Antibodies everywhere: The spectrum of IgG4-related disease—A case series and literature review

Introduction: IgG4-related disease (RD) is now known to affect multiple organs, including the gastrointestinal system, kidneys, lungs, and retroperitoneum. Diagnosis of IgG4-RD involves a combination of clinical, radiological, serological, and histopathological findings. Case Series: This case series underscores the importance of recognizing IgG4-RD as a potential etiology of diseases of unclear pathology with patient presentations, including pancreatitis, cholangitis, renal and mesenteric ischemia, back mass, and interstitial lung disease. Conclusion: Further, we discuss the histological findings, imaging, serology, other organ involvement and response therapy (HISORt) criterion of diagnosis, and treatment options including steroid-sparing agents.