Subchronic methionine load induces oxidative stress and provokes biochemical and histological changes in the rat liver tissue.

The aim of this study was to assess the effects of L-cysteine (Cys) (7 mg/kg) and N-acetyl-L-cysteine (NAC) (50 mg/kg) in the rat liver caused by subchronic i.p. application of methionine (Met) (0.8 mmol/kg) during 21 days. Malondialdehyde (MDA) concentration, glutathione content (GSH), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and acetylcholinesterase (AchE) activities were determined in the liver tissue and activities of liver enzymes (AST, ALT, ALP, and GGT) and concentrations of total proteins and albumin were determinated in plasma/serum. Catalase, superoxide dismutase, and acetylcholinesterase activities were increased by Cys and NAC. Met caused periportal mononuclear infiltration and rare focal necrosis of hepatocytes. In Cys- and NAC-supplemented groups, intracellular edema and microvesicular fatty changes without necrosis were noticed. We observed decrease of AST, ALT, and ALP activity in the methionine-treated group. Our results indicate that Cys and NAC application can increase activity of antioxidative enzymes and prevent intensive histological changes in liver in condition of subchronic methionine exposure.

The effect of subchronic supplementation with folic acid on homocysteine induced seizures.

Influence of folic acid on the CNS is still unclear. Folate has a neuroprotective effect, while on the other hand excess folate can exacerbate seizures in epileptics. The aim of the present study was to examine the effect of subchronic administration of folic acid on behavioural and electroencephalographic (EEG) characteristics of DL homocysteine thiolactone induced seizures in adult rats. The activity of Na⁺/K⁺-ATPase and Mg²âº-ATPase in different brain regions was investigated. Adult male Wistar rats were divided into groups: 1. Controls (C, 0.9% NaCl); 2. DL homocysteine-thiolactone 8.0 mmol/kg (H); 3. Subchronic supplementation with folic acid 5 mg/kg for 7 days (F) and 4. Subchronic supplementation with F + single dose of H (FH). Seizure behaviour was assessed by incidence, latency, number and intensity of seizure episodes. Seizure severity was described by a descriptive scale with grades 0-4. For EEG recordings, three gold-plated recording electrodes were implanted into the skull. Subchronic supplementation with folic acid did not affect seizure incidence, median number of seizure episodes and severity in FH, comparison with H (p > 0.05). The majority of seizure episodes in all groups were of grade 2. There were no significant differences in lethal outcomes at 24 h upon H injection in the FH vs. H group. The activity of Na⁺/K⁺-ATPase and Mg²âº-ATPase was significantly increased in almost all examined structures in the FH vs. H group. Subchronic folic acid administration did not exacerbate H induced seizures and completely recovered the activity of ATPases.

Primary cutaneous large B-cell non-Hodgkin lymphoma in first-degree relatives.

Primary cutaneous non-Hodgkin's lymphoma is a heterogeneous group of lymphoproliferative disorders characterized by indolent course, virtually exclusive skin involvement and the absence of systemic disease. We present two brothers, whose mother died of gastric diffuse large B-cell lymphoma, in whom in a period of 4 years primary cutaneous large B-cell non-Hodgkin lymphoma of the skin of the head was diagnosed. They were treated with immunochemotherapy according to R-CHOP protocol (rituximab and adriblastine, cyclophosphamide, oncovine and prednisone) achieving a complete remission. The possible etiological mechanism of this familial lymphoma occurrence is discussed.

Mixed phenotype acute leukemia of T/myeloid type with a prominent cellular heterogeneity and unique karyotypic aberration 45,XY, dic(11;17).

INTRODUCTION: A 26-yr-old male patient with mixed phenotype acute leukemia of T/myeloid type with prominent leukemic cell heterogeneity, and the presence of a so far unreported karyotype aberration in this type of acute leukemia 45,XY, dic(11;17)(11qter→11p11.2::17p11.2→17qter) is presented. METHODS: Flow immunocytometry was performed by direct multicolor immunofluorescent technique on bone marrow aspirates. Cytogenetic analyses were performed using G-banding method by direct preparation of unstimulated bone marrow cells and following 24 hours of culture in RPMI 1540 culture medium with 25% fetal calf serum at 37°C RESULTS: The flow immunocytometry of bone marrow nucleated cells revealed the existance of three distinct blast cell populations with overlapping immunophenotypes. Predominant blast cell population had an early myeloid phenotype and aberrant expression of CD7 antigen (HLA-DR(+), CD34(+), anti-MPO(+), CD117(+), CD33(+), CD13(+), CD7(+low), cyCD3(-), TdT(-)). The other two blast cell populations, smaller in cell diameter and less sizable in cell proportion, both shared the T-lymphoid features. The patient was treated with ADE protocol (etoposide, cytarabine and doxorubicine). A complete remission was achieved and lasted 5 months. CONCLUSION: A case of MPAL with complex biological features, 45,XY, dic(11;17)(11qter→11p11.2::17p11.2→17qter) karyotype and an aggressive, therapy-resistant clinical course, is presented.

