Immune dysregulation complicated by recurrent in-stent restenosis in patients with multivessel coronary artery disease: a case report.

BACKGROUND: 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. CASE PRESENTATION: We present a 74-year-old female with multivessel CAD, recurrent ISR, and comorbidities including hypertension, type 2 diabetes, and hyperlipidemia. Laboratory studies revealed hypogammaglobulinemia M (IgM: 0.306 g/L), an elevated CD4/CD8 ratio (3.24), and elevated hypogammaglobulinemia G3 (IgG3: 0.963 g/L). Intravascular imaging and PET/CT demonstrated neoatherosclerosis with peristrut inflammation. Despite multiple PCIs and guideline-directed medical therapy (GDMT), she experienced recurrent angina. Following adjunctive anti-inflammatory therapy with prednisone and immunomodulation with mycophenolate mofetil, she achieved symptomatic and angiographic stabilization. CONCLUSION: This case suggests a potential association between immune dysregulation and recurrent ISR. Anti-inflammatory and immunomodulatory therapy may represent a novel adjunctive strategy in selected refractory cases, though causality remains speculative and requires further validation.