A unified definition of clinical resistance/intolerance to hydroxyurea in essential thrombocythemia: results of a consensus process by an international working group.

A widely accepted definition of resistance or intolerance to hydroxyurea (HU) in patients with essential thrombocythemia (ET) is lacking. An international working group (WG) was convened to develop a consensus formulation of clinically significant criteria for defining resistance/intolerance to HU in ET. To this aim, an analytic hierarchy process (AHP), a multiple-attribute decision-making technique, was used. The steps consisted of selecting the candidate criteria for defining resistance/intolerance; identifying the motivations that could influence the preference of the WG for any individual criterion; comparing the candidate criteria in a pair-wise manner; and grading them according their ability to fulfill the motivations. Every step in the model was derived by questionnaires or group discussion. The WG proposed that the definition of resistance/intolerance should require the fulfillment of at least one of the following criteria: platelet count greater than 600,000/micro l after 3 months of at least 2 g/day of HU (2.5 g/day in patients with a body weight over 80 kg); platelet count greater than 400,000/micro l and WBC less than 2500/micro l or Hb less than 10 g/dl at any dose of HU; presence of leg ulcers or other unacceptable muco-cutaneous manifestations at any dose of HU; HU-related fever.

A comparative analysis of different automated von Willebrand factor glycoprotein Ib-binding activity assays in well typed von Willebrand disease patients.

Essentials Von Willebrand ristocetin cofactor activity (VWF:RCo) is not a completely reliable assay. Three automated VWF activity assays were compared within a von Willebrand disease (VWD) cohort. Raw values for all three assays were virtually the same. An overall problem within type 2A/IIE VWD using VWF:GPIb-binding activity/VWF:Ag was observed. SUMMARY: Background von Willebrand disease (VWD) is an inherited bleeding disorder caused by quantitative (type 1 and 3) or qualitative (type 2) von Willebrand factor (VWF) defect. VWD diagnosis and classification require numerous laboratory tests. VWF: glycoprotein Ib (GPIb)-binding activity assays are used to distinguish type 1 from type 2 VWD. Objectives Three different automated VWF:GPIb-binding activity assays were compared. Patients and methods BC-VWF:RCo (Siemens Healthcare Diagnostics), HemosIL® VWF:RCo (Instrumentation Laboratory) and INNOVANCE® VWF:Ac (Siemens Healthcare Diagnostics) were performed in a well typed VWD cohort (n = 142). Results Based on the three most used VWD parameters (FVIII:C, VWF:Ag and VWF:GPIb-binding activity) and using a cut-off of <0.70 for type 2 VWD revealed sensitivity and specificity of, respectively, 92% and 72.4% for VWF:RCo/VWF:Ag, 84% and 89.7% for VWF:GPIbR/VWF:Ag, and 92% and 85.1% for VWF:GPIbM/VWF:Ag, whereas a lowered cut-off of < 0.60 resulted in reduced sensitivity with increased specificity for all assays. Conclusion VWD classification based on FVIII:C, VWF:Ag and VWF:GPIb-binding activity revealed an overall problem with normal VWF:GPIb-binding activity/VWF:Ag within type 2, especially type 2A/IIE. Although all assays were practically identical, BC-VWF:RCo had higher %CV compared with both new assays but comparable lower limit of quantification (LLOQ) ~4 IU dL-1 . No clear improved distinction between type 1 and 2 VWD with new assays was seen. BC-VWF: RCo and HemosIL® are ristocetin dependent, whereas INNOVANCE® does not rely upon ristocetin and is not influenced by VWF polymorphisms increasing VWF:GPIb-binding activity levels. INNOVANCE® seems to be the best choice as a first-line VWF:GPIb-binding activity assay, providing the best balance between sensitivity and specificity for type 2 VWD.

[From gene to disease; primary erythermalgia--a neuropathic disease as a consequence of mutations in a sodium pump gene]. / Van gen naar ziekte; de neuropathische ziekte 'primaire erythermalgie' als gevolg van mutaties in een natriumpompgen.

