Adipose tissue-derived mesenchymal stromal cells for clinical application: An efficient isolation approach.

PURPOSE OF THE STUDY: Mesenchymal stromal cells (MSCs) are considered a promising tool for cell therapy approaches. The translation of research-based cell culture protocols into procedures that comply with Good Manufacturing Practice (GMP) is critical. The aim of this study was to design a new method for the expansion of MSCs from Adipose Tissue (AT-MSCs) in compliance with GMP, without enzymatic tissue digestion and without the use of animal proteins as source of growth factors. PATIENTS AND METHODS: MSCs were expanded from 10 periumbilical biopsies. Our new isolation approach is based on: (1) disruption of AT with an automated, closed system; (2) use of GMP-grade medium without the addition of fetal bovine serum or platelet lysate; (3) use of human recombinant Trypsin. AT-MSCs cultured in α-MEM and minced by scalpel were used as control. RESULTS: It was possible to expand MSCs from all the AT-samples for at least eight passages. MSCs displayed the typical spindle-shape morphology, a high viability, multilineage differentiation potential and high expression levels of the typical MSC-specific surface antigens and genes. Compared to standard method, MSCs obtained with the new method showed higher yield, up to passage 6, and higher purity in terms of percentage of CD34 and CD45 markers. All AT-MSCs exhibit in vitro immunosuppressive capacity and possess a normal karyotype. CONCLUSIONS: Our data clearly demonstrate that our new approach permits to generate AT-MSCs fully compliant for therapeutic use and better at least in terms of quantity and purity than those obtained with the standard method.

Involvement of MAF/SPP1 axis in the development of bone marrow fibrosis in PMF patients.

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by hyperplastic megakaryopoiesis and myelofibrosis. We recently described the upregulation of MAF (v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog) in PMF CD34+ hematopoietic progenitor cells (HPCs) compared to healthy donor. Here we demonstrated that MAF is also upregulated in PMF compared with the essential thrombocytemia (ET) and polycytemia vera (PV) HPCs. MAF overexpression and knockdown experiments shed some light into the role of MAF in PMF pathogenesis, by demonstrating that MAF favors the megakaryocyte and monocyte/macrophage commitment of HPCs and leads to the increased expression of proinflammatory and profibrotic mediators. Among them, we focused our further studies on SPP1 and LGALS3. We assessed SPP1 and LGALS3 protein levels in 115 PMF, 47 ET and 24 PV patients plasma samples and we found that SPP1 plasma levels are significantly higher in PMF compared with ET and PV patients. Furthermore, in vitro assays demonstrated that SPP1 promotes fibroblasts and mesenchymal stromal cells proliferation and collagen production. Strikingly, clinical correlation analyses uncovered that higher SPP1 plasma levels in PMF patients correlate with a more severe fibrosis degree and a shorter overall survival. Collectively our data unveil that MAF overexpression contributes to PMF pathogenesis by driving the deranged production of the profibrotic mediator SPP1.

Development and validation of an enzyme linked immunosorbent assay for palivizumab serum determination.

Palivizumab (Synagis) is a humanized monoclonal antibody (IgG1K) composed of 95 percent human and 5 percent murine sequences. It is directed to an epitope in the A antigenic site of the F protein of respiratory syncytial virus (RSV). Palivizumab is used for prevention of serious lower respiratory tract disease caused by RSV in pediatric patients who are at increased risk of severe disease and is administered intramuscularly (IM) for a total of 5 monthly doses. Herein, we report on the development and validation of a very sensitive enzyme-linked immunosorbent assay (ELISA) to measure serum concentrations of palivizumab by a rabbit polyclonal antibody specifically produced against the murine sequence. The method was developed and validated according to the guidelines "Guidance for Industry" (1998) and has proved suitable for the determination of palivizumab serum levels in the target infant population. The ELISA assay was successfully applied to test the serum samples in an infant population who received palivizumab intramuscularly; thus, the assay could be used to determine serum levels in palivizumab-treated infants to optimize dosing and scheduling and to study the relationship between dose and clinical response.

