Kim Janatpour

Neuroinvasion of Fluorescein-Positive Monocytes in Acute Simian Immunodeficiency Virus Infection

ABSTRACT Monocytes and macrophages play a central role in the pathogenesis of human immunodeficiency virus (HIV)-associated dementia. They represent prominent targets for HIV infection and are thought to facilitate viral neuroinvasion and neuroinflammatory processes. However, many aspects regarding monocyte brain recruitment in HIV infection remain undefined. The nonhuman primate model of AIDS is uniquely suited for examination of the role of monocytes in the pathogenesis of AIDS-associated encephalitis. Nevertheless, an approach to monitor cell migration from peripheral blood into the central nervous system (CNS) in primates had been lacking. Here, upon autologous transfer of fluorescein dye-labeled leukocytes, we demonstrate the trafficking of dye-positive monocytes into the choroid plexus stromata and perivascular spaces in the cerebra of rhesus macaques acutely infected with simian immunodeficiency virus between days 12 and 14 postinfection (p.i.). Dye-positive cells that had migrated expressed the monocyte activation marker CD16 and the macrophage marker CD68. Monocyte neuroinvasion coincided with the presence of the virus in brain tissue and cerebrospinal fluid and with the induction of the proinflammatory mediators CXCL9/MIG and CCL2/MCP-1 in the CNS. Prior to neuroinfiltration, plasma viral load levels peaked on day 11 p.i. Furthermore, the numbers of peripheral blood monocytes rapidly increased between days 4 and 8 p.i., and circulating monocytes exhibited increased functional capacity to produce CCL2/MCP-1. Our findings demonstrate acute monocyte brain infiltration in an animal model of AIDS. Such studies facilitate future examinations of the migratory profile of CNS-homing monocytes, the role of monocytes in virus import into the brain, and the disruption of blood-cerebrospinal fluid and blood-brain barrier functions in primates.

A comparison of multiplex suspension array large-panel kits for profiling cytokines and chemokines in rheumatoid arthritis patients.

Multiplex analysis allows measurements of a large number of analytes simultaneously in each sample. On the basis of the Luminex multiplex technology (xMAP), kits for measuring multiple cytokines and chemokines (immunomodulators) are commercially available and are useful in investigations on inflammatory diseases. This study evaluated four multiplex kits (Bio‐Plex, LINCOplex, Fluorokine, and Beadlyte) that contained 27, 29, 20, and 22 analytes each, respectively, for the analysis of immunomodulators in plasma of patients with rheumatoid arthritis (RA) who underwent treatment with antibody against CD20 (rituximab), a B‐cell reductive therapy.

Comparing Direct Thrombin Inhibitors Using aPTT, Ecarin Clotting Times, and Thrombin Inhibitor Management Testing

BACKGROUND: Patients with heparin-induced thrombocytopenia and thrombosis may be acutely anticoagulated with direct thrombin inhibitors (DTIs). The anticoagulation is typically monitored using the activated partial thromboplastin time (aPTT) or ecarin clotting time (ECT). OBJECTIVE: To compare 14 methods for measuring aPTT, as well as ECT and thrombin inhibitor management test (TIM), in samples containing DTIs. METHODS: DTIs were added to pooled normal plasma to achieve low (0.1–1.2 μg/mL) and high (1.5–8.0 μg/mL) drug concentrations. Each low-concentration DTI sample was tested using all aPTT reagents, while each low- and high-concentration DTI was tested using the ECT and TIM. RESULTS: All aPTT reagents had a significant dose-dependent correlation with drug concentration. Only Actin FSL and APTT-S demonstrated equivalent aPTT ratios obtained from any DTI. The TAS-aPTT was the most sensitive aPTT reagent to argatroban, with the aPTT ranging from 52.7 to 121.2 seconds corresponding to 0.1 to 1.2 μg/mL of drug concentration. The TAS-aPTT and Pathromtin were the most sensitive aPTT reagents to bivalirudin, with aPTTs of 87.4 seconds and 101.5 seconds, respectively, at 1.2 μg/mL of drug. Pathromtin was the most sensitive aPTT reagent to lepirudin, with a maximum aPTT of 108.9 seconds at 1.2 μg/mL of drug. There was no statistically significant difference between the TIM and ECT clotting times for each DTI. Lepirudin and bivalirudin ECT and TIM clotting times were equivalent. CONCLUSIONS: There are unique differences between reagent manufacturers in the monitoring of DTIs. Acceptable alternatives to aPTT monitoring of DTI anticoagulation include the ECT and TIM.

Usefulness of optical density values from heparin-platelet factor 4 antibody testing and probability scoring models to diagnose heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) is a complication caused by antibodies directed to the heparin-platelet factor 4 (PF4) complex with a seemingly paradoxical high risk of thrombosis. Discontinuation of heparin and administration of an alternative anticoagulant is important in prevention of catastrophic thrombosis. Diagnosis is challenging and based on clinical probability models (Warkentin 4 Ts and Chong scale) and, to a lesser degree, laboratory testing. Enzyme-linked immunosorbent assay (ELISA) measurement of heparin-PF4 antibodies is commonly used but has low predictive values for thrombosis. We analyzed 105 cases of suspected HIT and compared optical density values and the Warkentin 4 Ts for sensitivity, specificity, positive predictive value, and negative predictive value (NPV). The predictive value of ELISA alone was inferior to the Warkentin 4 Ts score. The sensitivity and NPV of the clinical score was improved by incorporating ELISA results. The combination of a negative ELISA result with low probability 4 Ts resulted in an NPV of 94%.

