New insights on innate B‐cell immunity in transplantation

Abstract

Innate B cells and natural antibodies (Nabs) have been extensively studied in normal physiological conditions as well as in several diseases. However, their significance in the context of ABO-compatible solid organ transplantation is only emerging. This review summarizes recent studies exploring these often neglected innate immune elements in situations related to sensitization and clinical graft rejection. A focus is placed on class-switched IgG Nabs that develop amidst inflammation, rather than IgM Nabs abundant at the steady state, as new evidence point to their implication in serum reactivity to HLA and kidney graft failure. The involvement of innate B cells in the pathophysiology of CAV is also presented. Lastly, we discuss key questions that need answering to understand whether and how innate B-cell immunity contributes to the outcome of solid organ transplantation.

Anti‐TSNARE1 IgG plasma levels differ by sex in patients with schizophrenia in a Chinese population

“…The increased antibody levels could result from a breakdown of immune tolerance to these schizophrenia‐associated proteins, causing an autoimmune response as discussed in our recent publication . However, increased natural IgG levels may reflect an increase in the expression of self‐molecules such as schizophrenia‐associated proteins due to genetic predisposition , leading to the activation of the class switch recombination; consequently, increased IgG may develop pathological immune responses such as autoimmune inflammation . Nevertheless, antibody studies in schizophrenia generally demonstrate inconsistencies, but this is largely a result of heterogeneity across studies.…”

The XVth Banff Conference on Allograft Pathology the Banff Workshop Heart Report: Improving the diagnostic yield from endomyocardial biopsies and Quilty effect revisited

“…In addition, polyreactive natural antibodies (NABs), a type of autoantibody, have resurfaced. 46,47 Quilty effect demonstrates all the features of a tertiary lym- in the production of autoantibodies. 51,52 The interaction of B and T cell arms may result in either tolerogenic or rejection responses, 51 providing, in part, an explanation for the conflicting results in the literature.…”

Non-canonical B cell functions in transplantation

“…Natural antibodies (antibodies produced without known history of exposure to foreign antigen), particularly polyreactive natural antibodies and particularly IgM, have properties distinct from the antibodies that exert effector functions [66,67]. Natural antibodies comprise a significant fraction of Ig in serum and recognize multiple antigens (as the term polyreactive implies), including histocompatibility antigens and saccharides of various types and components of cytoplasm and nucleus and neoantigens of the cell surface [68,69]. The antibodies provide an early defense against some pathogens and potentially a framework for generation of more specific antibodies [70,71].…”