Immunohistochemical analysis and Epstein-Barr virus in the tonsils of transplant recipients and healthy controls

Objective: To compare lymphocyte immunohistochemical markers and staining for Epstein-Barr virus (EBV) in tonsillectomy specimens from healthy children and pediatric transplant recipients. Design: Analysis of pathology specimens. Setting: Tertiary care medical center. Patients: Consecutive sample of tonsillectomy specimens from 60 pediatric solid organ transplant recipients and 60 healthy children. Intervention: Immunohistochemical staining of tonsillectomy specimens for κ and λ light chains, B and T lymphocytes, EBV-encoded small nuclear RNA (EBV-EBER), and EBV-encoded latent membrane protein (EBV-LMP). Main Outcome Measure: Detection of a difference in EBV activity in transplant recipients vs healthy controls. Results: There was 1 case of posttransplantation lymphoproliferative disorder (PTLD). All other tonsillectomy specimens from both groups demonstrated follicular hyperplasia. Tonsillectomy specimens from both groups were polyclonal, expressing κ and λ light-chain activity, including the case of PTLD. The number of specimens staining positive for CD3 activity, a marker of T lymphocytes, was reduced in the transplant group (85%), compared with 100% in the control group (P<.01). EBV-EBER is a nuclear stain indicating active EBV infection, whereas EBV-LMP staining denotes latent infection. Twenty-seven of 60 transplant specimens (45%) demonstrated EBV-EBER activity compared with 0 of 60 control specimens (P<.001). EBV-LMP activity was equal in both groups. Conclusions: Adenotonsillar hypertrophy in transplant recipients with no prior exposure to EBV may be a sign of active EBV infection. A high incidence of EBV-EBER was found in the tonsils of transplant recipients. Active adenotonsillar EBV infection in the setting of T-lymphocyte suppression in transplant recipients may be a potential early precursor of PTLD.