Category Archives: Publications

State-of-the-art monitoring in treatment of dengue shock syndrome: a case series

Moulton SL, Mulligan J, Srikiatkhachorn A, Kalayanarooj S, Grudic GZ, Green S, Gibbons RV, Muniz GW, Hinojosa-Laborde C, Rothman AL, Thomas SJ, Convertino VA

J Med Case Rep. 2016 Aug 24;10(1):233

PMID: 27553703

Abstract

BACKGROUND:

Early recognition and treatment of circulatory volume loss is essential in the clinical management of dengue viral infection. We hypothesized that a novel computational algorithm, originally developed for noninvasive monitoring of blood loss in combat casualties, could: (1) indicate the central volume status of children with dengue during the early stages of “shock”; and (2) track fluid resuscitation status.

METHODS:

Continuous noninvasive photoplethysmographic waveforms were collected over a 5-month period from three children of Thai ethnicity with clinical suspicion of dengue. Waveform data were processed by the algorithm to calculate each child’s Compensatory Reserve Index, where 1 represents supine normovolemia and 0 represents the circulatory volume at which hemodynamic decompensation occurs. Values between 1 and 0 indicate the proportion of reserve remaining before hemodynamic decompensation.

RESULTS:

This case report describes a 7-year-old Thai boy, another 7-year-old Thai boy, and a 9-year-old Thai boy who exhibited signs and symptoms of dengue shock syndrome; all the children had secondary dengue virus infections, documented by serology and reverse transcriptase polymerase chain reaction. The three boys experienced substantial plasma leakage demonstrated by pleural effusion index >25, ascites, and >20 % hemoconcentration. They received fluid administered intravenously; one received a blood transfusion. All three boys showed a significantly low initial Compensatory Reserve Index (≥0.20), indicating a clinical diagnosis of “near shock”. Following 5 days with fluid resuscitation treatment, their Compensatory Reserve Index increased towards “normovolemia” (that is, Compensatory Reserve Index >0.75).

CONCLUSIONS:

The results from these cases demonstrate a new variation in the diagnostic capability to manage patients with dengue shock syndrome. The findings shed new light on a method that can avoid possible adverse effects of shock by noninvasive measurement of a patient’s compensatory reserve rather than standard vital signs or invasive diagnostic methods.

Dynamics of Dengue Virus (DENV)-Specific B Cells in the Response to DENV Serotype 1 Infections, Using Flow Cytometry With Labeled Virions

Woda M, Friberg H, Currier JR, Srikiatkhachorn A, Macareo LR, Green S, Jarman RG, Rothman AL, Mathew A

J Infect Dis. 2016 Oct 1;214(7):1001-9

PMID: 27443614

Abstract

BACKGROUND:

The development of reagents to identify and characterize antigen-specific B cells has been challenging.

METHODS:

We recently developed Alexa Fluor-labeled dengue viruses (AF DENVs) to characterize antigen-specific B cells in the peripheral blood of DENV-immune individuals.

RESULTS:

In this study, we used AF DENV serotype 1 (AF DENV-1) together with AF DENV-2 on peripheral blood mononuclear cells (PBMCs) from children in Thailand with acute primary or secondary DENV-1 infections to analyze the phenotypes of antigen-specific B cells that reflected their exposure or clinical diagnosis. DENV serotype-specific and cross-reactive B cells were identified in PBMCs from all subjects. Frequencies of AF DENV(+) class-switched memory B cells (IgD(-)CD27(+) CD19(+) cells) reached up to 8% during acute infection and early convalescence. AF DENV-labeled B cells expressed high levels of CD27 and CD38 during acute infection, characteristic of plasmablasts, and transitioned into memory B cells (CD38(-)CD27(+)) at the early convalescent time point. There was higher activation of memory B cells early during acute secondary infection, suggesting reactivation from a previous DENV infection.

CONCLUSIONS:

AF DENVs reveal changes in the phenotype of DENV serotype-specific and cross-reactive B cells during and after natural DENV infection and could be useful in analysis of the response to DENV vaccination.

