Three cases of primary cerebral lymphoma in AIDS patients: detection of Epstein-Barr virus by in situ hybridization and Southern blot technique.

Three cases of primary cerebral lymphoma in acquired immunodeficiency syndrome were studied. Tumoral fragments taken at autopsy were frozen and studied by the Southern blot technique (SBT). Other tumoral fragments were fixed in formalin, embedded in paraffin and used for in situ hybridization (ISH) with biotinylated probes for DNA of Epstein-Barr virus (EBV). ISH was positive in each case with a spotty nuclear labelling of certain tumoral cells. SBT evidenced a clonal rearrangement of the immunoglobulin heavy chain gene in each case. In addition, EBV DNA was detected in each frozen fragment with only one restriction pattern, indicating that the EBV- infected cell population was a clonal expansion of a progenitor cell.