Quality control on mononuclear cells collected for extracorporeal photochemotherapy: comparison between two UV-A irradiation devices

Recently, MacoPharma released a new UV-A cell irradiator device (Macogenic G2) for extracorporeal photopheresis (ECP), smaller and lighter than the Macogenic G1 but with no integrated cooling system. We compared the two devices at different working temperatures (G1 at standard irradiation temperature - 21°C - and G2 set by purpose at 34°C) in patients affected with chronic graft-versus-host disease and chronic lung allograft dysfunction treated by ECP. We demonstrate that both G1 and G2 devices are efficient in inducing the inhibition of lymphocytic proliferation and mononuclear cells apoptosis after 48 h even when G2 is set at higher-than-standard temperature.

A thin-layer chromatography autographic method for the detection of inhibitors of the Salmonella PhoP-PhoQ regulatory system

INTRODUCTION

The PhoP-PhoQ system from Salmonella enterica serovar Typhimurium controls the expression of factors that are critical for the bacterial entry into host cells and the bacterial intramacrophage survival. Therefore it constitutes an interesting target to search for compounds that would control Salmonella virulence. Localisation of such compounds in complex matrixes could be facilitated by thin-layer chromatography (TLC) bioautography.

OBJECTIVE

To develop a TLC bioautography to detect inhibitors of the PhoP-PhoQ regulatory system in complex matrixes.

METHODS

The TLC plates were covered by a staining solution containing agar, Luria-Bertani medium, 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal), kanamycin and a S. typhimurium strain that harbours a reporter transcriptional lacZ-fusion to an archetypal PhoP-activated gene virK. After solidification, the plate was incubated at 37°C for 16 h.

RESULTS

A bioautographic assay suitable for the localisation of inhibitors of the PhoP-PhoQ system activity in S. enterica serovar Typhimurium present in a complex matrix is described. The assay was used to analyse a series of hydrolysed extracts prepared by alkaline treatment of crude plant extracts. Bioassay-guided analysis of the fractions by NMR spectroscopy and MS led to the identification of linolenic and linoleic acids as inhibitory input signals of the PhoP-PhoQ system.

CONCLUSION

A practical tool is introduced that facilitates detection of inhibitors of the Salmonella PhoP-PhoQ regulatory system. The assay convenience is illustrated with the identification of the first naturally occurring organic compounds that down-regulate a PhoP-PhoQ regulatory system from a hydrolysed extract.

Adhesive receptors, extracellular proteins and myosin IIA orchestrate proplatelet formation by human megakaryocytes

BACKGROUND

Megakaryocytes release platelets from the tips of cytoplasmic extensions, called proplatelets. In humans, the regulation of this process is still poorly characterized.

OBJECTIVE

To analyse the regulation of proplatelet formation by megakaryocyte adhesion to extracellular adhesive proteins through different membrane receptors.

METHODS

Human megakaryocytes were obtained by differentiation of cord blood-derived CD34(+) cells, and proplatelet formation was evaluated by phase contrast and fluorescence microscopy.

RESULTS

We found that human megakaryocytes extended proplatelets in a time-dependent manner. Adhesion to fibrinogen, fibronectin or von Willebrand factor (VWF) anticipated the development of proplatelets, but dramatically limited both amplitude and duration of the process. Type I, but not type III or type IV, collagen totally suppressed proplatelet extension, and this effect was overcome by the myosin IIA antagonist blebbistatin. Integrin alphaIIbbeta3 was essential for megakaryocyte spreading on fibrinogen or VWF, but was not required for proplatelet formation. In contrast, proplatelet formation was prevented by blockade of GPIb-IX-V, or upon cleavage of GPIbalpha by the metalloproteinase mocarhagin. Membrane-associated VWF was detected exclusively on proplatelet-forming megakaryocytes, but not on round mature cells that do not extend proplatelets.

CONCLUSIONS

Our findings show that proplatelet formation in human megakaryocytes undergoes a complex spatio-temporal regulation orchestrated by adhesive proteins, GPIb-IX-V and myosin IIA.