Therapy-related myelodysplastic syndrome and acute myeloid leukemia in patients with chronic lymphocytic leukemia treated with fludarabine and cyclophosphamide.

We retrospectively studied four cases of t-MDS/AML among 210 (1.9%) consecutive patients with CLL treated at a single center with fludarabine and cyclophosphamide (FC) either as the first- or second-line therapy. The median follow-up of the whole cohort of patients was 46months (range: 7-60). Two of these patients (2/130, 1.7%) had been treated with FC only, and two more (2/80, 2.3%) with CHOP and CHOP+FND, respectively, prior to FC. The median age was 61.5years (range: 49-71); three were male. They developed t-MDS/AML after a median latency period of 41months (range: 7-56) from the FC completion. Chromosomal aberrations with an adverse prognostic impact were present in the karyotype of all four patients, including abnormalities of chromosome 5 in three of them, and a rare chromosomal translocation in one patient. Median survival after t-MDS/AML diagnosis was 4months (range: 2-8). Although the agents administered prior to FC make it difficult to assess the risk of t-MDS/AML attributable to FC, this report might be a valuable addition to the literature.

Specific skin lesions in hairy cell leukemia at presentation: case report and review of literature.

Skin involvement in hairy cell leukemia (HCL) at presentation is a relatively rare manifestation of the disease. A 60-year-old male patient in whom cutaneous lesions were the initial manifestation of hairy cell leukemia together with leukocytosis, monocytopenia, massive splenomegaly, and leukemic maculopapulous infiltration of the almost whole skin is described. The present case is the forth mentioned in the literature with specify of leukocytosis in peripheral blood, consisting mostly of hairy cells. The patient was treated with two courses of 2-chlorodeoxiadenosine (2-CdA, Cladribine) and splenectomy and after this cutaneous lesion disappeared and general condition is improved.

Molecular response to imatinib in patient with Ph negative p190 BCR-ABL transcript positive chronic myeloid leukemia with cyclic leukocytosis.

An atypical case of Philadelphia (Ph) negative, e1a2 BCR-ABL transcript positive chronic myeloid leukemia (CML) characterized with cyclic periodic leukocytosis and spontaneous remissions is reported. The patient was treated with imatinib and good hematology response with molecular remission was achieved. So far, only few Ph positive CML patients expressing p190 BCR-ABL protein and different clinical characteristics and treatment have been described in the literature. This is the first report of Philadelphia negative, p190 BCR-ABL positive CML with cyclic spontaneous oscillation of white blood cell count (WBC), and excellent response to imatinib treatment.

Antiribosomal-P protein antibodies in a patient with systemic lupus erythematosus and non-Hodgkin's lymphoma: more than coincidental finding?

Patients with systemic lupus erythematosus (SLE) are at an increased risk of lymphomas, but mechanisms underlying this association are obscure. Recently, it has been shown that antiribosomal-P protein (anti-P) antibodies cross-react with phospholipids and enhance the production of cytokines which may influence lymphomagenesis. We report a 46-year-old woman who suffered high grade diffuse large B-cell non-Hodgkin's lymphoma (DLBCL) 28 months after the diagnosis of SLE. Development of lymphoma was associated with occurrence of serum monoclonal IgM, and pronounced prolongation of phospholipid-dependent clotting tests. Anti-P IgG antibodies were highly positive both on HEp-2 cells and in ELISA test. Anticardiolipin, anti-beta2 glycoprotein I, and antiprothrombin IgM antibodies have also been found in high concentrations. Complete remission of DLBCL and SLE, with normalisation of clotting tests, and disappearance of M component was achieved with administration of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone. The progression of SLE to DLBCL associated with presence of anti-P antibodies has not been previously reported. This association may not be coincidental, but further investigations are required to confirm this hypothesis.

Molecular characteristics and prognostic significance of Bcl-2/IgH gene rearrangement in Serbian follicular lymphoma patients.