Immunomodulatory properties of porcine, bone marrow-derived multipotent mesenchymal stromal cells and comparison with their human counterpart.

Thanks to their immunonodulatory properties, multipotent mesenchymal stromal cells (MSCs) are a promising strategy for preventing/reducing the risk of graft rejection after hematopoietic cell and solid organ transplantation. We have previously demonstrated that porcine MSCs (pMSCs) can be isolated from bone marrow and display similar morphology and differentiative capacity as compared to human MSC (hMSCs). In this study, we investigated the in vitro immunomodulatory properties (namely the ability to suppress lymphocyte proliferation in response to phytohemagglutinin and the cytokine production in the culture supernatants) of pMSCs from six Large White 6-month old piglets. Similarly to hMSCs, pMSCs reduced the phytohemagglutinin-induced lymphocyte proliferation. High levels of IL-6 were found in culture supernatants, whereas IL-10 and TGF-ß were not detectable. In conclusion, ex vivo expanded pMSCs share selected biological/functional properties with hMSCs. pMSCs may be used in in vivo models to investigate novel approaches of prevention of graft rejection in solid organ transplantation.

Effects of electromagnetic stimulation on osteogenic differentiation of human mesenchymal stromal cells seeded onto gelatin cryogel.

Bone tissue engineering typically uses biomaterial scaffolds, osteoblasts or cells that can become osteoblasts, and biophysical stimulations to promote cell attachment and differentiation. In this study, we investigated the effects of an electromagnetic wave on mesenchymal stromal cells isolated from the bone marrow and seeded upon gelatin cryogel disks. In comparison with control conditions without electromagnetic stimulus, the electromagnetic treatment (magnetic field, 2 mT; frequency, 75 Hz) increased the cell proliferation and differentiation and enhanced the biomaterial surface coating with bone extracellular matrix proteins. Using this tissue-engineering approach, the gelatin biomaterial, coated with differentiated cells and their extracellular matrix proteins, may be used in clinical applications as an implant for bone defect repair.

Co-infusion of ex vivo-expanded, parental MSCs prevents life-threatening acute GVHD, but does not reduce the risk of graft failure in pediatric patients undergoing allogeneic umbilical cord blood transplantation.

When compared with BMT, umbilical cord blood transplantation (UCBT) is associated with a lower rate of engraftment and delayed hematological/immunological recovery. This leads to increased risk of TRM in the early post transplantation period due to infection. Acute GVHD, although occurring less frequently in UCBT compared with BMT, is also significantly associated with increased rate of early TRM. BM MSCs are known to support normal in vivo hematopoiesis, and co-transplantation of MSCs has been shown to enhance engraftment of human cord blood hematopoietic cells in nonobese diabetic/SCID mice. In 13 children with hematological disorders (median age 2 years) undergoing UCBT, we co-transplanted paternal, HLA-disparate MSCs with the aim of improving hematological recovery and reducing rejection. We observed no differences in hematological recovery or rejection rates compared with 39 matched historical controls, most of whom received G-CSF after UCBT. However, the rate of grade III and IV acute GVHD was significantly decreased in the study cohort when compared with controls (P=0.05), thus resulting in reduced early TRM. Although these data do not support the use of MSCs in UCBT to support hematopoietic engraftment, they suggest that MSCs, possibly because of their immunosuppressive effect, may abrogate life-threatening acute GVHD and reduce early TRM.

Isolation and ex vivo expansion of bone marrow-derived porcine mesenchymal stromal cells: potential for application in an experimental model of solid organ transplantation in large animals.

Pharmacological aspecific immunosuppression, despite being widely used in solid organ transplantation recipients, is unable to completely prevent allograft rejection. It promotes the occurrence of sometimes life-threatening infections. Due to their immunosuppressive and anti- inflammatory properties, there is great interest in the therapeutic use of bone marrow (BM)-derived mesenchymal stromal cells (MSC). Large animal models play a crucial role to investigate the biological and functional properties of MSCs as novel cellular therapy. In the current study we sought to isolate expand ex vivo, and phenotypically characterize MSC derived from BM of 4 Large White 6-month-old piglets. Porcine MSC (pMSC) were characterized for their in vitro differentiation capacity. pMSC were successfully isolated from all BM samples. They showed spindle-shaped morphology and a stable doubling time on culture. They were positive for CD90, CD29, CD105, and negative for CD45 and CD11b. Furthermore, they differentiated, upon specific in vitro conditions toward adipogenic and osteogenic lineages. The optimization of methods for the isolation and characterization of pMSC may be useful to elucidate their biological and functional properties. The anatomy and physiology of the pig, which is similar to humans, make this animal model more attractive than small animals to test the safety and efficacy of MSC in the context of solid organ transplantation.

