Detection of humoral rejection in human cardiac allografts by assessing the capillary deposition of complement fragment C4d in endomyocardial biopsies

Circulating alloantibodies in transplant recipients are often associated with increased Ab-mediated as well as cellular rejection. We tested the hypothesis that alloantibodies facilitate cellular rejection by functioning as opsonins to enhance T cell activation using a BALB/c to C57BL/6 heart or skin transplant model. Long-term heart and skin survival induced with anti-CD154 alone or in combination with donor-specific transfusion (DST), respectively, was abrogated by the presence of anti-Kd mAbs, and alloreactive T cell activation as well as acute rejection was observed. The prevention of graft acceptance in the skin model was dependent on anti-Kd binding to and converting DST from tolerigenic to immunogenic. Adoptive transfer of CFSE-labeled TCR-transgenic T cells into B6 recipients treated with anti-CD154/DST revealed the ability of anti-Kd to enhance the proliferation of anti–Kd-specific T cells via the indirect pathway as well as of non–Kd-reactive, recipient MHC-restricted CD4+ and CD8+ T cells. Thus, alloantibodies with restricted specificity are able to facilitate the indirect presentation as well as the cross-presentation of a larger repertoire of “linked” donor-derived Ags. These observations highlight the ability of alloantibodies to function not only in classical humoral rejection but also as opsonins that facilitate the CD40-CD154–independent activation of alloreactive T cells.

supporting

confidence: 59%

Alloantibodies Prevent the Induction of Transplantation Tolerance by Enhancing Alloreactive T Cell Priming

Burns

Chong

2011

“…These studies demonstrated that binding of anti-HLA class I Abs stimulated the proliferation of epithelial, endothelial, and smooth muscle cells (7) However, there are many incidences of BOS in patients where Abs to mismatched donor HLA cannot be readily demonstrated, suggesting a role for Abs to non-HLA Ags in the pathogenesis of BOS. The importance of non-HLA Abs in acute as well as chronic rejection has been previously studied in liver, renal, and cardiac allografts (13)(14)(15). In this report, we demonstrate that Abs that recognize the K-␣1 tubulin expressed on epithelial surface can be defined in human lung transplant recipients undergoing BOS.…”

mentioning

confidence: 53%

“…However, a substantial proportion of the transplant recipients, despite the absence of development of any detectable Abs against donor-mismatched HLA Ags, undergo chronic rejection, and in many of these cases Ab as well as complement deposition have been observed in their grafts (25)(26)(27). In the case of kidney and liver allografts, an increasing number of studies have emphasized the clinical importance of Abs against non-HLA Ags (13,14,28,29) in the pathogenesis of rejection. In cardiac transplant, autoAbs against the vimentin molecule have been shown to cause accelerated onset of allograft vasculopathy (30, 31).…”

Section: Discussionmentioning

confidence: 99%

De Novo Production of K-α1 Tubulin-Specific Antibodies: Role in Chronic Lung Allograft Rejection

Goers¹,

Ramachandran²,

Aloush

et al. 2008

181

197

Lung transplantation is the treatment option for a variety of end-stage pulmonary diseases. Posttransplant development of Abs against donor HLA and non-HLA Ags have been associated with acute and chronic rejection of transplanted organs. Development of bronchiolitis obliterans syndrome (BOS) following lung transplantation has been correlated with de novo production of anti-donor-HLA Abs. However, only a portion of the patients with BOS demonstrate detectable anti-donor-HLA Abs. Airway epithelium is considered as a major target for lung allograft rejection. In this study we demonstrate that many BOS+ patients (12 of 36) develop Abs reactive to epithelial cell Ag that are distinct from HLA. Furthermore, de novo production of antiepithelial cell Ab precedes clinical onset of BOS. N-terminal sequencing and blastx analysis as well as blocking with K-α1 tubulin-specific Ab identified the epithelial Ag as K-α1 tubulin. Binding of the de novo-produced anti-K-α1 tubulin Abs to the airway epithelial cells resulted in the increased expression of transcription factors (TCF5 and c-Myc), leading to increased expression of fibrogenic growth factors, activation of cell cycle signaling, and fibroproliferation, the central events in immunopathogenesis of BOS following human lung transplantation.

