Cervical and vaginal cytokine determinations in pregnant women: methodologic issues.

Investigations of the role cytokines play in preterm birth are complicated by a number of methodologic issues that arise as to the most feasible and efficient methods to measure cytokines. The purpose of this article is to review methodologic issues surrounding the measurement of vaginal and cervical cytokines, specifically IL-1β, IL-6, and TNF-α, in pregnant women experiencing preterm labor. Specifically, two quantification methods, weight and protein assay, and cytokine specimens from two different sites, vaginal and cervical, were compared. There were no significant correlations between cytokine levels using the protein versus weight quantification method. The weight method had more negative values and thus the protein quantification method was more accurate. There were high correlations between cervical and vaginal IL-1β levels and IL-6 levels, but cervical and vaginal TNF-α levels were not correlated.