Christophe Picard

Hepatitis E virus as an emerging cause of chronic liver disease in organ transplant recipients.

et al. Histopathological features of hepatitis C in renal transplant candidates. Transplantation 2000;69:1479–1484. [6] Samonakis DN, Cholongitas E, Triantos CK, Griffiths P, Dhillon AP, Thalheimer U, et al. Sustained, spontaneous disappearance of serum HCV-RNA under immunosuppression after liver transplantation for HCV cirrhosis. J Hepatol 2005;43:1091–1093. [7] Roche B, Samuel D. Risk factors for hepatitis C recurrence after liver transplantation. J Viral Hepat 2007;14 (Suppl. 1): 89–96. [8] Cholongitas E, Quaglia A, Samonakis DN, Papatheodoridis G, Senzolo M, Triantos C, et al. Patients with recurrent HCV infection and renal dysfunction after liver transplantation have slower fibrosis progression. J Hepatol 2006;44:S58. Evangelos Cholongitas Pinelopi Manousou Dimitrios Samonakis Andrew K. Burroughs * The Royal Free Sheila Sherlock Liver Centre and Department of Surgery, Royal Free Hospital, Pond Street, Hampstead, London NW3 2QG, UK * Tel.: +44 20 74726229; fax: +44 20 74726226. E-mail address: Andrew.Burroughs@royalfree.nhs.uk (A.K. Burroughs).

Impact of donor specific anti-HLA antibodies on graft failure and survival after reduced intensity conditioning-unrelated cord blood transplantation. A Eurocord, Société Francophone d’Histocompatibilité et d’Immunogénétique (SFHI) and Société Française de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC) analysis

Graft failure is a major complication after unrelated cord blood transplantation. Presence of HLA-antibodies before cord blood transplantation may impact graft failure. To analyze the effect of anti-HLA antibodies on unrelated cord blood transplantation outcomes, we analyzed 294 unrelated cord blood transplant recipients after reduced intensity conditioning regimen. The majority of the patients (82%) were transplanted for malignancies, 60% with double-unrelated cord blood transplant, 63% were HLA mismatched. Retrospectively, pre-unrelated cord blood transplant serum was tested for HLA-Ab using Luminex™ platform. Results were interpreted as mean fluorescence intensity (MFI) against donor-specific mismatch. Among 62 recipients (23%) who had anti-HLA antibodies before unrelated cord blood transplant, 14 patients had donor specific anti-HLA antibodies (DSA) (7 were donor-specific anti-HLA antibodies for single unrelated cord blood transplant and 7 for double unrelated cord blood transplant). Donor specific anti-HLA antibodies threshold ranged from 1620–17629 of mean fluorescence intensity (MFI). Cumulative incidence of Day-60 neutrophil engraftment was 76%: 44% for recipients with donor specific anti-HLA antibodies and 81% in those without donor specific anti-HLA antibodies (P=0.006). The cumulative incidence of 1-year transplant related mortality was 46% in patients with donor specific anti-HLA antibodies and 32% in those without antibodies (P=0.06). The presence of donor specific anti-HLA antibodies was associated with a trend for decreased survival rate (42% vs. 29%; P=0.07). Donor specific anti-HLA antibody in recipients of unrelated cord blood transplant is associated with graft failure and decreased survival. Patient’s screening for donor specific anti-HLA antibodies before unrelated cord blood transplantation is recommended before choosing an HLA mismatched cord blood unit. Whenever possible it is important to avoid selecting a unit for which the patient has donor specific anti-HLA antibodies.

Posttranscriptional deregulation of MYC via PTEN constitutes a major alternative pathway of MYC activation in T-cell acute lymphoblastic leukemia

Cumulative evidence indicates that MYC, one of the major downstream effectors of NOTCH1, is a critical component of T-cell acute lymphoblastic leukemia (T-ALL) oncogenesis and a potential candidate for targeted therapy. However, MYC is a complex oncogene, involving both fine protein dosage and cell-context dependency, and detailed understanding of MYC-mediated oncogenesis in T-ALL is still lacking. To better understand how MYC is interspersed in the complex T-ALL oncogenic networks, we performed a thorough molecular and biochemical analysis of MYC activation in a comprehensive collection of primary adult and pediatric patient samples. We find that MYC expression is highly variable, and that high MYC expression levels can be generated in a large number of cases in absence of NOTCH1/FBXW7 mutations, suggesting the occurrence of multiple activation pathways in addition to NOTCH1. Furthermore, we show that posttranscriptional deregulation of MYC constitutes a major alternative pathway of MYC activation in T-ALL, operating partly via the PI3K/AKT axis through down-regulation of PTEN, and that NOTCH1(m) might play a dual transcriptional and posttranscriptional role in this process. Altogether, our data lend further support to the significance of therapeutic targeting of MYC and/or the PTEN/AKT pathways, both in GSI-resistant and identified NOTCH1-independent/MYC-mediated T-ALL patients.

