Characterization of the novel HLA-DRB1*04:04:20 allele by sequencing-based typing

HLA-DRB1*04:04:20 differs from HLA-DRB1*04:04:01:04 by one nucleotide substitution in codon 135 in exon 3.

Characterization of the novel HLA-DQA1*01:03:11 allele by sequencing-based typing

HLA-DQA1*01:03:11 differs from HLA-DQA1*01:03:01:02 by one nucleotide substitution in codon 59 in exon 2.

STAT expression and TFH1 cells in CVID granulomatosis and sarcoidosis: immunological and histopathological comparisons

Granulomatous disease is a serious complication of common variable immunodeficiency (CVID-GD) that occurs in 8-22% of these patients and can mimic sarcoidosis, with which it shares certain clinical, biological, and radiological features. However, few studies to date have compared the two pathologies immunologically and histologically. Therefore, we analyzed the immunological-histological findings for different tissue samples from ten patients with CVID-GD and compared them to those of biopsy-proven sarcoidosis. Specifically, we wanted to know whether or not the signaling abnormalities observed in sarcoidosis granulomas are also present in CVID-GD. Morphological differences were found between CVID-GD histology and classical sarcoidosis: mainly, the former's notable lymphoid hyperplasia associated with granulomas not observed in the latter. All CVID-GD involved organs contained several follicular helper-T (TFH) cells within the granulomatosis, while those cells were inconstantly and more weakly expressed in sarcoidosis. Moreover, CVID and sarcoidosis granulomas expressed the phosphorylated-signal transducer and activator of transcription (pSTAT)1 and pSTAT3 factors, regardless of the organ studied and without any significant difference between entities. Our results suggest that the macrophage-activation mechanism in CVID resembles that of sarcoidosis, thereby suggesting that Janus kinase (JAK)-STAT-pathway blockade might be useful in currently difficult-to-treat CVID-GD.

Heightened TLR7 signaling primes BCR-activated B cells in chronic graft-versus-host disease for effector functions

ABSTRACT

Chronic graft-versus-host disease (cGVHD) is a debilitating, autoimmune-like syndrome that can occur after allogeneic hematopoietic stem cell transplantation. Constitutively activated B cells contribute to ongoing alloreactivity and autoreactivity in patients with cGVHD. Excessive tissue damage that occurs after transplantation exposes B cells to nucleic acids in the extracellular environment. Recognition of endogenous nucleic acids within B cells can promote pathogenic B-cell activation. Therefore, we hypothesized that cGVHD B cells aberrantly signal through RNA and DNA sensors such as Toll-like receptor 7 (TLR7) and TLR9. We found that B cells from patients and mice with cGVHD had higher expression of TLR7 than non-cGVHD B cells. Using ex vivo assays, we found that B cells from patients with cGVHD also demonstrated increased interleukin-6 production after TLR7 stimulation with R848. Low-dose B-cell receptor (BCR) stimulation augmented B-cell responses to TLR7 activation. TLR7 hyperresponsiveness in cGVHD B cells correlated with increased expression and activation of the downstream transcription factor interferon regulatory factor 5. Because RNA-containing immune complexes can activate B cells through TLR7, we used a protein microarray to identify RNA-containing antigen targets of potential pathological relevance in cGVHD. We found that many of the unique targets of active cGVHD immunoglobulin G (IgG) were nucleic acid-binding proteins. This unbiased assay identified the autoantigen and known cGVHD target Ro-52, and we found that RNA was required for IgG binding to Ro-52. Herein, we find that BCR-activated B cells have aberrant TLR7 signaling responses that promote potential effector responses in cGVHD.

Characterization of the novel HLA-B*51:394Q allele by sequencing-based typing

HLA-B*51:394Q differs from HLA-B*51:01:01:05 by one nucleotide substitution in codon 339 in exon 7.

Characterization of the novel HLA-B*14:121 allele by sequencing-based typing

HLA-B*14:121 differs from HLA-B*14:01:01:01 by one nucleotide substitution in codon 319 in exon 6.

Characterization of the novel HLA-C*01:263 allele by sequencing-based typing

HLA-C*01:263 differs from HLA-C*01:02:01:01 by one nucleotide substitution in codon 98 in exon 3.

