Laboratory indicators of mastitis are not associated with elevated HIV-1 DNA loads or predictive of HIV-1 RNA loads in breast milk

Background. Mother-to-child transmission (MTCT) of HIV-1 has been associated with symptomatic and asymptomatic mastitis and with the quantity of HIV-1 RNA and DNA in maternal milk. An improved understanding of the relationship between indicators of inflammation and HIV-1 loads in breast milk could improve MTCT prevention strategies. Methods. In a cross-sectional study, laboratory indicators of mastitis (breast milk sodium [Na ⁺] concentration, sodium:potassium ratio [Na ⁺:K ⁺], and leukocyte count) were related to breast milk HIV-1 RNA and DNA loads and were evaluated for predicting viral loads in milk. Results. Mastitis was present in 63 (15%) of 407, 60 (15%) of 407, and 76 (18%) of 412 milk specimens, as defined by Na ⁺ concentration >12 mmol/L, Na ⁺:K ⁺ >1, and total leukocyte counts ≥106 cells/mL, respectively. Each indicator was associated with an increased milk HIV-1 RNA load (P < .05) but not with HIV-1 DNA load. Neutrophils correlated better with milk HIV-1 RNA load than total leukocytes. However, neither neutrophil count, Na ⁺ concentration, nor Na ⁺:K ⁺ displayed a threshold that was both sensitive and specific for the detection of HIV-1 RNA in milk at thresholds of ≥50 or ≥10 ⁴ copies/mL. Conclusions. HIV-1 DNA loads in breast milk were not increased during mastitis. Neither milk cell counts nor electrolyte concentrations were useful predictors of milk HIV-1 RNA or DNA loads for individual women.