Steven Z. Pavletic

Epstein-Barr Virus–Associated Posttransplantation Lymphoproliferative Disorder after High-Dose Immunosuppressive Therapy and Autologous CD34-Selected Hematopoietic Stem Cell Transplantation for Severe Autoimmune Diseases

High-dose immunosuppressive therapy followed by autologous hematopoietic stem cell transplantation (HSCT) is currently being evaluated for the control of severe autoimmune diseases. The addition of antithymocyte globulin (ATG) to high-dose chemoradiotherapy in the high-dose immunosuppressive therapy regimen and CD34 selection of the autologous graft may induce a higher degree of immunosuppression compared with conventional autologous HSCT for malignant diseases. Patients may be at higher risk of transplant-related complications secondary to the immunosuppressed state, including Epstein-Barr virus (EBV)-associated posttransplantation lymphoproliferative disorder (PTLD), but this is an unusual complication after autologous HSCT. Fifty-six patients (median age, 42 years; range, 23-61 years) with either multiple sclerosis (n = 26) or systemic sclerosis (n = 30) have been treated. The median follow-up has been 24 months (range, 2-60 months). Two patients (multiple sclerosis, n = 1; systemic sclerosis, n = 1) had significant reactivations of herpesvirus infections early after HSCT and then developed aggressive EBV-PTLD and died on days +53 and +64. Multiorgan clonal B-cell infiltrates that were EBV positive by molecular studies or immunohistology were identified at both autopsies. Both patients had positive screening skin tests for equine ATG (Atgam) and had been converted to rabbit ATG (Thymoglobulin) from the first dose. Of the other 54 patients, 2 of whom had partial courses of rabbit ATG because of a reaction to the intravenous infusion of equine ATG, only 1 patient had a significant clinical reactivation of a herpesvirus infection (herpes simplex virus 2) early after HSCT, and none developed EBV-PTLD. The T-cell count in the peripheral blood on day 28 was 0/microL in all 4 patients who received rabbit ATG; this was significantly less than in patients who received equine ATG (median, 174/microL; P =.001; Mann-Whitney ranked sum test). Although the numbers are limited, the time course and similarity of the 2 cases of EBV-PTLD and the effect on day 28 T-cell counts support a relationship between the development of EBV-PTLD and the administration of rabbit ATG. The differences between equine and rabbit ATG are not yet clearly defined, and they should not be considered interchangeable in this regimen without further study.

Fluorescence in situ Hybridization Detection of Cytogenetic Abnormalities in B-cell Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma

Routine cytogenetic analysis of B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (B-CLL/SLL) frequently fails to identify an abnormal clone due to the low rate of spontaneous mitoses and poor response to mitogen stimulation. Recent studies utilizing interphase fluorescence in situ hybridization (FISH) suggest that prognostically significant chromosomal abnormalities occur more frequently in B-CLL/SLL than has been previously recognized. The purpose of this study was to compare the chromosomal abnormalities detected by karyotyping and FISH in cases of B-CLL/SLL, and to correlate these with clinical features and survival. Seventy-two cases were studied for chromosome 3, 12 or 18 aneuploidy, and for rearrangements involving 11q13, 11q23, 13q14, 14q32 and 17p13. The median age of the patients was 54 years (range, 30-87 years). Clinical staging of B-CLL patients showed that 70% of the patients were Rai stage 0, 1, or 2, and 30% stage 3 or 4. Karyotyping identified chromosomal abnormalities in 31% of the cases, whereas FISH studies were abnormal in 72% of cases including 64% of the cases with normal karyotypes. The most common abnormalities were deletion 13q14 (46%), trisomy 12 (21%), and 14q32 rearrangements (21%). At diagnosis, patients with trisomy 12 were more likely to have a high LDH (P = 0.04), but no other significant differences in the clinical or laboratory features, Rai stage, or survival were found among patients with normal cytogenetics vs. those with chromosomal abnormalities. Univariate analysis showed that B-symptoms (P = 0.044), anemia (P = 0.0006), absolute lymphocytosis > or = 30,000/mm3 (P = 0.029), and Rai stage 3 or 4 (P = 0.0038) at initial presentation were associated with an increased risk of death, but only Rai stage 3 or 4 (P = 0.0038) was significant in multivariate analysis. Interphase FISH studies improve the cytogenetic diagnosis when performed in conjunction with karyotyping in B-CLL/SLL, but the prognostic relevance of various abnormalities could not be confirmed in this study.

High-dose cyclophosphamide in multiple sclerosis patients undergoing autologous stem cell transplantation

High-dose cyclophosphamide (CTX) is commonly used in preparation for autologous and allogeneic stem cell transplantation. CTX is a pro-drug, which undergoes complex oxidative metabolism with the metabolites being eliminated both renally and hepatically. In the following study, we evaluated the pharmacokinetic characteristics of high-dose CTX in three patients undergoing autologous stem cell transplantation for multiple sclerosis. The plasma concentration-time profiles for CTX and its hydroxy-metabolite were similar in multiple sclerosis patients to those reported in cancer patients undergoing stem cell transplantation. There was an increase in drug clearance after the second CTX dose indicating that the drug induced its own metabolism consistent with reports in other populations receiving high-dose CTX. One of the three patients cleared the drug slowly but this was not associated with greater toxicity. The patient with the slow clearance value and therefore highest drug exposure had stable disability scores at 2 years posttransplant compared with baseline values taken prior to transplantation. In conclusion, in this small case series, there was no indication that CTX metabolism was different than that in other populations undergoing transplantation.