Diagnostic and clinical relevance of the number of circulating CD34(+) cells in myelofibrosis with myeloid metaplasia

The absolute content of CD34(+) cells in the peripheral blood of 84 patients with myelofibrosis with myeloid metaplasia (MMM) and 23 patients with other Philadelphia-negative (Ph(-)) chronic myeloproliferative disorders (CMDs) was investigated. In MMM, the median absolute number of circulating CD34(+) cells was consistently high (91.6 x 10(6)/L; range, 0-2460 x 10(6)/L). Receiver operating characteristic curve analysis showed that 15 x 10(6)/L as a decision criterion for CD34(+) cells produced an almost complete discrimination between MMM patients out of therapy and other Ph(-) CMDs (positive predictive value, 98.4%; negative predictive value, 85.0%). MMM patients with higher numbers of CD34(+) cells had a significantly longer disease duration (P =.019) and higher spleen volume index (P =.014), liver volume (P =.000), percentage of circulating immature myeloid cells (P =.020), and percentage of myeloid blasts (P =.000). When CD34(+) cells were correlated with the use of Dupriez risk stratification, CD34(+) cells increased significantly from low-risk (median, 68.1 x 10(6)/L) to intermediate-risk (median, 112.8 x 10(6)/L) and high-risk patients (median 666.1 x 10(6)/L) (F = 4.95; P =.009). When CD34(+) cells were correlated with a severity score on the basis of both myeloproliferative and myelodepletive characteristics of the disease, only the myeloproliferation index was significantly associated with CD34(+) cell level (F = 5.7; P =.000). Overall survival and interval to blast transformation from the time of CD34(+) cell analysis were significantly shorter in patients with more than 300 x 10(6)/L CD34(+) cells (P =.005 and.0005, respectively). In conclusion, the absolute number of CD34(+) circulating cells allows MMM to be distinguished from other Ph(-) CMDs; it is strongly associated with the extent of myeloproliferation and predicts evolution toward blast transformation.

Extracorporeal photochemotherapy for treatment of acute and chronic GVHD in childhood

BACKGROUND

Extracorporeal photochemotherapy (EPC) has recently been proposed for the treatment of adults with either acute or chronic GVHD. However, data on children given this therapy are scarce. A Phase I-II study was carried out on EPC in children experiencing GVHD after allogeneic transplantation of HPCs.

STUDY DESIGN AND METHODS

Nine patients with steroid-resistant, grade II-IV acute GVHD and 14 with chronic GVHD, all of whom had been refractory to at least one line of treatment, were enrolled in this study and analyzed. The median age was 10.3 years (range, 5.4-18.1), and the median body weight was 35 kg (range, 17-89).

RESULTS

Seven of the nine patients with acute GVHD showed a response to EPC, whereas the disease progressed in the remaining two children (both with skin, gastrointestinal, and liver GVHD), and they died of grade IV acute GVHD. Among the seven children who responded to EPC, it was possible to completely discontinue immunosuppressive treatment in three. In the 14 children with chronic GVHD, 4 and 5 patients experienced complete and partial response to EPC, respectively, whereas the remaining 5 patients, all with extensive chronic GVHD, had stable disease or disease that progressed during EPC. Among these latter 5 patients, 3 died. In 6 of the 9 patients with chronic GVHD responding to EPC, immunosuppressive therapy was discontinued.

CONCLUSION

EPC is safe, feasible, and effective in children with either acute or chronic GVHD occurring after an allograft.

Autologous platelet collection and storage to support thrombocytopenia in patients undergoing high-dose chemotherapy and circulating progenitor cell transplantation for high-risk breast cancer

OBJECTIVES

The use of circulating progenitor cell support following high-dose chemotherapy for malignancies decreases but does not entirely abolish platelet transfusion requirement. We investigated the feasibility of supporting the posttransplant thrombocytopenic phase exclusively with autologous platelets collected by apheresis and cryopreserved.