Characterization of the novel HLA-C*05:286 allele by sequencing-based typing

HLA-C*05:286 differs from HLA-C*05:01:01:02 by one nucleotide substitution in codon 283 in exon 5.

Characterization of the novel HLA-C*06:176:02 allele by sequencing-based typing

HLA-C*06:176:02 differs from HLA-C*06:176:01 by two nucleotide substitutions in codons 236 and 237 in exon 4.

Characterization of the novel HLA-DRB3*02:194 allele by sequencing-based typing

HLA-DRB3*02:194 differs from HLA-DRB3*02:02:01:02 by one nucleotide substitution in codon 78 in exon 2.

25-hydroxyvitamin D sufficiency is associated with lower de novo anti-HLA donor specific antibody and better kidney transplant outcomes

T-cell mediated rejection (TCMR), de novo anti-HLA donor-specific antibodies (dnDSAs) and ensuing antibody-mediated rejection (ABMR) reduce kidney transplantation (KT) survival. The immunomodulatory effects of 25-hydroxyvitamin D [25(OH)D] could be beneficial for KT outcomes. We aimed to evaluating the association between 25(OH)D levels, the development of dnDSAs, clinical TCMR and ABMR, and graft survival. This single center retrospective study included 253 KT recipients (KTRs) transplanted without preformed DSA between 2010 and 2013. We measured 25(OH)D in successive serum samples: at KT (M0) and M12 for the entire cohort, and additionally at M24 and/or M36 when sera were available. We assessed graft outcomes up to 5 years post-KT. The proportion of KTRs having sufficient 25(OH)D at KT (M0) was high (81.4%) and then dropped at M12 (71.1%). KTRs with sufficient 25(OH)D at M0 experienced less clinical TCMR (HR, 0.41; 95% CI, 0.19-0.88 in multivariate analysis). A sufficient 25(OH)D at M12 was independently associated with a longer dnDSA-free survival (HR, 0.34; 95% CI, 0.17-0.69). There was no association between 25(OH)D and clinical AMBR. Studying the KTRs with 25(OH)D measurements at M12, M24 and M36 (n = 203), we showed that 25(OH)D sufficiency over the 3 first-years post-KT was associated with a longer graft survival in multivariate analyses (HR, 0.39; 95% CI, 0.22-0.70). To our knowledge, this study is the first showing an association between 25(OH)D sufficiency post-KT and dnDSA occurrence in KTRs. Moreover, we reinforce previously published data showing an association between 25(OH)D, TCMR and graft survival in KT.

Characterization of the novel HLA-C*16:98:02 allele by sequencing-based typing

HLA-C*16:98:02 differs from HLA-C*16:98:01 by one nucleotide substitution in codon 132 in exon 3.

Characterization of the novel HLA-B*39:06:09 allele by sequencing-based typing

HLA-B*39:06:09 differs from HLA-B*39:06:02:01 by one nucleotide substitution in codon 135 in exon 3.

Characterization of the novel HLA-B*40:539 allele by sequencing-based typing

HLA-B*40:539 differs from HLA-B*40:01:01 by one nucleotide substitution in codon 46 in exon 2.

Characterization of the novel HLA-DRB1*11:01:01:12N allele by sequencing-based typing

HLA-DRB1*11:01:01:12N differs from HLA-DRB1*11:01:01:03 by one nucleotide substitution in intron 3 at position c.652+1G>C, hg19.

Measurement of the Immunosuppressant Possession Ratio by Transplant Clinical Pharmacists Captures a Non-Adherence Associated With Antibody-Mediated Rejection