Primary erythermalgia is a rare autosomal dominant inherited disorder characterized by recurrent attacks of red, warm and painful burning extremities. The gene involved in primary erythermalgia, SCN9A, encodes for a voltage dependent sodium channel alpha subunit (NaV1.7). NaV1.7 is located in dorsal root ganglions and in nociceptive peripheral neurons. It has been hypothesized that mutations lead to a gain of function and hyperexcitability of peripheral sensory neurons contributing to symptoms in primary erythermalgia.

Amplification of the c-myc and the pvt-like region in human multiple myeloma.

Genetic alterations that lead to the clonal expansion of differentiated cells in multiple myeloma have still to be elucidated. Many chromosomal aberrations have been found, but until now, none of them is typically associated with multiple myeloma. In search for genetic defects in multiple myeloma we studied the structure and expression of the c-myc oncogene and the pvt-like region because of their frequent association with other B-cell malignancies. Here we report co-amplification of the c-myc oncogene and the 5' part of the pvt-like region in two out of 26 cases of multiple myeloma. In both cases only kappa-light chains were produced. The amplification also manifested itself at the RNA level. Total RNA was analysed in one of these two cases showing abundant c-myc mRNA. In the same RNA sample we also detected a strong hybridizing band of about 7 kb, when the pSS.4 probe, representing the 5' part of the pvt-like region, was used. This band was not present in total RNA from normal bone marrow cells or bone marrow from multiple myeloma patients without the amplification of c-myc and the pvt-like region. Until now, transcripts of the pvt-like region were only found in a few human cell lines ranging in size from 1 to 11 kb. This is the first case in which a high expression of a +/- 7 kb transcript of the pvt-like region has been found in freshly obtained tumor material probably due to a pvt-amplification. The occurrence of abnormalities in the c-myc and the pvt-like region in multiple myeloma is a rare event and may be associated with the progression of this type of tumor.

T-lymphoblastic lymphoma terminating as malignant histiocytosis with rearrangement of immunoglobulin heavy chain gene.

A 19-year-old man presented with cutaneous, mediastinal and intrapleural localization of a T-lymphoblastic non-Hodgkin's lymphoma (NHL) of immature phenotype. Two weeks after mediastinal irradiation the T-lymphoblasts had disappeared from the pleural effusion, but a clonal monocytic cell population was detected, as documented by immunological marker analysis and the presence of t(10;11), a cytogenetic aberration often associated with monocytic malignancies. Intensive chemotherapy induced a complete remission of the T-lymphoblastic NHL. However, the patient died from massive infiltration of lympho-hemopoietic tissue by cells with the morphology and immunological phenotype of macrophages. Southern blot analysis revealed the presence of a clonally rearranged immunoglobulin heavy chain (lgH) gene in tumorous tissue obtained at autopsy. The same clonally rearranged lgH was detectable in the post-irradiation pleural fluid 2 weeks after initial diagnosis. The observed germline configuration of T-cell receptor beta-genes and both lg light chain genes in this monoclonal proliferation provides additional evidence for the true histiocytic nature of the fatal disease. Therefore we conclude that a true histiocytic NHL with one rearranged lgH gene was most probably already present at initial diagnosis when the patient presented with the T-lymphoblastic NHL and that this true histiocytic NHL further developed despite the cytostatic treatment.

Richter's syndrome with identical immunoglobulin gene rearrangements in the chronic lymphocytic leukemia and the supervening non-Hodgkin lymphoma.

