Browsing by Author "Anzala, Omu"

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    CLSI-Derived Hematology and Biochemistry Reference Intervals for Healthy Adults in Eastern and Southern Africa
    (2009-02-06) Karita, Etienne; Ketter, Nzeera; Price, Matt A; Kayitenkore, Kayitesi; Kaleebu, Pontiano; Nanvubya, Annet; Anzala, Omu; Jaoko, Walter; Mutua, Gaudensia; Ruzagira, Eugene; Mulenga, Joseph; Sanders, Eduard J.; Mwangome, Mary; Allen, Susan; Bwanika, Agnes; Bahemuka, Ubaldo; Awuondo, Ken; Omosa, Gloria; Farah, Bashir; Amornkul, Pauli; Birungi, Josephine; Yates, Sarah; Stoll-Johnson, Lisa; Gilmour, Jill; Stevens, Gwynn; Shutes, Erin; Manigart, Olivier; Hughes, Peter; Dally, Len; Scott, Janet; Stevens, Wendy; Fast, Pat; Kamali, Anatoli
    Background: Clinical laboratory reference intervals have not been established in many African countries, and non-local intervals are commonly used in clinical trials to screen and monitor adverse events (AEs) among African participants. Using laboratory reference intervals derived from other populations excludes potential trial volunteers in Africa and makes AE assessment challenging. The objective of this study was to establish clinical laboratory reference intervals for 25 hematology, immunology and biochemistry values among healthy African adults typical of those who might join a clinical trial. Methods and Findings: Equal proportions of men and women were invited to participate in a cross sectional study at seven clinical centers (Kigali, Rwanda; Masaka and Entebbe, Uganda; two in Nairobi and one in Kilifi, Kenya; and Lusaka, Zambia). All laboratories used hematology, immunology and biochemistry analyzers validated by an independent clinical laboratory. Clinical and Laboratory Standards Institute guidelines were followed to create study consensus intervals. For comparison, AE grading criteria published by the U.S. National Institute of Allergy and Infectious Diseases Division of AIDS (DAIDS) and other U.S. reference intervals were used. 2,990 potential volunteers were screened, and 2,105 (1,083 men and 1,022 women) were included in the analysis. While some significant gender and regional differences were observed, creating consensus African study intervals from the complete data was possible for 18 of the 25 analytes. Compared to reference intervals from the U.S., we found lower hematocrit and hemoglobin levels, particularly among women, lower white blood cell and neutrophil counts, and lower amylase. Both genders had elevated eosinophil counts, immunoglobulin G, total and direct bilirubin, lactate dehydrogenase and creatine phosphokinase, the latter being more pronounced among women. When graded against U.S.-derived DAIDS AE grading criteria, we observed 774 (35.3%) volunteers with grade one or higher results; 314 (14.9%) had elevated total bilirubin, and 201 (9.6%) had low neutrophil counts. These otherwise healthy volunteers would be excluded or would require special exemption to participate in many clinical trials. Conclusions: To accelerate clinical trials in Africa, and to improve their scientific validity, locally appropriate reference ranges should be used. This study provides ranges that will inform inclusion criteria and evaluation of adverse events for studies in these regions of Africa.
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    Concordant Proficiency in Measurement of T-Cell Immunity in Human Immunodeficiency Virus Vaccine Clinical Trials by Peripheral Blood Mononuclear Cell and Enzyme-Linked Immunospot Assays in Laboratories from Three Continents
    (Clinical and vaccine immunology, 2009-02) Boaz, Mark J.; Hayes, Peter; Tarragona, Tony; Seamons, Laura; Cooper, Andrew; Birungi, Josephine; Kitandwe, Paul; Semaganda, Aloysius; Kaleebu, Pontiano; Stevens, Gwynneth; Anzala, Omu; Farah, Bashir; Ogola, Simon; Indangasi, Jackton; Mhlanga, Patrick; Eeden, Melanie Van; Thakar, Madhuri; Pujari, Ashwini; Mishra, Shadri; Goonetilleke, Nilu; Moore, Stephen; Mahmoud, Abdul; Sathyamoorthy, Pattabiraman; Mahalingam, Jayashri; Narayanan, Paranji R.; Ramanathan, Vadakkuppattu D.; Cox, Josephine H.; Dally, Len; Gill, Dilbinder K.; Gilmour, Jill
