Proinflammatory TH17 cytokine activation, disease severity and outcomes in peripartum cardiomyopathy

Background: Immune dysregulation is implicated in the development and clinical outcomes of peripartum cardiomyopathy (PPCM).

Methods and results: 98 women with PPCM were enrolled and followed for 1 year postpartum (PP). LVEF was assessed at entry, 6-, and 12-months PP by echocardiography. Serum levels of soluble interleukin (IL)-2 receptor (sIL2R), IL-2, IL-4, IL-17, IL-22, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ were measured by ELISA at entry. Cytokine levels were compared between women with PPCM by NYHA class. Outcomes including myocardial recovery and event-free survival were compared by cytokine tertiles. For cytokines found to impact survival outcomes, parameters indicative of disease severity including baseline LVEF, medications, and use of inotropic and mechanical support were analyzed. Levels of proinflammatory cytokines including IL-17, IL-22, and sIL2R, were elevated in higher NYHA classes at baseline. Subjects with higher IL-22 levels were more likely to require inotropic or mechanical support. Higher levels of TNF-α and IL-22 were associated with poorer event-free survival. Higher TNF-α levels were associated with lower mean LVEF at entry and 12 months. In contrast, higher levels of immune-regulatory cytokines such as IL-4 and IL-2 were associated with higher LVEF during follow up.

Conclusion: Proinflammatory cytokines IL-22 and TNF-α were associated with adverse event-free survival. IL-17 and IL-22 were associated with more severe disease. In contrast, higher levels of IL-2 and IL-4 corresponded with higher subsequent LVEF. Increased production of TH17 type cytokines in PPCM correlated with worse disease and outcomes, while an increased immune-regulatory response seems to be protective.