In a patient who developed Richter's syndrome, complex cytogenetic abnormalities of the centroblastic non-Hodgkin lymphoma (NHL) was associated with chemotherapy resistance. The clonal origin of the preexisting chronic lymphocytic leukemia (CLL) and the subsequent NHL cells was investigated. Both cell populations were present in the peripheral blood and could be separated efficiently by counterflow centrifugal elutriation. In the lymph node biopsy mainly NHL centroblasts were found and only a minor population of small lymphocytes. The separated CLL and NHL cells from blood as well as the lymph node cells were found to express mu and kappa Ig chains. Since expression of identical light chains is not synonymous with common clonal origin, Southern blot analysis of the Ig heavy chain genes was also performed, which showed that the two cell populations had identical Ig heavy chain gene rearrangements. Therefore, it was concluded that the CLL cells and the NHL cells in the present case originate from the same precursor cell and that the NHL has to be regarded as a malignant progression of the CLL. These findings are different from our previous report on another patient with Richter's syndrome, in whom the CLL and the NHL represented two unrelated malignancies. Therefore, the occurrence of NHL in Richter's syndrome apparently may represent either a clonal progression of the CLL or a second lymphoid malignancy.

A critical appraisal of non-invasive diagnosis and exclusion of deep vein thrombosis and pulmonary embolism in outpatients with suspected deep vein thrombosis or pulmonary embolism: how many tests do we need?

The requirement for a safe diagnostic strategy should be based on an overall posttest incidence of venous thromboembolism of less than 1% during 3 month follow-up. Compression ultrasonography (CUS) has a negative predictive value (NPV) of 97% to 98% indicating the need of repeated CUS testing. Serial CUS testing is safe but you have to repeat 100 CUS to find 1 or 2 CUS positive for deep vein thrombosis (DVT), which is not cost-effective indicating the need to improve the diagnostic work-up of DVT by the use of clinical score assessment and D-dimer testing. The combination of a less sensitive D-dimer test (SimpliRed) and low clinical score does not, whereas the combination of a sensitive D-dimer test (ELISA VIDAS or Tinaquant) and low clinical score does safely exclude DVT without the need of CUS. The combination of a first negative CUS and a negative less sensitive D-dimer test (SimpliRed) or a sensitive ELISA D-dimer at a higher cut off level of 1,000 ng/ml safely excludes DVT with a NPV of > 99% without the need to repeated CUS in about 60%. The sequential use of a sensitive D-dimer and clinical score assessment will safely reduce the need for CUS testing by 40% to 60%. Large prospective outcome studies demonstrate that one negative examination with complete duplex color ultrasonography (CCUS) of the proximal and distal veins of the affected leg with suspected DVT is safe to withhold anticoagulant treatment with a NPV of 99.5%. This indicates that CCUS is equal or superior to serial CUS or the combined use of clinical score, D-dimer testing and CUS. Pulmonary angiography is the gold standard for segmental pulmonary embolism (PE) but not for subsegmental PE. A normal perfusion lung scan and a normal rapid ELISA VIDAS D-dimer test safely exclude PE. Helical spiral CT detects all clinically relevant PE and a large number of alternative diagnoses in symptomatic patients with a non-diagnostic ventilation perfusion scan (VP-scan) or a high probability VP-scan. Single-slice helical CT as the primary diagnostic test in patients with suspected PE in 5 retrospective studies and in 3 prospective management studies indicate that the NPV of a normal helical spiral CT, a negative CUS of the legs together with a low or intermediate pretest clinical probability is 99%. Helical spiral CT can replace both the VP-scan and pulmonary angiography to safely rule in and out PE. The combination of clinical assessment, a rapid ELISA VIDAS D-dimer followed by CUS will reduce the need for helical spiral CT by 40% to 50%.

Thrombophilia and venous thromboembolism. International consensus statement. Guidelines according to scientific evidence.

Thrombophilia is the term now used to describe predisposition to increased risk of venous and occasionally arterial thromboembolism due to hematological abnormalities. It can be a multifactorial disorder where congenital defects of anticoagulant or procoagulant factors may be combined with acquired hematological abnormalities. It should be considered in patients with a documented unexplained thrombotic episode or a positive family history. The aim of this document is to provide guidelines for investigation and management of patients with thrombophilia in the presence or absence of venous thromboembolism (VTE).

Non-invasive diagnosis of pulmonary embolism, anno 2005.

