Search

Objectives: Acquired thrombotic thrombocytopenic purpura (aTTP) is a rare autoimmune disorder characterized by auto-antibodies to Willebrand factor (vWF) cleaving enzyme (ADAMTS13), resulting in unusually large vWF multimers that lead to platelet aggregation, microthrombi formation and microangiopathic hemolytic anemia. Hemolysis in aTTP is mechanical; thus, direct antiglobulin test (Coombs test) is usually negative. Multiple autoimmune conditions and various auto-antibodies have been described in the context of chronic myelomonocytic leukemia (CMML). In this paper, we describe the first case of CMML with auto-antibodies to ADAMTS13, presenting initially as plasmapheresis-refractory Coombs-positive aTTP. Results: Although our patient was not treated for CMML, a complete remission of aTTP was eventually achieved with rituximab. Conclusion; We propose that aTTP should be in the differential diagnosis of CMML patients with thrombocytopenia and anemia (Coombs positive or not) who develop signs of thrombotic microangiopathy. Further studies are much needed to decipher the immune-mediated processes in CMML.

Objectives: Serum chitotriosidase activity (CHIT1) is a biomarker of macrophage activation with an important role in inflammation-induced tissue remodeling and fibrosis. Macrophages have been described to play a crucial role in regulating pathological erythropoiesis in polycythemia vera (PV). The aim of this study was to evaluate CHIT1 in patients diagnosed with Philadelphia-negative myeloproliferative neoplasms (MPNs)., Methods: Using fluorometric assay, we measured CHIT1 in 28 PV, 27 essential thrombocythemia (ET), 17 primary myelofibrosis (PMF), 19 patients with secondary myelofibrosis and in 25 healthy controls., Results: CHIT1 was significantly higher in PV (p < .001) and post-PV myelofibrosis (MF) transformation (post-PV MF) (p = .020), but not in ET (p = .080), post-ET MF transformation (p = .086), and PMF patients (p = .287), when compared to healthy controls. CHIT1 in PV was positively correlated with hemoglobin (p = .026), hematocrit (p = .012), absolute basophil count (p = .030) and the presence of reticulin fibrosis in the bone marrow (p = .023)., Discussion: A positive correlation between CHIT1 and these distinct laboratory PV features might imply macrophages closely related to clonal erythropoiesis as cells of CHIT1 origin. In addition, a positive association between CHIT1 and reticulin fibrosis might indicate its potential role in PV progression., Conclusion: CHIT1 might be considered as a circulating biomarker in PV. Additional studies are needed to clarify the role of CHIT1 in promoting disease progression and bone marrow fibrosis in PV.

The effects of granulocyte colony-stimulating factor (G-CSF) and engraftment quality on the rate of hematopoietic system recovery were assessed in patients with solid tumors and lymphoproliferative diseases after autologous hematopoietic stem cell ransplantation. Treatment with autologous hematopoietic stem cell transplantation was performed in 40 patients for non- Hodgkin's lymphoma (n= 20), Hodgkin's lymphoma (n= 8), multiple myeloma (n= 8), and breast cancer (n=4). In 20 patients with solid tumors and ymphoproliferative diseases, treatment with autologous hematopoietic stem cell transplantation was followed by G-CSF therapy (experimental group). Another 20 patients with solid tumors and lymphoproliferative diseases were treated with autologous hematopoietic stem cell transplantation without G-CSF therapy (control group). The two patient groups were matched for age, sex, diagnosis, number of chemotherapy courses, and engraftment quality (nucleated cells or CD34+ cells). The experimental group received G-CSF in a dose of 5 μg/kg body weight subcutoneous from day 1 of autologous hematopoietic stem cell transplantation until leukocyte count increase to > 1.0 x 109/L over three consecutive days. Nonparametric tests (x2-test, median test, extended median test) were used in statistical analysis. The hematopoietic system showed rapid recovery. Leukocyte count > 1.0 x 109/L was recorded on median day 11 (range 8-21) in the experimental group vs median day 12 (range 9-16) in the control group; gra-nulocyte count > 0.5 x 109/L on median day 12 (range 8-23) vs day 14 (range 10-16) in the control group; and platelet count > 20 x 109/L on median day 13 (range 8-80) vs day 11 (range 7-15) in the control group. Differences between the two patient groups were not statistically significant. G-CSF therapy administered after autologous hematopoietic stem cell transplantation did not result in faster leukocyte, granulocyte or platelet recovery. The patients receiving a relatively lower number of cells showed the same rate of recovery as those who received a higher cell number. The number of CD34+ cells per kg body weight did not correlate with the rate of leukocyte, granulocyte or platelet recovery.