Franca Giacchino

Polyomavirus BK DNA quantification assay to evaluate viral load in renal transplant recipients

BACKGROUND Several studies have disclosed a correlation between polyomavirus BK (BKV) and interstitial nephritis in renal transplant recipients and its quantification in urine and serum is therefore required to assess the role of BKV infection in nephropathy. OBJECTIVE This paper describes a urine and serum BKV-DNA quantification protocol devised to evaluate the viral load. STUDY DESIGN Screening of samples containing > or =10(3)/ml viral genome copies by a semi-quantitative polymerase chain reaction (PCR) assay is followed by precise quantification of the samples containing a high number of viral genomes in a quantitative-competitive (QC)-PCR assay. Generation of the competitor construct relied on the different sizes of wild-type and competitor amplicons. RESULTS AND CONCLUSIONS Screening by semi-quantitative PCR selects samples with a high number of viral genomes for use in the more labor-intensive and -expensive QC-PCR assay and thus provides a handy means for quantitative DNA analysis of large numbers of samples. The results obtained in BKV-DNA quantification in urine and serum samples from 51 renal transplant recipients (22 on treatment with tacrolimus (FK506) and 29 on cyclosporine A (Cy A)) are interesting: BKV-DNA findings (43.1%) in urine samples are in agreement with the BKV urinary shedding reported in literature (5-45%). With regard to immunosuppressive treatment, the percentage of activation of the infection (revealed by BKV-DNA detection in urine samples) in the two groups of therapy is similar (40.9% vs 44.8%). The observation that the viral load in urine is dissociated with that of serum suggests that both parameters should be investigated in evaluation of the pathogenetic role of BKV reactivation in renal transplant recipients. Moreover, our BKV-DNA quantification protocol could be used to monitor viral load in urine and serum samples from renal transplant recipients so as to detect those at risk of nephropathy and monitor their response to immunosuppression reduction therapy if it occurs.

A best practice position statement on the role of the nephrologist in the prevention and follow-up of preeclampsia: the Italian study group on kidney and pregnancy

Preeclampsia (PE) is a protean syndrome causing a transitory kidney disease, characterised by hypertension and proteinuria, ultimately reversible after delivery. Its prevalence is variously estimated, from 3 to 5% to 10% if all the related disorders, including also pregnancy-induced hypertension (PIH) and HELLP syndrome (haemolysis, increase in liver enzyme, low platelets) are included. Both nephrologists and obstetricians are involved in the management of the disease, according to different protocols, and the clinical management, as well as the role for each specialty, differs worldwide. The increased awareness of the role of chronic kidney disease in pregnancy, complicating up to 3% of pregnancies, and the knowledge that PE is associated with an increased risk for development of CKD later in life have recently increased the interest and redesigned the role of the nephrologists in this context. However, while the heterogeneous definitions of PE, its recent reclassification, an emerging role for biochemical biomarkers, the growing body of epidemiological data and the new potential therapeutic interventions lead to counsel long-term follow-up, the lack of resources for chronic patients and the increasing costs of care limit the potential for preventive actions, and suggest tailoring specific interventional strategies. The aim of the present position statement of the Kidney and Pregnancy Study Group of the Italian Society of Nephrology is to review the literature and to try to identify theoretical and pragmatic bases for an agreed management of PE in the nephrological setting, with particular attention to the prevention of the syndrome (recurrent PE, presence of baseline CKD) and to the organization of the postpartum follow-up.

