Fetal CD103+ IL-17-Producing Group 3 Innate Lymphoid Cells Represent the Dominant Lymphocyte Subset in Human Amniotic...

Area of Science:

• Immunology
• Fetal Development
• Pregnancy Biology

Background:

• Amniotic fluid (AF) is crucial for fetal development and used in genetic diagnostics.
• Intra-amniotic infections are a major cause of preterm birth, a leading cause of perinatal mortality.
• The role of mature hematopoietic cells in AF during pregnancy remains largely unexplored.

Purpose of the Study:

• To identify the dominant viable hematopoietic cell populations in amniotic fluid.
• To investigate the potential immune functions of these cells during pregnancy.
• To explore the link between these cells and pregnancy complications like preterm birth.

Main Methods:

• Flow cytometry analysis of viable CD45+ cells in amniotic fluid.
• Characterization of cell populations based on markers like CD103.
• Assessment of cytokine production (IL-17, TNF) by identified cell subsets.
• Analysis of cell distribution in fetal mucosal tissues.

Main Results:

• The predominant viable CD45+ cells in AF are fetal CD103+ group 3 innate lymphoid cells (ILCs).
• These ILC3s exhibit high production of IL-17 and TNF.
• High frequencies of CD103+ ILC3s were found in second-trimester fetal mucosal tissues (intestine, lung).
• Data suggest CD103+ ILC3s accumulate in the fetal intestine and migrate to AF during gestation.

Conclusions:

• CD103+ ILC3s are a major immune cell component in fetal AF.
• Their cytokine profile suggests a role in combating intra-amniotic infections and inflammation.
• These ILC3s may be critical in preventing preterm birth.