Background: The pathogenesis of the severe form of dengue virus infection, dengue hemorrhagic fever, is still obscure. A major research objective has been to determine which body organs are being damaged by dengue virus in this form of dengue. Research has been difficult because dengue hemorrhagic fever is sporadic and tends to occur in parts of the world where modern facilities are scarce and fresh or frozen patient materials are not available. However, major hospitals in these areas have accumulated libraries of paraffin-embedded surgical and autopsy tissues over the years. These tissues may have been subjected to less than optimal fixation and storage. Attempts to localize dengue virus using antigen detection in the stored tissue have encountered many difficulties.
Objective: Since viral nucleic acid may be preserved under circumstances which destroy protein antigens, our objective was to detect dengue viral RNA in situ in histologic sections of tissues from patients dying of dengue hemorrhagic fever in Thailand.
Study design: Tissues from an 11-year-old boy who died at Ramathibodi Hospital, Bangkok, Thailand in November, 1987 with the clinical diagnosis of dengue hemorrhagic fever were treated by transcribing the dengue viral RNA to DNA followed by amplification using the polymerase chain reaction with subsequent in situ hybridization in order to visualize the cells infected with dengue virus.
Results: Viral RNA was detected in hepatocytes in the mid-zonal region of the liver, as well as scattered macrophages in skin and lymph nodes.
Conclusion: Dengue virus infection can be detected in paraffin-embedded autopsy tissues which have been stored for five years. The same procedure can be used for diagnosing dengue viral infection and for studying the pathogenesis of dengue hemorrhagic fever.