Forty Years of Dengue Surveillance at a Tertiary Pediatric Hospital in Bangkok, Thailand, 1973-2012

Nisalak A, Clapham HE, Kalayanarooj S, Klungthong C, Thaisomboonsuk B, Fernandez S, Reiser J, Srikiatkhachorn A, Macareo LR, Lessler JT, Cummings DA, Yoon IK

Am J Trop Med Hyg. 2016 Jun 1;94(6):1342-7

PMID: 27022151

Abstract

Long-term observational studies can provide valuable insights into overall dengue epidemiology. Here, we present analysis of dengue cases at a pediatric hospital in Bangkok, Thailand, during a 40-year period from 1973 to 2012. Data were analyzed from 25,715 hospitalized patients with laboratory-confirmed dengue virus (DENV) infection. Several long-term trends in dengue disease were identified including an increase in mean age of hospitalized cases from an average of 7-8 years, an increase after 1990 in the proportion of post-primary cases for DENV-1 and DENV-3, and a decrease in the proportion of dengue hemorrhagic fever and dengue shock syndrome cases in primary and post-primary cases over time. Exploratory mechanistic analysis of these observed trends considered changes in diagnostic methods, demography, force of infection, and Japanese encephalitis vaccination as possible explanations. Thailand is an important setting for studying DENV transmission as it has a “mature” dengue epidemiology with a strong surveillance system in place since the early 1970s. We characterized changes in dengue epidemiology over four decades, and possible impact of demographic and other changes in the human population. These results may inform other countries where similar changes in transmission and population demographics may now or may soon be occurring.

Dengue Virus (DENV) Neutralizing Antibody Kinetics in Children After Symptomatic Primary and Postprimary DENV Infection

Clapham HE, Rodriguez-Barraquer I, Azman AS, Althouse BM, Salje H, Gibbons RV, Rothman AL, Jarman RG, Nisalak A, Thaisomboonsuk B, Kalayanarooj S, Nimmannitya S, Vaughn DW, Green S, Yoon IK, Cummings DA

J. Infect. Dis. 2016 May;213(9):1428-35

PMID: 26704615

Abstract

The immune response to dengue virus (DENV) infection is complex and not fully understood. Using longitudinal data from 181 children with dengue in Thailand who were followed for up to 3 years, we describe neutralizing antibody kinetics following symptomatic DENV infection. We observed that antibody titers varied by serotype, homotypic vs heterotypic responses, and primary versus postprimary infections. The rates of change in antibody titers over time varied between primary and postprimary responses. For primary infections, titers increased from convalescence to 6 months. By comparing homotypic and heterotypic antibody titers, we saw an increase in type specificity from convalescence to 6 months for primary DENV3 infections but not primary DENV1 infections. In postprimary cases, there was a decrease in titers from convalescence up until 6 months after infection. Beginning 1 year after both primary and postprimary infections, there was evidence of increasing antibody titers, with greater increases in children with lower titers, suggesting that antibody titers were boosted due to infection and that higher levels of neutralizing antibody may be more likely to confer a sterilizing immune response. These findings may help to model virus transmission dynamics and provide baseline data to support the development of vaccines and therapeutics.

Interaction of a dengue virus NS1-derived peptide with the inhibitory receptor KIR3DL1 on natural killer cells

Townsley E, O’Connor G, Cosgrove C, Woda M, Co M, Thomas SJ, Kalayanarooj S, Yoon IK, Nisalak A, Srikiatkhachorn A, Green S, Stephens HA, Gostick E, Price DA, Carrington M, Alter G, McVicar DW, Rothman AL, Mathew A

