Volume 8, Issue 7
Article number e67956
Coinfection; HIV Infections--blood; Leukocyte Count; Neutrophils; Sputum--microbiology; Tuberculosis, Pulmonary--blood
Increasing evidence suggests that neutrophils play a role in the host response toMycobacterium tuberculosis. We determined whether neutrophil counts in peripheral blood are associated with tuberculosis (TB) and with mycobacterial load in sputum in HIV-infected patients.
Adults enrolling in an antiretroviral treatment (ART) clinic in a Cape Town township were screened for TB regardless of symptoms. Paired sputum samples were examined using liquid culture, fluorescence microscopy, and the Xpert MTB/RIF assay. Absolute neutrophil counts (ANC) were measured in blood samples. Of 602 HIV-infected patients screened, 523 produced one or more sputum samples and had complete results available for analysis. Among these 523 patients, the median CD4 count was 169×109/L (IQR, 96–232) and median ANC was 2.6×109/L (IQR, 1.9–3.6). Culture-positive pulmonary tuberculosis was diagnosed in 89 patients. Patients with TB had a median ANC of 3.4×109/L (IQR, 2.4–5.1) compared to 2.5×109/L (IQR, 1.8–3.4) among those who were culture negative (p7.5×109/L; p = 0.0005). Patients were then classified into four mutually exclusive groups with increasing sputum mycobacterial load as defined by the results of culture, Xpert MTB/RIF and sputum smear microscopy. Multivariable analyses demonstrated that increasing sputum mycobacterial load was positively associated with blood ANC ≥2.6×109/L and with neutrophilia.
Increased blood neutrophil counts were independently associated with pulmonary TB and sputum mycobacterial burden in this HIV-infected patient group. This observation supports the growing body of literature regarding the potential role for neutrophils in the host response to TB.
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Kerkhoff, A. D., Wood, R., Lowe, D. M., Vogt, M., & Lawn, S. D. (2013). Blood neutrophil counts in HIV-infected patients with pulmonary tuberculosis: Association with sputum mycobacterial load. PLoS ONE, 8(7):e67956