Detection of human herpesvirus-6, Epstein-Barr virus and cytomegalovirus in formalin-fixed tissues from sudden infant death: A study with quantitative real-time PCR

The role of viruses in the context of sudden infant death in early childhood is still unclear, although there are many findings pointing to a viral infection possibly leading to death.

To analyse the prevalence and viral loads of human herpesvirus-6 (HHV-6), Epstein-Barr virus (EBV), and cytomegalovirus (CMV), three viruses that have been previously detected in some cases of sudden death in infants, in tissues from sudden infant death syndrome (SIDS) patients and controls.

Materials and methods
Thirty-nine formalin-fixed paraffin-embedded tissue sections of eleven consecutive cases of SIDS, and thirty-nine formalin-fixed paraffin-embedded tissue sections of nine control cases were analysed by a specific quantitative real-time PCR for the detection of HHV-6, EBV, and CMV.

The comparison of the whole viral DNA prevalence in cases and tissue sections between SIDS and controls showed a statistical significance (72.7% vs. 22.2%, p = 0.025; 41.1% vs. 10.3%, p = 0.001, respectively); in particular, we found a statistical significant difference for the EBV DNA prevalence among cases (p = 0.042) and tissues (p = 0.048), and a statistical significant difference for the HHV-6 DNA prevalence among cases (p = 0.017).

This is one of the first studies using quantitative real-time PCR for virus detection in cases of SIDS, and the results suggest that some herpesvirus infections, and particularly those caused by EBV and HHV-6 could be related with some cases of SIDS. Further studies will be necessary to understand the real significance of these findings in the context of SIDS.