No abstract

Umbilical cord blood (UCB) stem cells from related and unrelated allogeneic donors have emerged as novel treatment for patients with hematologic malignancies. The incidence and severity of acute graft-versus-host disease (GVHD) after UCB transplantation compares favorably with that observed in recipients of matched unrelated donor allogeneic grafts, but remains a major cause of morbidity and mortality. It has been shown that stimulated lymphocytes from UCB have reduced production of cytokines including interferon-γ (IFN-γ) and tumor necrosis factor- (TNF-), which play a role in GVHD pathophysiology. We investigated the molecular mechanisms underlying this reduced cytokine production by analyzing expression of nuclear factor of activated T cells-1 (NFAT1) in UCB T cells. We detected no constitutive expression of NFAT1 protein in unstimulated UCB T cells compared with adult T cells. Moreover, although NFAT1 expression in UCB T cells was upregulated after prolonged (40 hours) T-cell stimulation, it was only partially upregulated when compared with adult controls. Our observation of minimal NFAT1 expression after stimulation correlated with reduced cytoplasmic IFN-γ and TNF- production in UCB T cells studied simultaneously. Reduced NFAT1 expression may blunt amplification of donor UCB T-cell alloresponsiveness against recipient antigens, thereby potentially limiting GVHD incidence and severity after allogeneic UCB transplantation.

Summary Acute chest syndrome (ACS) is defined as fever, respiratory symptoms and a new pulmonary infiltrate in an individual with sickle cell disease (SCD). Nearly half of ACS episodes occur in SCD patients already hospitalized, potentially permitting pre‐emptive therapy in high‐risk patients. Simple transfusion of red blood cells may abort ACS if given to patients hospitalized for pain who develop fever and elevated levels of secretory phospholipase A2 (sPLA2). In a feasibility study (PROACTIVE; http:\\ClinicalTrials.gov NCT00951808), patients hospitalized for pain who developed fever and elevated sPLA2 were eligible for randomization to transfusion or observation; all others were enrolled in an observational arm. Of 237 enrolled, only 10 were randomized; one of the four to receive transfusion had delayed treatment. Of 233 subjects receiving standard care, 22 developed ACS. A threshold level of sPLA2 ≥ 48 ng/ml gave optimal sensitivity (73%), specificity (71%) and accuracy (71%), but a positive predictive value of only 24%. The predictive value of sPLA2 was improved in adults and patients with chest or back pain, lower haemoglobin concentration and higher white blood cell counts, and in those receiving less than two‐thirds maintenance fluids. The hurdles identified in PROACTIVE should facilitate design of a larger, definitive, phase 3 randomized controlled trial.

CD45 is the major protein tyrosine phosphatase receptor on T cell surfaces that functions as both a positive and a negative regulator of T cell receptor (TCR) signaling. Although CD45 is required for the activation of TCR-associated Src family kinases, it also dephosphorylates phosphoproteins involved in the TCR-signaling cascade. This study links CD45 to the inhibitory activity of placental protein 14 (PP14), a major soluble protein of pregnancy that is now known to be a direct modulator of T cells and to function by desensitizing TCR signaling. PP14 and CD45 co-capped with each other, pointing to a physical linkage between the two. Interestingly, however, the binding of PP14 to T cell surfaces was not restricted to CD45 alone, with evidence showing that PP14 binds to other surface molecules in a carbohydratedependent fashion. Notwithstanding the broader molecular binding potential of PP14, its interaction with CD45 appeared to have special functional significance. Using transfected derivatives of the HPB.ALL mutant T cell line that differ in CD45 expression, we established that the inhibitory effects of PP14 are dependent upon the expression of intact CD45 on T cell surfaces. Based upon these findings, we propose a new immunoregulatory model for PP14, wherein one of its surface molecular targets, CD45, mediates its T cell inhibitory activity, accounting for the intriguing capacity of PP14 to elevate TCR activation thresholds and thereby down-regulate T cell activation.

Thus, our studies do not support the previous hypothesis that reduced GVHD observed after UCB transplantation is attributable to increased CsA sensitivity of UCB T cells. Rather, reduced UCB T-cell cytokine production and increased AICD may be important cellular mechanisms underlying these favorable rates of GVHD in UCB transplant recipients.

A major state drug abuse initiative, California's Proposition 36 of 2000, mandated that adults convicted of drug possession be offered treatment in lieu of incarceration. While the law expanded public treatment for arrestees, the counties were given discretion in structuring their systems of care and procedures to manage clients. Using data from a study of key informants in eight counties, this article examines local planning to increase drug treatment capacity and manage clients' access to treatment. In both these planning domains, it describes the counties' strategies and concerns, reasons for their differences in approaches, and whether and how this state initiative, which explicitly incorporated treatment objectives into penal drug law, will shift the debate over drug abuse policy toward greater consideration of public health goals.

There were 2 related objectives of this qualitative study focused on caregivers of children with sickle cell disease (SCD): (1) to assess caregiver perspectives on the acceptability and utility of the Psychosocial Assessment Tool (PAT) as a screener of family psychosocial risk in pediatric SCD and (2) to examine caregiver perspectives on psychosocial risk factors, as well as their resiliencies and coping strategies, to help inform possible modifications to the PAT. Caregivers (n ϭ 43) of youth with SCD completed the PAT to assess feasibility of administration and a subset (n ϭ 22) completed a qualitative interview organized around principles of cognitive interviewing for instrument validation. Constant comparative analyses involved coding interviews, organizing coding categories into themes, and systematically reintegrating themes regarding caregiver perspectives. Caregivers had positive reactions to the PAT, including its ability to broadly assess risk factors, potential utility in helping connect families to resources, and the brevity and ease of completion. Caregivers described salient family stressors as well as adaptive coping strategies that generally aligned well with areas assessed by the PAT, and also provided feedback that can help inform modification of the PAT to better fit the SCD population. Families of youth with SCD face significant psychosocial stressors but demonstrate resiliency in using adaptive coping strategies. Study results support the continuing development of the PAT as a family psychosocial risk screener in pediatric SCD that can enhance the delivery of evidence-based care and reduce health disparities.

Human placental protein 14 (PP14), a member of the lipocalin structural superfamily, is an abundant amniotic fluid glycoprotein with documented immunoinhibitory activities. While receptors have been characterized for several other lipocalins, none have been reported to date for PP14. In the present study, two-color immunofluorescence and flow cytometry was used to screen peripheral blood mononuclear cell subpopulations for their capacity to engage fluoresceinated recombinant PP14. The tagged PP14 bound strongly in a specific and saturable fashion to CD14 + (monocyte lineage) cells, but not to CD20 + (B cell lineage) or CD3 + (T cell lineage) cells. This binding was both pH-and temperature-sensitive, and was reduced by proteolytic pre-digestion of the cells with trypsin or proteinase K. Scatchard analysis demonstrated a single class of receptors on CD14 + cells, with a K h of V1U10 3V and V10^35 000 receptors per cell. These findings constitute the first report of a cell surfaceassociated binding protein for PP14 and set the stage for exploring the molecular mechanisms of PP14-mediated signaling and immunomodulation.z 1998 Federation of European Biochemical Societies.