B lymphocyte subsets and their functional activity in the early months of life.

In the present study we evaluated B-cell subsets and their functional development in 74 newborns from birth to 6 months of life. Moreover, we evaluated natural antibody production in vitro. The results documented a predominance of naive B-lymphocytes at all time-points evaluated, decreasing from birth to 6 months (p=0.009). The percentages of CD27+IgD+ and CD27+IgDneg memory B-cells were very low at birth and significantly increased only at 6 months (p=0.02 and p less than 0.001, respectively). We found a significant increase only in in vitro stimulated IgG production at 6 months as compared to birth (p less than 0.001). Moreover, a lower secretion of anti-Pn IgM antibodies up to 6 months of age, as compared to controls was observed. Our results underline that the susceptibility and severe course of infection in the neonate can be attributed, at least in part, to the lack of pre-existing immunological memory and competent adaptive immunity.

A prospective study on children with initial diagnosis of transient hypogammaglobulinemia of infancy: results from the Italian Primary Immunodeficiency Network.

Transient hypogammaglobulinemia of infancy (THI) is a heterogeneous disorder characterized by reduced serum IgG levels in early infancy. A putative diagnosis is initially made after exclusion of other causes of hypogammaglobulinemia while a definitive diagnosis of THI can only be made a posteriori in patients with normalization of IgG levels. The aim of this study is to characterize clinical and immunological features of children with an initial diagnosis of THI in correlation to natural outcome, and to assess predictive laboratory parameters of clinical evolution for this disorder. We prospectively analysed clinical and immunological characteristics of 77 THI children at initial diagnosis and of 57 patients at follow-up. Memory B cell subsets and in vitro immunoglobulin production were evaluated. Seventy patients (91 percent) showed clinical symptoms. Patients suffered from infections (91 percent), allergies (47 percent) and autoimmune disease (4 percent). During follow-up 41/57 children (72 percent) normalized IgG values, mostly within 24 months of age (p less than 0.001), allowing the diagnosis of THI. The 16 children who did not normalize their IgG levels showed a higher frequency of severe infections and autoimmune disease (p less than 0.01). Moreover, they expressed a reduced frequency of IgM and switched memory B cells (p less than 0.01) and an inability to produce IgG in vitro (p less than 0.02). We conclude that most patients with an initial diagnosis of THI spontaneously recover within 24 months of age and have a benign clinical course, while a subgroup of children with undefined hypogammaglobulinemia share a clinical and immunological profile with other primary immunodeficiencies. Early recognition of children with hypogammaglobulinemia during infancy who are likely to suffer from permanent immunodeficiencies later in life would allow prompt and appropriate laboratory and clinical interventions.

Human colostrum T lymphocytes and their effector cytokines actively aid the development of the newborn immune system.

Colostrum contains soluble and cellular components, the latter mainly T lymphocytes. We expanded in vitro colostrum T lymphocytes (CoTL) to evaluate phenotype and capability of cytokine production. We also considered paired cord blood T-lymphocytes (CBTL) representing the newborn "virgin" immune system. CoTL showed memory phenotype while CBTL expressed mainly naïve phenotype. CoTL included a balanced percentage of helper and cytotoxic subsets. We observed higher percentages of IL-2 (p=0.003) and IL-4 (p=0.027) producing cells by helper rather than by cytotoxic T lymphocytes. The greatest percentage of IFN-gamma producing cells was in cytotoxic cells (p=0.0048), while no difference was found for IL-10. Cord blood samples consisted of a statistically significant greater percentage of helper than cytotoxic cells (p<0.001), with a low percentage of cytokine producing cells, confirming the immaturity of the newborns immune system. CBTL percentage of IL-2 producing cells was higher for helper than cytotoxic subset (p<0.001). We observed a greater percentage of IFN-gamma (p=0.001), IL-4 (p=0.003) and IL-10 (p<0.001) producing cells by cytotoxic than helper T lymphocytes. CoTL demonstrated to protect the newborn through the mothers previous immune experience and to supply active cytokines, which can help the postnatal development of both T type 1/T type 2 response.

