Hugo Soudeyns trained in microbiology and immunology. He has been mostly active in three main areas of HIV/AIDS research. In January 2000, Dr Soudeyns opened a research unit devoted to the study of viral immunopathology at Centre de recherche du CHU Sainte-Justine. In collaboration with the Centre maternel et infantile sur le sida (CHU Sainte-Justine), the work of Dr. Soudeyns has led to the identification of important differences in cell-mediated immunity between adults and children, and contributed to the understanding of the pathogenesis of pediatric HIV infection. At the present time, the primary research interests of Dr. Soudeyns are mainly focused on mother-to-child transmission of viral diseases, notably HIV-AIDS and hepatitis C. His team is pursuing work on three main subjects.
Study of the pathogenesis of hepatitis C in pregnancy and childhood
Hepatitis C is a chronic disease of the liver that is caused by a virus called hepatitis C virus (HCV). This disease, which affects more than 250,000 Canadians, can lead to cirrhosis, hepatic dysfunction, and, in certain cases, necessitates the patient to undergo liver transplantation. Hepatitis C tends to worsen after pregnancy in infected women. In addition, HCV can be transmitted to the child during pregnancy and childbirth. The work of Dr. Soudeyns and his team are aimed at acquiring a better understanding of the mechanisms that lead to the worsening of hepatitis C, at better defining the role of the immune system in the control of this disease, and at identifying the precise manner (where, when and how) by which HCV is passed from the mother to the child. The ultimate goal of this research is to improve the clinical care of women suffering from hepatitis C and to prevent mother-to-child transmission of HCV. As there are new and efficient drugs that now allow HCV infection to be cured, the role that these treatments will play in the management of hepatitis C in women and children must be better defined.
Studies of long-term remission of HIV infection in children and adolescents
Like HCV, human immunodeficiency virus (HIV), also known as the AIDS virus, can be transmitted from mother to child during pregnancy, childbirth, and breastfeeding. For many years, drugs have been available that can prevent mother-to-child transmission of HIV in the large majority of cases when administered to the pregnant woman and her newborn. However, there are some children who nonetheless become infected. In these children, it is thought that treatment with powerful drug combinations in the first hours of life could allow a better control of HIV Infection in the long term. This is what apparently happened in the case of the ''Mississippi Baby'', a young girl who was able to keep HIV in check for over 2 years, event after her treatment was interrupted. Such long-term remissions were also observed in a minority of teenagers, who are also capable of controlling HIV in absence of medication. Understanding of the mechanism(s) whereby this kind of durable remission can take place could open the door to the development of novel practices in the management of HIV infection in our young patients. In the context of the EPIC4 Study, Dr. Soudeyns, his team and his collaborators in Canada and the United States are following multiple leads, including that of the existence of so-called ''non-conventional'' immune responses that could play a key role in this process.
Study of the reconstitution of antiviral immunity in transplanted children
Hematopoietic stem cell transplantation is commonly used to reconstitute the blood and immune systems in leukemic children who have been treated with chemotherapy and radiation therapy. These stem cells can originate from the bone marrow of a compatible or related donor, or can be sourced from umbilical cord blood (UCB). After receiving such a transplantation, leukemic children face multiple, potentially dangerous clinical complications: graft rejection (engraftment failure), graft-versus-host disease, leukemic relapse, and opportunistic infections, often times caused by viruses that are innocuous for most healthy people. This susceptibility to infections is caused in part by delayed reconstitution of the immune system in the young graft recipient, reconstitution that sometimes takes many months. Dr. Soudeyns and his team intend to understand the mechanisms that delay immune reconstitution and to identify at an early stage the children who are most at risk to develop infectious complications and/or leukemic relapse, with the goal of putting new tools and modes of intervention in the hands of medical oncologists and transplantation specialists.