The distribution of receptors for the pro-inflammatory cytokines interleukin (IL)-6 and IL-8 in the developing human fetus.

UNLABELLED: Interleukin-6 receptor alpha (IL-6R) and interleukin-8 receptor (IL-8RB) are widely expressed in adult human and murine tissues. Little is known about the expression of these receptors and the function of their ligands in the developing human fetus.
OBJECTIVES: To determine the tissue distribution and cellular expression of IL-6R and IL-8RB in the developing human fetus.
METHODS: Reverse transcription-PCR and immunohistochemical staining were performed on brain, spinal cord, eye, heart, lung, liver, spleen, adrenal, kidney, intestine, and placenta from fetuses of 8 and 16+/-2 weeks post-conception.
RESULTS: IL-6R and IL-8RB mRNA were detected in all tissues tested at both time points. Immunoreactivity to anti-IL-6R antibody was present on neurons, and in neuropil of the brain, as well as in bone marrow, bronchi, hepatocytes, zona glomerulosa of the adrenal, glomerular cells in kidney, spleen, and placental trophoblasts. Cell-specific expression for IL-8RB in the central nervous system was localized to specific groups of neurons and astrocytes in the brain and spinal cord, including the neural retina. In somatic organs IL-8RB was detected in bone marrow, myocardiocytes, bronchiolar epithelial cells, hepatocytes, cells of the zona glomerulosa and the zona fasciculata of the adrenal, the collecting system of the kidney, enterocytes of the bowel and in placental cells.
CONCLUSION: The widespread expression of these cytokine receptors suggests a nonhematopoietic role for their ligand in the developing fetus.