Predictors of maternal‐origin microchimerism in young women in the Philippines

Abstract

Objectives: Microchimerism is the presence of a small quantity of cells or DNA from a genetically distinct individual. This phenomenon occurs with bidirectional maternalfetal exchange during pregnancy. Microchimerism can persist for decades after delivery and have long-term health implications. However, little is known about why microchimerism is detectable at varying levels in different individuals. We examine the variability and the following potential determinants of maternal-origin microchimerism (MMc) in young women in the Philippines: gestational duration (in utero exposure to MMc), history of being breastfed (postpartum exposure to MMc), maternal telomere length (maternal cells' ability to replicate and persist), and participant's pregnancies in young adulthood (effect of adding fetal-origin microchimerism to preexisting MMc). Materials and Methods: Data are from the Cebu Longitudinal Health and Nutrition Survey, a population-based study of infant feeding practices and long-term health outcomes. We quantified MMc using quantitative PCR (qPCR) in 89 female participants, ages 20-22, and analyzed these data using negative binomial regression. Results: In a multivariate model including all predictors, being breastfed substantially predicted decreased MMc (detection rate ratio = 0.15, p = 0.007), and there was a trend of decreasing MMc in participants who had experienced more pregnancies (detection rate ratio = 0.55, p = 0.057). Discussion: These results might be explained by breastfeeding having lasting impact on immune regulatory networks, thus reducing MMc persistence. MMc may also decrease in response to the introduction of fetal-origin microchimerism with pregnancies experienced in adulthood.

Quantification of Female Chimeric Cells in the Tonsils of Male Children and Their Determinants

“…Female cells were identified in almost two-thirds of patients. The reported prevalence of microchimerism is consistent with previous reports ranging from 20% to 60% [ 17 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. The reasons for the inability to detect female cells in some children may rely on the sensitivity of the technique.…”

“…These numbers contrast with those found in the literature for fetal microchimerism [ 8 ], but were consistent with those reported recently for maternal microchimerism. The latter were obtained using HLA-specific PCR on blood DNA extract and averages varied from 0 to 153 genomic equivalents (gEq)/100,000 gEq [ 17 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], with individual maximum values up to 1200 gEq/100,000 gEq in a 15-week-old child [ 18 ] or 354 gEq/100,000 gEq in 22-year-old women [ 30 ]. With a cell density of about 1 maternal cell per 5000–10,000 cells, a complete description of maternal microchimerism for each organ and its dynamics over time is required to further improve knowledge in this field.…”