The evolving art of hematopoietic stem cell transplantation: translational research in post-transplant immune reconstitution and immunosuppression

Immunologic Research - Allogeneic hematopoietic stem cell transplantation (SCT) offers the best chance for cure and/or long-term survival for a broad range of diseases, including many high-risk...     

Double-chimaerism after transplantation of two human leucocyte antigen mismatched,unrelated cord blood units

The small number of progenitor cells is the major limitation to the use of umbilical cord blood (UCB) for the transplantation of adults. We tested the hypothesis that two units transplanted simultaneously could each contribute to haematopoietic reconstitution. A patient with advanced acute lymphocytic leukaemia received a mismatched, unrelated UCB transplant using units from two donors after conditioning. The recipient achieved a complete remission without graft-versus-host disease. Double chimaerism was documented in several leucocyte subpopulations; both units contributed to haematopoiesis until relapse. Triple chimaerism was present from relapse until death due to leukaemia. This approach may potentially improve UCB transplantation outcome for adults lacking a histocompatible donor.     

The influence of a bupivacaine and fentanyl epidural infusion after epidural fentanyl in patients allowed to ambulate in early labor

Epidural fentanyl after a lidocaine and epinephrine test dose provides adequate analgesia and allows for ambulation during early labor. This study was designed to determine the influence of an epidural infusion of bupivacaine plus fentanyl administered after initiation of epidural labor analgesia with fentanyl. Specifically, we evaluated whether there is an increase in motor block or an increased time to request for further analgesic medication. Fifty-one laboring primigravid women at <5 cm cervical dilation who requested epidural analgesia were enrolled. After a 3-mL epidural test dose of 1.5% lidocaine with epinephrine (5 microg/mL), patients received fentanyl 100 microg via the epidural catheter. They then randomly received either an infusion (10 mL/h) of 0.0625% bupivacaine with fentanyl (3 microg/mL) or an infusion of preservative-free saline. After the administration of the initial analgesic, pain scores and side effects were recorded for each patient at 10, 20, and 30 min, every 30 min thereafter, and at the time of request for additional analgesic medication, by an observer blinded to the technique used. There were no demographic differences between the two groups. The mean duration of analgesia (time from initial dose to request for additional analgesia) was increased in the group that received a continuous infusion of bupivacaine and fentanyl compared with the Saline group (198 +/- 86 vs 145 +/- 50 min; P < 0.009). Side effects were similar between the two groups. No patient in either group experienced any detectable motor block. Fourteen patients chose to ambulate in the Saline group, and 12 patients chose to ambulate in the Infusion group. In early laboring patients, a continuous infusion of 0.0625% bupivacaine infusion with fentanyl (3 microg/mL) prolonged the duration until top-up was required, after epidural fentanyl 100 microg after a lidocaine and epinephrine test dose, and did not cause any clinically detectable motor block. IMPLICATIONS: A 0.0625% bupivacaine and fentanyl (3 microg/mL) infusion, when added to epidural fentanyl (100 microg), prolongs the analgesic duration without increasing motor block in women in early labor.     

Transepithelial paracellular leakiness induced by chronic phorbol ester exposure correlates with polyp-like foci and redistribution of protein kinase C-alpha

Although exposure of LLC-PK1 epithelial cell sheets to phorbol esters (TPA) causes a near immediate and total decrease of transepithelial electrical resistance (TER), continuation of exposure for 3 to 4 days results in a tachyphylactic response as TER begins to return to control levels. Recovery of TER is maximal by 5 to 6 days, but reaches only 70 to 80% of control level. A reciprocal change in the transepithelial flux of D-mannitol indicates that the TER decrease is indicative of an increase in tight junction permeability. Exposure of cell sheets to TPA for several days also results in the appearance of multilayered polyp- like foci (PLFs) across the otherwise one cell layer thick cell sheets. The pattern of penetration of the electron dense dye, ruthenium red, from the apical surface, across the tight junction and into the lateral intercellular space indicates that the tight junctions of the cell sheet become uniformly leaky after acute exposure to TPA. However, when exposure is continued for several days, only the junctions of cells in the PLFs manifest leakiness. The decrease in TER following acute TPA exposure correlates with the translocation of protein kinase C-alpha (PKC alpha) into a membrane-associated compartment. With exposure of several days, only a trace of PKC alpha is visible by Western immunoblot, and this is in the membrane-associated compartment. Immunofluorescent microscopy indicates that the trace of PKC alpha seen in the Western immunoblots is ascribable distinctly to cells of the PLFs. Monolayer areas between PLFs show no discernible immunofluorescent signal. The data therefore indicate that tight junction barrier function may be restored in certain areas by the down regulation of PKC alpha from the membrane-associated compartment. Failure to down regulate may result in the paracellular leakiness and abnormal cell architecture of the PLFs. Possible implications of this model for in vivo epithelial tumor promotion are discussed.