Cytokine Profile of Children Hospitalized with Virologically-Confirmed Dengue during Two Phase III Vaccine Efficacy Trials

Abstract

Background: Two large-scale efficacy studies with the recombinant yellow fever-17D-dengue virus, live-attenuated, tetravalent dengue vaccine (CYD-TDV) candidate undertaken in Asia (NCT01373281) and Latin America (NCT01374516) demonstrated significant protection against dengue disease during two years' active surveillance (active phase). Long-term follow up of participants for breakthrough disease leading to hospitalization is currently ongoing (hospital phase).

Methodology/principal findings: We assessed the cytokine profile in acute sera from selected participants hospitalized (including during the active phase) up to the beginning of the second year of long-term follow up for both studies. The serum concentrations of 38 cytokines were measured in duplicate using the Milliplex Human Cytokine MAGNETIC BEAD Premixed 38 Plex commercial kit (Millipore, Billerica, MA, USA). Partial least squares discriminant analyses did not reveal any difference in the overall cytokine profile of CYD-TDV and placebo recipients hospitalized for breakthrough dengue regardless of stratification used. In addition, there was no difference in the cytokine profile for breakthrough dengue among those aged <9 years versus those aged ≥ 9 years.

Conclusions/significance: These exploratory findings show that CYD-TDV does not induce a particular immune profile versus placebo, corroborating the clinical profile observed.

Conflict of interest statement

I have read the journal's policy and the authors of this manuscript have the following competing interests: All authors are employees of Sanofi Pasteur.

Figures

Fig 1. Differentially expressed cytokines in acute samples as compared to baseline.

Median cytokine values in children at baseline (1 month post-dose 3) (N = 40) and during the acute phase of dengue illness (N = 33) irrespective of treatment group. Upper error bars represent the 75% (Q3) percentile; the lower error bars represent the 25% (Q1) percentile. Cytokines with a significant difference (p

Fig 2. IL-1Ra and MCP-1 levels are significantly different between groups.

Median cytokine values in children during the acute phase of dengue illness in CYD-TDV (N = 99) and placebo (N = 108) recipients. Upper error bars represent the 75% (Q3) percentile; the lower error bars represent the 25% (Q1) percentile. Cytokines with a significant difference (p

Fig 3. IL-1Ra and MCP-1 levels are significantly different between groups in severe cases.

Box and whisker plots of circulating IL-1Ra (left panel) and MCP-1 (right panel) levels during the acute phase of dengue illness in CYD-TDV and placebo recipients: (A) irrespective of severity (CYD-TDV N = 99, Placebo N = 108); (B) in severe cases (CYD-TDV N = 24, Placebo N = 28); and (C) in non-severe cases (CYD-TDV N = 74, Placebo N = 80). The boundary of the box closest to zero indicates the 25th percentile, the line within the box marks the median, and the boundary of the box farthest from zero indicates the 75th percentile. Whiskers (error bars) above and below the box indicate the 90th and 10th percentiles. The individual points represent outliers. Values below the lower limit of quantification were replaced by half of the limit of quantification. Significant differences are indicated by *p

Fig 4. Higher IL-1Ra and IP-10 and lower EGF and sCD40L levels in severe cases.

Box and whisker plots of circulating IL-1Ra (A), EGF (B), sCD40L (C) and IP-10 (D) levels during the acute phase of dengue illness in severe (N = 52 for IL-IRA and EGF, N = 50 for sCD40L and IP-10) and non-severe (N = 154 for IL-IRA and EGF, N = 148 for sCD40L and IP-10) cases irrespective of the treatment group. The boundary of the box closest to zero indicates the 25th percentile, the line within the box marks the median, and the boundary of the box farthest from zero indicates the 75th percentile. Whiskers (error bars) above and below the box indicate the 90th and 10th percentiles. The individual points represent outliers. Values below the lower limit of quantification were replaced by half of the limit of quantification. Significant differences are indicated by *p

Fig 5. Significant differences in IL-10 and MCP-1 levels between groups among

Box and whisker plots of circulating (A) IL-10 and (B) MCP-1 levels during the acute phase of dengue illness in CYD-TDV and placebo recipients in children