Diagnosis and differential diagnosis of progressive lymphoproliferation and malignant lymphoma in persistent active herpesvirus infection.

Persistent active Epstein-Barr virus (EBV) and human herpesvirus-6 (HHV-6) infections may be accompanied by extensive lymphoproliferative reactions mimicking malignant lymphoma. Such atypical polyclonal lymphoproliferations (APL) can frequently be separated from malignant lymphoma only by detailed immunopathologic and virologic studies. Recommended procedures include immunotyping of lymphoid cells, extensive viral serology, in situ hybridization and Southern blotting for viral DNA, gene rearrangement and DNA ploidy studies. Clear separation of APL from malignant lymphoma is essential for therapeutic planning.