Polyreactive natural antibodies in transplantation

Area of Science:

• Immunology
• Transplantation Science
• Autoimmunity

Background:

• Antibody-mediated rejection (ABMR) is a major cause of late graft loss in solid organ transplantation.
• Autoantibodies, including natural antibodies (Nabs), are increasingly recognized alongside anti-HLA antibodies in the humoral response to allografts.
• Nabs, secreted by innate B cells, can bind to altered self-antigens like oxidized lipids on apoptotic cells.

Purpose of the Study:

• To review the role of natural antibodies (Nabs) in the pathophysiology of antibody-mediated rejection (ABMR).
• To highlight the emerging evidence implicating Nabs in late graft loss following solid organ transplantation.

Main Methods:

• This is a review article, synthesizing existing research.
• Analysis of recent findings on the contribution of immunoglobulin (Ig) G Nabs to ABMR.
• Examination of the association between pretransplant IgG Nabs levels and graft outcomes.

Main Results:

• New evidence supports the contribution of IgG Nabs to ABMR.
• Significantly higher serum IgG Nabs levels were observed in patients with ABMR compared to controls with stable graft function.
• Pretransplant IgG Nabs are associated with ABMR and late graft loss, with IgG1 and IgG3 subclasses capable of complement activation.

Conclusions:

• Nabs are significant components of the host immune response to solid organ grafts.
• The identified role of Nabs in ABMR and late kidney graft loss necessitates further investigation.
• Understanding Nab pathogenicity is crucial for improving transplant outcomes.