HIV Persists in Breast Milk despite Antiretroviral Therapy

By Liz Highleyman

Recent studies have shown that maternal antiretroviral therapy during breast-feeding can lower the risk of mother-to-child HIV transmission. But HIV persists in breast milk despite treatment, according to a study in the July 31, 2008 issue of AIDS.

Dara Lehman from the Fred Hutchinson Cancer Research Center in Seattle and colleagues studied a group of Kenyan women who received short-course zidovudine (AZT; Retrovir), single-dose nevirapine (Viramune), zidovudine plus single-dose nevirapine, or short-course combination highly active antiretroviral therapy (HAART).

Breast milk samples were collected 2-3 times weekly for 4-6 weeks. HIV-1 DNA was quantified using real-time PCR. Cell-free and cell-associated HIV RNA levels were quantified using the Gen-Probe HIV-1 viral load assay.

Results

• Cell-free HIV RNA levels in breast milk were significantly suppressed by single-dose nevirapine, zidovudine plus single-dose nevirapine, and HAART, compared with zidovudine alone, between day 3 and week 4 post-partum (P < 0.03).

• Breast milk HIV DNA levels (infected cell levels) were not significantly different across the treatment arms at any time point during the 4-6-week follow-up.

• At 3 weeks post-partum, when the difference in cell-free HIV RNA levels was the greatest, median HIV DNA levels (in log10 copies) were:

• 2.78 in the zidovudine monotherapy arm;
• 2.54 in the single-dose nevirapine only arm;
• 2.69 in the zidovudine plus single-dose nevirapine arm;
• 2.31 HAART arm (P = 0.23).

• Cell-associated HIV RNA levels were modestly suppressed in the HAART arm versus the zidovudine plus single-dose nevirapine arm during week 3 (3.37 vs 4.02; P = 0.04), as well as over time according to a linear mixed-effects model.

Based on these findings, the study authors concluded, "Cell-free and, to a lesser extent, cell-associated HIV-1 RNA levels in breast milk were suppressed by antiretroviral regimens used to prevent [mother-to-child transmission]."

However, they added, "even with HAART, there was no significant reduction in the reservoir of infected cells, which could contribute to breast milk HIV-1 transmission."

7/22/08

Reference

DA Lehman, MH Chung, GC John-Stewart, and others. HIV-1 persists in breast milk cells despite antiretroviral treatment to prevent mother-to-child transmission. AIDS 22(12):1475-85. July 31, 2008. (Abstract)