Follicular lymphoma (FL) is characterized by the presence of a t(14;18) chromosomal translocation that results in overexpression of bcl-2 protein. Bcl-2/IgH gene rearrangement is detected in 80-90% of follicular lymphomas in Western countries. The aim of this study was to analyze the bcl-2/IgH rearrangement in FL lymphoma patients in Serbia, by PCR technique, correlate molecular findings with clinical characteristics and outcome and assess the prognostic significance of these rearrangements. One hundred-seven patients (median age, 54 years; male/female ratio:60/47) diagnosed with FL were included in the study. DNA samples were obtained from paraffin embedded lymphoid tissue of patients. Bcl-2/IgH rearrangement was assessed for the major breakpoint region (MBR), 5' MBR and the minor cluster region (mcr) breakpoints by PCR technique. We detected a t(14;18) in 81.3% (87/107) of patients. The distribution of bcl-2-IgH rearrangement was as follows: 88,5% (77/87) in MBR breakpoint, 10,35% (9/87) in 5' MBR, whereas mcr bcl-2-IgH rearrangement was observed in one patient (1.15%). No rearrangements were detected in remaining 20 patients (18.7%). This is the first analyses of the frequency of the bcl-2/IgH gene rearrangement in Serbian FL patients, as well as in Eastern European countries. There was no correlation between presence of bcl-2/IgH gene rearrangement and clinical outcome of disease. Incidence of bcl-2/IgH gene rearrangement in Serbian FL patients is relatively high, and similar to frequency in Western countries. Presence of this rearrangement in tumor tissue is not of prognostic significance.

Triple-way therapeutic approach for paraganglioma-dependent erythrocytosis: drugs and surgery plus "multi-manner" apheresis.

Paragangliomas are tumors arising from the extra-adrenal paragangliar neural crest cells. The sympathoadrenal neuroendocrine system consists of extra-adrenal paragangliar cellular layer along the paravertebral and para-aortic axis, and the adrenal medullae. Paraganglioma should be included in the differential diagnosis of secondary erythrocytosis due to its possible ectopic erythropoietin (EPO) secretion. Thus, in this report we present a 24-year-old female patient with onset of unregulated ectopic EPO secretion, and consecutive erythrocytosis followed by hypertension, secondary to paraganglioma of multifocal retroperitoneal localization. Clinical, laboratory, and radiological investigations confirmed both an elevated EPO level and the presence of multiple paraganglioma. This paraneoplastic-mediated medical condition with high risk of cellular hyperviscosity syndrome (CHVS) requires prompt diagnosis and rapid therapeutic interventions. Initially, simple phlebotomy procedures were used; following that, tumors were surgically removed. In the course of the disease, this tumor relapsed, and urgent apheresis, as a treatment of life-threatening state, was used. The therapy performed resulted in a rapid blood viscosity depletion and a significant (P < 0.01) serum EPO reduction, as well as the general clinical benefit. Therefore, we conclude that the use of our own "multi-manner" apheresis (erythrocythapheresis plus plasma exchange), for long-time interval (until further causative therapy), effectively cross-bridged the possible hazards of EPO-dependent CHVS.

Expression of VEGF and microvessel density in patients with multiple myeloma: clinical and prognostic significance.

The conflicting data are reported on the clinical significance of VEGF deregulation and intensity of angiogenesis in multiple myeloma. The aim of this study was to evaluate the incidence and prognostic significance of VEGF expression and microvessel density (MVD) in multiple myeloma, as well as the relationship of their expression with selected clinical data, histological features, and proliferative activity of myeloma cells. We analyzed bone marrow biopsy specimens obtained from 59 patients with newly diagnosed multiple myeloma. Expression of VEGF and MVD was analyzed using standard immunohistochemical method (antibodies against VEGF and CD34, respectively) on B5-fixed and routinely processed paraffin-embedded bone marrow specimens. MVD was estimated by counting the number of microvessels in three "hot spots" at 400x magnification. VEGF immunoreactivity was estimated on the basis of intensity and percentage of positive plasma cells. VEGF was expressed in 47/59 (79.7%) specimens. There was no significant correlation between VEGF overexpression and age, clinical stage, the extent of osteolytic lesions, type of monoclonal protein, hemoglobin concentration, platelet count, serum concentration of creatinine, calcium, and albumins, the extent of bone marrow infiltration, histological grade, and proliferative activity index (measured with Ki-67 immunoreactivity). No significant difference was observed regarding the overall survival between VEGF-positive and VEGF-negative patients (29 vs. 34 months, P = 0.8). Median MVD was 15, ranging from 1 to 89 microvessels per three "hot spots". There was significant correlation between MVD and histological grade, the extent of bone marrow infiltration, and proliferative activity. Significant difference was observed regarding the overall survival between patients with low MVD (<15) and patients with high MVD (> or = 15) (46 vs. 22 months, P = 0.009; univariate analysis). The results of this study did not reveal clinical significance of VEGF overexpression in multiple myeloma. On the contrary, the extent of bone marrow angiogenesis is an indicator of biological potency of malignant clone and a predictor of poor survival in newly diagnosed myeloma.