Comparison of X-ray vs. gamma irradiation of CPDA-1 red cells

Background and Objectives  Transfusion‐associated graft‐versus‐host disease (TA‐GVHD) is a serious, potential complication of blood transfusion that is essentially prevented by blood product irradiation. Blood product irradiation is currently performed using gamma irradiation. X‐ray irradiation is an alternative that has certain advantages: an X‐ray irradiator is less expensive and does not have a radioactive source. However, the biochemical effects of X‐ray irradiation on red blood cells (RBCs) have not been well characterized. The primary purpose of our study was to compare the effects of X‐ray irradiation with gamma irradiation on RBC membrane permeability. A secondary purpose was to verify that X‐ray irradiation has the same effect on lymphocytes as gamma irradiation.

Visual assessment of hemolysis in red blood cell units and segments can be deceptive

BACKGROUND:  Blood components that appear hemo‐lyzed are discarded. However, visual inspection is subjec‐tive and criteria for excessive hemolysis are poorly defined.

Multiplexed measurements of immunomodulator levels in peripheral blood of healthy subjects: Effects of analytical variables based on anticoagulants, age, and gender.

Multiplex microbead immunoassay (MMIA) is a powerful technology for a wide range of biomedical and clinical applications. It is important to study the normal concentration ranges of immunomodulators under different sample preparation conditions and age groups of subjects in order to more precisely determine their reference values for use in assessing alterations of their levels in disease. The aim of this study was to determine the plasma concentrations of immunomodulators (cytokines, chemokines, and growth factors) in the peripheral blood from healthy subjects by the use of a large multiplex panel, and to determine the effects of different anticoagulants, age, and gender on the immunomodulator levels. In addition, the assay precision for these biomarker analytes was determined. Plasma samples from 107 healthy subjects, aged 18 to 85 years, were collected in three different anticoagulants (sodium citrate, EDTA, Heparin); corresponding serum samples were also obtained. Multiplex microbead immunoassays were performed for measuring a total of 23 analytes including chemokines, cytokines, and growth factors (IL‐1β, IL‐1ra, IL‐2, IL‐6, IL‐7, IL‐8, IL‐12 p70, IL‐17, IFN‐γ, IP‐10, MCP‐1, PDGF‐BB, RANTES, TNF‐α, IL‐1a, IL‐16, HGF, MIG, TNF‐β, PDGF‐ABBB, EGF, Flt‐3 Ligand, VEGF). For these analytes, our results showed that the anticoagulant affected the concentration measurements and the coefficients of variation. However, the relative levels of the analytes (profiles) of samples collected in a particular anticoagulant are consistent. The analytes IL‐1β, IL‐7, Flt‐3 Ligand, and IL‐12p70 show the largest variation (up to fourfold) between the age groups. In addition, no statistically significant differences in the level of the analytes were found between the sexes.

Platelet function abnormalities in qualified whole‐blood donors: effects of medication and recent food intake

Background and Objectives  Platelet function abnormalities have been reported in blood donors who have not consumed aspirin. Our objective was to identify factors other than aspirin that may contribute to impaired platelet function in qualified volunteer blood donors.

Variability of Plasma Anti-Xa Activities with Different Lots of Enoxaparin

BACKGROUND Previous studies have indicated the variability of anti-Xa activity in different sources of heparin and the variability of different methods used for measuring anti-Xa activity. Manufacturers of low-molecular-weight heparins (LMWHs) determine each lots anti-Xa activity against the World Health Organization standard, but little information is known about anti-Xa activity variation between lots of LMWH and the impact on reported anti-Xa activity in patient samples. OBJECTIVE To determine the variation of plasma anti-Xa activity in patients receiving enoxaparin when different lots of enoxaparin are used for test calibration. METHODS We obtained 7 lots of enoxaparin containing approximately 10 000 IU/mL and one lot containing approximately 15 000 IU/mL of anti-Xa activity. For each lot, a 2.0 anti-Xa IU/mL dilution was prepared and a calibration curve performed using a chromogenic method. To test the variation in reported results between the different calibration lots, 20 patient samples were tested. Nineteen patients receiving enoxaparin and one patient not receiving enoxaparin (negative control) were tested in a blinded fashion, and the changes in light absorbance recorded. Anti-Xa activity results from tested plasmas were then extrapolated from each enoxaparin lot calibration curve. RESULTS Using Students paired t-test, there were statistically significant differences between the plasma anti-Xa activities generated from the various enoxaparin lots. In the range of 0.5–1.0 IU/mL of anti-Xa activity, 3 (4.2%) samples had a >0.2 IU/mL difference (maximum difference 0.33 IU/mL) in anti-Xa activity between 2 lots of enoxaparin. For samples that had supratherapeutic anti-Xa activities (1.0–1.5 IU/mL anti-Xa activity), there was a wider variation (>0.2 IU/mL) in anti-Xa activity, which may have resulted in a dosing change. CONCLUSIONS The statistical differences in plasma anti-Xa activities noted between enoxaparin lots are not clinically significant. However, anti-Xa activities in the upper therapeutic and supratherapeutic ranges (>1.0 IU/mL of anti-Xa activity) resulted in a deviation of >0.3 IU/mL in reported anti-Xa activity, which may result in dosing changes.

Does donating blood for the first time during a national emergency create a better commitment to donating again

Background and Objectives  Emergency situations often elicit a generous response from the public. This occurred after attacks on the US on September 11, 2001 when many new blood donors lined up to donate. This study was performed to compare return rates for first time donors (FTD) after September 11th, 2001 to FTD during a comparable period in 2000.