Pulmonary angiography is the gold standard for segmental pulmonary embolism (PE) but no longer for subsegmental PE, because the inter-observer agreement for angiographically documented subsegmental PE is only 60%. Two non-invasive tools exclude PE with a negative predictive value of >99% : a normal perfusion lung scan and a normal rapid ELISA VIDAS D-dimer test. The positive predictive value is 85 to 88% for a high probability ventilation-perfusion lung scan (VP-scan) and >95% for helical spiral CT. The prevalence of PE in management studies of symptomatic patients with a non-diagnostic VP-scan is 20 to 24%. Helical spiral CT detects all clinically relevant PE and a large number of alternative diagnoses in symptomatic patients with a non-diagnostic VP-scan or a high probability VP-scan. Single-slice helical CT as the primary diagnostic test in patients with suspected PE in three retrospective studies and in two prospective management study indicate that the negative predictive value of a normal helical spiral CT, a negative compression ultrasonography of the legs (CUS) together with a low or intermediate pre-test clinical probability is >99%. Therefore, helical spiral CT can replace both the VP-scan and pulmonary angiography to safely rule in and out PE. The combination of clinical assessment, a rapid ELISA VIDAS D-dimer followed by CUS will reduce the need for helical spiral CT by 40 to 50%.

Diagnosis of deep vein thrombosis: how many tests do we need?

The requirement for a safe diagnostic strategy should be based on an overall post-test incidence of venous thromboembolism (VTE) of less than 1% during 3 month follow-up. Compression ultrasonography (CUS) has a negative predictive value (NPV) of 97 to 98% indicating a post-CUS incidence of deep vein thrombosis (DVT) of 2 to 3%. A post-CUS DVT incidence of 3% implicates that 90 to 120 DVTs per 1 million inhabitants will be overlooked each year indicating the need to improve the diagnostic work-up of DVT as much as possible. The qualitative D-dimer test (SimpliRed) has a sensitivity of 82 to 89% and a negative predictive value of 94 to 95% indicating a 5 to 6% post-test incidence of DVT, which is not sensitive enough for venous thrombosis exclusion. The post-test DVT incidence could be reduced from 3.2% to 0.6% in one study and from 11% to 2% in another study by the combination of a normal CUS and low clinical score and from 4.5% to 1.6% by the combination of low clinical score and a negative SimpliRed test in one study. The combination of a negative CUS and a negative SimpliRed test reduced the post-test incidence of DVT from 2.6% to < 1% or even < 1% in two management studies without the need of a repeated CUS on the basis of which anticoagulant therapy can safely be withheld. The rapid quantitative turbidimetric D-dimer assay (Tinaquant) has a sensitivity and a negative predictive value (NPV) of 97.7% with a 2.3% post-test incidence of DVT. The combination of a normal Tinaquant D-Dimer test result plus a low to moderate clinical score reduces the post-test incidence of DVT from 2.3 to 0.6% without the need of CUS testing in 29% of patients with suspected DVT. The rapid ELISA VIDAS D-dimer assay has a sensitivity and NPV of 98.6 and 99.5% in two management studies for the exclusion of DVT irrespective of clinical score. The combination of a normal ELISA VIDAS D-Dimer test with clinical score assessment will reduce the post-test DVT incidence of less than 0.5% and the need for CUS testing by 40 to 50%. It is concluded that the sequential use of a rapid quantitative D-dimer test, clinical score and CUS appears to be safe and the most cost-effective diagnostic work-up of DVT.

Transient neurologic and ocular manifestations in primary thrombocythemia.

We report the presenting neurologic and visual symptoms in 17 patients with primary thrombocythemia. Poorly localizing symptoms occurred in 14 patients: transient unsteadiness in 13, dysarthria in eight, and scintillating scotomata in four. Nine patients had focal symptoms: transient monocular blindness in two patients, transient mono- or hemiparesis in six, and both of these in one patient. The attacks all had a sudden onset, occurred sequentially rather than simultaneously, lasted for a few seconds to several minutes, and were usually associated with a dull or pulsatile headache. A causal platelet-mediated arterial thrombosis was evident in 15 patients. There were no recurrences of thrombotic or ischemic events during long-term treatment of 12 patients with aspirin and during cytostatic reduction of platelet count to normal in seven patients. We conclude that low-dose aspirin and reduction of platelet count to normal are effective, but coumarin is ineffective, in the treatment and prevention of arterial thrombosis in thrombocythemia.

