Abbreviations: +LR, positive likelihood ratio; AMR, antibody-mediated rejection; anti-dHLA, anti-denatured HLA antibodies; anti-nHLA, anti-native HLA antibodies; AUC, area under curve; B-FCXM, B-lymphocyte flow cytometry crossmatch; DSA, donor-specific antibodies; EDTA, ethylenediaminetetraacetic acid; FCXM, flow cytometry crossmatch; −LR, negative likelihood ratio; MFI, mean fluorescence intensity; NPV, negative predictive value; PPV, positive predictive value; ROC, receiver operating characteristic; SAFB, single antigen flow bead(s); T-FCXM, T-lymphocyte flow cytometry crossmatch.Anti-denatured HLA-Cw antibodies are highly prevalent, whereas anti-native HLA-Cw antibodies seem to lead to random flow cytometry crossmatch results. We aimed to reassess crossmatch prediction for anti-HLA-Cw using 2 types of single antigen flow beads (classical beads and beads with diminished expression of denatured HLA), and to compare the pathogenicity of preformed anti-denatured and anti-native HLA-Cw antibodies in kidney transplantation. We performed 135 crossmatches with sera reacting against donor HLA-Cw (classical beads fluorescence ≥500); only 20.6% were positive. Forty-three (31.6%) were anti-denatured HLA antibodies (beads with diminished expression of denatured HLA fluorescence <300); all were crossmatch negative.The correlation between classical beads fluorescence and the crossmatch ratio was low (ρ = 0.178), and slightly higher with beads with diminished expression of denatured HLA (ρ = 0.289). We studied 52 kidney recipients with preformed anti-HLA-Cw
In organ transplantation, apheresis is frequently used for removal of anti‐HLA antibodies. However, it is unclear whether plasmapheresis (PP) or semi‐selective immunoadsorption (IA) should be employed, and the optimal number of apheresis sessions required to reach post‐treatment objectives is also unknown.
We enrolled 43 patients from Bordeaux University Hospital who were treated with PP (n = 29) or IA (n = 14) for antibody‐mediated rejection or pre‐transplant desensitization. Using Luminex single‐antigen flow beads, we assessed the initial mean fluorescence intensity (MFI) of 1416 positive beads with MFIs obtained after 7 to 8 apheresis sessions (extended protocol) and, if a serum was available, after the first four sessions (short protocol).
MFI reduction after extended apheresis protocol was stronger with IA [87% (61%‐100%)] than with PP [73% (22%‐100%)] (P < .001). Indeed, 59% of the beads had a final MFI < 2000 with IA, whereas only 38% with PP (P < .001). The efficacy of removal depended on initial MFI but not on HLA specificity. A short protocol of apheresis showed excellent results without superiority of IA over PP for antibodies with an initial MFI < 3000. For antibodies showing MFI ≥2000 after four sessions, the residual MFI predicted the effectiveness of four additional sessions.
Monitoring the MFI of anti‐HLA antibodies before and during apheresis protocol can guide physicians in the selection of apheresis technique and the number of sessions to be performed.
Background. Highly sensitized (HS) anti-HLA patients awaiting kidney transplantation benefit from specific allocation programs. Serological monitoring at 3-mo intervals is recommended to prevent unexpected positive crossmatch (XM), but this strategy is not evidence-based. Therefore, we assessed its relevance when using single-antigen flow bead (SAFB) and screening flow bead (SFB) assays. Methods. We included 166 HS patients awaiting a transplant and assessed their SAFB profile during the year preceding their inclusion. Anti-HLA antibodies were evaluated by SAFB assay and compared within patients as serum pairs at 3, 6, and 9 mo. We assessed the performance of SFB for detecting changes in SAFB profiles with 35 serum pairs. Results. On comparing 354, 218, and 107 serum pairs at 3, 6, and 9 mo, respectively, only 0.6%, 0.7%, and 1% of all antigens tested exceeded for the first time the unacceptable antigen threshold (mean fluorescence intensity ≥2000) in the most recent sample. Irrespective of the follow-up period, the calculated panel-reactive antibodies increased by a mean of 1%, and there was no significant increase in the proportion of donors at risk for positivity of flow-or complementdependent cytotoxicity XM. The SFB did not accurately detect the variations of SAFB profiles. Conclusions. Changes in HS patient profiles are anecdotal and show little association with transplant access or risk for positive XM. Less-frequent monitoring in HS patients should be considered to improve cost-effectiveness without affecting transplant safety.
Description of five cases of bartonellosis with fever and atypical clinical presentations in kidney transplant recipients : thrombotic microangiopathies, recurrent haemophagocytosis and immune reconstitution syndrome after treatment. The diagnosis, the pathological lesions, and treatments are described. Bartonellosis must be researched in solid organ transplant recipients with fever of undetermined origin.
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