Improved phagocyte response by co-amoxiclav in renal transplant recipients

Background. Infectious diseases are a major source of morbidity and mortality for immunosuppressed transplant recipients and the antimicrobial chemotherapy can be often less effective in these individuals, because the contribution of underlying host defenses is absent. Methods. The influence of co-amoxiclav on the functions of polymorphonuclear granulocytes (PMNs) from renal transplant recipients were investigated. Results. PMNs from renal transplant recipients showed a diminished phagocytic activity with reduced phagocytosis and bactericidal activity against intracellular Klebsiellapneumoniae, compared to that seen with PMNs from healthy subjects. Co-amoxiclav significantly elicited the functions of PMNs from uremic patients, resulting in an increased percentage of ingested klebsiellae and in a higher bactericidal effect (98–99%), compared with the drug-free control system. When PMNs were collected from renal transplant recipients treated with co-amoxiclav a significant high increase in both phagocytosis and killing activity were detected, showing the co-amoxiclav capability of “restoring” even in vivo the depressed primary functions of PMNs. Conclusions. The interesting beneficial properties of co-amoxiclav, which result in restoring the phagocyte-dependent response in renal transplant patients both in vitro and in vivo, may make this drug more suitable for the treatment of infections in patients with defects of phagocyte functions.

Human Polyomavirus BK Monitoring by Quantitative PCR in Renal Transplant Recipients

Objective: To study the relation between human polyomavirus BK (BKV) infection and the risk of developing nephropathy, we monthly investigated the BKV load in urine and serum samples from 15 renal transplant recipients during 6 months in relation with immunosuppressive treatment and renal function. Methods: BKV-DNA in serum samples was detected by nested PCR. BKV-DNA in urine and positive serum samples was quantified by a PCR protocol developed in our laboratory. Results: Fifty-three percent of the patients had quantifiable BKV-DNA both in urine and serum samples but there was no relation between viruria and viraemia. Seventy-five percent of the patients on FK506 therapy and 71.4% of those on CyA therapy showed activation of BKV infection. No patients developed interstitial nephritis during the study. In ten patients serum creatinine levels were <2 mg/dl for the whole study, even if 80% presented BKV viruria and/ or viraemia. On the other hand, in 4 patients serum creatinine levels reached higher values, but they were BKV viruria and/or viraemia negative during the study. Conclusions: Our results suggest that viruria and viraemia may reflect independent BKV reactivation in different tissues. The activation of the infection does not seem to be related to the type of immunosuppressive treatment nor to impairment of renal function. To better understand the pathogenetic role of BKV infection in renal transplant recipients further investigations are needed.

Role of caspofungin in restoring the impaired phagocyte-dependent innate immunity towards Candida albicans in chronic haemodialysis patients

Phagocyte-dependent cellular immunity in chronic kidney disease patients undergoing haemodialysis treatment is frequently impaired owing to the uraemic state, resulting in an intrinsic susceptibility to developing invasive fungal infections with high mortality rates. Since synergism between phagocytic cells and antifungal drugs may be crucial for successful therapy, the aim of this study was to evaluate the effects exerted by caspofungin (CAS) on the functional activities of polymorphonuclear cells (PMNs) in haemodialysed patients (HDs) towards Candida albicans compared with those of PMNs from healthy subjects (HSs). PMNs were separated from venous blood samples of 66 HDs and 30 HSs (as controls), and measurement of phagocytic and intracellular fungicidal activities of HD-PMNs and HS-PMNs was performed in the presence of CAS at the minimum inhibitory concentration (MIC) and at sub-MICs. CAS-free controls were also included. In the drug-free test condition, no significant difference between the phagocytic activity of HD-PMNs and HS-PMNs was detected. In contrast, a progressive decline in the intracellular killing activity of HD-PMNs against proliferating yeasts was observed. CAS at MIC and sub-MIC levels was able to improve significantly the intracellular fungicidal activity of HD-PMNs against C. albicans, restoring their functionality. These findings provide evidence that CAS exerts a synergistic effect on HD-PMNs against C. albicans, being able to strength the depressed intracellular killing activity. These results corroborate the use of CAS as an effective therapeutic option for the treatment of invasive fungal infections in HDs, in whom even a marginal influence of antifungal drugs on host response may have a relevant effect.

N-Acetylcysteine in hemodialysis diabetic patients resets the activation of NF-kB in lymphomonocytes to normal values.