Malignant histiocytosis with central nervous system involvement and hepatic mucinous cystadenoma in a single patient with review of the literature.

Malignant histiocytosis is a rare neoplasm of the reticuloendothelial system characterized by neoplastic proliferation of tissue histiocytes. We report a case of malignant histiocytosis in a 64-year-old female initially operated on for a mucinous cystadenoma of her liver. Four months after the operation, skin induration on the neck and anterior thoracic wall and systemic lymphadenopathy were noted. Histology and immunohistochemistry of the lymph node and bone marrow specimens showed extensive infiltration with atypical cells, resembling malignant histiocytes (CD45, CD45RO, CD11c, CD68, lysozyme, antitrypsin and alpha1-antichymotrypsin positive; CD1, CD35, B-cell and T-cells markers negative). She was treated with vinblastine, methotrexate and dexamethasone (3 cycles) without response. The therapy was switched to CHOP (cyclophosphamide, vincristine, doxorubicin, and prednisone) with disappearance of lymphadenopathy. Bone marrow infiltration by histiocytes was reduced to 20%. Two months after completion of 8 cycles of CHOP she experienced severe headaches, vomiting, loss of consciousness, and developed paraparesis. A CT scan of the brain was normal but the cerebrospinal fluid cytology showed presence of histiocytes. The patient was then treated with intrathecal methotrexate, prednisolone and cytosine-arabinoside and systemic chemotherapy with etoposide and cyclophosphamide. Her condition improved, she became conscious, her headache diminished, she became mobile but skin and nodal lesions reappeared along with extensive marrow histiocytic infiltration. She finally died 22 months after diagnosis.

Immunophenotypic profile and clinical characteristics in patients with advanced stage mantle cell lymphoma.

The objective of this study was to evaluate immunophenotypic profile along with clinical follow-up in patients with advanced stage mantle cell lymphoma (MCL), and their possible influence on overall survival (OS). Bone marrow (BM) cell and/or peripheral blood mononuclear cell flow cytometric analyses of the following antigens were performed: HLA-DR, CD19, CD20, CD22, CD23, CD25, CD10, SmIg, kappa, lambda, CD79b, CD38, FMC7, CD3, CD2, and CD5. There were 14 patients in IV CS, and 26 patients in CS V. All patients were treated with CHOP. Immunological markers showed a typical phenotype (CD5+ CD23-, Cyclin D1) in all cases. Pathohistological type of BM infiltration was predominantly diffuse (72.5%), and in remainder of patients, nodular. Comparison of patients with leukemic phase of MCL with CSIV (BM), has shown significantly higher expression of CD19, CD20, and CD23, followed by permanently negative expression of CD23. Patients with blastic variant of MCL had higher expression of CD23, compared to typical MCL (P < 0.001). Median OS was 20 months, and there were no significant OS-differences between CS IV and leukemic phase patients. Survival analyses showed that negative prognostic influence had high IPI (P < 0.01), presence of extranodal localization (P < 0.01), and diffuse type of BM involvement (P < 0.01). Using Cox regression according to OS, IPI had independent prognostic value (P < 0.001). Our results demonstrated that in the advanced MCL patients the most powerful prognostic factor was IPI, while extranodal localization and type of BM infiltration were of a limited value.

Systemic lupus Erythematosus and IgA multiple myeloma: a rare association?

