RESEARCH - Serum fetal DNA levels tied to RA improvement during pregnancy

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Serum Fetal DNA Levels Tied to Rheumatoid Arthritis Improvement During

Pregnancy

NEW YORK (Reuters Health) Jun 27 - Women with rheumatoid arthritis (RA)

often improve when they are pregnant. An inverse association between serum

levels of fetal DNA and disease activity could account for the improvement,

and the rapid relapse postpartum, according to a report in the July issue of

Arthritis and Rheumatism

Dr. Zhen Yan, from the Fred Hutchinson Cancer Research Center in Seattle,

and her associates obtained blood samples from 25 pregnant patients with RA

throughout their pregnancies. The cohort included six patients who were

diagnosed with juvenile idiopathic arthritis (JIA).

" Group A " was comprised of women who experienced improved symptoms during

pregnancy, including 15 adult-onset RA patients and all six patients with

JIA. That improvement was either sustained or increased further during the

course of gestation, followed by relapse within 3 to 4 months after delivery

The four " Group B " patients did not experience any improvement throughout

their pregnancies.

Real-time quantitative PCR was used to measure serum levels of free fetal

DNA. Circulating levels reached a median of 24 fetal genomic equivalents per

milliliter (gE/mL) during the first trimester, 61 gE/mL in the second

trimester, and 199 gE/mL in the third trimester.

The authors found that serum fetal DNA levels were significantly higher in

the third trimester among women in Group A as compared with Group B (median

270 gE/mL versus 78 gE/mL, p < 0.001).

By 3 to 4 months after delivery, RA disease recurrence was experienced by

90% of women in Group A, at which time fetal DNA was almost completely gone

from the serum.

As noted, there was an inverse association between serum fetal DNA levels

and RA disease activity. Dr. Yan's team suggests that fetal DNA may modulate

the immune system, perhaps by induction or alteration of the mother's

peripheral T cell repertoire.

Arthritis Rheum 2006;54:2069-2073.

http://www.medscape.com/viewarticle/537449

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