Life-saving mutation discovery
Philippe Gros, Professor in the Department of Biochemistry, and his colleagues have found two distinct disease-causing mutations, a finding which helped save the life of a baby girl.
Mutations in interferon regulatory factor 8 (IRF8) cause a primary immunodeficiency that manifests with disseminated infection from bacille Calmette–Guérin (BCG) vaccine, the researchers found.
The novel, yet rare, class of primary immunodeficiency mutations is the first known to impact development of mononuclear phagocytes. The findings were recently published in New England Journal of Medicine.
Among the McGill researchers involved in the study are Sandra Salem, Albert Berghuis, David Burk, and Anny Fortin.
Following up on mouse model findings, Gros’ group looked to characterize mutations that affect human IRF8 and found two distinct disease-causing mutations.
The researchers evaluated a 10-week-old baby girl with disseminated BCG infection after vaccination was suspected as a signal of severe immunodeficiency. After multiple rounds of aggressive antibiotics were only partially effective, she received hematopoietic stem cell transplantation, saving her life.
The researchers found that she carried the K108E variant, which was associated with an autosomal recessive severe immunodeficiency with a complete lack of circulating monocytes and dendritic cells — subgroups of mononuclear phagocytes.
The results should not only help in giving more individuals a reason behind their immunodeficiency, but also could help explain how the immune system works, Gros’ group noted.