially benefit from treatment that includes immune boosters or "cytokines," including IL-2, IL-12, interferon gamma, and GM-CSF.
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