B cell repertoires in HLA-sensitized kidney transplant candidates undergoing desensitization therapy

Abstract

BackgroundKidney transplantation is the most effective treatment for end-stage renal disease. Sensitization refers to pre-existing antibodies against human leukocyte antigen (HLA) protein and remains a major barrier to successful transplantation. Despite implementation of desensitization strategies, many candidates fail to respond. Our objective was to determine whether measuring B cell repertoires could differentiate candidates that respond to desensitization therapy.MethodsWe developed an assay based on high-throughput DNA sequencing of the variable domain of the heavy chain of immunoglobulin genes to measure changes in B cell repertoires in 19 highly HLA-sensitized kidney transplant candidates undergoing desensitization and 7 controls with low to moderate HLA sensitization levels. Responders to desensitization had a decrease of 5% points or greater in cumulated calculated panel reactive antibody (cPRA) levels, and non-responders had no decrease in cPRA.ResultsDominant B cell clones were not observed in highly sensitized candidates, suggesting that the B cells responsible for sensitization are either not present in peripheral blood or present at comparable levels to other circulating B cells. Candidates that responded to desensitization therapy had pre-treatment repertoires composed of a larger fraction of class-switched (IgG and IgA) isotypes compared to non-responding candidates. After B cell depleting therapy, the proportion of switched isotypes increased and the mutation frequencies of the remaining non-switched isotypes (IgM and IgD) increased in both responders and non-responders, perhaps representing a shift in the repertoire towards memory B cells or plasmablasts. Conversely, after transplantation, non-switched isotypes with fewer mutations increased, suggesting a shift in the repertoire towards naïve B cells.ConclusionsRelative abundance of different B cell isotypes is strongly perturbed by desensitization therapy and transplantation, potentially reflecting changes in the relative abundance of memory and naïve B cell compartments. Candidates that responded to therapy experienced similar changes to those that did not respond. Further studies are required to understand differences between these two groups of highly sensitized kidney transplant candidates.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-017-1118-7) contains supplementary material, which is available to authorized users.

Advances of the experimental models of idiopathic membranous nephropathy (Review)

“…Furthermore, although megalin is expressed in human podocytes (34,35), it is not detected in the glomerular subepithelial immune complex and no circulating anti-megalin antibodies are found in patients with iMn (36). in addition, the complement pathway and subclass of igG in this model are still unknown (37)(38)(39). Therefore, it is not equivalent to human iMn.…”

Composition and diversity analysis of the B‑cell receptor immunoglobulin heavy chain complementarity‑determining region 3 repertoire in patients with acute rejection after kidney transplantation using high‑throughput sequencing

“…Whether these observed changes in IGHV genes and IGHD genes may serve as better markers in B-cell immunology requires further investigation. The study by Beausang et al (27) suggested that subjects that responded to de-sensitization therapy had pre-treatment repertoires composed of a larger fraction of class-switched (IgG and IgA) isotypes compared to non-responding candidates, indicating that the measurement of B-cell repertoires may be applied to identify candidates that respond to de-sensitization therapy. In the present study, three patients with acute rejection after kidney transplantation were assessed for the purpose of performing a composition and diversity analysis of the BCR H-CDR3 repertoire.…”

Matchmaker, matchmaker make me a match: Opportunities and challenges in optimizing compatibility of HLA eplets in transplantation

“…Anti‐HLA antibodies may wax and wane over time, resulting in a fluctuating repertoire of unacceptable mismatches and, consequently, also resulting in different proportions of potentially compatible donors from the pool. Acknowledging this, transplant centres may use the cumulative cPRA, which considers anti‐HLA antibodies that have been detected over the entire course of pre‐transplant screening (Beausang et al., 2017; Tinckam et al., 2015). The cumulative cPRA is also dependent on the detection of antibodies, which is itself dependent on laboratory practices.…”