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Reed RG, Hillmann AR, Nation M, Braksator S, Sigler K. Remote dried blood spot collection for inflammatory markers in older adults is feasible, reliable, and valid. Brain Behav Immun 2024; 120:545-553. [PMID: 38971206 DOI: 10.1016/j.bbi.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 05/24/2024] [Accepted: 07/03/2024] [Indexed: 07/08/2024] Open
Abstract
Dried blood spots (DBS) provide a minimally invasive method to assess inflammatory markers and can be collected remotely at-home or in-person in the lab. However, there is a lack of methodological information comparing these different collection methods and in older adults. We investigated the feasibility (including adherence, yield, quality, and participant preferences) and measurement properties (reliability, validity) of remotely collected DBS inflammatory markers in older adults. Participants (N = 167, mean age = 72, range: 60-96 years) collected their own DBS (finger prick on filter paper) during three remote interviews over ∼ 6 months. Within 4-5 days on average of their last remote interview, a subset of 41 participants also attended an in-person lab visit that included a researcher-collected DBS sample, venous blood draw, and survey to assess participant preferences of DBS collection. DBS and venous blood were assayed for CRP, IL-6, and TNF-α. Adherence: 98% of expected DBS samples (493 out of 501) were completed and mailed back to the lab. Yield: 97% of DBS samples were sufficient for all assays. Quality: On average, 0.80 fewer optimal spots (60uL of blood that filled the entire circle) were obtained remotely vs. in-person (p = 0.013), but the number of useable or better spots (at least 30-40uL of blood) did not differ (p = 0.89). Preference: A slight majority of participants (54%) preferred in-person DBS collection. Reliability: DBS test-retest reliabilities were good: CRP (ICC = 0.74), IL-6 (ICC = 0.76), and TNF-α (ICC = 0.70). Validity: Inflammatory levels from DBS correlated strongly with levels from venous blood (r = 0.60-0.99) and correlated as expected with sociodemographic and physical health and function variables. Older adults can remotely collect their own DBS to acquire reliable and valid inflammatory data. Remote DBS collection is highly feasible and may allow for inflammatory markers to be assessed in larger, more representative samples than are possible with lab- or clinic-based research designs.
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Affiliation(s)
- Rebecca G Reed
- Department of Psychology, University of Pittsburgh, PA, United States.
| | - Abby R Hillmann
- Department of Psychology, University of Pittsburgh, PA, United States
| | - Maegan Nation
- Department of Psychology, University of Nevada, Las Vegas, NV, United States
| | - Shay Braksator
- Illinois School of Professional Psychology, Chicago, IL, United States
| | - Kirby Sigler
- Department of Psychology, University of Pittsburgh, PA, United States
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Hergott DEB, Owalla TJ, Staubus WJ, Seilie AM, Chavtur C, Balkus JE, Apio B, Lema J, Cemeri B, Akileng A, Chang M, Egwang TG, Murphy SC. Assessing the daily natural history of asymptomatic Plasmodium infections in adults and older children in Katakwi, Uganda: a longitudinal cohort study. THE LANCET. MICROBE 2024; 5:e72-e80. [PMID: 38185134 PMCID: PMC10790327 DOI: 10.1016/s2666-5247(23)00262-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 08/13/2023] [Accepted: 08/16/2023] [Indexed: 01/09/2024]
Abstract
BACKGROUND Low-density asymptomatic Plasmodium infections are prevalent in endemic areas, but little is known about their natural history. The trajectories of these infections and their propensity to fluctuate to undetectable densities can affect detection in clinical trials and field studies. We aimed to classify the natural history of these infections in a high transmission area over 29 days. METHODS In this longitudinal cohort study, we enrolled healthy, malaria-asymptomatic, afebrile, adults (age 18-59 years) and older children (age 8-17 years) in Katakwi District, Uganda, who were negative for Plasmodium infection on rapid diagnostic tests. Participants were instructed to self-collect one dried blood spot (DBS) per day for a maximum of 29 days. We excluded people if they were pregnant or taking antimalarials. During weekly clinic visits, staff collected a DBS and a 4 mL sample of venous blood. We analysed DBSs by Plasmodium 18S rRNA quantitative RT-PCR (qRT-PCR). We classified DBS by infection type as negative, P falciparum, non-P falciparum, or mixed. We plotted infection type over time for each participant and categorised trajectories as negative, new, cleared, chronic, or indeterminate infections. To estimate the effect of single timepoint sampling, we calculated the daily prevalence for each study day and estimated the number of infections that would have been detected in our population if sampling frequency was reduced. FINDINGS Between April 9 and May 20, 2021, 3577 DBSs were collected by 128 (40 male adults, 60 female adults, 12 male children, and 16 female children) study participants. 2287 (64%) DBSs were categorised as negative, 751 (21%) as positive for P falciparum, 507 (14%) as positive for non-P falciparum, and 32 (1%) as mixed infections. Daily Plasmodium prevalence in the population ranged from 45·3% (95% CI 36·6-54·1) at baseline to 30·3% (21·9-38·6) on day 24. 37 (95%) of 39 P falciparum and 35 (85%) of 41 non-P falciparum infections would have been detected with every other day sampling, whereas, with weekly sampling, 35 (90%) P falciparum infections and 31 (76%) non-P falciparum infections would have been detected. INTERPRETATION Parasite dynamics and species are highly variable among low-density asymptomatic Plasmodium infections. Sampling every other day or every 3 days detected a similar proportion of infections as daily sampling, whereas testing once per week or even less frequently could misclassify up to a third of the infections. Even using highly sensitive diagnostics, single timepoint testing might misclassify the true infection status of an individual. FUNDING US National Institutes of Health and Bill and Melinda Gates Foundation.
