Etiology, Prevalence, and Epidemiology Takayasu arteritis, also known as pulseless disease or Martorell syndrome, is an idiopathic chronic granulomatous arteritis affecting medium and large arteries with a predilection for the…

Etiology Rheumatoid arthritis (RA) is an autoimmune disorder of unknown cause with variable clinical manifestations. Genetic factors play a major role in disease susceptibility and expression. The B lymphocyte is…

Eosinophilic diseases of the lung include a heterogeneous group of pulmonary disorders that characteristically feature peripheral or tissue eosinophilia. Patients with these illnesses have a variable clinical presentation and may…

Etiology The pathogenesis of systemic lupus erythematosus (SLE) involves genetic and environmental factors, hormonal influences, and cell-mediated responses. In SLE, B lymphocytes lose self-tolerance and inappropriately produce autoantibodies. Serologic positivity…

Etiology Sjögren’s syndrome, or “sicca syndrome,” is a disorder of the immune system that is largely defined by its two most common symptoms—dry eyes and a dry mouth; these symptoms…

Etiology, Prevalence, and Epidemiology Behçet disease is an uncommon systemic disorder of unknown etiology characterized by vasculitis and the triad of recurrent ulcers of the oral and genital mucosa with…

Interstitial pneumonia with autoimmune features (IPAF) refers to the clinical entity of interstitial lung disease (ILD) in patients with features of autoimmunity but without overt connective tissue disease (CTD). IPAF…

Etiology, Prevalence, and Epidemiology Goodpasture syndrome, also known as anti–basement membrane antibody disease, is an autoimmune disorder characterized by repeated episodes of pulmonary hemorrhage, usually associated with glomerulonephritis and the…

Etiology Immune-mediated muscle inflammation and vascular damage are the hallmarks of polymyositis (PM) and dermatomyositis (DM). In PM the immune system is primed to act against muscle antigens, whereas in…

Etiology Lymphangioleiomyomatosis (LAM) is a systemic disease of unknown etiology, affecting almost exclusively women. LAM is characterized by idiosyncratic smooth muscle cell proliferation (LAM cells), which leads to lung cysts,…