Our objective was to calculate an immunosuppressant possession ratio (IPR) to diagnose non-adherence at the time of antibody-mediated rejection (ABMR). IPR was defined as the ratio of number of pills collected at the pharmacy to the number of pills prescribed over a defined period. In a first cohort of 91 kidney transplant recipients (KTRs), those with an IPR < 90% had more frequently a tacrolimus through level coefficient of variation >30% than patients with an IPR = 100% (66.7% vs. 29.4%, p = 0.05). In a case-control study, 26 KTRs with ABMR had lower 6 months IPRs than 26 controls (76% vs. 99%, p < 0.001). In KTRs with ABMR, non-adherence was more often diagnosed by a 6 months IPR < 90% than by clinical suspicion (73.1% vs 30.8%, p = 0.02). In the multivariable analysis, only de novo DSA and 6 months IPR < 90% were independently associated with ABMR, whereas clinical suspicion was not (odds ratio, 4.73; 95% CI, 1.17-21.88; p = 0.03; and odds ratio, 6.34; 95% CI, 1.73-25.59; p = 0.007, respectively). In summary, IPR < 90% is a quantifiable tool to measure immunosuppressant non-adherence. It is better associated with ABMR than clinical suspicion of non-adherence.

Impact of Preformed Donor-Specific Anti-HLA-Cw and Anti-HLA-DP Antibodies on Acute Antibody-Mediated Rejection in Kidney Transplantation

Given the risk of rejection, the presence of preformed donor specific antibodies (DSA) contraindicates transplantation in most allocation systems. However, HLA-Cw and -DP DSA escape this censorship. We performed a multicentric observational study, in which the objective was to determinate risk factors of acute antibody-mediated rejection (aABMR) in recipients transplanted with preformed isolated Cw- or DP-DSA. Between 2010 and 2019, 183 patients were transplanted with a preformed isolated Cw- or DP-DSA (92 Cw-DSA; 91 DP-DSA). At 2 years, the incidence of aABMR was 12% in the Cw-DSA group, versus 28% in the DP-DSA group. Using multivariable Cox regression model, the presence of a preformed DP-DSA was associated with an increased risk of aABMR (HR = 2.32 [1.21-4.45 (p = 0.001)]) compared with Cw-DSA. We also observed a significant association between the DSA's MFI on the day of transplant and the risk of aABMR (HR = 1.09 [1.08-1.18], p = 0.032), whatever the DSA was. Interaction term analysis found an increased risk of aABMR in the DP-DSA group compared with Cw-DSA, but only for MFI below 3,000. These results may plead for taking these antibodies into account in the allocation algorithms, in the same way as other DSA.

Characterization of the novel HLA-DPA1*01:159 allele by sequencing-based typing

HLA-DPA1*01:159 differs from HLA-DPA1*01:03:01:03 by one nucleotide substitution in codon 120 in exon 3.

Characterization of the novel HLA-DRB3*02:192 allele by sequencing-based typing

HLA-DRB3*02:192 differs from DRB3*02:02:01:02 by one nucleotide substitution in codon 204 in exon 4.

Characterization of the novel HLA-DPA1*01:150 allele by sequencing-based typing

HLA-DPA1*01:150 differs from HLA-DPA1*01:03:01:05 by one nucleotide substitution in codon 190 in exon 4.

Characterization of the novel HLA-C*12:384 allele by sequencing-based typing

HLA-C*12:384 differs from HLA-C*12:03:01:02 by one nucleotide substitution in codon 42 in exon 2.

Characterization of the novel HLA-DPA1*02:115 allele by sequencing-based typing

HLA-DPA1*02:115 differs from HLA-DPA1*02:01:01:06 by one nucleotide substitution in codon 224 in exon 4.

Characterization of the novel HLA-B*51:370 allele by sequencing-based typing

HLA-B*51:370 differs from HLA-B*51:01:01:04 by one nucleotide substitution in codon 276 in exon 5.

Characterization of the novel HLA-DPB1*1463:01N allele by sequencing-based typing

HLA-DPB1*1463:01N differs from HLA-DPB1*02:01:02:04 by one nucleotide substitution in codon 128 in exon 3.

Characterization of the novel HLA-B*44:324:02 allele by sequencing-based typing

HLA-B*44:324:02 differs from HLA-B*44:324:01 by one nucleotide substitution in codon 99 in exon 3.

Characterization of the novel HLA-DQA1*01:64:02 allele by sequencing-based typing

HLA-DQA1*01:64:02 differs from HLA-DQA1*01:64:01 by one nucleotide substitution in codon 123 in exon 3.

