MORPHOLOGIC BONE-MARROW CHANGES IN PATIENTS WITH POSTTRANSPLANTATION LYMPHOPROLIFERATIVE DISORDERS

The clinical workup of patients with posttransplantation lymphoprolife rative disorders (PTLPDs) frequently involves bone marrow biopsies. Ho wever, little is known about the morphologic bone marrow changes in pa tients with PTLPD. To define the spectrum of morphologic bone marrow c hanges in such patients, we evaluated the bone marrow biopsy samples o f 26 transplant patients with proven extramedullary PTLPD and of 20 tr ansplant patients without PTLPD. Morphologic changes were present in 1 4 of 26 patients with PTLPD (54%) and consisted of aggregates of lymph oid and plasma cells with variable histologic and cytologic features. Cells expressing Epstein-Barr virus-encoded small transcripts (EBER) w ere seen in 9 of 13 bone marrow biopsy samples with morphologic change s and in none of the biopsy samples without morphologic changes. Bone marrow changes were significantly more frequent in patients with PTLPD who were younger than 18 years of age (76%) compared with those who w ere older than 18 years of age (11%). The difference in mortality rate s between the patient groups with and without bone marrow changes was statistically not significant, possibly because of the small sample si ze. The finding that children with PTLPD have an increased incidence o f hone marrow changes supports the notion that Epstein-Barr virus-asso ciated PTLPD involves different pathogenetic mechanisms in pediatric p atients than in adults.