Anti-CD20 antibody as consolidation therapy in a patient with primary plasma cell leukemia after high-dose therapy and autologous stem cell transplantation.

In multiple myeloma (MM), circulating malignant B cells are proposed as the proliferative compartment of the disease. In view of the close relationship between multiple myeloma and primary plasma cell leukemia (PCL), an anti-CD20 antibody treatment might also be considered as consolidation for patients with PCL. A 55-year-old patient diagnosed with PCL achieved complete remission after autologous transplantation. A total of four weekly courses of rituximab (375 mg/m(2)) were administered. Prior to antibody therapy, CD20+ cells comprised 22.6% of the mononuclear cells in peripheral blood (PB) assessed by flow cytometry and were enriched by magnetic activated cell sorting (MACS). In the enriched CD20+ fraction, 0.093% clonotypic cells were detected using a quantitative polymerase chain reaction (PCR) assay based on limiting dilutions. The proportion of clonotypic cells was 0.034% in PB and 0.032% in bone marrow (BM). Rituximab depleted CD20+ cells completely in PB and BM. Tumor load in PB and BM at day 40 and in PB at day 70 did not change in comparison to prior to therapy (0.037% in PB, 0.026% in BM). At day 90, the tumor load increased to 0.066% in PB. At day 120, the patient relapsed with 0.65% CD38++/CD138+/CD20- plasma cells and furthermore no CD20+ B cells in PB. The expansion of plasma cells was accompanied by an increase in the tumor load in both compartments (PB: 0.65%, BM: 1.8%). The accumulation of plasma cells during disease progression without the reappearance of CD20+ cells did not sustain the role of circulating clonotypic B cells as proliferative compartment in our patient. However, it cannot be excluded that rituximab was not able to eradicate malignant B cells, which subsequently contributed to relapse.

Persistent polyclonal B-cell lymphocytosis--an important differential diagnosis of B-cell chronic lymphocytic leukemia.

Over the last 17 years, 83 cases of polyclonal B-cell lymphocytosis (PPBL) have been published. This rare hematological disorder of unknown etiology is characterized by morphologically atypical lymphocytes, polyclonal immunoglobulin M production in association with smoking, female gender, and HLA-DR7 phenotype. We studied another male patient with PPBL. In contrast to normal B-cells, PPBL cells showed no response to interleukin-4 with regard to CD23 and human leukocyte antigen-DR expression. F2mu antibodies failed to co-stimulate interleukin-4-mediated CD23 expression. Crosslinking membrane immunoglobulin M receptors by F2mu resulted in elevated human leukocyte antigen-DR expression but did not induce in vitro proliferation of PPBL cells. This indicates a different activation and differentiation status than normal B-cells.

Fluorouracil versus folinic acid/fluorouracil in advanced colorectal cancer--preliminary results of a randomized trial.

Patients with advanced colorectal cancer were randomized to receive either fluorouracil (5-FU) 370 mg/m2 IV days 1 to 5 followed by weekly applications of 5-FU 600 mg/m2 or the same doses of 5-FU preceded by folinic acid 200 mg/m2. Because of toxicity, the weekly 5-FU dose in the combination treatment schedule was reduced to 500 mg/m2 in the course of the study. As of November 1990, 135 patients entered the study; 71 have received combination therapy, and 64 monotherapy. Sixty-three and 59 patients, respectively, are included in the present interim analysis. The two groups are well matched for age, performance status, site of disease, number of metastatic sites, and biochemical parameters. Treatment results are evaluable in 118 patients. Thirty percent receiving combination treatment and 20% receiving monotherapy achieved a complete or partial remission. There is no survival time difference between the groups. However, time to progression is superior in the combination treatment group (median 26 weeks compared with 13 weeks). The main toxicity was diarrhea during the weekly therapy. This was especially true for patients receiving combination treatment before the reduction of 5-FU dosage. In contrast to only four of 56 patients with monotherapy, 14 of 39 with the combination treatment at the initial dosage had severe diarrhea with two treatment-related deaths in this latter group. By reduction of 5-FU dosage during the weekly therapy severe diarrhea could be clearly reduced with only one of 18 patients suffering from diarrhea of World Health Organization grade 3. Other toxicity was usually mild. In conclusion, a prolongation of time to progression could be achieved by combination treatment of folinic acid and 5-FU, which was well tolerated when the weekly dose of 5-FU did not exceed 500 mg/m2.