Relief of Preintegration Inhibition and Characterization of Additional Blocks for HIV Replication in Primary Mouse T Cells

Development of a small animal model to study HIV replication and pathogenesis has been hampered by the failure of the virus to replicate in non-primate cells. Most studies aimed at achieving replication in murine cells have been limited to fibroblast cell lines, but generating an appropriate model requires overcoming blocks to viral replication in primary T cells. We have studied HIV-1 replication in CD4+ T cells from human CD4/ CCR5/Cyclin T1 transgenic mice. Expression of hCD4 and hCCR5 in mouse CD4+ T cells enabled efficient entry of R5 strain HIV-1. In mouse T cells, HIV-1 underwent reverse transcription and nuclear import as efficiently as in human T cells. In contrast, chromosomal integration of HIV-1 proviral DNA was inefficient in activated mouse T cells. This process was greatly enhanced by providing a secondary T cell receptor (TCR) signal after HIV-1 infection, especially between 12 to 24 h post infection. This effect was specific for primary mouse T cells. The pathways involved in HIV replication appear to be PKCθ−, CARMA1-, and WASp-independent. Treatment with Cyclosporin A (CsA) further relieved the pre-integration block. However, transcription of HIV-1 RNA was still reduced in mouse CD4+ T cells despite expression of the hCyclin T1 transgene. Additional post-transcriptional defects were observed at the levels of Gag expression, Gag processing, Gag release and virus infectivity. Together, these post-integration defects resulted in a dramatically reduced yield of infectious virus (300–500 fold) after a single cycle of HIV-1 replication. This study implies the existence of host factors, in addition to those already identified, that are critical for HIV-1 replication in mouse cells. This study also highlights the differences between primary T cells and cell lines regarding pre-integration steps in the HIV-1 replication cycle

The Oxford IgA nephropathy clinicopathological classification is valid for children as well as adults

To study the predictive value of biopsy lesions in IgA nephropathy in a range of patient ages we retrospectively analyzed the cohort that was used to derive a new classification system for IgA nephropathy. A total of 206 adults and 59 children with proteinuria over 0.5 g/24 h/ 1.73 m2and an eGFR of stage-3 or better were followed for a median of 69 months. At the time of biopsy, compared with adults children had a more frequent history of macroscopic hematuria, lower adjusted blood pressure, and higher eGFR but similar proteinuria. Although their outcome was similar to that of adults, children had received more immunosuppressants and achieved a lower follow-up proteinuria. Renal biopsies were scored for variables identified by an iterative process as reproducible and independent of other lesions. Compared with adults, children had significantly more mesangial and endocapillary hypercellularity, and less segmental glomerulosclerosis and tubulointerstitial damage, the four variables previously identified to predict outcome independent of clinical assessment. Despite these differences, our study found that the cross-sectional correlation between pathology and proteinuria was similar in adults and children. The predictive value of each specific lesion on the rate of decline of renal function or renal survival in IgA nephropathy was not different between children and adults

Geographic Differences in Genetic Susceptibility to IgA Nephropathy: GWAS Replication Study and Geospatial Risk Analysis

Peer reviewe

The Oxford classification of IgA nephropathy: pathology definitions, correlations, and reproducibility

Pathological classifications in current use for the assessment of glomerular disease have been typically opinion-based and built on the expert assumptions of renal pathologists about lesions historically thought to be relevant to prognosis. Here we develop a unique approach for the pathological classification of a glomerular disease, IgA nephropathy, in which renal pathologists first undertook extensive iterative work to define pathologic variables with acceptable inter-observer reproducibility. Where groups of such features closely correlated, variables were further selected on the basis of least susceptibility to sampling error and ease of scoring in routine practice. This process identified six pathologic variables that could then be used to interrogate prognostic significance independent of the clinical data in IgA nephropathy (described in the accompanying article). These variables were (1) mesangial cellularity score; percentage of glomeruli showing (2) segmental sclerosis, (3) endocapillary hypercellularity, or (4) cellular/ fibrocellular crescents; (5) percentage of interstitial fibrosis/ tubular atrophy; and finally (6) arteriosclerosis score. Results for interobserver reproducibility of individual pathological features are likely applicable to other glomerulonephritides, but it is not known if the correlations between variables depend on the specific type of glomerular pathobiology. Variables identified in this study withstood rigorous pathology review and statistical testing and we recommend that they become a necessary part of pathology reports for IgA nephropathy. Our methodology, translating a strong evidence-based dataset into a working format, is a model for developing classifications of other types of renal disease

EFFET DES TRANSFUSIONS HLA SEMI-IDENTIQUES EN TRANSPLANTATION RENALE

ST ETIENNE-BU Médecine (422182102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Thymoglobulin induction and sirolimus versus tacrolimus in kidney transplant recipients receiving mycophenolate mofetil and steroids.

International audienceBACKGROUND: To define the role of mammalian target of rapamycin inhibitors in kidney transplantation, we compared efficacy and safety of two immunosuppressive regimens-a calcineurin inhibitor-free regimen with depletive induction versus a calcineurin inhibitor-based regimen. METHODS: De novo renal allograft recipients were randomized before transplantation to receive sirolimus (SRL; n=71, group A) or tacrolimus (n=70, group B). All patients received mycophenolate mofetil and corticosteroids. In group A, patients received rabbit antithymocyte globulin induction. In group B, antithymocyte globulin therapy could be given in case of delayed graft function. The estimated glomerular filtration rate (GFR) (Nankivell's formula) at month 12 was the primary endpoint. RESULTS: GFR showed no significant difference at month 12, with 56.1 in group A versus 58.4 mL/min/1.73 m in group B. In functioning grafts, renal function was significantly better in the SRL group, with higher GFR values at months 1, 2, 3, 6, and 9 (P<0.05). At month 12, patient survival and incidence of biopsy-proven rejection were not different between groups (95.8% vs. 97.1%, and 16.9% vs. 12.9%, respectively). However, proportion of graft loss was higher with SRL at months 6 and 12 (11.3% vs. 0.0%, P=0.004; 14.1% vs. 4.3%, P=0.044, respectively). Adverse events and premature withdrawals were more frequent with SRL (P<0.001 and P<0.05, respectively), whereas cytomegalovirus infections were more frequent with tacrolimus (P<0.001). CONCLUSION: Patients treated with induction plus SRL, mycophenolate mofetil, and corticosteroids may obtain good renal function but have a higher risk of adverse events, drug withdrawal, and graft loss