Single-cell landscape analysis unravels molecular programming of the human B cell compartment in chronic GVHD

Alloreactivity can drive autoimmune syndromes. After allogeneic hematopoietic stem cell transplantation (allo-HCT) chronic graft-versus-host disease (cGVHD), a B cell-mediated autoimmune-like syndrome, commonly occurs. Because donor-derived B cells continually develop under selective pressure from host alloantigens, aberrant B Cell Receptor (BCR)-activation and IgG production can emerge and contribute to cGVHD pathobiology. To better understand molecular programing of B cells under selective pressure of alloantigens, we performed scRNA-Seq analysis on high numbers of purified B cells from allo-HCT patients. An unsupervised analysis revealed 10 clusters, distinguishable by signature genes for maturation, activation and memory. We found striking transcriptional differences in the memory B cell compartment after allo-HCT compared to healthy or infected individuals. To identify intrinsic properties when B-cell tolerance is lost after allo-HCT, we then assessed clusters for differentially expressed genes (DEGs) between patients with vs. without autoimmune-like manifestations (Active cGVHD vs. No cGVHD, respectively). DEGs were found in Active cGVHD in both naive and BCR-activated clusters, suggesting functional diversity. Some DEGs were also differentially expressed across most clusters, suggesting common molecular programs that may promote B cell plasticity. Our study of human allo-HCT and cGVHD provides new understanding of B-cell memory in the face of chronic alloantigen stimulation.

Characterization of the novel HLA-A*24:587 allele by sequencing-based typing

HLA-A*24:587 differs from HLA-A*24:02:01:01 by one nucleotide substitution in codon 220 in exon 4.

Characterization of the novel HLA-C*03:552 allele by sequencing-based typing

HLA-C*03:552 differs from HLA-C*03:04:01:01 by one nucleotide substitution in codon 72 in exon 2.

Characterization of the novel HLA-DPB1*1348:01 allele by sequencing-based typing

HLA-DPB1*1348:01 differs from HLA-DPB1*14:01:01:01 by one nucleotide substitution in codon 147 in exon 3.

Characterization of the novel HLA-DPB1*11:01:06 allele by sequencing-based typing

HLA-DPB1*11:01:06 differs from HLA-DPB1*11:01:01:01 by one nucleotide substitution in codon 21 in exon 2.

Characterization of the novel HLA-DQA1*05:05:14 allele by sequencing-based typing

HLA-DQA1*05:05:14 differs from HLA-DQA1*05:05:01:04 by one nucleotide substitution in codon -8 in exon 1.

Characterization of the novel HLA-B*08:302 allele by sequencing-based typing

HLA-B*08:302 differs from HLA-B*08:01:01:01 by one nucleotide substitution in codon 116 in exon 3.

Characterization of the novel HLA-DQA1*02:01:14 allele by sequencing-based typing

HLA-DQA1*02:01:14 differs from HLA-DQA1*02:01:01:02 by one nucleotide substitution in codon 105 in exon 3.

Characterization of the novel HLA-DPA1*02:01:21 allele by sequencing-based typing

HLA-DPA1*02:01:21 differs from HLA-DPA1*02:01:01:03 by one nucleotide substitution in codon 190 in exon 4.

Characterization of the novel HLA-C*05:01:01:81Q allele by sequencing-based typing

HLA-C*05:01:01:81Q differs from HLA-C*05:01:01:02 by one nucleotide substitution in position 202 in intron 1 (c.74-2A>G, hg19).

Characterization of the novel HLA-A*24:585 allele by sequencing-based typing

HLA-A*24:585 differs from HLA-A*24:02:01:01 by one nucleotide substitution in codon -15 in exon 1.

Characterization of the novel HLA-DRB1*01:140 allele by sequencing-based typing

HLA-DRB1*01:140 differs from HLA-DRB1*01:02:01:01 by one nucleotide substitution in codon 147 in exon 3.

Cytomegalovirus DNAemia Requiring (Val)Ganciclovir Treatment for More Than 8 Weeks Is a Key Factor in the Development of Antiviral Drug Resistance

Background

Prolonged (val)ganciclovir [(V)GCV] exposure for ≥6 weeks is a known predisposing factor for cytomegalovirus (CMV) drug resistance. However, the selection of this threshold was based on limited data. In this study, we sought to reappraise the risk factors for the development of (V)GCV resistance through a specific focus on kidney transplant recipients (KTRs).