Clin. Exp. Immunol. 2016 Mar;183(3):419-30

PMID: 26439909

Abstract

Killer immunoglobulin-like receptors (KIRs) interact with human leucocyte antigen (HLA) class I ligands and play a key role in the regulation and activation of NK cells. The functional importance of KIR-HLA interactions has been demonstrated for a number of chronic viral infections, but to date only a few studies have been performed in the context of acute self-limited viral infections. During our investigation of CD8(+) T cell responses to a conserved HLA-B57-restricted epitope derived from dengue virus (DENV) non-structural protein-1 (NS1), we observed substantial binding of the tetrameric complex to non-T/non-B lymphocytes in peripheral blood mononuclear cells (PBMC) from a long-standing clinical cohort in Thailand. We confirmed binding of the NS1 tetramer to CD56(dim) NK cells, which are known to express KIRs. Using depletion studies and KIR-transfected cell lines, we demonstrated further that the NS1 tetramer bound the inhibitory receptor KIR3DL1. Phenotypical analysis of PBMC from HLA-B57(+) subjects with acute DENV infection revealed marked activation of NS1 tetramer-binding natural killer (NK) cells around the time of defervescence in subjects with severe dengue disease. Collectively, our findings indicate that subsets of NK cells are activated relatively late in the course of acute DENV illness and reveal a possible role for specific KIR-HLA interactions in the modulation of disease outcomes.

Evaluation of Cardiac Involvement in Children with Dengue by Serial Echocardiographic Studies

Kirawittaya T, Yoon IK, Wichit S, Green S, Ennis FA, Gibbons RV, Thomas SJ, Rothman AL, Kalayanarooj S, Srikiatkhachorn A

PLoS Negl Trop Dis 2015 Jul;9(7):e0003943

PMID: 26226658

Abstract

BACKGROUND: Infection with dengue virus results in a wide range of clinical manifestations from dengue fever (DF), a self-limited febrile illness, to dengue hemorrhagic fever (DHF) which is characterized by plasma leakage and bleeding tendency. Although cardiac involvement has been reported in dengue, the incidence and the extent of cardiac involvement are not well defined.

METHODS AND PRINCIPAL FINDINGS: We characterized the incidence and changes in cardiac function in a prospective in-patient cohort of suspected dengue cases by serial echocardiography. Plasma leakage was detected by serial chest and abdominal ultrasonography. Daily cardiac troponin-T levels were measured. One hundred and eighty one dengue cases were enrolled. On the day of enrollment, dengue cases that already developed plasma leakage had lower cardiac index (2695 (127) vs 3188 (75) (L/min/m2), p = .003) and higher left ventricular myocardial performance index (.413 (.021) vs .328 (.026), p = .021) and systemic vascular resistance (2478 (184) vs 1820 (133) (dynes·s/cm5), p = .005) compared to those without plasma leakage. Early diastolic wall motion of the left ventricle was decreased in dengue cases with plasma leakage compared to those without. Decreased left ventricular wall motility was more common in dengue patients compared to non-dengue cases particularly in cases with plasma leakage. Differences in cardiac function between DF and DHF were most pronounced around the time of plasma leakage. Cardiac dysfunction was transient and did not require treatment. Transient elevated troponin-T levels were more common in DHF cases compared to DF (14.5% vs 5%, p = 0.028).

CONCLUSIONS: Transient left ventricular systolic and diastolic dysfunction was common in children hospitalized with dengue and related to severity of plasma leakage. The functional abnormality spontaneously resolved without specific treatment. Cardiac structural changes including myocarditis were uncommon.

Absence of neutralizing antibodies against influenza A/H5N1 virus among children in Kamphaeng Phet, Thailand

Khuntirat B, Love CS, Buddhari D, Heil GL, Gibbons RV, Rothman AL, Srikiatkhachorn A, Gray GC, Yoon IK

J. Clin. Virol. 2015 Aug;69:78-80

PMID: 26209384

Abstract

BACKGROUND: Influenza A/H5N1 actively circulated in Kamphaeng Phet (KPP), Thailand from 2004 to 2006. A prospective longitudinal cohort study of influenza virus infection in 800 adults conducted during 2008-2010 in KPP suggested that subclinical or mild H5N1 infections had occurred among this adult cohort. However, this study was conducted after the peak of H5N1 activity in KPP. Coincidentally, banked serum samples were available from a prospective longitudinal cohort study of primary school children who had undergone active surveillance for febrile illnesses from 2004 to 2007 and lived in the same district of KPP as the adult cohort.

OBJECTIVES: We sought to investigate whether subclinical or mild H5N1 infections had occurred among KPP residents during the peak of H5N1 activity from 2004 to 2006.

STUDY DESIGN: H5N1 microneutralization (MN) assay was performed on banked serum samples from a prospective longitudinal cohort study of primary school children who had undergone active surveillance for febrile illnesses in KPP. Annual blood samples collected from 2004 to 2006 from 251 children were selected based on the criteria that they lived in villages with documented H5N1 infection.

