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Breast Milk CD4+ T Cells Express High Levels of CCR5 and CXCR4 and Are Preserved in HIV Infection
Athena Kourtis*1, C Ibegbu2, R Theiler3, Y X Wu2, D Jamieson1, M Lindsay3, S Butera4, and A Duerr1
1Natl Ctr for Chronic Disease Prevention and Hlth Promotion, CDC, Atlanta, GA, US; 2Emory Vaccine Ctr, Emory Univ, Atlanta, GA, US; 3Emory Univ Sch of Med, Atlanta, GA, US; and 4Natl Ctr for HIV, Viral Hepatitis, STD, and TB Prevention, CDC, Atlanta, GA, US
Background: Transmission of HIV
to the infant through breastfeeding is a major problem worldwide. However, the
biologic circumstances of such transmission remain unclear, and little
characterization of the breast milk CD4+ T lymphocytes has been
done.
Methods: We performed a
detailed immunophenotypic analysis of T lymphocytes
in the breast milk, compared with blood, of HIV-infected (n = 10) and -uninfected (n
= 9) women, using multiparameter flow cytometry. Descriptive statistics and non-parametric comparisons
were carried out using SAS software.
Results: In uninfected women,
44 to 78% of the breast milk CD4+ T cells expressed the C chemokine receptor 5 (CCR5), whereas 26 to 73% of cells co-expressed
CCR5 and CXC chemokine receptor 4 (CXCR4). In
contrast, only 7 to 20% of peripheral blood CD4+ T cells expressed
CCR5 and 1 to 20% co-expressed CCR5 and CXCR4. The level of CCR5 expression in
CD4+ cells in breast milk was higher than in blood. In HIV-infected
women, the high frequency of CD4+CCR5+ T cells in the
breast milk was preserved.
Conclusions: A majority of CD4+
T cells in the breast milk express high levels of CCR5 and CxCR4. Unlike other
mucosal immune sites, in which CD4+CCR5+ cells are
rapidly eliminated by HIV, these cells are preserved in the breast milk during
HIV infection.
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