In vitro activation of mononuclear cells by two probiotics: Lactobacillus paracasei I 1688, Lactobacillus salivarius I 1794, and their mixture (PSMIX).

BACKGROUND: Most studies on probiotics have described their effects on the human immune system after ingestion of LAB, but little is known about their effect on in vitro stimulation of human immune cells. AIM OF THE STUDY: Evaluate the "in vitro" activity of Lactobacillus paracasei (I 1688), Lactobacillus salivarius (I 1794), and a commercial mix of the two (PSMIX, Proge Farm), on immune cells from healthy individuals. MATERIALS: Two probiotic strains, Lactobacillus salivarius (I 1794; Proge Farm, Italy) and Lactobacillus paracasei (I 1688; Proge Farm, Italy), which are contained in the functional food ENTEROBACILLI, were evaluated for their ability to stimulate peripheral blood mononuclear cells and modulate surface phenotype and cytokine production. RESULTS: All subjects responded to the bacteria, with different levels of response. The cell populations that showed a significant percent increase were CD4+/CD25+ cells (T-helper activated regulatory cells), CD8+/CD25+ (T-suppressor/cytotoxic activated cells), and CD16+/CD56+ (NK cells) (p<0.05). IL-12 and IFN-gamma in vitro production significantly increased with exposure to probiotics (p<0.05 for both). CONCLUSIONS: This study provides the first evidence that Lactobacillus paracasei and Lactobacillus salivarius are capable of inducing a specific immune response that may be useful in the clinical setting for improving innate and adaptive immune responses.

Escherichia coli specific secretory IgA and cytokines in human milk from mothers of different ethnic groups resident in northern Italy.

Breast milk supplies many bioactive components. Neonates protection from pathogenic bacteria is mainly attributable to secretory IgA antibodies present in human milk in an amount depending on previous antigenic exposure. To bring new details into the field of immunological memory in secretory immunity, we evaluated the production of s-IgA specific for E. coli (E. coli s-IgA), and of pro-inflammatory (IL-6 and IL-8) or anti-inflammatory (IL-10) cytokines in the milk of mothers of different ethnic groups exposed in the past to poor conditions, but nowadays living in Italy in adequate conditions. Mothers from Italy, Africa, Asia and Eastern European Countries were included in the study. Anti-E. coli s-IgA, IL-6, IL-8 and IL-10 were determined by ELISA. Breast milk of all the foreign mothers presented higher levels of E. coli s-IgA than Italians, and for Asian and African mothers were significative (p=0.031 and p=0.015, respectively). Milk from women of Eastern European Countries revealed the highest IL-8 levels (p=0.026), while milk from Asian women presented the greatest concentration of IL-6 (p=0.04); however, the Africans reported the lowest concentrations of IL-10 (p=0.045). Since all the mothers had been living in Italy for some time, we believe that the presence of high levels of E.coli s-IgA, supported by high levels of pro-inflammatory cytokine, is part of a persisting immunological secretory memory.

A new sensitive enzyme-linked immunosorbent assay (ELISA) for Alemtuzumab determination: development, validation and application.

Alemtuzumab is a humanized (IgG(1)) rat monoclonal antibody to CD52 antigen and is currently used in the treatment of chronic lymphocytic leukemia (CLL) and other CD52-positive lymphoproliferative disorders. Various techniques have been developed to measure Alemtuzumab levels in human serum/plasma. The authors report on the validation of a very sensitive enzyme-linked immunosorbent assay (ELISA) to measure serum concentrations of the humanized IgG(1) using a rabbit polyclonal antibody specifically produced against the rat sequence of Alemtuzumab after papain digestion. The assay was successfully applied to test the serum samples of patients with B-lymphocyte CLL who received Alemtuzumab subcutaneously. This ELISA assay could be easily used to determine human serum levels of Alemtuzumab pre- and post-treatment to optimize dosing and scheduling and to study the relationship between dose and clinical response.

