The clinical importance of preexisting HLA antibodies at the time of transplantation, identified by contemporary techniques, is not well understood. We conducted an observational study analyzing the association between preexisting donor-specific HLA antibodies (HLA-DSA) and incidence of acute antibody-mediated rejection (AMR) and survival of patients and grafts among 402 consecutive deceaseddonor kidney transplant recipients. We detected HLA-DSA using Luminex single-antigen assays on the peak reactive and current sera. All patients had a negative lymphocytotoxic cross-match test on the day of transplantation. We found that 8-year graft survival was significantly worse (61%) among patients with preexisting HLA-DSA compared with both sensitized patients without HLA-DSA (93%) and nonsensitized patients (84%). Peak HLA-DSA Luminex mean fluorescence intensity (MFI) predicted AMR better than current HLA-DSA MFI (P ϭ 0.028). As MFI of the highest ranked HLA-DSA detected on peak serum increased, graft survival decreased and the relative risk for AMR increased: Patients with MFI Ͼ6000 had Ͼ100-fold higher risk for AMR than patients with MFI Ͻ465 (relative risk 113; 95% confidence interval 31 to 414). The presence of HLA-DSA did not associate with patient survival. In conclusion, the risk for both AMR and graft loss directly correlates with peak HLA-DSA strength. Quantification of HLA antibodies allows stratification of immunologic risk, which should help guide selection of acceptable grafts for sensitized patients.

This study describes clinical relevance of subclinical antibody-mediated rejection (SAMR) in a cohort of 54 DSA-positive kidney transplant recipients receiving a deceased donor. In 3 months screening biopsies, 31.1% of patients met the criteria of SAMR. A total of 48.9% had an incomplete form of SAMR (g+/ptc+/C4d-negative) whereas 20% had no humoral lesions. Patients with SAMR at 3 months had at 1 year: a higher C4d score, ptc score, and arteriosclerosis score, higher rate of IFTA (100% vs. 33.3%, p < 0.01) and a higher rate of transplant glomerulopathy (43% vs. 0%, p = 0.02) compared to patients without 3-month SAMR. Patients with SAMR at 3 months exhibited at 1 year a higher class II MFImax-DSA and a lower mGFR compared to patients without SAMR (39.2 ± 13.9 vs. 61.9 ± 19.2 mL/min/1.73 m 2 respectively, p < 0.01). The group of patients with C4d-negative SAMR at 3 months developed more ptc and IFTA lesions, and lower GFR at 1 year in comparison to biopsies without humoral lesions. SAMR is a frequent entity in KTR with preexisting DSAs and promotes subsequent GFR impairment and development of chronic AMR. C4d-negative SAMR patients displayed an intermediate course between the no-SAMR group and the C4d+ SAMR group. Screening biopsies may be useful to recognize patients more likely to develop SAMR.

Transplantation of patients possessing antibodies against allo-HLA antigens can be delayed for years. We have shown that administration of intravenous immunoglobulins (IVIg) can induce a profound and sustained decrease in the titers of anti-HLA antibodies. We report here the first series of patients desensitized, then transplanted using IVIg therapy. Fifteen patients have been included and treated with IVIg, given as 3 monthly courses of 2 g/kg body weight. Thirteen of those 15 patients (87%) were effectively desensitized and underwent immediate transplantation. Eleven were transplanted with a cadaveric donor, and two with a living donor against which the pretreatment cross-match was positive. One graft was lost from thrombosis and one from rejection. All other patients had uneventful courses, without any episodes of rejection, with a follow-up of more than 1 year. Thus, IVIg therapy allows safe and prompt kidney transplantation of immunized patients.

We conclude that: (1) high dose IVIg alone is inferior to Plasmapheresis/IVIg/anti-CD20 as therapy for AMR and (2)DSA postrejection can be quantified using solid phase assays, showing that 3 months after AMR, DSA levels are higher in patients with graft loss.

This study analyzes the influence of preformed DSA, identified by HLA-specific ELISA assays, on graft survival and evaluates the incidence of antibodymediated rejection (AMR) in patients with and without pregraft desensitization.Kidney graft survival at 8 years was significantly worse in patients with DSA (n = 43) than in those without DSA (n = 194)(p = 0.03). The incidence of AMR in patients with DSA is 9-fold higher than in patients without DSA (p < 0.001) and their graft survival is significantly worse than in DSA patients without AMR and in non-DSA patients (p = 0.005). The prevalence for AMR in patients with DSA detected on historic serum is 32.3% in nondesensitized patients and 41.7% in desensitized patients. The risk for AMR is significantly more elevated in patients with strongly positive DSA (score 6-8) compared to those with DSA score 4 (p < 0.001), and in patients with historic DSA+/CXM+ compared to those with DSA+/CXM− (p = 0.01).The presence of preformed DSA is strongly associated with graft loss in kidney transplants, related to an increased risk of AMR. Our findings demonstrate the importance of detection and characterization of DSA before transplantation. Stratification of this risk could be used to determine kidney allocation and to devise specific strategies for these patients.

This study raises the possibility that a more intensive day 0 prophylactic immunosuppressive strategy combining intravenous immunoglobulin/anti-CD20/plasmapheresis in this high-risk population, despite similar rates of early acute clinical humoral rejection, is associated with significant differences in long-term function and chronic AMR rate. Future prospective randomized studies are needed to assess the best strategies to be applied in light of the pretransplant immunologic risk stratification.

In the context of lung transplant (LT), because of diagnostic difficulties, antibody-mediated rejection (AMR) remains a matter of debate. We retrospectively analyzed an LT cohort at Foch Hospital to demonstrate the impact of AMR on LT prognosis. AMR diagnosis requires association of clinical symptoms, donor-specific antibodies (DSAs), and C4d

This study analyzes the incidence and course of antibody-mediated rejection (AMR) in a cohort of 237 renal transplant patients followed for 30 ± 20 months. Among these, 32 patients were considered to be at risk for AMR and received intravenous immunoglobulin (IVIg), either as preconditioning (Group A, n = 18) or at the time of transplant (Group B, n = 14). The prevalence of AMR was 27.8% in Group A, 57.1% in Group B and 3.9% in the remainder of the population. Although graft loss remains greater among AMR than for acute cellular rejection (ACR) or the overall transplant population, we have identified a good outcome group (GFR > 15 mL/min/1.73 m 2 ) (n = 13), whose renal function at the end of follow-up was comparable to that of the general transplant population. The factors associated with bad outcome are: (1) immunologic: presence and/or persistence of donor-specific anti-HLA antibodies post-transplantation and (2) histologic: neutrophilic glomerulitis, peritubular capillary dilatation with neutrophil infiltrates and interstitial edema at the time of first biopsy; and at the time of late biopsy (3-6 months): lesions of vascular rejection, and monocyte/macrophage infiltrates in glomeruli and dilated peritubular capillaries. Persistence of C4d does not predict outcome. This study outlines for the first time the immunologic and histologic profiles of AMR patients with poor prognosis.