A prospective, randomized study of the use of platelet concentrates irradiated with ultraviolet-B light in patients with hematologic malignancy

BACKGROUND: Irradiation of platelet concentrates (PCs) with ultraviolet-B (UVB) light inactivates the contaminating white cells and might be an alternative to filtration for the prevention of alloimmunization to HLA antigens and subsequent refractoriness to further platelet transfusions in multiply transfused patients with bone marrow failure. STUDY DESIGN AND METHODS: Patients with hematologic malignancy, mainly acute myeloid leukemia, were prospectively assigned in a random manner to receive either UVB-irradiated or control, nonirradiated PCs. All patients were given red cells that were white cell reduced by filtration. Transfusion efficacy and alloimmunization were assessed by means of corrected count increments, requirement for red cells and PCs, and measurement of lymphocyte-reactive antibodies. RESULTS: UVB-irradiated PCs had a clinical efficacy similar to controls as judged by corrected count increments at 1 to 6 and 12 to 24 hours and by the median requirement for red cell and platelet transfusions. Alloimmunization determined by measurements of lymphocyte-reactive antibodies using both conventional and antiglobulin-augmented lymphocytotoxicity techniques was not abolished in recipients of UVB-irradiated PCs (4/30, 13%) but was less than that in controls (5/20, 25%; p = NS). The mean number of platelet transfusion episodes prior to the occurrence of alloimmunization was greater in the control group (27 vs. 10; p = 0.017). CONCLUSION: In this trial, UVB irradiation did not diminish the clinical efficacy of platelet transfusions. There was a small but nonsignificant reduction alloimmunization, but no difference in refractoriness of the two groups was observed. Larger prospective randomized studies are required to confirm these findings and to compare UVB irradiation with white cell reduction.     

Effect of androstenedione administration on the maternal hypothalamo-pituitary-adreno-placental axis in the pregnant rhesus monkey

To assess the interaction among androgens, placenta, and the hypothalamo-pituitary-adrenal axis we studied effects of androstenedione administered intravascularly to the pregnant monkey on maternal plasma CRH, ACTH, dehydroepiandrosterone sulfate (DHEAS), cortisol, and estradiol concentrations. Ten monkeys (128 +/- 3 days gestation; mean +/- SEM) were instrumented under general halothane anesthesia with maternal femoral artery and venous catheters and uterine electromyogram electrodes. At 137-144 days gestation, baseline maternal femoral artery samples for CRH, ACTH, DHEAS, cortisol, and estradiol measurements were taken at 1.5-h intervals for 7 h starting 2 h before darkness. On the following day, a continuous iv androstenedione infusion (0.3 mg/kg.min at 0.25 ml/h) in 10% intralipid was started at 0930 h in four monkeys; the other six animals received vehicle alone at the same rate starting at the same time. Maternal blood sampling was repeated 1 and 3 days after androstenedione or vehicle administration. Maternal plasma CRH, ACTH, DHEAS, cortisol, and estradiol levels were unaffected by intralipid. In contrast, androstenedione infusion produced a sustained increase in maternal plasma estradiol and a sustained fall in maternal plasma ACTH, but did not affect maternal plasma CRH, DHEAS, or cortisol concentrations. These results provide evidence for negative feedback regulation by androgens at the hypothalamo-pituitary-adrenal axis in the pregnant monkey. Lack of inhibition of maternal plasma CRH after androstenedione administration supports differential regulation of hypothalamic and placental CRH by androgens.     

Recombinant subunit vaccines as an approach to study correlates of protection against primate lentivirus infection

Using pathogenic simian immunodeficiency virus (SIV) infection of macaques as a model, we explored the limits of the protective immunity elicited by recombinant subunit vaccines and examined factors that affect their efficacy. Envelope gp 160 vaccines, when used in a live recombinant virus-priming and subunit-protein-boosting regimen, protected macaques against a low-dose, intravenous infection by a cloned homologous virus SIVmne E11S. The same regimen was also effective against intrarectal challenge by the same virus and against intravenous challenge by E11S grown on primary macaque peripheral blood mononuclear cells (PBMC). However, only limited protection was observed against uncloned SIVmne. Priming with live recombinant virus was more effective than immunization with subunit gp 160 alone, indicating a potential advantage of native antigen presentation and the possible role of cell-mediated immunity in protection. Whole gp 160 was more effective than the surface antigen (gp 130), even though both antigens elicited similar levels of neutralizing antibodies. Animals immunized with the core (gag-pol) antigens failed to generate any neutralizing antibody and were all infected following challenge. However, their proviral load was 10-100-fold lower than that of the control animals, indicating that immune mechanisms such as cytotoxic T lymphocytes (CTL) may play a role. Finally, animals immunized with both the core and the envelope antigens generated significant protective immunity, even with relatively low neutralizing antibodies. Taken together, these results indicate that multiple mechanisms may contribute to protection. It may therefore be advantageous to incorporate multiple antigens in the design of recombinant subunit vaccines against acquired immunodeficiency syndrome (AIDS).     

