BK Virus Infection and BK-Virus-Associated Nephropathy in Renal Transplant Recipients

Poliomavirus BK virus (BKV) is highly infective, causing asymptomatic infections during childhood. After the initial infection, a stable state of latent infection is recognized in kidney tubular cells and the uroepithelium with negligible clinical consequences. BKV is an important risk factor for BKV-associated diseases, and, in particular, for BKV-associated nephropathy (BKVN) in renal transplanted recipients (RTRs). BKVN affects up to 10% of renal transplanted recipients, and results in graft loss in up to 50% of those affected. Unfortunately, treatments for BK virus infection are restricted, and there is no efficient prophylaxis. In addition, consequent immunosuppressive therapy reduction contributes to immune rejection. Increasing surveillance and early diagnosis based upon easy and rapid analyses are resulting in more beneficial outcomes. In this report, the current status and perspectives in the diagnosis and treatment of BKV in RTRs are reviewed

Emergence of Carbapenem-Resistant Klebsiella pneumoniae: Progressive Spread and Four-Year Period of Observation in a Cardiac Surgery Division

Frequent use of carbapenems has contributed to the increase to K. pneumoniae strains resistant to this class of antibiotics (CRKP), causing a problem in the clinical treatment of patients. This investigation reports the epidemiology, genetic diversity, and clinical implication of the resistance to drugs mediated by CRKP in our hospital. A total of 280 K. pneumoniae strains were collected; in particular 98/280 (35%) were CRKP. Sequencing analysis of CRKP isolated strains showed that 9/98 of MBL-producing strains carried the VIM-1 gene and 89/98 of the isolates were positive for KPC-2 . Antimicrobial susceptibility tests revealed a complete resistance to third-generation cephalosporins and a moderate resistance to tigecycline, gentamicin, and fluoroquinolones with percentages of resistance of 61%, 64%, and 98%, respectively. A resistance of 31% was shown towards trimethoprimsulfamethoxazole. Colistin was the most active agent against CRKP with 99% of susceptibility. Clonality was evaluated by PFGE and MLST: MLST showed the same clonal type, ST258, while PFGE analysis indicated the presence of a major clone, namely, pulsotype A. This finding indicates that the prevalent resistant isolates were genetically related, suggesting that the spread of these genes could be due to clonal dissemination as well as to genetic exchange between different clones

Evaluation of multiple stemness markers in normal thyroid and in thyroid carcinoma (TC) specimens.

The tumorigenic capacity in cancer, including TC, is confined in a small subpopulation of stem-like cells termed cancer stem cells (CSCs). To date, markers for thyroid CSCs remain to be confirmed. Thus, the identification of a specific antigen to distinguish thyroid CSCs from normal SCs represents a crucial step to develop targeted therapies. The aim of this study was to investigate the expression of stemness markers and to isolate putative SCs from both normal thyroid and TC. Normal and neoplastic tissue samples were harvested from a cohort of 19 pa-tients affected by TC, who underwent thyroidectomy. Fresh specimens were enzymatically digested. Cell suspensions were characterized by flow cytometry using anti-CD133, -CD45, -CD31, -CD44 and -CD105 antibodies. A portion of cells was suspended in SC medium (SCM) in order to obtain thyroid spheres. CD133+ and CD105+ cell rates were significantly higher in TC than in normal thyroid tissue (2.5% vs. 0.1% and 3.9% vs. 0.5% respectively, p<0.02). No difference was found regarding CD44+. In TC both CD45+ and CD31+ cell rates were 1.3%, but 1.45% of CD133+ cells were also positive for CD45 and 0.8% for CD31. In normal tissues CD45+ and CD31+ cell rates were 0.5% and 0.03%, respectively, but none of CD133+ cells were positive for CD45 and CD31. Putative SCs were isolated particularly from TC samples; they grew as both free-floating spheres and adherent cells. The re-evaluation of markers in putative SC isolated from 2 cases of normal tissue showed that cells expressed higher levels of CD133, CD105 and CD44 with respect to those obtained after tissue digestion. These preliminary findings suggest the presence of a higher fraction of CD133+ and CD105+ cells in TC samples compared to normal tissues. The higher expression of the stemness markers in TC may be related to the better survival of cells obtained from the TC samples in the SCM. Further investigation is required to draw any conclusion, but our approach seems to be promising. Keywords Stemness markers, normal thyroid, TC. Funded by a D.1 grant, UCS

Regulatory T cell proliferative potential is impaired in human autoimmune disease

Human CD4(+)CD25(high)CD127(-)FoxP3(+) regulatory T (Treg) cells suppress immune responses in vitro and in vivo. Reduced suppressive function and/or number of peripheral Treg cells has been previously reported in autoimmune disorders. Treg cells represent the most actively replicating compartment within the CD4(+) cells in vivo, but they are hyporesponsive to classical T cell receptor (TCR) stimulation in vitro, a condition that is secondary to their overactive metabolic state. Here we report that proliferation of Treg cells after TCR stimulation is impaired in subjects with relapsing-remitting multiple sclerosis (RRMS) because of altered interleukin-2 (IL-2) secretion and IL-2 receptor (IL-2R)-signal transducer and activator of transcription 5 (STAT5) signaling. This is associated with decreased expression of the forkhead box P3 (FoxP3) 44- and 47-kDa splicing forms, overactivation of S6 ribosomal protein (a downstream target of the mammalian target of rapamycin, mTOR) and altered activity of the cyclin-dependent kinase inhibitor p27 (p27(kip1)) and extracellular signal-related kinases 1 and 2 (ERK1/2). The impaired capacity of Treg cells to proliferate in RRMS correlates with the clinical state of the subject, where increasing disease severity is associated with a decline in Treg cell expansion. These results suggest a previously unrecognized mechanism that may account for the progressive loss of Treg cells in autoimmune disease