Optimization of in vitro expansion of human multipotent mesenchymal stromal cells for cell-therapy approaches: further insights in the search for a fetal calf serum substitute.

There is great interest in mesenchymal stromal cells (MSCs) for cell-therapy and tissue engineering approaches. MSCs are currently expanded in vitro in the presence of fetal calf serum (FCS); however, FCS raises concerns when used in clinical grade preparations. The aim of this study was to evaluate whether MSCs expanded in medium supplemented with platelet-lysate (PL), already shown to promote MSC growth, are endowed with biological properties appropriate for cell-therapy approaches. We confirm previously published data showing that MSCs expanded in either FCS or PL display comparable morphology, phenotype, and differentiation capacity, while PL-MSCs were superior in terms of clonogenic efficiency and proliferative capacity. We further extended these data by investigating the immune-regulatory effect of MSCs on the alloantigen-specific immune response in mixed lymphocyte culture (MLC). We found that MSCs-PL are comparable to MSCs-FCS in their capacity to: (i) decrease alloantigen-induced cytotoxic activity; (ii) favor differentiation of CD4+ T-cell subsets expressing a Treg phenotype; (iii) increase early secretion of IL-10 in MLC supernatant, as well as induce a striking augmentation of IL-6 production. As compared with MSCs-PL, MSCs-FCS were more efficient in suppressing alloantigen-induced lymphocyte subset proliferation and reducing early IFNgamma-secretion. Resistance to spontaneous transformation into tumor cells of expanded MSCs was demonstrated by molecular karyotyping and maintenance of normal morphology/phenotype after prolonged in vitro culture. Our data support the immunological functional plasticity of MSCs and suggest that MSCs-PL can be used as an alternative to MSCs-FCS, although these latter cells might be more suitable for preventing/treating alloreactivity-related immune complications.

Deficiency of INFgamma producing cells in adenoids of children exposed to passive smoke.

Exposure to passive smoke is a very common event associated with increased susceptibility to respiratory tract infections. Many related adverse effects result from the ability of cigarette smoke extracts to interfere with the immune system, but the mechanism is not yet completely understood. The aim of the present study is to evaluate the intracellular cytokine profile in adenoids and peripheral blood cells of children exposed to passive smoke. Children undergoing adenoidectomy exposed or not exposed to passive smoke were studied. The intracellular cytokine profile of lymphocyte subsets in adenoids and in peripheral blood were evaluated by flow cytometry analysis. Children exposed to tobacco smoke showed a significantly lower percentage of INF-gamma producing CD4+ and CD8+ cells in adenoids. Moreover a significant correlation was observed between the quantity of exposure and reduction in Th1 (CD4+INFgamma+ and CD8+INFgamma+) cells in adenoids. This reduction may be a contributing factor in the increasing susceptibility to respiratory tract infection in children exposed to tobacco smoke.

The immunosuppressive effect of human cytomegalovirus infection in recipients of allogeneic hematopoietic stem cell transplantation.

In immune-competent individuals, human cytomegalovirus (HCMV) infection is associated with impairment of T-cell function. Our goal was to evaluate prospectively whether clinically asymptomatic HCMV infection in allogeneic hematopoietic stem cell transplantation (alloHSCT) recipients, treated pre emptively with ganciclovir, influences T-cell function as well. Mitogen-stimulated T-cell proliferative activity, together with cell surface markers, was tested in 49 patients on days + 30, + 45, + 60, and + 90 after alloHSCT and, additionally, in cases of positive HCMV pp65-antigenemia. HCMV infection was diagnosed in 19 patients. None of them developed HCMV disease. T-cell proliferative activity was significantly decreased on days when HCMV antigenemia was positive as compared to days without antigenemia. The number of pp65-positive cells negatively correlated with proliferative response. Comparison of patients who did experience HCMV infection with those who did not reveals significant decrease of T-cell proliferative activity observed on days + 30 and + 45, a time period when antigenemia was most frequently found to be positive, whereas no difference was detected on days + 60 and + 90. We conclude that, even clinically asymptomatic, HCMV infection has negative impact on T-cell proliferation capacity in alloHSCT recipients. However, pre emptive therapy with ganciclovir makes this immunosuppressive effect transient and restricted to the time of infection duration.

