Publications

After an inpatient phlebotomy-laboratory test request audit for 2 general inpatient wards identified 5 tests commonly ordered on a recurring basis, a multidisciplinary committee developed a proposal to minimize unnecessary phlebotomies and laboratory tests by reconfiguring the electronic order function to limit phlebotomy-laboratory test requests to occur singly or to recur within one 24-hour window. The proposal was implemented in June 2003. Comparison of fiscal year volume data from before (2002-2003) and after (2003-2004) implementation revealed 72,639 (12.0%) fewer inpatient tests, of which 41,765 (57.5%) were related directly to decreases in the 5 tests frequently ordered on a recurring basis. Because the electronic order function changes did not completely eliminate unnecessary testing, we concluded that the decrease in inpatient testing represented a minimum amount of unnecessary inpatient laboratory tests. We also observed 17,207 (21.4%) fewer inpatient phlebotomies, a decrease sustained in fiscal year 20042005. Labor savings allowed us to redirect phlebotomists to our understaffed outpatient phlebotomy service.

IL-12p40 is induced in macrophages and dendritic cells (DC) after activation by microbial TLR ligands and cytokines and constitutes a component of IL-12 and IL-23. In an effort to understand the location and kinetics of these cytokines during the course of an immune response, we generated knockin (gene-targeted) mice that express the p40 gene linked via a viral internal ribosome entry site element with fluorescent reporters, eYFP or eGFP. Macrophages and DC from these mice faithfully reported biallelic p40 induction using the fluorescent marker. s.c. inoculation with Listeria monocytogenes or LPS led to a rapid, but transient, accumulation of p40-expressing DC in draining lymph nodes, which could be blocked by the addition of pertussis toxin. In situ analysis also revealed the accumulation of IL-12p40 protein around high endothelial venules located in close proximity to p40-expressing DC. Consistent with the in vivo findings, in vitro-activated DC that expressed p40 migrated to draining lymph nodes and promoted Th1 differentiation more efficiently than DC that did not express p40. Accordingly, these mice provide a valuable tool for tracking critical functions of DC in vivo and should bestow a useful reagent for exploring the effector biology of these cells in models of infectious disease, cancer immunity, and vaccine development.

CTL-associated antigen 4 (CTLA-4) engagement negatively regulates T cell activation and function and promotes immune tolerance. However, it has been difficult to explore the biology of selective engagement of CTLA-4 in vivo because CTLA-4 shares its ligands, B7-1 and B7-2, with CD28. To address this issue, we developed a Tg mouse expressing a single-chain, membrane-bound anti-CTLA-4 Ab (scFv) on B cells. B and T cells developed normally and exhibited normal phenotype in the steady state and after activation in these mice. However, B cells from scFv Tg+ mice (scalphaCTLA4+) prevented T cell proliferation and cytokine production in mixed lymphocyte reactions. Additionally, mice treated with scalphaCTLA4+ B cells had decreased T cell-dependent B cell Ab production and class switching in vivo after antigen challenge. Furthermore, expression of this CTLA-4 agonist protected NOD mice from spontaneous autoimmune diabetes. Finally, this disease prevention occurred in Treg-deficient NOD.B7-1/B7-2 double-knockout mice, suggesting that the effect of the CTLA-4 agonist directly attenuates autoreactive T cell activation, not Treg activation. Together, results from this study demonstrate that selective ligation of CTLA-4 attenuates in vivo T cell responses, prevents development of autoimmunity, and represents a novel immunotherapeutic approach for the induction and maintenance of peripheral tolerance.

Liver biopsy has been in use for more than a century for diagnosis and staging of acute and chronic liver diseases. Several serum markers and panels offer the opportunity to assess the extent of liver disease noninvasively and spare some patients the risks associated with percutaneous liver biopsy, but only a few of the noninvasive serum markers allow the determination of different stages of fibrosis on a continuum similar to that achieved with liver biopsy. This article reviews the results of recent published and preliminary studies on serum markers, focusing on their comparison with liver biopsy and their clinical utility.

PURPOSE

We performed a systematic review to define the relative and absolute risk of clinically relevant adverse events with the antiplatelet agents, aspirin and clopidogrel.

MATERIALS AND METHODS

Databases were searched for randomized controlled trials of low-dose aspirin (75-325 mg/day) or clopidogrel administered for cardiovascular prophylaxis. Relative risks (RR) were determined by meta-analysis of 22 trials for aspirin versus placebo and from single studies for aspirin versus clopidogrel, aspirin versus aspirin/clopidogrel, and clopidogrel versus aspirin/clopidogrel. Absolute risk increase was calculated by multiplying RR increase by the pooled weighted incidence of the control.

RESULTS

Aspirin increased the risk of major bleeding (RR=1.71; 95% confidence interval [CI], 1.41-2.08), major gastrointestinal (GI) bleeding (RR=2.07; 95% CI, 1.61-2.66), and intracranial bleeding (RR=1.65; 95% CI, 1.06-5.99) versus placebo. No difference between 75-162.5 mg/day and >162.5-325 mg/day aspirin versus placebo was seen. The absolute annual increases attributable to aspirin were major bleeding: 0.13% (95% CI, 0.08-0.20); major GI bleeding: 0.12% (95% CI, 0.07-0.19), intracranial bleeding: 0.03% (95% CI, 0.01-0.08). No study compared clopidogrel with placebo. One study showed increased major GI bleeding (but not non-GI bleeding endpoints) with aspirin versus clopidogrel (RR=1.45; 95% CI, 1.00-2.10). The absolute annual increase was 0.12% (95% CI, 0.00-0.28).

CONCLUSIONS

Low-dose aspirin increases the risk of major bleeding by approximately 70%, but the absolute increase is modest: 769 patients (95% CI, 500-1250) need to be treated with aspirin to cause one additional major bleeding episode annually. Compared with clopidogrel, aspirin increases the risk of GI bleeding but not other bleeding; however, 883 patients (95% CI, 357-infinity) would need to be treated with clopidogrel versus aspirin to prevent one major GI bleeding episode annually at a cost of over 1 million dollars.

Hepatocellular carcinoma (HCC) is rare in young children. We attempted to see if immunohistochemical and mutational-analysis studies could demonstrate that deficiency of the canalicular bile acid transporter bile salt export pump (BSEP) and mutation in ABCB11, encoding BSEP, underlay progressive familial intrahepatic cholestasis (PFIC)--or "neonatal hepatitis" suggesting PFIC--that was associated with HCC in young children. We studied 11 cases of pediatric HCC in the setting of PFIC or "neonatal hepatitis" suggesting PFIC. Archival liver were retrieved and immunostained for BSEP. Mutational analysis of ABCB11 was performed in leukocyte DNA from available patients and parents. Among the 11 nonrelated children studied aged 13-52 months at diagnosis of HCC, 9 (and a full sibling, with neonatal hepatitis suggesting PFIC, of a tenth from whom liver was not available) had immunohistochemical evidence of BSEP deficiency; the eleventh child did not. Mutations in ABCB11 were demonstrated in all patients with BSEP deficiency in whom leukocyte DNA could be studied (n = 7). These mutations were confirmed in the parents (n = 14). With respect to the other 3 children with BSEP deficiency, mutations in ABCB11 were demonstrated in all 5 parents in whom leukocyte DNA could be studied. Thirteen different mutations were found. In conclusion, PFIC associated with BSEP deficiency represents a previously unrecognized risk for HCC in young children. Immunohistochemical evidence of BSEP deficiency correlates well with demonstrable mutation in ABCB11.