Lymphocyte subset reconstitution after unrelated cord blood or bone marrow transplantation in children

We report the post‐transplant lymphocyte subset recovery of 226 children treated with Unrelated Cord Blood transplant (UCBT) (n = 112) or Unrelated Bone Marrow Transplant (UBMT) (n = 114) for malignant or non‐malignant diseases. Absolute numbers of natural killer (NK), B and T cells were monitored by flow cytometry up to 5 years post‐transplant. Immunological endpoints were: time to achieve a CD3+ cell count >0·5 and 1·5 × 109/l, CD4+ > 0·2 and 0·5 × 109/l, CD8+ > 0·25 × 109/l, CD19+ > 0·2 × 109/l, NK > 0·1 × 109/l. These endpoints were analysed through the use of cumulative incidence curves in the context of competing risks. CD8+ T cell recovery was delayed after UCBT with a median time to reach CD8+ T cells > 0·25 × 109/l of 7·7 months whereas it was 2·8 months in UBMT (P < 0·001). B cell recovery was better in UCBT, with a median time to reach CD19+ cells > 0·2 × 109/l of 3·2 months in UCBT and 6·4 months in UBMT (P = 0·03). Median time for CD4+ T cell and NK cell recovery was similar in UCBT and UBMT. CD4+ T cells recovery was negatively correlated to age (better reconstitution in younger patients, P = 0·002). CD8+ T cells recovery was shorter in recipients with a positive cytomegalovirus serology (P = 0·001).

Hypoxia inducible factor 1α gene (HIF-1α) splice variants: potential prognostic biomarkers in breast cancer

BackgroundHypoxia-inducible factor 1 (HIF-1) is a master transcriptional regulator of genes regulating oxygen homeostasis. The HIF-1 protein is composed of two HIF-1α and HIF-1β/aryl hydrocarbon receptor nuclear translocator (ARNT) subunits. The prognostic relevance of HIF-1α protein overexpression has been shown in breast cancer. The impact of HIF-1α alternative splice variant expression on breast cancer prognosis in terms of metastasis risk is not well known.MethodsUsing real-time quantitative reverse transcription PCR assays, we measured mRNA concentrations of total HIF-1α and 4 variants in breast tissue specimens in a series of 29 normal tissues or benign lesions (normal/benign) and 53 primary carcinomas. In breast cancers HIF-1α splice variant levels were compared to clinicopathological parameters including tumour microvessel density and metastasis-free survival.ResultsHIF-1α isoforms containing a three base pairs TAG insertion between exon 1 and exon 2 (designated HIF-1αTAG) and HIF-1α736mRNAs were found expressed at higher levels in oestrogen receptor (OR)-negative carcinomas compared to normal/benign tissues (P = 0.009 and P = 0.004 respectively). In breast carcinoma specimens, lymph node status was significantly associated with HIF-1αTAGmRNA levels (P = 0.037). Significant statistical association was found between tumour grade and HIF-1αTAG(P = 0.048), and total HIF-1α (P = 0.048) mRNA levels. HIF-1αTAGmRNA levels were also inversely correlated with both oestrogen and progesterone receptor status (P = 0.005 and P = 0.033 respectively). Univariate analysis showed that high HIF-1αTAGmRNA levels correlated with shortened metastasis free survival (P = 0.01).ConclusionsOur results show for the first time that mRNA expression of a HIF-1αTAGsplice variant reflects a stage of breast cancer progression and is associated with a worse prognosis.See commentary: http://www.biomedcentral.com/1741-7015/8/45

Positive association of DRB1*04 and DRB1*15 alleles with Fya immunization in a Southern European population

BACKGROUND: Anti‐Fya has been implicated in hemolytic transfusion reactions. However, not all Fy(a−) patients develop anti‐Fya after transfusion with 1 unit of blood [Fy(a+)]. This study was designed to identify HLA‐DRB1 alleles associated with a predisposition to Fya immunization after blood transfusion.

HIV-2 and SIV Nef Proteins Target Different Src Family SH3 Domains than Does HIV-1 Nef because of a Triple Amino Acid Substitution

The nef gene is required for optimal viral spread of human and simian immunodeficiency viruses. However, the molecular mechanisms underlying the action of the Nef proteins may not be identical for all viral families. Here we investigate the interaction between the Nef protein of human and simian immunodeficiency viruses and SH3 domains from Src family kinases. Using the yeast two-hybrid system and immunoblotting we show that, in contrast to HIV-1 Nef, SIV and HIV-2 Nef poorly interact with Hck SH3 but bind to Src and Fyn SH3 domains. The molecular basis of these differences in SH3 targeting was revealed by sequence analysis and homology modeling of the putative SH3-Nef structures. Three amino acids (Trp-113, Thr-117, and Gln-118) that localize in a “hydrophobic pocket” implicated in SH3 binding of HIV-1 Nef, are systematically substituted in SIV/HIV-2 alleles (by Tyr, Glu, and Glu, respectively). We demonstrate that site-directed mutagenesis of these residues in SIVmac239 Nef suffices to restore Hck SH3 binding and co-immunoprecipitation with full-length Hck from transfected cells. Our findings identify fundamental mechanistic differences in targeting of Src family kinases by HIV and SIV Nef. The herein described mechanism of SH3 selection by Nef via a “pocket” proximal to the canonical proline-rich motif may be a common feature for SH3 recognition by their natural ligands.