RESULT: No H5N1 neutralizing antibodies were detected in 753 annual blood samples from 251 children.

CONCLUSION: During 2004-2006, very few subclinical or mild H5N1 infections occurred in KPP. Elevated H5N1 MN titers found in the adult cohort in 2008 were likely due to cross-reactivity from other influenza virus subtypes highlighting the complexities in interpreting influenza serological data.

Improving Dengue Virus Capture Rates in Humans and Vectors in Kamphaeng Phet Province, Thailand, Using an Enhanced Spatiotemporal Surveillance Strategy

Thomas SJ, Aldstadt J, Jarman RG, Buddhari D, Yoon IK, Richardson JH, Ponlawat A, Iamsirithaworn S, Scott TW, Rothman AL, Gibbons RV, Lambrechts L, Endy TP

Am. J. Trop. Med. Hyg. 2015 Jul;93(1):24-32

PMID: 25986580

Abstract

Dengue is of public health importance in tropical and sub-tropical regions. Dengue virus (DENV) transmission dynamics was studied in Kamphaeng Phet Province, Thailand, using an enhanced spatiotemporal surveillance of 93 hospitalized subjects with confirmed dengue (initiates) and associated cluster individuals (associates) with entomologic sampling. A total of 438 associates were enrolled from 208 houses with household members with a history of fever, located within a 200-m radius of an initiate case. Of 409 associates, 86 (21%) had laboratory-confirmed DENV infection. A total of 63 (1.8%) of the 3,565 mosquitoes collected were dengue polymerase chain reaction positive (PCR+). There was a significant relationship between spatial proximity to the initiate case and likelihood of detecting DENV from associate cases and Aedes mosquitoes. The viral detection rate from human hosts and mosquito vectors in this study was higher than previously observed by the study team in the same geographic area using different methodologies. We propose that the sampling strategy used in this study could support surveillance of DENV transmission and vector interactions.

Sequential dengue virus infections detected in active and passive surveillance programs in Thailand, 1994-2010

Bhoomiboonchoo P, Nisalak A, Chansatiporn N, Yoon IK, Kalayanarooj S, Thipayamongkolgul M, Endy T, Rothman AL, Green S, Srikiatkhachorn A, Buddhari D, Mammen MP, Gibbons RV

BMC Public Health 2015;15:250

PMID: 25886528

Abstract

BACKGROUND: The effect of prior dengue virus (DENV) exposure on subsequent heterologous infection can be beneficial or detrimental depending on many factors including timing of infection. We sought to evaluate this effect by examining a large database of DENV infections captured by both active and passive surveillance encompassing a wide clinical spectrum of disease.

METHODS: We evaluated datasets from 17 years of hospital-based passive surveillance and nine years of cohort studies, including clinical and subclinical DENV infections, to assess the outcomes of sequential heterologous infections. Chi square or Fisher’s exact test was used to compare proportions of infection outcomes such as disease severity; ANOVA was used for continuous variables. Multivariate logistic regression was used to assess risk factors for infection outcomes.

RESULTS: Of 38,740 DENV infections, two or more infections were detected in 502 individuals; 14 had three infections. The mean ages at the time of the first and second detected infections were 7.6 ± 3.0 and 11.2 ± 3.0 years. The shortest time between sequential infections was 66 days. A longer time interval between sequential infections was associated with dengue hemorrhagic fever (DHF) in the second detected infection (OR 1.3, 95% CI 1.2-1.4). All possible sequential serotype pairs were observed among 201 subjects with DHF at the second detected infection, except DENV-4 followed by DENV-3. Among DENV infections detected in cohort subjects by active study surveillance and subsequent non-study hospital-based passive surveillance, hospitalization at the first detected infection increased the likelihood of hospitalization at the second detected infection.

CONCLUSIONS: Increasing time between sequential DENV infections was associated with greater severity of the second detected infection, supporting the role of heterotypic immunity in both protection and enhancement. Hospitalization was positively associated between the first and second detected infections, suggesting a possible predisposition in some individuals to more severe dengue disease.