The coexistence of systemic lupus Erythematosus (SLE) and multiple myeloma (MM) is uncommon and the pathogenetic mechanisms underlying this association remain unclear. We report the case of a woman who was diagnosed with SLE in 1993 aged 57, then developing IgA lambda type MM in the IIB clinical stage 7 years later. The SLE was treated successfully with methylprednisolone and chloroquine, and low dose maintenance steroid was continued with bisphosphonate protection until December 1994 when she suffered multiple vertebral fractures. She continued to receive 4 mg alternate day methylprednisolone and calcitonin until she decided to discontinue her own treatment 2 years later. In 2000, while still in stable SLE remission, she was diagnosed with MM. Protein electrophoresis revealed the IgA lambda paraprotein (40.5 g/l) and she had a Bence Jones (BJ) proteinuria of the lambda light chain type. Bone marrow trephine biopsy revealed a massive patchy infiltrate of abnormal plasmocytes (70%), while an extensive x-ray skeletal survey did not show any new fractures or osteolysis. The patient was treated according to the VMCP protocol without attaining a plateau phase. There was a similar poor clinical response to second and third line treatments (VAD, Thalidomide, Melphalan, and high dose dexamethasone). After 4 years of refractory disease the patient died from severe bilateral pneumonia. This case is discussed with reference to the literature.

Interferon alpha sensitisation induced fatal renal insufficiency in a patient with chronic myeloid leukaemia: case report and review of literature.

Renal dysfunction as a sequel to extended interferon alfa (IFNalpha) treatment in chronic myeloid leukaemia (CML) has been reported previously in six patients. An additional patient is presented with Philadelphia chromosome positive (Ph+) CML and nephrotic syndrome in whom initial renal insufficiency developed after only one month of low dose IFNalpha therapy. The renal biopsy showed a focal segmental mononuclear cell infiltration, basal membrane thickening, and deposits of immunoglobulins (IgG; IgAGM IC3). In spite of discontinuation of IFNalpha, renal function deteriorated and the patient died six months later. This case represents an instance of fatal kidney insufficiency as an untoward effect of sensitisation to the IFNalpha, confirmed by modified Coombs assay.

Ki-67 proliferative marker in lymph node aspirates of patients with non-Hodgkin's lymphoma.

Proliferative activity of lymphoma cells was tested by immunocytochemical staining with Ki-67 monoclonal antibody in 63 aspirates of peripheral lymph nodes sampled from patients suffering from non-Hodgkin's lymphoma. Referring to the dominant cell population in nodal aspirates, a rising trend of Ki-67 proliferative marker was noted from the small cells (X = 13.20) and small cells with notched nucleus (X = 43.52) and large cells (X = 79.47) with histopathologic equivalents corresponding to aggressive lymphoma. Statistical testing of the difference in the Ki-67 proliferative marker against demographic and clinical-laboratory characteristics of the studied patients revealed the levels of significance for the performance status, bone marrow infiltration, and albumin serum value. Correlation of cytomorphological and immunocytochemical results was tested against International Prognostic Index (IPI). Statistically significant correlation of Ki-67 with cytomorphology and REAL-immunocytochemical classification of lymphoma was confirmed, but not with the IPI index. In order to determine the prognostic importance of Ki-67 marker, the patients were classified into those with low Ki-67 (<20% of proliferating cells), mean proliferation index Ki-67 (range 20-59%), and high proliferative index Ki-67 (positive in over 60% of lymphoma cells). Testing Ki-67 with survival we have found that the low proliferative index was associated with the longest survival, median about 36 mo; for proliferative marker values ranging between 20 and 59%, the median survival was 30.4 mo; and survival of patients with the high proliferative index was only 12.9 mo.

Predictive value of prognostic indices in patients with follicular lymphomas.

PURPOSE: The aim of this study was to compare which of three indices--International Prognostic Index (IPI), Italian Lymphoma Intergroup (ILI) index, Follicular Lymphoma adapted International Prognostic Index (FLIPI)--is the most useful in predicting outcome in follicular lymphoma (FL) patients and to identify other clinical and laboratory prognostic factors that influence survival. PATIENTS AND METHODS: Clinical and prognostic studies were carried out in 99 patients with FL. RESULTS: The distribution of patients in IPI risk groups was 44.4%, 19.2%, and 36.4% of cases classified as low, intermediate, and high risk. According to ILI, low-, intermediate-, and high-risk scores were present in 34.3%; 27.3%, and 38.4% of FL patients. After applying the FLIPI index, the patients were divided into three risk groups: low (21.2% of cases), intermediate (39.4%), and high (39.4%) of FL patients. Survival curves demonstrated a high significant difference for the low- and high-risk group according to IPI and FLIPI (log rank=91.13 and 82.17 respectively; p < 0.0001). Difference in overall survival (OS) and failure-free survival (FFS) among low-, intermediate-, and high-risk groups according to ILI was statistically significant (log rank test p < 0.0001). CONCLUSION: All three indices are important tools for prognostic evaluation of FL patients, as well as useful in identifying FL patients with poor outcome. IPI and FLIPI classify patients into two risk groups (low/intermediate- and high-risk groups) with significance difference in OS and FFS, but ILI is more reliable in stratifying patients in low-, intermediate-, and high-risk groups.

