[Biological roles of complement and recent topics in clinical medicine]

Area of Science:

• Immunology
• Molecular Biology

Context:

• The complement system, comprising C1-C9 and regulatory molecules, is crucial for immune responses.
• It plays key roles in opsonization, microbial destruction via the membrane attack complex (MAC), and inflammatory responses.

Purpose:

• To review the complement system's fundamental roles and therapeutic advancements for paroxysmal nocturnal hemoglobinuria (PNH) and hereditary angioedema (HAE).
• To explore emerging biological functions of complement factors outside of their established roles in innate immunity.
• To briefly discuss 3MC syndrome, a rare autosomal recessive disorder.

Summary:

• The complement system enhances antibody efficacy and mediates pathogen clearance through phagocytosis and direct lysis via MAC.
• This review details current understanding and treatments for PNH and HAE, highlighting complement's involvement.
• New non-innate immune functions of complement factors are proposed, alongside a discussion of 3MC syndrome.

Impact:

• Provides a comprehensive overview of complement biology and its clinical relevance in specific hematologic and immunologic disorders.
• Highlights recent therapeutic strategies for PNH and HAE, offering insights for clinical practice.
• Expands the understanding of complement's diverse biological roles, potentially opening new avenues for research and therapeutic targeting.