Chlamydia pneumoniae and acute chest syndrome in patients with sickle cell disease

Purpose: Few studies address the association of Chlamydia pneumoniae infection with pulmonary disease and outcome in patients with underlying pathology such as sickle cell disease (SCD). SCD patients are susceptible to the pulmonary disorder known as acute chest syndrome (ACS), where the etiology remains ill defined. The purpose of this study was to analyze the clinical course and outcome of C. pneumoniae-associated ACS among SCD patients as part of the National Acute Chest Syndrome Study. Patients and Methods: This was a longitudinal study of SCD patients presenting with ACS to multiple U.S. medical centers. Two hundred ninety-six SCD patients who developed ACS were tested by PCR for C. pneumoniae and by standard techniques for other respiratory pathogens. These infections were evaluated for association with ACS, clinical course, and complications. Results: Forty-one (14%) patients with first episodes of ACS were PCR positive for C. pneumoniae. Compared with other infections, C. pneumoniae-infected patients were older, were more likely to present with chest pain, and had higher hemoglobin levels at diagnosis. Both groups had similar rates of respiratory failure and prolonged hospitalization. Of the 89 patients with single-pathogen infections, 27 (30%) were due to C. pneumoniae, 21% to Mycoplasma pneumoniae, 10% to RSV, 4% to Staphylococcus aureus, and 3% to Streptococcus pneumoniae. Conclusions: C. pneumoniae was the most prevalent pathogen in this study of ACS and was responsible for significant morbidity. Additional research is required to develop effective treatment guidelines for ACS.