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Affiliation(s)
- Dianna E B Hergott
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA; Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA
| | - Tonny J Owalla
- Department of Parasitology and Immunology, Med Biotech Laboratories, Kampala, Uganda
| | - Weston J Staubus
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA; Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Annette M Seilie
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA; Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Chris Chavtur
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA; Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Jennifer E Balkus
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA
| | - Bernadette Apio
- Department of Parasitology and Immunology, Med Biotech Laboratories, Kampala, Uganda
| | - Jimmy Lema
- Department of Parasitology and Immunology, Med Biotech Laboratories, Kampala, Uganda
| | - Barbara Cemeri
- Department of Parasitology and Immunology, Med Biotech Laboratories, Kampala, Uganda
| | - Andrew Akileng
- Department of Parasitology and Immunology, Med Biotech Laboratories, Kampala, Uganda
| | - Ming Chang
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA; Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Thomas G Egwang
- Department of Parasitology and Immunology, Med Biotech Laboratories, Kampala, Uganda
| | - Sean C Murphy
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA; Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, USA; Department of Microbiology, University of Washington, Seattle, WA, USA.
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Owalla TJ, Hergott DEB, Seilie AM, Staubus W, Chavtur C, Chang M, Kublin JG, Egwang TG, Murphy SC. Rethinking detection of pre-existing and intervening Plasmodium infections in malaria clinical trials. Front Immunol 2022; 13:1003452. [PMID: 36203582 PMCID: PMC9531235 DOI: 10.3389/fimmu.2022.1003452] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/22/2022] [Indexed: 02/02/2023] Open
Abstract
Pre-existing and intervening low-density Plasmodium infections complicate the conduct of malaria clinical trials. These infections confound infection detection endpoints, and their immunological effects may detract from intended vaccine-induced immune responses. Historically, these infections were often unrecognized since infrequent and often analytically insensitive parasitological testing was performed before and during trials. Molecular diagnostics now permits their detection, but investigators must weigh the cost, complexity, and personnel demands on the study and the laboratory when scheduling such tests. This paper discusses the effect of pre-existing and intervening, low-density Plasmodium infections on malaria vaccine trial endpoints and the current methods employed for their infection detection. We review detection techniques, that until recently, provided a dearth of cost-effective strategies for detecting low density infections. A recently deployed, field-tested, simple, and cost-effective molecular diagnostic strategy for detecting pre-existing and intervening Plasmodium infections from dried blood spots (DBS) in malaria-endemic settings is discussed to inform new clinical trial designs. Strategies that combine sensitive molecular diagnostic techniques with convenient DBS collections and cost-effective pooling strategies may enable more thorough and informative infection monitoring in upcoming malaria clinical trials and epidemiological studies.
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Affiliation(s)
- Tonny J. Owalla
- Department of Immunology and Parasitology, Med Biotech Laboratories, Kampala, Uganda
| | - Dianna E. B. Hergott
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States,Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, United States
| | - Annette M. Seilie
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, United States
| | - Weston Staubus
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, United States
| | - Chris Chavtur
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, United States
| | - Ming Chang
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, United States
| | - James G. Kublin
- Department of Global Health, University of Washington, Seattle, WA, United States,Seattle Malaria Clinical Trials Center, Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States
| | - Thomas G. Egwang
- Department of Immunology and Parasitology, Med Biotech Laboratories, Kampala, Uganda
| | - Sean C. Murphy
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, United States,Seattle Malaria Clinical Trials Center, Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States,Department of Microbiology, University of Washington, Seattle, WA, United States,*Correspondence: Sean C. Murphy,
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