In Infectious Diseases, a fundamental enigma is why some individuals are unusually prone to infections, while others are not. Research is increasingly showing that these susceptible individuals may have an underlying Primary Immunodeficiency disorder (PID). PID are inherited (i.e. genetic) conditions in which the immune system is impaired. The immune system is the body's army for fighting infections. When a gene of the immune system does not function properly, it results in a "hole" in the immune system that allows microbes to cause disease. Although individually, each PID is rare (affecting less than 1 in 2000 people), collectively, PIDs affect 1-2% of the population. Because they are uncommon, they may not be recognized, and affected individuals may be debilitated by severe or unexplained symptoms.
My research program focuses on investigating patients with unusual susceptibility to infections to determine if they have an underlying PID. We combine clinical and laboratory expertise in infections, genetics and immunology to identify PID, including the discovery of new diseases. We are focusing on a fungal brain infection (due to the gene, CARD9) and have identified that this genetic immune deficiency may be relatively prevalent in Québec because of a founder effect. We are also studying cohorts of patients with combined immunodeficiencies (in which myeloid and lymphoid lineages are impaired) and patients with recurrent viral warts of the throat, among others.
Each person with a PID is a lesson from Nature, giving researchers more clues about how the healthy immune system functions. More importantly, identifying the mechanism by which a faulty gene weakens the immune system allows for better disease management of each affected patient and provides opportunities to develop new types of therapy to treat their infections. These new therapies can then be used to treat other individuals with the same condition, even if it is not genetic, such that a substantial number of patients can benefit from studying these rare disorders.