Abstract 16587: Racial Differences in Circulating Natural Killer Cells in Peripartum Cardiomyopathy: Results of the NHLBI Sponsored IPAC Investigation
Introduction: Peripartum cardiomyopathy (PPCM) is a major cause of maternal morbidity and mortality and the etiology remains unknown. Cellular immunity is altered in pregnancy and the puerperium, and in subjects with acute cardiomyopathy. We examined peripheral cell subsets and the role of NK (natural killer) cells in the NHLBI sponsored IPAC investigation.
Method: IPAC (Investigation of Pregnancy Associated Cardiomyopathy) is a multicenter investigation of myocardial recovery in PPCM. Women presenting with an LVEF<0.45 within two months of delivery were enrolled at 30 centers. Peripheral immune cell subsets and cellular activation were assessed by flow-cytometry in the women with PPCM (n=85), at entry, 2 months and 6 months postpartum and compared with healthy postpartum women (PP, n=10), non-postpartum controls (NC, n=13), and women with recent onset non-ischemic cardiomyopathy (DCM, n=5) unrelated to pregnancy.
Results: For the IPAC cohort of women with PPCM, (mean age=30 ± 6 % NYHA class I/II/III/IV=12/46/24/17, and % race= 66 white, 30 black, 4 other) LVEF was 0.34 ± 0.11 at entry and 0.51 ± 0.11 at 6 months. LVEF was lower in blacks compared to whites at entry (p=0.002) and 6 months (p=0.02). The % NK cells (CD3-CD56+CD16+) was decreased in PPCM compared to PP early (6.8± 4.3 vs. 11.9± 5.0, p=0.001) and at 2 months (8.5± 4.6 vs.11.7± 9.6, p=0.03). The % NK was also decreased in DCM early after presentation (4.6± 2.2) compared to NC (p=0.049) and PP (p=0.02) and persisted at 2 month follow up (4.9± 3.7). In contrast, no differences were observed in the percentage of CD3+CD4+ or CD3+CD8+ T-cell populations among the 4 groups at any time point. In comparison by race, the decrease in %NK cells in PPCM was similar early (B/W= 5.9± 3.7/6.8± 4.2, p=0.48) but persisted at 2 months only in blacks (B/W=5.7± 3.4/9.8± 5.0, p=0.002).
Conclusions: The percentage of NK cells is significantly decreased in PPCM subjects compared to healthy PP women. A change in immune cell % was not observed in the major T-cell classes. In comparisons of PPCM subjects by race, this decline in NK cells resolved by 2 months in whites, but persisted in blacks. The role of NK cells in the pathogenesis of PPCM and in racial differences in recovery requires further investigation.
- © 2013 by American Heart Association, Inc.