BACKGROUND Oxidative stress pathways are activated in diabetes, particularly when dialysis is required (DD). NF-kB is activated in this clinical condition. Since N-Acetyl-cysteine (NAC) is an anti-oxidant, we aimed at investigating its effect in modulating NF-kB activation in lymphomonocytes (PBMC) of DD patients. METHODS Twenty-five DD patients were enrolled in a cross-over designed study. Tests were performed at T0 and after one month (T1) of treatment with NAC and three months after NAC withdrawal. We assessed NF-kB activation by EMSA, levels of advanced oxidation protein products (AOPP) by spectral analysis, total antioxidant capacity (TAC) by colorimetry, and apoptosis by FACS. RESULTS At T0 a statistically significant increased activation of the subunits of NF-kB, p50/p65, was detected in PBMC of DD patients in comparison to controls (both P<.0001). After one month of NAC both p50-p50/p50-p65 dimers were significantly reduced (P<.004 and .006). Three months after drug withdrawal NF-kB increased again to basal levels (P<.002 and P<.001 vs. end of treatment with NAC). AOPP and TAC levels and the percentage of apoptotic PBMC revealed modifications in accordance with NFkB activation. In a multivariate linear regression model using delta AOPP as the dependent variable and delta p50-p50, delta TAC, and delta APO as independent variables, we found that all three dependent parameters all retained an independent correlation with delta AOPP. CONCLUSIONS Our data indicate in vivo a modulation by NAC of parameters indicating a redox imbalance in DD patients on hemodialysis. The use of NAC might suggest a potential clinical benefit.

Candida albicans Infections in Renal Transplant Recipients: Effect of Caspofungin on Polymorphonuclear Cells

ABSTRACT This study aimed to compare the caspofungin immunomodulating activities against Candida albicans on polymorphonuclear cells (PMNs) from renal transplant recipients (RTRs) and healthy subjects (HSs). RTR PMNs showed a significantly reduced fungicidal activity compared with that of HS PMNs. Addition of caspofungin to RTR PMNs significantly potentiated the yeast intracellular killing rate, achieving values similar to those observed for HS PMNs. These data show that caspofungin is suitable for invasive candidiasis treatment in patients with immune system-impaired components.

Caspofungin benefit on phagocytes from patients with renal dysfunction infected with multidrug-resistant Candida glabrata

AIM We evaluated the potential impact of caspofungin (CAS) on the functional activities of polymorphonuclear leukocytes (PMNs) from hemodialyzed patients (HDs) and renal transplant recipients (RTRs) against a multidrug-resistant clinical strain of Candida glabrata compared with those of PMNs from healthy subjects (HSs). MATERIALS & METHODS Effects of CAS on PMN phagocytosis and intracellular killing towards multidrug-resistant C. glabrata were evaluated in 66 HDs, 54 RTRs and 30 HSs in the absence and presence of CAS at MIC and sub-MICs. RESULTS When HD PMNs and RTR PMNs were exposed to both MICs and sub-MICs of CAS, their fungicidal activity against the multidrug-resistant C. glabrata strain was significantly higher than that of drug-free controls, with survival index values that overlapped with those achieved by HS PMNs. CONCLUSION The obtained results underline the role of CAS in the restoration of the impaired PMN functions in HDs and RTRs. CAS might still constitute an effective therapeutic option for the treatment of invasive fungal infections caused by multidrug-resistant C. glabrata in patients with altered phagocyte-dependent innate immunity.

Opsonization Capacity of Plasma and Peritoneal Dialysate in CAPD Patients

Plasma fibronectin concentrations in CAPD patients were found not to be different from healthy controls. During peritonitis plasma fibronectin concentration was lowered and the plasma fibronectin/ peritoneal fibronectin ratio increased. In two patients with recurrent peritonitis the plasma fibronectin/peritoneal fibronectin ratio remained very low. Since fibronectin is an important opsonic protein for staphylococcal destruction, its low concentration in some patients with frequent peritonitis suggests a causal role in these patients.