Expansion of Polyreactive B Cells Cross-Reactive to HLA and Self in the Blood of a Patient With Kidney Graft Rejection

Abstract

Antibody rejection is often accompanied by non-donor HLA specific antibodies (NDSA) and self-reactive antibodies that develop alongside donor-specific antibodies (DSA). To determine the source of these antibodies, we immortalized 107 B cell clones from a kidney transplant recipient with humoral rejection. Two of these clones reacted to HLA class I or MICA. Both clones were also reactive to self antigens and a lysate of a kidney cell line, hence revealing a pattern of polyreactivity. Monoclonality was verified by the identification of a single rearranged immunoglobulin heavy chain variable region (VH) sequence for each clone. By tracking their unique CDR3 sequence, we found that one such polyreactive clone was highly expanded in the patient blood, representing ~0.2% of circulating B cells. The VH sequence of this clone showed evidence of somatic mutations that were consistent with its memory phenotype and its expansion. Lastly, the reactivity of the expanded polyreactive B cell clone was found in the patient serum at time of rejection. In conclusion, we provide here proof of principle at the clonal level that human antibodies can cross-react to HLA and self. Our findings strongly suggest that polyreactive antibodies contribute to DSA, NDSA as well as autoantibodies, in transplant recipients.

Long-Term Results in Recipients of Combined HLA-Mismatched Kidney and Bone Marrow Transplantation Without Maintenance Immunosuppression

“…Of note, transient IgG reactive to multiple HLA alleles were observed before or around 6 months posttransplant for Subjects 6, 7 and 9 (data not shown). These IgG displayed characteristics of polyreactive antibodies (39) and were not accompanied by any clinical manifestation. A detailed analysis of B cell reconstitution in ITN036 subjects, including early polyreactive IgG secretion, will be presented in a separate study.…”

Dynamics of B Cell Recovery In Kidney/Bone Marrow Transplant Recipients

“…Superscript III reverse transcriptase kit (Invitrogen, Carlsbad, CA) was used to generate cDNA. Variable regions of the Ig heavy chain were then amplified by PCR using 6 family-specific forward primers (VH1–VH6) and a consensus JH reverse primer as previously described 13,14 with minor modifications. All 6 forward VH primers and the JH reverse primer used for each specimen (subject time point) included a unique barcode.…”

Increased Negative Impact of Donor HLA-Specific Together With Non-HLA–Specific Antibodies on Graft Outcome

“…A putative synergistic effect of hightitered AT 1 R-ab and HLA class II DSA has been postulated to contribute to an accelerated kidney transplant rejection and hypertensive encephalopathy (14,34). Antibodies to non-HLA and self antigens have been reported to develop in concert with antibodies to donor HLA as part of a global immune response to the allograft (5).…”