Autoinflammatory bone disorders: update on immunologic abnormalities and clues about possible triggers

Area of Science:

• Genetics and Immunology
• Skeletal Biology
• Innate Immunity

Background:

• Autoinflammatory bone disorders, including chronic recurrent multifocal osteomyelitis (CRMO), are increasingly understood as genetically influenced conditions.
• Monogenic forms provide insights into the immunologic defects underlying sterile bone inflammation.

Purpose of the Study:

• To review current knowledge on the genetic and immunologic basis of autoinflammatory bone disorders.
• To highlight the role of monogenic forms in understanding disease pathogenesis.

Main Methods:

• Review of recent research in murine, canine, and human models of sterile bone inflammation.
• Analysis of genetic mutations (e.g., Pstpip2, LPIN2, IL1RN) in monogenic disorders.
• Examination of innate immune system function in conditions like DIRA, Majeed syndrome, and SAPHO syndrome.

Main Results:

• Genetic mutations are confirmed drivers of sterile bone inflammation.
• Defects in innate immunity and IL-1 pathway dysregulation are implicated in CRMO, DIRA, Majeed syndrome, and SAPHO syndrome.
• Therapeutic IL-1 blockade shows promise in managing these conditions.

Conclusions:

• Innate immunity plays a significant role in the pathogenesis of sterile osteomyelitis.
• The IL-1 pathway is a key factor in the development of sterile bone inflammation, particularly in monogenic autoinflammatory bone disorders.