METHODS

25 patients underwent plateletpheresis during the platelet rebound occurring after high-dose cyclophosphamide. Autologous platelets were cryopreserved in 5% dimethylsulfoxide, thawed and transfused during the aplastic phase after the myeloablative regimen whenever clinically required.

RESULTS

A single plateletpheresis was carried out in all patients, allowing the harvest of a platelet concentrate with a mean value of 7.7 x 10(11) platelets. No significant procedure- or transfusion-related side effects were recorded. Mean platelet recovery after freezing and thawing was 63% and the mean number of platelet reinfused was 4.8 x 10(11); 23 of 25 patients were fully supported with autologous platelets.

CONCLUSION

Plateletpheresis performed in our selected group of patients was found to be a safe and effective procedure to collect large amounts of autologous platelets; the numbers obtained proved to be sufficient for the transfusion demand of almost all patients.

Feasibility and safety of a new technique of extracorporeal photochemotherapy: experience of 240 procedures

BACKGROUND AND OBJECTIVE

Extracorporeal photochemotherapy (ECP) is a therapeutic approach based on the biological effects of ultraviolet light (UV) - A and psoralens on mononuclear cells collected by apheresis. Recently, ECP has been under investigation as an alternative treatment for various immune and autoimmune diseases. The aim of this study was to evaluate the safety and feasibility of a new three-step ECP technique, in terms of reproducibility, acceptance, tolerability, and short and long term side effects.

DESIGN AND METHODS

Seventeen patients affected by acute or chronic graft-versus-host disease (GvHD), pemphigus vulgaris, or interferon-resistant chronic hepatitis C and one patient being treated for prevention of heart transplant rejection underwent 240 ECP procedures. MNC collection and processing parameters were recorded, biological effects of UV-A/8 methoxy-psoralen (8-MOP) were evaluated, and short and long term side effects were monitored.

RESULTS

At a mean follow up of 7 months (range 2-19) 240 ECP had been completed, a mean of 7,136 mL (range 1,998-10,591) of whole blood having beenprocessed per procedure. The mean of total nucleated cells collected per procedure was 6.5x109 (range 0.65-23.8), with a mean MNC percentage of 85% (41. 4-98%) in a mean final volume of 115.5 mL (37-160). No severe side effects were documented and no infectious episodes occurred throughout the course of the treatment.

INTERPRETATION AND CONCLUSIONS

The new ECP technique was highly reproducible as regards the collection and each processing step. Short and long term side effects were mild. No increase in infectious episodes was recorded. All patients willingly underwent ECP, demonstrating an excellent tolerability for the procedure even after several courses.

Phagocyte activation in coronary artery disease

Recent studies suggest that granulocytes (PMNs) play a role in the pathogenesis of acute and chronic myocardial ischemia and extension of myocardial injury. Granulocytes can release a variety of molecules mediating tissue injury which act synergistically with other molecules and cells. The aim of our investigation was to evaluate the granulocyte function in patients affected by coronary artery disease (CAD) and during coronary angioplasty (PTCA). We studied 20 patients suffering from CAD. The PMN's aggregating activity was greater in the coronary sinus than in the aorta (P < 0.01). The increase in aggregating activity was evident in patients who were smokers: their cells release significantly lower quantities of leukotriene C4 (P < 0.025). In the 20 patients who underwent coronary angioplasty we analyzed superoxide release after stimulation with phorbol-myristate-acetate (PMA). The results showed a greater decrease of PMN's superoxide production in the coronary sinus than in the aorta (P < 0.05). In all patients affected by CAD we evaluated the PMN's expression of CD11b/CD18 membrane integrins. In these patients the increase in expression of CD11b/CD18 was statistically significant in comparison with the controls (P < 0.01). This increase in expression correlates with a higher aggregation (r = 0.87, P < 0.001). The potential role of leukocytes, oxygen radicals, leukotrienes and granulocyte enzymes in the pathophysiology of myocardial injury due to regional ischemia and reperfusion is an area of intense investigation. This paper presents studies carried out in vivo which have been instrumental in demonstrating the role of granulocytes as mediators of myocardial ischemia.