Immune Dysregulation Complicated by Recurrent In-Stent Restenosis in Patients with Multivessel Coronary Artery Disease: A Case Report

The management of complex coronary artery disease (CAD) predominantly relies on percutaneous coronary intervention (PCI), yet in-stent restenosis (ISR) remains a critical long-term complication. Emerging evidence implicates immune dysregulation in ISR pathogenesis. We present a 74-year-old female with refractory angina pectoris, multivessel coronary lesions, and recurrent ISR complicated by hypertension, type 2 diabetes mellitus, hyperlipidemia, and immunological abnormalities. Despite multiple PCI procedures, postinterventional recurrence of ISR has persisted. Laboratory investigations revealed hypogammaglobulinemia M (IgM: 0.45 g/L) and an elevated CD4/CD8 ratio (3.8:1), whereas intravascular imaging demonstrated neoatherosclerosis with peri-strut inflammation. These findings suggest that immune-inflammatory activation may drive restenosis progression. Notably, symptomatic remission and angiographic stabilization were achieved following adjunctive anti-inflammatory therapy (low-dose prednisone 10 mg/d) combined with an immunomodulatory regimen (mycophenolate mofetil 1 g/d). This case highlights the potential role of immune checkpoint modulation in ISR management, offering insights for mechanistically guided precision therapy.