Acquired von Willebrand syndromes: clinical features, aetiology, pathophysiology, classification and management.

Acquired von Willebrand syndrome (AVWS) associated with hypothyroidism is of type I, results from a decreased synthesis of factor VIII and von Willebrand factor (VWF), responds to desmopressin with normal half-life times for factor VIII and VWF parameters, and disappears after treatment with I-thyroxine. AVWS type I or III, which occurs in a minority of patients with Wilms' tumour in the complete absence of an inhibitor against VWF and no absorption of factor VIII or VWF onto nephroblastoma cells, responds to chemotherapy and/or tumour resection. Hyaluronic acid produced by nephroblastoma cells may be the causative factor in atypical AVWS in Wilms' tumour. AVWS associated with thrombocythaemia of various myeloproliferative disorders is characterized by normal factor VIII and von Willebrand factor antigen (VWF: Ag) levels and a selective deficiency of functional ristocetin co-factor activity (VWF: RCo) and collagen-binding activity (VWF: CBA). AVWS type II in thrombocythaemia is caused by a platelet-dependent proteolysis of large VWF multimers, given the inverse relationship between platelet count and large VWF multimers in plasma and specific increases in the number of proteolytic VWF fragments in plasma. The laboratory findings of AVWS associated with systemic lupus erythematosus or IgG benign monoclonal gammopathy are characterized by a prolonged bleeding time and activated partial thromboplastin time, decreased or absent ristocetin-induced platelet activity, low to very low levels of factor VIII coagulant activity (mean 15%), VWF: Ag (mean 10.7%) and VWF: RCo (mean 6.2%), and a type II multimeric pattern of VWF. Neutralizing and non-neutralizing anti-VWF autoantibodies, usually IgG, have been detected in patient plasma either free or tightly bound to the intermediate and high molecular weight VWF factor VIII particles. The bound auto antibody-antigen complex is rapidly cleared from the circulation, resulting in low levels of factor VIII, VWF parameters as documented by a poor response to desmopressin and VWF factor VIII concentrate. High-dose intravenous immunoglobulin transiently corrects the factor VIII coagulant and VWF levels, lasting for a few weeks in AVWS type II associated with systemic lupus erythematosus or IgG benign monoclonal gammopathy. Prednisolone is effective in AVWS associated with autoimmune disorder. Prednisolone and chemotherapy will not affect AVWS associated with IgG benign monoclonal gammopathy because the monoclonal IgG protein remains to act as an anti-VWF autoantibody. An absorption of VWF to malignant cells has been documented in a few patients with various lymphoproliferative disorders or adrenal carcinoma and suggested to result in a depletion of VWF. The clinical picture of AVWS associated with early-stage IgG multiple myeloma, chronic lymphocytic leukaemia or non-Hodgkin's lymphoma without a paraprotein or no detectable underlying disorder is similar to that of AVWS type II in IgG benign monoclonal gammopathy but poorly documented with regard to the underlying immune mechanism of AVWS. The mechanical destruction of large VWF multimers may be of relevance in conditions in which the shear rate of flowing blood is increased, as may occur in cases of aortic stenosis, other heart valve defects or stenosed vessels. Drug-induced AVWS has been described in association with the use of pesticides valproic acid, ciprofloxacin, griseofulvin, tetracycline, thrombolytic agents and hydroxyethyl starch.

Homozygosity for a novel missense mutation in the prothrombin gene causing a severe bleeding disorder.