Myelofibrosis in primary myelodysplastic syndromes: clinical and biological significance.

In a retrospective study of 236 patients with primary myelodysplastic syndromes (MDS), 130 cases (55.1%) revealed myelofibrosis in bone marrow biopsies. It was observed that fibrosis mostly occurs focally or patchy, and collagen deposits were found very rarely (only four patients). The histopathology of bone marrow biopsies revealed several differences between fibrotic and non-fibrotic MDS: cellularity is significantly higher, dysmegakaryopoiesis is more pronounced, plasmocytes and mast cells are more often increased, and disturbance of marrow topography (particularly of the MK- and G-line) can be found more frequently in MDS with myelofibrosis. Reticulin fibrosis occurred in all subtypes of MDS; however, there was a higher incidence in chronic myelomonocytic leukemia. The frequency of abnormal growth of GM-progenitors was significantly higher in the MDS cases with myelofibrosis, compared to the cases without fibrosis. Clinical data showed significantly higher WBC, more frequent presence of immature granulocytes, and higher percentage of myeloblasts in peripheral blood and bone marrow in MDS with myelofibrosis compared to cases without myelofibrosis. Life expectancy was reduced to 13 mo, compared with 35 mo in MDS without fibrosis (p=0.00055). Time to leukemic transformation was 32 mo in MDS with fibrosis, compared with >56 mo in MDS without fibrosis (p=0.015). Myelofibrosis therefore seems to herald a poor prognosis.

The comparison of spontaneous LDH release activity from cultured PBMC with sera LDH activity in non-Hodgkin's lymphoma patients.

Based on the fact that lactate dehydrogenase (LDH) enzyme is a very sensitive indicator of the cellular metabolic state, aerobic or anaerobic direction of glycolysis, activation status, and malignant transformation, in this study we compared values of the spontaneous LDH release from circulating PBMC with sera LDH activity in 53 different subtypes of non-Hodgkin's lymphoma (NHL) patients. Results shows that serum LDH was significantly (p < 0.05) elevated in comparison to the range values only in the advance clinical stage (III and IV) in all investigated subtypes of NHL according to The Working and REAL classification. On the other hand, the spontaneous LDH release from cultures PBMC is significantly (p < 0.01) elevated in early and advanced stage in all investigated forms of NHL in comparison to healthy controls. Based on consideration that an increase in spontaneous LDH release appears before elevated sera LDH activity, we conclude that determination of spontaneous LDH release by microassay from cultured cells together with other findings may help in the diagnosis of NHL patients, especially in patients with early stage of disease.

Acute panmyelosis with myelofibrosis: clinical, immunophenotypic and cytogenetic study of twelve cases.

The clinical, cytogenetic, and immunophenotypic features in 12 adult patients with acute panmyelosis with myelofibrosis (APMF; ICD-0-3: 9931/3; C42.1) are reported (median age: 57 years; f/m = 1.4). The white cell count (WBC) was normal in 3 patients; 9 had leucopenia. The median hemoglobin value was 64.5 g/l, and median platelet count 12 x 10(9)/l. Bone marrow biopsy showed a hypercellular marrow in 10/12 patients with a significant infiltration of pathological blasts (range: 30 - 60%). All the cases had marked reticulin fibrosis. Immunophenotyping of bone marrow blast cells showed the expression of early (CD34) and lineage-unspecified antigens (HLA-DR) in 6/7, and 7/7 patients, respectively. "Early" myeloid antigens (CD13, CD33) were seen in 6/7 and 4/6 patients respectively. Monocyte antigen (CD14) was expressed in 3/7 patients. Megakaryocyte antigen (CD61) and erythroid cell antigen (GpA) were each expressed in only 1 patient. Two patients had expression of CD34, HLA-DR and "early" myeloid antigens by their bone marrow blast cells and 1 of these also had a co-expression of the antigens from a differentiated monocytic cell proliferation (lysozyme+, CD68+). Nonspecific chromosomal aberrations were recorded in 8/10 patients. The median survival was 2 months. These findings suggest an immature myeloid phenotype of blast cells in APMF. In 6/9 patients a leukemic cell differentiation into monocytic, megakaryocytic or erythroid lineage was also demonstrated.