Expression of interleukin-22 in decidua of patients with early pregnancy and unexplained recurrent pregnancy loss.
OBJECTIVE
Researchers have hypothesized that an imbalance of immune cells in the uterine decidua and a dysfunction in cytokines they produce may contribute to recurrent pregnancy loss (RPL). The objective of this study was to determine if IL-22, IL-23 and IL-17 are expressed abnormally in the decidua of patients with RPL compared to those women with a normal pregnancy. We also sought to confirm that uterine natural killer (uNK) cells are lower in the decidua of patients with RPL, as well as identify IL-22 expression by uNK cells.


METHODS
After meeting strict inclusion criteria, maternal decidua of nine patients with unexplained RPL and a confirmed euploid fetal loss, and 11 gestational age-matched patients undergoing elective pregnancy termination were included in our analysis. Quantitative real time-polymerase chain reaction (qRT-PCR) was performed to quantify RNA expression, Western blot was performed to quantify protein expression and immunohistochemistry (IHC) was performed to identify IL-22 and uNK cells.


RESULTS
We found that women with unexplained RPL and a euploid fetal loss had significantly less gene and protein expression of IL-22 in the decidua. Additionally, we found that IL-22 is primarily expressed by uNK cells in the decidua.


CONCLUSIONS
In conclusion, our results suggest that lower levels of IL-22 in the uterine decidua in patients with unexplained RPL may contribute to a disruption of decidual homeostasis and ultimately lead to early pregnancy loss.
Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Stanford University Medical Center, 900 Welch Rd, Suite 20, Palo Alto, CA, 94304, USA, cperfetto@infertilitytexas.com.
Candice
C
O'Hern Perfetto
Xiujun
X
Fan
Sabita
S
Dahl
Sacha
S
Krieg
Lynn Marie
LM
Westphal
Ruth
R
Bunker Lathi
Nihar R
NR
Nayak
D000026:Abortion, Habitual / Q000378:metabolism*; D000022:Abortion, Spontaneous / Q000378:metabolism*; D000328:Adult; D003656:Decidua / Q000378:metabolism*; D005260:Female; D006706:Homeostasis; D006801:Humans; D007378:Interleukins / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D000097043:Interleukin-22
D007378:Interleukins; D000097043:Interleukin-22