Low and undetectable breast milk interleukin-7 concentrations are associated with reduced risk of postnatal HIV transmission.
OBJECTIVE
To investigate if breast milk interleukin [IL]-7 concentrations are associated with postnatal HIV transmission.


METHODS
A case-control study nested within a cohort of women recruited in Lusaka, Zambia.


METHODS
IL-7 breast milk concentrations were measured in samples from 24 HIV-infected breast-feeding women who transmitted HIV to their child after the neonatal period and from 47 women who did not transmit. Samples were frequency-matched by the time of sample collection (1 week and 1 month postpartum). Logistic regression was used to adjust for possible confounders. For comparison, samples from 18 HIV-uninfected women from the same community were included in the analysis, and plasma IL-7 was determined.


RESULTS
Breast milk IL-7 concentrations were significantly higher than plasma IL-7 concentrations in all 3 groups. In contrast to levels among transmitters and HIV-uninfected women, breast milk IL-7 concentrations exhibited a bimodal distribution among nontransmitters. Breast milk IL-7 concentrations undetectable or less than 30 pg/mL were significantly associated with less HIV transmission (odds ratio = 0.13, 95% confidence interval: 0.03 to 0.64). The association remained strong after adjustment for breast milk viral load and sodium, maternal CD4 cell counts, parity, and time of sample collection.


CONCLUSIONS
Breast milk IL-7 may be necessary for effective HIV transmission.
Walter
Jan
J
Gertrude H. Sergievsky Center and Department of Epidemiology, Mailman School of Public Health, Columbia University; New York, NY, USA.
Kuhn
Louise
L
Ghosh
Mrinal K
MK
Kankasa
Chipepo
C
Semrau
Katherine
K
Sinkala
Moses
M
Mwiya
Mwiya
M
Thea
Donald M
DM
Aldrovandi
Grace M
GM
D000328:Adult; D001942:Breast Feeding / Q000009:adverse effects; D016022:Case-Control Studies; D005260:Female; D015658:HIV Infections / Q000635:transmission*; D015497:HIV-1; D006801:Humans; D007223:Infant; D018445:Infectious Disease Transmission, Vertical; D015851:Interleukin-7 / Q000032:analysis* / Q000097:blood; D008895:Milk, Human / Q000276:immunology*; D012307:Risk Factors; D015024:Zambia
D015851:Interleukin-7