The objectives of the study are to evaluate whether quantitative NS1 antigen and IgM/IgG antibody titres predict clinical severity in paediatric dengue and to determine whether the IgM/IgG ratio reliably differentiates primary from secondary infection. A 1-year cross-sectional study was conducted at a tertiary care centre in South India, enrolling children aged 1 month to 18 years with laboratory-confirmed dengue. Quantitative NS1 antigen, IgM, and IgG titres were measured at point-of-care and correlated with clinical outcomes. Severity indices included bleeding manifestations, third spacing, thrombocytopenia, hepatic and renal involvement, shock, and duration of hospitalization. Statistical analysis was performed using chi-square and Mann–Whitney U tests, with receiver operating characteristic (ROC) and area under the ROC curve (AUROC) analyses using IBM SPSS version 29. High NS1 titres (60–100 and ≥ 100) were significantly associated with bleeding, renal dysfunction, elevated SGOT, haemoconcentration, and thrombocytopenia. IgM titres < 4 correlated strongly with third spacing (82.1%, p = 0.019), while IgG titres ≥ 35 predicted third spacing (75%), thrombocytopenia, and elevated transaminases. An IgM/IgG ratio < 0.85 differentiated secondary dengue with superior sensitivity and specificity compared with higher cutoffs (AUROC 0.793). Infantile dengue demonstrated greater severity, with hypoalbuminemia (62%) and central nervous system involvement (25%), despite lower NS1 detection rates, and showed reversal of the typical SGOT > SGPT pattern. Conclusion: Quantitative NS1 antigen and IgM/IgG antibody titres provide early severity-predictive information in paediatric dengue. An IgM/IgG ratio < 0.85 reliably identifies secondary infection. Incorporating these markers into routine clinical evaluation may enhance early risk stratification, particularly in resource-limited settings. <Table Float="No" ID="Taba"> <tgroup cols="2"> <colspec align="left" colname="c1" colnum="1" /> <colspec align="left" colname="c2" colnum="2" /> <tbody> <row> <entry nameend="c2" namest="c1"> What is Known: • NS1 antigen and IgM/IgG antibody titters are widely used for diagnosis, and IgM/IgG ratio is commonly used to classify primary versus secondary dengue. • Dengue severity is higher in secondary infection and is usually assessed using haemoconcentration, thrombocytopenia, and clinical warning signs which often appear late. </entry> </row> <row> <entry nameend="c2" namest="c1"> What is New: • Quantitative titters—High NS1 and low IgM antibody titres predict paediatric dengue severity early, allowing identification of high-risk children at presentation. • Infants show lower NS1 titters but higher severity; IgG titres in secondary dengue do not correlate with day of illness; an IgM/IgG ratio < 0.85 outperforms higher cutoffs (1.59) in identifying secondary dengue. </entry> </row> </tbody> </tgroup> </Table>

Predictive value of quantitative NS1 antigen, IgM and IgG antibody titres in assessing dengue severity in children

期刊论文
发表日期：

2026年4月28日

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Padma Priya K.H.,
Preetha Gerin,
Vasanthi Thiruvengadam

摘要

The objectives of the study are to evaluate whether quantitative NS1 antigen and IgM/IgG antibody titres predict clinical severity in paediatric dengue and to determine whether the IgM/IgG ratio reliably differentiates primary from secondary infection. A 1-year cross-sectional study was conducted at a tertiary care centre in South India, enrolling children aged 1 month to 18 years with laboratory-confirmed dengue. Quantitative NS1 antigen, IgM, and IgG titres were measured at point-of-care and correlated with clinical outcomes. Severity indices included bleeding manifestations, third spacing, thrombocytopenia, hepatic and renal involvement, shock, and duration of hospitalization. Statistical analysis was performed using chi-square and Mann–Whitney U tests, with receiver operating characteristic (ROC) and area under the ROC curve (AUROC) analyses using IBM SPSS version 29. High NS1 titres (60–100 and ≥ 100) were significantly associated with bleeding, renal dysfunction, elevated SGOT, haemoconcentration, and thrombocytopenia. IgM titres < 4 correlated strongly with third spacing (82.1%, p = 0.019), while IgG titres ≥ 35 predicted third spacing (75%), thrombocytopenia, and elevated transaminases. An IgM/IgG ratio < 0.85 differentiated secondary dengue with superior sensitivity and specificity compared with higher cutoffs (AUROC 0.793). Infantile dengue demonstrated greater severity, with hypoalbuminemia (62%) and central nervous system involvement (25%), despite lower NS1 detection rates, and showed reversal of the typical SGOT > SGPT pattern.

Conclusion: Quantitative NS1 antigen and IgM/IgG antibody titres provide early severity-predictive information in paediatric dengue. An IgM/IgG ratio < 0.85 reliably identifies secondary infection. Incorporating these markers into routine clinical evaluation may enhance early risk stratification, particularly in resource-limited settings.

What is Known:

• NS1 antigen and IgM/IgG antibody titters are widely used for diagnosis, and IgM/IgG ratio is commonly used to classify primary versus secondary dengue.

• Dengue severity is higher in secondary infection and is usually assessed using haemoconcentration, thrombocytopenia, and clinical warning signs which often appear late.

What is New:

• Quantitative titters—High NS1 and low IgM antibody titres predict paediatric dengue severity early, allowing identification of high-risk children at presentation.

• Infants show lower NS1 titters but higher severity; IgG titres in secondary dengue do not correlate with day of illness; an IgM/IgG ratio < 0.85 outperforms higher cutoffs (1.59) in identifying secondary dengue.