HLA-DRB1 genotypes and the risk of developing anti citrullinated protein antibody (ACPA) positive rheumatoid arthritis.

Objective To provide a table indicating the risk for developing anti citrullinated protein antibody (ACPA) positive rheumatoid arthritis (RA) according to one’s HLA-DRB1 genotype. Methods We HLA-DRB1 genotyped 857 patients with ACPA positive RA and 2178 controls from South Eastern and Eastern France and calculated Odds Ratios (OR) for developing RA for 106 of 132 possible genotypes accounting for 97% of subjects. Results HLA-DRB1 genotypic ORs for developing ACPA positive RA range from 28 to 0.19. HLA-DRB1 genotypes with HLA-DRB1*04SE (HLA-DRB1*0404, HLA-DRB1*0405, HLA-DRB1*0408), HLA-DRB1*04∶01, HLA-DRB1*01 are usually associated with high risk for developing RA. The second HLA-DRB1 allele in genotype somewhat modulates shared epitope associated risk. We did not identify any absolutely protective allele. Neither the Reviron, nor the du Montcel models accurately explains our data which are compatible with the shared epitope hypothesis and suggest a dosage effect among shared epitope positive HLA-DRB1 alleles, double dose genotypes carrying higher ORs than single dose genotypes. Conclusion HLA-DRB1 genotypic risk for developing ACPA positive RA is influenced by both HLA-DRB1 alleles in genotype. We provide an HLA-DRB1 genotypic risk table for ACPA positive RA.

Reconstitution of Natural Killer Cells in HLA-Matched HSCT after Reduced-Intensity Conditioning: Impact on Clinical Outcome

Recent advances in the development of reduced-intensity conditioning (RIC) have allowed a broader range of patients to access allogeneic hematopoietic stem cell transplantation (HSCT). Reconstitution of an effective immune system post-transplant, including natural killer (NK) cells, is critical for both tumor control and infectious disease control or prevention. The development and functions of NK cells in such settings remain elusive. Here we analyzed NK cell development in HLA-matched HSCT from related or unrelated donors, after RIC that included antithymocyte globulin (N = 45 patients). Our data reveal that NK cells quickly recover after RIC-HSCT, irrespective of donor type. Rapidly re-emerging NK cells, however, remain immature for more than 6 months. Effector functions resemble that of immature NK cells because they poorly produce IFN-γ and TNF-α in response to target cell stimulation, despite a rapid acquisition of degranulation ability and MIP-1β production. Strikingly, rapid reconstitution of cytokine production correlates with a lower relapse incidence (P = .01) and a better survival rate (P < .0001) at 1 year post-transplant, whereas degranulation capacity was associated with less relapse (P = .05). Our study demonstrates rapid quantitative reconstitution of the NK cell compartment despite administration of potent immune suppressive drugs as part of the conditioning regimen and after transplantation. However, there is a prolonged persistence of functional defects, the correction of which positively correlates with clinical outcome.

HLA-G UTR Haplotype Conservation in the Malian Population: Association with Soluble HLA-G

The HLA-G molecule plays an important role in immunomodulation. In a previous study carried out on a southern French population our team showed that HLA-G haplotypes, defined by SNPs in the coding region and specific SNPs located in 5′URR and 3′UTR regulatory regions, are associated with differential soluble HLA-G expression (sHLA-G). Furthermore, the structure of these HLA-G haplotypes appears to be conserved in geographically distant populations. The aim of our study is to confirm these expectations in a sub-Saharan African population and to explore additional factors, such as HLA-A alleles, that might influence sHLA-G expression. DNA and plasma samples were collected from 229 Malians; HLA-G and HLA-A genotyping were respectively performed by the Snap Shot® method and by Luminex™ technology. sHLA-G dosage was performed using an ELISA kit. HLA-G and HLA-A allelic and haplotypic frequencies were estimated using an EM algorithm from the Gene[Rate] program. Associations between genetic and non genetic parameters with sHLA-G were performed using a non-parametric test with GRAPH PAD Prism 5. Our results reveal a good conservation of the HLA-G UTR haplotype structure in populations with different origins and demographic histories. These UTR haplotypes appear to be involved in different sHLA-G expression patterns. Specifically, the UTR-2 haplotype was associated with low sHLA-G levels, displaying a dominant negative effect. Furthermore, an allelic effect of both HLA-G and HLA-A, as well as non genetic parameters, such as age and gender possibly linked to osteogenesis and sexual hormones, also seem to be involved in the modulation of sHLA-G. These data suggest that further investigation in larger cohorts and in populations from various ethnical backgrounds is necessary not only to detect new functional polymorphism in HLA-G regulatory regions, but also to reveal the extent of biological phenomena that influence sHLA-G secretion and this might therefore have an impact on transplantation practice.