Lung-Restricted Antibodies Mediate Primary Graft Dysfunction and Prevent Allotolerance after Murine Lung Transplantation

Abstract

Over one-third of lung recipients have preexisting antibodies against lung-restricted antigens: collagen (Col) type V and K-a1 tubulin (KAT). Although clinical studies have shown association of these antibodies with primary graft dysfunction (PGD), their biological significance remains unclear. We tested whether preexisting lungrestricted antibodies can mediate PGD and prevent allotolerance. A murine syngeneic (C57BL/6) or allogeneic (C57BL/6 to BALB/c) left lung transplantation model was used. Rabbit polyclonal antibodies were produced against KAT and Col-V and injected pretransplantation. T cell frequency was analyzed using enzyme-linked immunospot, whereas alloantibodies were determined using flow cytometry. Wet:dry ratio, arterial oxygenation, and histology were used to determine PGD. Preexisting Col-V or KAT, but not isotype control, antibodies lead to dose-dependent development of PGD after syngeneic lung transplantation, as evidenced by poor oxygenation and increased wet:dry ratio. Histology confirmed alveolar and capillary edema. The native right lung remained unaffected. Epitope spreading was observed where KAT antibody treatment led to the development of IL-17-producing CD4 1 T cells and humoral response against Col-V, or vice versa. In contrast, isotype control antibody failed to induce Col-V-or KAT-specific cellular or humoral immunity. In addition, none of the mice developed immunity against a non-lung antigen, collagen type II. Preexisting lung-restricted antibodies, but not isotype control, prevented development of allotolerance using the MHC-related 1 and cytotoxic T-lymphocyteassociated protein 4-Ig regimen. Lung-restricted antibodies can induce both early and delayed lung graft dysfunction. These antibodies can also cause spreading of lung-restricted immunity and promote alloimmunity. Antibody-directed therapy to treat preexisting lung-restricted antibodies might reduce PGD after lung transplantation.

Autoantibodies in lung transplantation

“…Pre‐existing Abs to lung SAgs can increase the risk for primary graft dysfunction (PGD), as they increase the development of pro‐inflammatory cytokines and increase the risk of development of Abs to HLA and non‐HLA antigens, which are known risk factors for CLAD . Recently, pre‐existing Abs to lung‐associated SAgs (in the absence of Abs to donor HLA) were shown to result in antibody‐mediated acute rejection . Since patients with primary lung disease are known to be susceptible for comorbid conditions, our studies might explain why some patients waiting for LTx have pre‐existing autoantibodies.…”

“…Our group has shown that pre‐existing autoimmunity is one of the most predominant risk factors for the development of CLAD . Pre‐existing Abs to lung SAgs can increase the risk for primary graft dysfunction (PGD), as they increase the development of pro‐inflammatory cytokines and increase the risk of development of Abs to HLA and non‐HLA antigens, which are known risk factors for CLAD .…”

Impact and production of Non‐HLA‐specific antibodies in solid organ transplantation

“…Antibodies to collagen V have been found deposited in lung allograft in human as well as in a mouse model (Sumpter & Wilkes, 2004). Preexisting of K‐α1‐tubulin antibodies can cause development of primary graft dysfunction in a dose dependent manner in a mouse model (Bharat et al., 2016). Patients who clear antibodies against K‐α1‐tubulin and collagen V after the rituximab and/or IVIG therapy are significantly less likely to develop bronchiolitis obliterans syndrome than those who have persistent K‐α1‐tubulin and collagen V antibodies, which further confirms the pathological effect of antibodies against K‐α1‐tubulin and collagen V (Hachem et al., 2012).…”

Immune Responses to Tissue-Restricted Nonmajor Histocompatibility Complex Antigens in Allograft Rejection

“…Because a number of clinical factors can confound the association between preexisting Abs to lung SAgs and PGD, we tested whether these two variables are mechanistically linked using the murine model of unilateral LTx [71]. In this recent study, recipients were passively given one or more Abs to lung-restricted antigens before transplantation of syngeneic lung grafts.…”