The murine IL-13 receptor alpha 2: molecular cloning, characterization, and comparison with murine IL-13 receptor alpha 1

Two components of a receptor complex for IL-13, the IL-4R and a low affinity IL-13-binding chain, IL-13R alpha 1, have been cloned in mice and humans. An additional high affinity binding chain for IL-13, IL-13R alpha 2, has been described in humans. We isolated a cDNA from the thymus that encodes the murine orthologue of the human IL-13R alpha 2. The predicted protein sequence of murine IL-13R alpha 2 (mIL-13R alpha 2) has 59% overall identity to human IL-13R alpha 2 and is closely related to the murine low affinity IL-13-binding subunit, IL-13R alpha 1. The genes for both mIL-13-binding chains map to the X chromosome. A specific interaction between mIL-13R alpha 2.Fc protein and IL-13 was demonstrated by surface plasmon resonance using a BIACORE instrument. Ba/F3 cells that were transfected with mIL-13R alpha 2 expressed 5000 molecules per cell and bound IL-13 with a single Kd of 0.5 to 1.2 nM. However, these cells did not proliferate in response to IL-13, and the IL-4 dose response was unaffected by high concentrations of IL-13. In contrast, the expression of mIL-13R alpha 1 by Ba/F3 cells resulted in a sensitive proliferative response to IL-13. Consistent with its lower affinity for IL-13, IL-13R alpha 1.Fc was 100-fold less effective than IL-13R alpha 2.Fc in neutralizing IL-13 in vitro. These results show that mIL-13R alpha 2 and mIL-13R alpha 1 are not functionally equivalent and predict distinct roles for each polypeptide in IL-13R complex formation and in the modulation of IL-13 signal transduction.     

Medical management of iatrogenic rents in the wall of the feline urinary bladder

Surgical closure may not be necessary to successfully manage all patients with ruptured urinary bladders. If the margins of the walls of tears in the bladder wall are not devitalized, and if they remain in close apposition via maintenance of the bladder lumen in a nondistended state for an appropriate period, these conditions may simulate those created by use of surgical sutures. This is not advocating an all-or-none choice. Because the clinical status of patients with ruptured urinary bladders can range from that characterized by only hematuria and dysuria to life-threatening postrenal uremia, a range of surgical and medical options should be considered.     

Activation of human complement by totally human monoclonal antibodies

A uniquely developed series of totally human monoclonal antibodies (mAbs) were examined for their complement fixing properties in comparison to human myeloma preparations and to commercially available human polyclonal immunoglobulins. C3b and C4b deposition was measured using a kinetic ELISA technique. When the IgG myeloma proteins were tested for classical pathway activation, our findings were similar to those previously described, where IgG1 and IgG3 were more potent activators of the classical pathway than IgG2 and IgG4. However, those same studies determined that IgG2 was the best activator of the alternative pathway followed by IgG1 and IgG3 while IgG4 does not activate complement via either pathway. In our studies of alternative pathway activation, the IgG2 myeloma exhibited strong activation of the alternative pathway, but, at levels lower than the other three IgG subtypes. Using this test system, we examined the complement activating potential of four totally human mAbs that were constructed from the peripheral blood lymphocytes of a colon carcinoma patient in long term remission. We found that our uniquely constructed totally human IgG2 mAbs (A3, E1, F6 and F8) were able to activate complement by both the classical and alternative pathways to varying degrees. In addition, we found that the complement activating ability of the human mAbs was greater than that of the human IgG2 myeloma immunoglobulins or normal human IgG2 preparations. This study represents the first report of complement activation by totally human mAbs and confirms more recent findings which indicate that levels of complement activation by human IgG immunoglobulins cannot be predicted based solely on their subclass identity.