Preterm labor: CD55 in maternal blood leukocytes.
OBJECTIVE
Intrauterine inflammation is a frequent and significant factor associated with the pathogenesis of preterm labor/birth (PTL/PTB). However, it remains unclear whether the intrauterine inflammatory responses activate the maternal peripheral circulation. We explored the association between PTL/PTB and the 'activation' of the peripheral circulatory system by determining whether CD55 mRNA expression within peripheral WBCs differed between PTL and control patients not in labor.


METHODS
RNA was purified from white blood cells collected from pregnant women with preterm labor (n = 45), and from pregnant (n = 30) control women. CD55 gene expression was evaluated by quantitative PCR.


RESULTS
The mean CD55 mRNA level within the PTL group (0.77 +/- 0.03) was 1.48-fold higher than that observed (0.52 +/- 0.02) within the control group (P < 0.0001); 71% of PTL patients and only 6.7% of control subjects expressed elevated CD55 mRNA. The receiver operating characteristics (with 95% CI) of CD55 as a marker for PTL were as follows: Sensitivity, 69% (53-82%); Specificity, 93% (78-99%); Positive Predictive Value, 94% (80-99%); and Negative Predictive Value, 67% (51-80%). In the patient population that delivered prematurely (before 37 weeks), 81% expressed elevated CD55 mRNA levels with a mean of 0.78 +/- 0.03 and 95% CI of 0.71-0.84. The receiver operating characteristics were as follows: Sensitivity, 73% (54-88%); Specificity, 86% (71-95%); Positive Predictive Value, 81.5% (62-94%); and Negative Predictive Value, 80% (64-91%).


CONCLUSIONS
Here we report for the first time that CD55 mRNA expression was elevated in the peripheral WBCs of subjects with preterm labor compared with control gestationally-matched pregnant woman and that elevated leukocyte CD55 may be a useful predictor of subsequent PTB.
Nowicki
Stella
S
Departments of Obstrics and Gynocology, and Microbial Pathogenesis and Immune Response, Meharry Medical College, 1005 Dr. D.B. Todd, Jr. Blvd., Nashville, TN 37208, USA. snowicki@mmc.edu
Izban
Michael G
MG
Pawelczyk
Edyta
E
Agboto
Vincent K
VK
Pratap
Siddarth
S
Olson
Gayle
G
Nowicki
Bogdan
B