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Pediatrics:Chlamydia, Sickle Cell Anemia and Stroke Risk - Ancillary to STOP II

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ClinicalTrials.gov Identifier: NCT00037388
Recruitment Status : Completed
First Posted : May 17, 2002
Last Update Posted : July 29, 2016
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary:
To establish a link among Chlamydia infection, sickle cell anemia, and stroke risk.

Condition or disease
Blood Disease Anemia, Sickle Cell Chlamydia Infections Cerebrovascular Accident

Detailed Description:


Infection with Chlamydia pneumoniae (C. pneumoniae) is associated with an increased risk of cerebrovascular disease in the general population. Children with sickle cell anemia (SCA) are 200 times more likely to have cerebrovascular disease than normal children and are known to have an altered immune response to many infectious pathogens. C. pneumoniae is the leading infectious cause of acute chest syndrome which, interestingly, is a well- established risk factor for stroke in children with SCA. Preliminary data indicates that SCA patients with magnetic resonance imaging (MRI)-documented cerebral infarction are 12 times more likely to have C. pneumoniae infection than SCA patients with normal MRI scans. The investigators hypothesize that SCA patients have an abnormal immune response to C. pneumoniae that results in persistent infection which, in turn, triggers the development of cerebrovascular disease. Sickle cell anemia patients with an elevated velocity on transcranial doppler ultrasound (TCD) are known to be at high risk to develop stroke and an elevated TCD likely reflects underlying vascular disease. In addition, the Stroke Prevention in Sickle Cell Anemia Trial (STOP) demonstrated that almost 40 percent of children with an elevated TCD have evidence of cerebral infarction on MRI. Children with abnormal TCDs are, therefore, an appropriate population to investigate an association between cerebrovascular disease and C. pneumoniae infection.

The study is in response to an initiative on Ancillary Studies in Heart, Lung, and Blood Disease Trials released in June, 2000.


The study is ancillary to the STOP II clinical trial. The intent is: 1) To determine if C. pneumoniae infection is associated with cerebral infarction in children with SCA; 2) To characterize the immunological response to C. pneumoniae infection in patients with SCA. Establishing a link between C.pneumoniae infection and cerebral infarction will open the door to novel, less toxic approaches to the treatment and prevention of stroke in SCA, including antibiotics and vaccines.

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Study Type : Observational
Time Perspective: Retrospective
Study Start Date : July 2004
Actual Primary Completion Date : June 2006
Actual Study Completion Date : June 2006

Resource links provided by the National Library of Medicine

Information from the National Library of Medicine

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Ages Eligible for Study:   up to 100 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
No eligibility criteria

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00037388

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
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OverallOfficial: Lori Styles UCSF Benioff Children's Hospital Oakland
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ClinicalTrials.gov Identifier: NCT00037388    
Other Study ID Numbers: 1167
R01HL069114 ( U.S. NIH Grant/Contract )
First Posted: May 17, 2002    Key Record Dates
Last Update Posted: July 29, 2016
Last Verified: January 2008
Additional relevant MeSH terms:
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Chlamydia Infections
Anemia, Sickle Cell
Hematologic Diseases
Cerebrovascular Disorders
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Vascular Diseases
Cardiovascular Diseases
Chlamydiaceae Infections
Gram-Negative Bacterial Infections
Bacterial Infections
Bacterial Infections and Mycoses
Sexually Transmitted Diseases, Bacterial
Sexually Transmitted Diseases
Communicable Diseases
Anemia, Hemolytic, Congenital
Anemia, Hemolytic
Genetic Diseases, Inborn