This cluster of papers focuses on hemophagocytic syndromes, particularly hemophagocytic lymphohistiocytosis (HLH) and related disorders such as macrophage activation syndrome. It covers topics including diagnostic guidelines, therapeutic approaches, genetic mutations, cytokine involvement, and treatment efficacy in both pediatric and adult patients with various forms of the syndrome. The cluster also explores the association of these syndromes with conditions like juvenile idiopathic arthritis and provides insights into the pathogenesis, classification criteria, and long-term outcomes.