Circulating B-cell activating factor in acute coronary syndromes – association with adverse outcomes and progression of heart failure

BACKGROUND: B cells and B-cell activating factor (BAFF) are involved in the development of myocardial infarction (MI), but data on the regulation and role of BAFF in MI are scarce. OBJECTIVES: To examine possible associations between plasma BAFF levels and outcomes in non-ST-elevation MI (NSTEMI) and STEMI. METHODS: We analyzed plasma BAFF at hospital admission by enzyme immunoassay in 732 patients with NSTEM and 261 patients with STEMI, and in STEMI also during follow-up. Plasma levels were related to pre-defined clinical outcomes (mortality and a composite of major adverse cardiac events [MACE]) in both groups and included infarct size and left ventricular ejection fraction (LVEF) evaluated by cardiac magnetic resonance imaging (CMR) in the STEMI group. RESULTS: Our major findings were: (i) BAFF levels at hospital admission were associated with adverse clinical outcome (i.e., mortality and MACE) in NSTEMI, also after adjustment for demographic variables, but only MACE was significant after adjustment for CRP, TnT and eGFR. (ii) In STEMI, BAFF levels increased from baseline and were highest at 4-months in patients who died during long term follow-up. Levels at 4 months were associated with all-cause death in adjusted analysis including CRP, TnT and the Thrombolysis in Myocardial Infarction (TIMI) risk score. (iii) STEMI patients with the largest infarct size and those with LVEF <50 % at 4 months, had higher levels of BAFF at 4 months, compared with the other STEMI patients. CONCLUSION: Our study supports a role for BAFF in the development of MI, potentially also in post-MI remodeling.