B cell lymphoproliferative disorders following hematopoietic stem cell transplantation: risk factors, treatment and outcome

Twenty-six cases of B cell lymphoproliferative disorder (BLPD) were identified among 2395 patients following hematopoietic stem cell transplants (HSCT) for which an overall incidence of BLPD was 1.2%. The true incidence was probably higher, since 9/26 of the diagnoses were made at autopsy. No BLPD was observed following autologous HSCT, so risk factor analyses were confined to the 1542 allogeneic HSCT. Factors assessed were HLA-mismatching (greater than or equal to 1 antigen), T cell depletion (TCD), presence of acute GVHD (grades II-IV), donor type (related vs unrelated), age of recipient and donor, and underlying disease. Factors found to be statistically significant included patients transplanted for immune deficiency and CML, donor age greater than or equal to 18 years, TCD, and HLA-mismatching, with recipients of combined TCD and HLA-mismatched grafts having the highest incidence. Factors found to be statistically significant in a multiple regression analysis were TCD, donor age and immune deficiency, although 7/8 of the patients with immunodeficiencies and BLPD received a TCD graft from a haploidentical parent, The overall mortality was 92% (24/26), One patient had a spontaneous remission, but subsequently died >1 year later of chronic GVHD. Thirteen patients received therapy for BLPD, Three patients received lymphocyte infusions without response, The only patients with responses and longterm survival received alpha interferon (alpha IFN). Of seven patients treated with alpha IFN there were four responses tone partial and three complete). These data demonstrate that alpha IFN can be an effective agent against BLPD following HSCT, if a timely diagnosis is made.