Methods

This single-center retrospective study included 313 consecutive KTRs treated for a first CMV episode. Adjusted Cox multivariate regression analysis was used for identifying independent risk factors.

Results

Antiviral drug resistance was identified in 20 (6%) KTRs. A cumulative (V)GCV exposure for more than 6 weeks (regardless of the viral load) was not associated with antiviral drug resistance (hazard ratio [HR] = 2.45, 95% confidence interval [CI] = 0.33-18.30, P = .38). In contrast, persistent CMV DNAemia requiring (V)GCV treatment for more than 8 weeks was the main independent risk factor for antiviral drug resistance (HR = 11.68, 95% CI = 2.62-52.01, P = .001). The (V)GCV treatment for more than 8 weeks was given to 9% and 18% of patients who had persistent or recurrent CMV DNAemia, respectively. These scenarios were associated with the occurrence of drug resistance in 39% and 12% of cases, respectively.

Conclusions

Cumulative (V)GCV exposure ≥6 weeks regardless of the viral load is not associated with antiviral drug resistance. In contrast, prolonged exposure to (V)GCV during CMV replication (with a cutoff ³8 weeks) seems to be a key factor.

Characterization of the novel HLA-A*11:422 allele by sequencing-based typing

HLA-A*11:422 differs from HLA-A*11:01:01:01 by one nucleotide substitution in codon 285 in exon 5.

Characterization of the novel HLA-C*17:01:18 allele by sequencing-based typing

HLA-C*17:01:18 differs from HLA-C*17:01:01:05 by one nucleotide substitution in codon 18 in exon 2.

Characterization of the novel HLA-DRB3*02:179N allele by sequencing-based typing

HLA-DRB3*02:179N differs from DRB3*02:02:01:02 by one nucleotide substitution in codon 98 in exon 3.

Characterization of the novel HLA-DQA1*01:89 allele by sequencing-based typing

HLA-DQA1*01:89 differs from HLA-DQA1*01:01:01:01 by one nucleotide substitution in codon -5 in exon 1.

Magnetic Resonance Elastography as Surrogate Marker of Interstitial Fibrosis in Kidney Transplantation: A Prospective Study

Background

Fibrosis progression is a major prognosis factor in kidney transplantation. Its assessment requires an allograft biopsy, which remains an invasive procedure at risk of complications.

Methods

We assessed renal stiffness by magnetic resonance elastography (MRE) as a surrogate marker of fibrosis in a prospective cohort of kidney transplant recipients compared with the histologic gold standard. Interstitial fibrosis was evaluated by three methods: the semi-quantitative Banff ci score, a visual quantitative evaluation by a pathologist, and a computer-assisted quantitative evaluation. MRE-derived stiffness was assessed at the superior, median, and inferior poles of the allograft.

Results

We initially enrolled 73 patients, but only 55 had measurements of their allograft stiffness by MRE before an allograft biopsy. There was no significant correlation between MRE-derived stiffness at the biopsy site and the ci score (ρ=-0.25, P=0.06) or with the two quantitative assessments (pathologist: ρ=-0.25, P=0.07; computer assisted: ρ=-0.21, P=0.12). We observed negative correlations between the stiffness of both the biopsy site and the whole allograft, with either the glomerulosclerosis percentage (ρ=-0.32, P=0.02 and ρ=-0.31, P=0.02, respectively) and the overall nephron fibrosis percentage, defined as the mean of the percentages of glomerulosclerosis and interstitial fibrosis (ρ=-0.30, P=0.02 and ρ=-0.28, P=0.04, respectively). At patient level, mean MRE-derived stiffness was similar across the three poles of the allograft (±0.25 kPa). However, a high variability of mean stiffness was found between patients, suggesting a strong influence of confounding factors. Finally, no significant correlation was found between mean MRE-derived stiffness and the slope of eGFR (P=0.08).

Conclusions

MRE-derived stiffness does not directly reflect the extent of fibrosis in kidney transplantation.