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 kappa and lambda 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 kappa and lambda 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.