    The gamma interferon (IFN-_) enzyme-linked immunospot (ELISPOT) assay is used routinely to evaluate the potency of human immunodeficiency virus (HIV) vaccine candidates and other vaccine candidates. In order to compare candidates and pool data from multiple trial laboratories, validated standardized methods must be applied across laboratories. Proficiency panels are a key part of a comprehensive quality assurance program to monitor inter- and intralaboratory performance, as well as assay performance, over time. Seven International AIDS Vaccine Initiative-sponsored trial sites participated in the proficiency panels described in this study. At each laboratory, two operators independently processed identical sample sets consisting of frozen peripheral blood mononuclear cell (PBMC) samples from different donors by using four blind stimuli. PBMCM recovery and viability after overnight resting and the IFN-_ ELISPOT assay performance were assessed. All sites demonstrated good performance in PBMC thawing and resting, with a median recovery of 78% and median viability of 95%. The laboratories were able to detect similar antigen-specific T-cell responses, ranging from 50 to >3,000 spot-forming cells per million PBMC. An approximate range of a half log in results from operators within or across sites was seen in comparisons of antigen-specific responses. Consistently low background responses were seen in all laboratories. The results of these proficiency panels demonstrate the ability of seven laboratories, located across three continents, to process PBMC samples and to rank volunteers with differential magnitudes of IFN-_ ELISPOT responses. These findings also illustrate the ability to standardize the IFN-_ ELISPOT assay across multiple laboratories when common training methods, reagents such as fetal calf serum, and standard operating procedures are adopted. These results are encouraging for laboratories that are using cell-based immunology assays to test HIV vaccines and other vaccines.
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    Standardization of cytokine flow cytometry assays
    (BioMed Central Ltd., 2005-06-24) Maecker, Holden T.; Rinfret, Aline; D'Souza, Patricia; Darden, Janice; Roig, Eva; Landry, Claire; Hayes, Peter; Birungi, Josephine; Anzala, Omu; Garcia, Miguel; Harari, Alexandre; Frank, Ian; Baydo, Ruth; Baker, Megan; Holbrook, Jennifer; Ottinger, Janet; Lamoreaux, Laurie; Epling, C. Lorrie; Sinclair, Elizabeth; Suni, Maria A.; Punt, Kara; Calarota, Sandra; El-Bahi, Sophia; Alter, Gailet; Maila, Hazel; Kuta, Ellen; Cox, Josephine; Gray, Clive; Altfeld, Marcus; Nougarede, Nolwenn; Boyer, Jean; Tussey, Lynda; Tobery, Timothy; Bredt, Barry; Roederer, Mario; Koup, Richard; Maino, Vernon C.; Weinhold, Kent; Pantaleo, Giuseppe; Gilmour, Jill; Horton, Helen; Sekaly, Rafick P.
    Background: Cytokine flow cytometry (CFC) or intracellular cytokine staining (ICS) can quantitate antigen-specific T cell responses in settings such as experimental vaccination. Standardization of ICS among laboratories performing vaccine studies would provide a common platform by which to compare the immunogenicity of different vaccine candidates across multiple international organizations conducting clinical trials. As such, a study was carried out among several laboratories involved in HIV clinical trials, to define the inter-lab precision of ICS using various sample types, and using a common protocol for each experiment (see additional files online). Results: Three sample types (activated, fixed, and frozen whole blood; fresh whole blood; and cryopreserved PBMC) were shipped to various sites, where ICS assays using cytomegalovirus (CMV) pp65 peptide mix or control antigens were performed in parallel in 96-well plates. For one experiment, antigens and antibody cocktails were lyophilised into 96-well plates to simplify and standardize the assay setup. Results (CD4+cytokine+ cells and CD8+cytokine+ cells) were determined by each site. Raw data were also sent to a central site for batch analysis with a dynamic gating template. Mean inter-laboratory coefficient of variation (C.V.) ranged from 17–44% depending upon the sample type and analysis method. Cryopreserved peripheral blood mononuclear cells (PBMC) yielded lower inter-lab C.V.'s than whole blood. Centralized analysis (using a dynamic gating template) reduced the inter-lab C.V. by 5–20%, depending upon the experiment. The inter-lab C.V. was lowest (18–24%) for samples with a mean of >0.5% IFNγ + T cells, and highest (57–82%) for samples with a mean of <0.1% IFNγ + cells. Conclusion: ICS assays can be performed by multiple laboratories using a common protocol with good inter-laboratory precision, which improves as the frequency of responding cells increases. Cryopreserved PBMC may yield slightly more consistent results than shipped whole blood. Analysis, particularly gating, is a significant source of variability, and can be reduced by centralized analysis and/or use of a standardized dynamic gating template. Use of pre-aliquoted lyophilized reagents for stimulation and staining can provide further standardization to these assays.