Congenital autoinflammatory syndromes are genetic disorders of innate immunity (e.g., FMF, TRAPS, CAPS) causing recurrent fever, rash, serositis without autoantibodies. Acquired forms (e.g., Schnitzler syndrome, MAS) involve cytokine dysregulation (IL-1β, IL-18) triggering systemic inflammation. Both lack antigen-specific T-cells. Diagnosis requires genetic testing (congenital) and exclusion of infection/malignancy.