Tissue HHV6 and 7 determination in pediatric solid organ recipients--a pilot study

Area of Science:

• Virology
• Transplantation Immunology
• Pediatric Infectious Diseases

Background:

• Human herpesvirus 6 (HHV6) and 7 are common viral infections.
• Blood viral load of HHV6 and 7 is linked to kidney transplant pathology.
• The role of tissue-specific HHV6 and 7 infections in transplantation is poorly understood.

Purpose of the Study:

• To investigate the significance of HHV6 and 7 tissue infections in pediatric solid organ transplant recipients.
• To correlate tissue viral loads with clinical outcomes.
• To compare viral loads in transplant recipients versus native kidneys.

Main Methods:

• Analysis of 18 tissue biopsies (kidney, GI, BAL) from nine pediatric transplant patients.
• Blood HHV6 IgG and IgM testing.
• Semi-quantitative PCR, ELISA, and quantitative methods for tissue HHV6 and 7 detection.
• Study of four native kidney biopsies from children with other kidney diseases.

Main Results:

• 78% of transplant patients were HHV6 IgG positive; 6/9 had positive IgM.
• Only two symptomatic patients with multi-organ failure showed significant tissue HHV6 viral load.
• Significant HHV6 tissue viral load detected in an immunocompromised patient post-febrile illness.
• HHV7 DNA detected alongside HHV6 in one patient.
• Significant tissue HHV6 loads found in ill organ recipients and native kidneys.

Conclusions:

• Significant HHV6 tissue viral loads are associated with severe illness in organ transplant recipients.
• Primary HHV6 infection may lead to detectable viral loads in native kidneys.
• These findings highlight the importance of investigating HHV6 and 7 tissue tropism in transplantation.
• Further research using molecular techniques is warranted to understand HHV6 and 7 roles.