“…Briefly, RNA samples (2 g) were treated with DNase I (amplification grade; Life Technologies) and reverse transcribed into cDNA in reaction mixtures containing 0.5 l RNasin (40 U/ml; Promega, Madison, WI), 2.5 l 10 mM dNTP (Pharmacia Biotech, Piscataway, NJ), 1 g oligo(dT) [12][13][14][15][16][17][18] (Promega), 400 U (Moloney murine leukemia virus) reverse transcriptase (Bethesda Research Laboratory, Bethesda, MD), 10 l 5ϫ reverse transcriptase buffer, and diethylpyrocarbonate-water to a final volume of 50 l. The RT reactions were conducted at 37°C for 90 min, heat-inactivated at 65°C for 10 min, and cooled for 3 min. PCRs were set up by using 5 l cDNA (equivalent to 50 ng total RNA), 5 l 10ϫ amplification buffer, 3 l 25 mM MgCl 2 , 3 l 2.5 mM dNTP, 1 l of 10 mM of each primer, 0.25 l of 5 U/ l Taq DNA polymerase (Promega), and dH 2 O to a final volume of 50 l. This mixture was overlaid with 100 l light mineral oil (Sigma).…”

Section: Analysis Of C6 Mrna By Competitive Template Rt-pcrmentioning

confidence: 99%

“…An increasing number of clinical and experimental studies of renal and cardiac allografts have linked complement activation to alloantigen-independent and -dependent responses. Complement activation occurs during the perioperative period (1-4), acute rejection (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17), and chronic graft dysfunction (18 -21). Split products of early complement components influence the localization, activation, and effector functions of platelets, granulocytes, monocytes, and lymphocytes, while membrane attack complex (MAC), 3 which is formed by the terminal components of complement (C5b-C9), can lead to rapid activation and destruction of target cells (1,4,22).…”

mentioning

confidence: 99%

Membrane Attack Complex Contributes to Destruction of Vascular Integrity in Acute Lung Allograft Rejection

Nakashima

Qian

Rahimi

et al. 2002

The lung is known to be particularly susceptible to complement-mediated injury. Both C5a and the membrane attack complex (MAC), which is formed by the terminal components of complement (C5b-C9), can cause acute pulmonary distress in nontransplanted lungs. We used C6-deficient rats to investigate whether MAC causes injury to lung allografts. PVG.R8 lungs were transplanted orthotopically to MHC class I-incompatible PVG.1U recipients. Allografts from C6-sufficient (C6+) donors to C6+ recipients were rejected with an intense vascular infiltration and diffuse alveolar hemorrhage 7 days after transplantation (n = 5). Ab and complement (C3d) deposition was accompanied by extensive vascular endothelial injury and intravascular release of von Willebrand factor. In contrast, lung allografts from C6-deficient (C6−) donors to C6− recipients survived 13–17 days (n = 5). In the absence of C6, perivascular mononuclear infiltrates of ED1+ macrophages and CD8+ T lymphocytes were present 7 days after transplantation, but vascular endothelial cells were quiescent, with minimal von Willebrand factor release and no evidence of alveolar hemorrhage or edema. Lung allografts were performed from C6− donors to C6+ recipients (n = 5) and from C6+ donors to C6− recipients (n = 5) to separate the effects of systemic and local C6 production. Lungs transplanted from C6+ donors to C6− recipients had increased alveolar macrophages and capillary injury. C6 production by lung allografts was demonstrated at the mRNA and protein levels. These results demonstrate that MAC causes vascular injury in lung allografts and that the location of injury is dependent on the source of C6.