The majority of cells in so-called "mesenchymal stem cell" population are neither stem cells nor progenitors.

OBJECTIVES: The first-passage adherent human bone marrow fibroblast-like cell population corresponds, in terms of phenotype and three-lineage differentiation capacity (assayed in bulk culture), to commonly termed "mesenchymal stem cells". Here we determine the proportion of high proliferative capacity multipotent cells present in this population in order to estimate the proportion of cells that can or cannot be considered as stem and progenitor cells. MATERIAL AND METHODS: The single-cell cultures were established starting from human bone marrow-derived first-passage fibroblast-like cells and the proliferating clones were either transferred to secondary cultures to evaluate their further clonogenicity, or split into three wells to assess differentiation into each of the three different lineages. RESULTS: The analysis of 197 single-cell cultures from three different bone marrow donors shows that only∼40% of so-called "mesenchymal stem cells" exhibit multipotency and are capable of sustained clonogenicity in secondary cultures. CONCLUSION: Even in the first ex vivo passage under favorable conditions the majority (∼60%) of so-called "mesenchymal stem cells" are not multipotent and thus do not represent a stem cell entity.

Score for pulmonary tuberculosis in patients with clinical presumption of tuberculosis in a low-prevalence area.

OBJECTIVES: To develop a diagnostic predictive model for the identification of patients with presumptive pulmonary tuberculosis (PTB) at high risk for active disease and those requiring nucleic acid amplification (NAAT) testing and/or preventive respiratory isolation in low-incidence, high-income countries. DESIGN: A 1:1 case-control study was conducted in consecutive immunocompetent patients with presumed PTB hospitalised between 2009 and 2012 in Paris, France. Cases were defined as individuals with culture-confirmed PTB, regardless of smear result. Those with presumed PTB and three smear- and culture-negative samples were selected as controls. A score was derived using conditional logistic regression. Internal validity of the score was assessed using the bootstrap method. RESULTS: A total of 354 patients were included in the analysis (177 cases, 177 controls). Among the 177 cases, 74 (42%) were smear-negative but culture-positive. Factors independently associated with PTB were age <50 years (adjusted OR [aOR] 4.7, 95%CI 1.8-12), diabetes (aOR 3.2, 95%CI 1.1-9.8), absence of cough with or without sputum (aOR 3.7, 95%CI 1.7-8.3), fever >15 days (aOR 3.5, 95%CI 1.3-9.5), apical infiltration without cavity (aOR 3.4, 95%CI 1.4-8.5) and cavitation or miliary pattern (aOR 19.7, 95%CI 7.6-51.1). Score C-index was 0.84 (95%CI 0.79-0.88). Calibration for the overall population (P = 0.770) and in smear-negative patients (P = 0.980) was appropriate. A score of 3.3 had 90% sensitivity, 50% specificity and 79% (IQR 28-95) median probability of PTB. CONCLUSIONS: This score could be used to build an algorithm to determine the need for respiratory isolation and/or NAAT use in PTB disease.