Defining Immunodeficiency in Heterotaxy Syndrome: Pilot Study Data
The investigators aim with this study is to investigate the mechanisms of immune deficiency in patients with heterotaxy syndrome through the use of novel biomarkers and a prospective questionnaire survey documenting the burden of infectious sequelae following enrollment. It is known that patients with under-active spleens (functional asplenia or hyposplenia) secondary to other (non-cardiac) conditions such as Sickle Cell Disease or Inflammatory Bowel Disease have a characteristic paucity of a B cell sub-class known as IgM memory B cell. This specific sub-class of B cell normally matures in the spleen and in those with an improperly functioning spleen a significant deficiency of this B cell class is seen on flow cytometry.
Similarly, these same patients are noted to have increased amounts of 'junk' DNA / nuclear remnant in their red cells. This is seen on microscopy as a dark particle inside the red cell and is termed a Howell Jolly Body (normally less than 2% of red cells have these dark particles present). Part of a functioning spleen's normal task is to rid the blood of red cells that contain nuclear remnants and an under-active spleen gets behind on this task with a build-up of Howell Jolly Bodies in red cells present in the bloodstream. Flow cytometry can very quickly and accurately quantify Howell Jolly Bodies as well as IgM memory B cells from a small (~1.5cc) sample of blood. Normal IgM memory B cell ranges are known for healthy children from infancy onwards allowing interpretation of results against normative data ranges.
The investigators aim to enroll 10 patients in this pilot study who have a diagnosis of heterotaxy syndrome (both asplenia and polysplenia) and to prospectively follow them after obtaining the initial biomarker sample. The family will be contacted once every two weeks for a period of 12 weeks and asked a series of simple questions taking approximately 5 minutes on any recent infectious sequelae or symptoms. The questions will elucidate history of minor illness such as low-grade fever or cough to more significant events such as admission for in-patient antibiotic therapy of bacterial sepsis. Ultimately, with this pilot study, the investigators hope to obtain sufficient data to support funding applications for a larger, multi-center trial that will allow us to develop biomarker thresholds for future risk of sepsis.
|Study Design:||Observational Model: Cohort
Time Perspective: Prospective
|Official Title:||Defining Immunodeficiency in Heterotaxy Syndrome: Pilot Study Data|
- Howell Jolly Body quantification [ Time Frame: At time of recruitment ]
- IgM Memory B Cell quantification [ Time Frame: At time of recruitment ]
- Results of phone questionnaire of parents documenting infectious symptoms and sequelae [ Time Frame: Once every 2 weeks for 12 weeks following enrollment ]
|Study Start Date:||August 2013|
|Study Completion Date:||June 2014|
|Primary Completion Date:||June 2014 (Final data collection date for primary outcome measure)|
Patients with a diagnosis of heterotaxy syndrome, as objectively defined by visceral heterotaxy (malrotation, interrupted inferior vena cava) with either documented polysplenia or asplenia by radiological imaging
Please refer to this study by its ClinicalTrials.gov identifier: NCT01929967
|United States, Massachusetts|
|Boston Children's Hospital|
|Boston, Massachusetts, United States, 02115|
|Principal Investigator:||Terence Prendiville, MB BCh BAO||Boston Children’s Hospital|