IFN-gamma low production capacity in type 1 diabetes mellitus patients at onset of disease.

In type 1 diabetes mellitus (T1DM), cytokines can be directly cytotoxic to beta-cells, and/or play an indirect role influencing some cells of the immune system. Since several factors could impair cytokine serum levels, the purpose of our study was to longitudinally evaluate intracellular cytokines, in T1DM patients, and in subject at risk, by flow cytometry analysis. At T1DM onset we observed significantly lower percentage of peripheral CD4 + and CD8 + cells producing IFN-gamma in patients compared to controls and subjects at risk. The 15-month follow-up patients showed significantly lower percentage of CD4 + and CD8 + cells producing IFN-gamma compared to the other groups. At 8-year follow-up no significant differences were observed among the groups in the percentage of cells producing cytokines. We could have considered "exhausted cells" or these T cell subsets may be migrated from peripheral blood to pancreas. On the other hand, our results are in agreement with those reported in literature: in animal model the absence of IFN-gamma production makes beta-cells highly susceptible to viral infection and subsequent attack by natural killer cells, which lead to hyperglycaemia and diabetes mellitus.

Antigen-specific T cell response in infants after recombinant hepatitis B virus vaccination at birth: evaluation of T helper lymphocyte diversity.

Recombinant hepatitis B virus antigen (rHBsAg)-specific CD4+ T cell clones (TCC) were isolated and expanded from the peripheral blood of nine children vaccinated at birth against the hepatitis B (HB) virus. Four of them responded with protective antibody production (responders), three subjects were unable to produce detectable antibody levels even after revaccination (nonresponders), and two infants produced antibodies only after revaccination (slow responders). TCC were then characterized for their ability to produce cytokines known to be important for T cell expansion (interleukin-2, IL-2) and/or effector functions (IL-4, IFN-gamma, IL-10). Results demonstrated that the frequency of rHBsAg-specific TCC in the samples of nonresponders was comparable to or higher than that in the samples of responders. Nevertheless, the majority of TCC obtained from responders or from slow responders before revaccination displayed the T helper 1 (T(H1))-dominant phenotype, while the majority of TCC obtained from nonresponders were nonpolarized T lymphocytes. After revaccination, the distribution of the different T(H) subsets in slow responders was heterogeneous. Overall, our present data suggest that an absence or delay in developing an rHBsAg-specific antibody response to vaccination is not associated with the capacity to generate an Ag-specific T cell response. However, compared to responders, nonresponding infants react to the rHBsAg vaccination with a reduced capacity to expand and differentiate toward polarized T(H) cells.

Decline of maternal hepatitis A virus antibody levels in infants.

UNLABELLED: Hepatitis A is a common viral infection causing substantial morbidity and mortality. The anti-hepatitis A virus (HAV) vaccination in infants would guarantee control of the infection. However, the immunogenicity of the HAV vaccine in infants could be impaired by the presence of passively acquired maternal HAV antibodies. This study evaluated the prevalence of HAV antibodies in 103 women at delivery and in their babies in the first year of life. Eighteen mothers (17.5%) had anti-HAV serum level >10 mIU ml(-1). In their infants the anti-HAV level was still positive in 11 out of 18 (61.1%) at 12 mo. Two out of 85 infants born to anti-HAV-negative mothers and anti-HAV negative at birth were found to be positive at 5 mo of age. CONCLUSION: It is proposed that all women be screened at delivery for anti-HAV antibodies. Children born to anti-HAV-negative mothers could be vaccinated early during the first year of life, whereas vaccination could be postponed in children born to anti-HAV-positive mothers, if necessary.