The Maternal–Foetal Interface and Gestational Chimerism: The Emerging Importance of Chimeric Bodies

Abstract

The science of gestational cell transfer—research into the transfer of cells between a pregnant woman and foetus during gestation—and subsequent mingling of transferred cells, or microchimerism, is bringing new attention to the maternal/foetal interface. These findings challenge previous biological understandings of a barrier between the body of a pregnant woman and developing foetus, a barrier maintaining the identity integrity as it were, of two beings, two separate subjects. In this sense, the maternal–foetal interface is an interesting bio-political object, predicated upon understandings of individuals as discrete and bounded organisms, an understanding that has been strongly implicated in immunology, as Donna Haraway, Emily Martin and others have argued. Findings of cellular transfer across this interface raise questions about intermingling and permeability of human organism boundaries. However, these findings are important not only for insight into gestational biology, but because they are emerging in a broader biomedical context of the development of cellular therapies and regenerative medicine. These therapeutic strategies call attention to chimerism as a naturally occurring and iatrogenic biological state, highlighting the permeability and permissiveness of bodies to the intermingling of cells, an idea that runs counter to biological, political and social understandings of selves as individuated, discrete and purely self. A theoretical framework of immuno-politics raises implications of trouble at the maternal/foetal interface, and suggests that chimeric, permeable bodies are of increasing value as cellular therapeutic strategies gain in importance for human health.

Keywords:

• Chimerism
• immuno-politics
• foetal–maternal relations

Notes

As of October 2011, the US based company Sequenom has announced the launch of such a test.

One might make the argument that the material maternal/foetal interface is an object that falls within the domains of several different sciences, depending on what questions are raised about it (Toulmin, 1972, p. 149). Nonetheless, the argument I wish to make is that the relative invisibility of the maternal/foetal boundary as an object of inquiry has been disturbed by evidence produced in reproductive cell transfer science, evidence that challenges previously held assumptions more taken for granted in some disciplines than others of the barrier functions of that boundary.

Peter Medawar's work on tissue graft rejection and acquired immune tolerance was critical to the development of organ transplantation, and led to the award of the Nobel Prize in Physiology or Medicine in 1960.

It is worth noting that efforts to develop non-invasive prenatal genetic diagnostic techniques based on the presence of genetic material originating from the developing foetus in the venous blood of the pregnant woman have turned nearly exclusively to cell-free foetal DNA and RNA, and in many applications to quantitative rather than qualitative approaches, avoiding this cell-identity conundrum (see, for example, Avent et al., 2008; Chiu et al., 2011). As stated previously, the Y chromosome (or locations on the Y chromosome) remains the gold standard for foetal cell identification.