Prenatally diagnosable differences in the cellular immunity of fetuses with Down's and Edwards' syndrome

Lymphocyte subpopulations are identified by the uniform CD classification (Cluster of Differentiation) and can be accurately differentiated with monoclonal antibodies using the method of flow cytometry. With the aid of cordocentesis it is possible to perform studies on the status and development of cellular immunity as early as in the second trimester of pregnancy.

To compare lymphocyte subpopulations present in fetuses with chromosomal abnormalities (Down's syndrome (DS), Edwards' syndrome (ES)) and fetuses with normal karyotype.

Prospective observational study.

We examined a total of 61 pregnant women with an average age of 31.5 years (20- 46 years).

In fetuses with DS we found a significant decrease in B lymphocytes (CD19),a decrease in the subpopulations of multi-reactive B-cells (CD5(+)CD19(+), B-CLL),and a decrease in the index of CD4/CD8 and class II HLA-DR. In contrast, the representation of NK cells expressing /CD3-CD (16 + 56)+/ was greatly increased. In ES we found a decrease in T lymphocytes (CD3), a decrease in T-helper lymphocytes (monocytes CD4), a decreased index of CD4/CD8 and a greater representation of NK cells /CD3-CD (16 + 56)+/.

We determined the normal values of lymphocyte subpopulations in physiological fetuses. We demonstrated that the immunological defect of the affected fetuses is already present antenatally, and can be reliably diagnosed in the second trimester of pregnancy.