Characterization of a Unique γδ T-Cell Subset as a Specific Marker of Cytomegalovirus Infection Severity.

Cytomegalovirus (CMV) is a major infectious cause of death and disease after transplantation. We have previously demonstrated that the tissue-associated adaptive Vδ2neg γδ T cells are key effectors responding to CMV and associated with recovery, contrasting with their innatelike circulating counterparts, the Vγ9posVδ2pos T cells that respond to phosphoantigens but not to CMV. A third Vγ9negVδ2pos subgroup with adaptive functions has been described in adults. In the current study, we demonstrate that these Vγ9negVδ2pos T cells are also components of the CMV immune response while presenting with distinct characteristics from Vδ2neg γδ T cells. In a cohort of kidney transplant recipients, CMV seropositivity was the unique clinical parameter associated with Vγ9negVδ2pos T-cell expansion and differentiation. Extensive phenotyping demonstrated their substantial cytotoxic potential and activation during acute CMV primary infection or reinfection. In vitro, Vγ9negVδ2pos T cells responded specifically to CMV-infected cells in a T-cell receptor-dependent manner and through strong interferon γ production. Finally, Vγ9negVδ2pos T cells were the only γδ T-cell subset in which expansion was tightly correlated with the severity of CMV disease. To conclude, our results identify a new player in the immune response against CMV and open interesting clinical perspectives for using Vγ9negVδ2pos T cells as an immune marker for CMV disease severity in immunocompromised patients.

Incidence, prognostic impact and clinical outcomes of renal impairment in patients with multiple myeloma: a population-based registry.

BACKGROUND: Renal impairment (RI), a severe complication in multiple myeloma (MM), is considered as a poor prognostic factor. Patient survival has increased with the use of novel drugs and autologous stem-cell transplantation (ASCT). However, specific evolution of the incidence of RI in MM and its impact on prognosis remain unclear. METHODS: Using a population-based registry of 1038 newly diagnosed MM in Gironde, France, we evaluated the incidence trends of RI in MM patients and assessed net survival according to factors of interest using Pohar-Perme indicator and excess mortality rate regression. We also reviewed 114 cases of MM with RI to describe their clinical outcomes. RESULTS: In our population-based study, 24.6% of MM patients presented with RI (12.9% required haemodialysis). Median survival time was 21 months in patients with RI versus not reached at 3 years for other patients (P < 0.01). Age >73 years, RI, comorbidities and non-use of drugs or ASCT were associated with excess mortality risk. The effect of RI on excess mortality rates was maximum in the first 6 months after diagnosis. In the observational study, median follow-up time was 22.5 months; factors associated with renal response were haematologic response [odds ratio (OR) 6.81; P < 0.01] and previous chronic kidney disease (OR 0.26; P = 0.04). Factors associated with 1-year overall survival were haematological [hazard ratio (HR) 0.13; P < 0.01] and renal response (HR 0.27; P = 0.03). CONCLUSIONS: RI represents an independent negative prognostic factor in MM in the first 6 months after diagnosis. Renal recovery and haematologic response are the strongest markers associated with patient survival.

The disappointing contribution of anti-human leukocyte antigen donor-specific antibodies characteristics for predicting allograft loss.

Background: Pathogenicity of donor-specific antibodies (DSAs) can be assessed using the single-antigen flow beads (SAFB) assays through mean fluorescence intensity (MFI) with or without serum ethylenediaminetetraacetic acid (EDTA) treatment, measurement of C1q or C3d binding and/or their intragraft detection [graft-bound donor-specific antibody (gDSA)]. We aimed to investigate which of these markers best associates with antibody-mediated rejection (ABMR) and kidney allograft loss at the time of a for-cause biopsy. Methods: This retrospective, single-centre study included 77 kidney transplant recipients who underwent a for-cause biopsy between December 2004 and July 2013. All displayed serum DSAs were identified on the same day as the biopsy. Sera were tested in parallel with the classical SAFB assay with or without serum EDTA treatment, C1q- and C3d-binding assays. gDSAs were eluted from biopsy fragments and identified with SAFB. Results: The median time between transplantation and biopsy was 25 months (range 0.5-251). The median follow-up was 36 months (range 0-140). ABMR was histologically proven in 40% of recipients. The sensitivity and specificity of C1q, C3d and gDSA assays for predicting ABMR were 68% and 61%, 52% and 70% and 64.5% and 56.5%, respectively. At the time of biopsy, only the DSA MFI after EDTA treatment and C3d positivity were associated with graft loss. In multivariate analyses, glomerular filtration rate, transplant glomerulopathy and C4d positivity were the only factors associated with graft loss. Conclusions: Our findings weaken the rationale for systematically implementing C1q, C3d or gDSA assays in this situation, because they do not independently predict ABMR and graft loss.