A patient with a severe bleeding tendency and hypoprothrombinemia (Factor II activity 2%, Factor II antigen 5%) was screened for the presence of alterations in his prothrombin gene. Direct sequencing of PCR fragments derived from the coding and flanking regions of the prothrombin gene, revealed that the patient was homozygous for an A-->G substitution in exon 3. This substitution predicts the replacement of Tyr44 (TAC) by Cys (TGC) in the prothrombin molecule. Both parents were found to be heterozygous for the same mutation. Further family studies revealed complete cosegregation of the mutation with the prothrombin deficiency. Only the five homozygous brothers and sisters of the propositus were clinically affected (severe hemorrhages including epistaxis, soft tissue, muscle and joint bleedings in all, and severe hemorrhages in the two women). The bleeding tendency therefore seems to inherit as an autosomal recessive trait.

Platelet consumption in thrombocythemia complicated by erythromelalgia: reversal by aspirin.

The involvement of platelets in the pathogenesis of erythromelalgia, a frequent and characteristic microvascular thrombotic manifestation in patients with primary thrombocythemia and polycythemia rubra vera, was investigated by measuring the survival and turnover of 51Cr labeled autologous platelets in 10 patients with thrombocythemia complicated by erythromelalgia, in 10 asymptomatic thrombocythemia patients and in 6 subjects with reactive thrombocytosis. The mean platelet survival time of the erythromelalgia patients was 4.2 +/- 0.2 days, which is significantly decreased as compared with asymptomatic thrombocythemia patients (6.6 +/- 0.3 days, p < 0.001) and patients with reactive thrombocytosis (8.0 +/- 0.4 days, p < 0.001). The mean platelet survival time of asymptomatic thrombocythemia patients was significantly decreased (p < 0.01) as compared with reactive thrombocytosis patients. Treatment of erythromelalgia with aspirin increased the mean platelet survival time from 4.0 +/- 0.3 days to 6.9 +/- 0.4 days (p < 0.001) and was associated with an elevation of the platelet count of 216 +/- 30 x 10(9) platelets per liter (p < 0.001). Coumadin failed to improve platelet survival or symptoms caused by erythromelalgia. The increased platelet consumption in erythromelalgia is attributed to the formation of platelet thrombi in the arterial microvasculature. This conclusion is supported by the ability of aspirin to interrupt platelet consumption and clinical features of erythromelalgia.

Phenotyping and genotyping of coagulation factor V Leiden.

The currently used activated Protein C resistance test demonstrated to be of limited diagnostic value for the detection of the mutant Factor V Leiden. Moreover, this assay is not useful for patients under anticoagulant therapy. A modification of the APC resistance test, applying Factor V deficient plasma is described which demonstrates a specificity and sensitivity of 1.0. The superiority of the modified APC resistance test over the existing APC resistance test was verified by genotyping. For that purpose, the Amplification Refractory Mutation System (ARMS) was applied to the detection of the G to A mutation at position 1691 in the gene encoding coagulation Factor V. The mutation at that position could be easily detected by using each of two allele-specific oligonucleotide primers concomitantly with one common primer in two separate polymerase chain reactions, thereby amplifying a fragment of 186 base-pairs of the Factor V gene.

Erythromelalgia in essential thrombocythemia is characterized by platelet activation and endothelial cell damage but not by thrombin generation.

Erythromelalgia, a characteristic aspirin-responsive microvascular thrombotic complication in essential thrombocythemia (ET), may develop despite oral anticoagulant treatment or treatment with heparin, suggesting that the generation of thrombin is not a prerequisite for its development. To study this, a cross-sectional comparison of the plasma levels of thrombomodulin (TM), platelet factor 4 (PF4), beta-thromboglobulin (beta-TG), prothrombin fragment 1 + 2 (F1 + 2) and total degradation products of fibrin(ogen) (TDP) was made between 5 ET patients suffering from erythromelalgia, 16 asymptomatic ET patients and 20 control subjects, and after treatment with aspirin, respectively. Furthermore, 2 ET patients with a history of erythromelalgia were studied at regular time intervals after discontinuation of aspirin until erythromelalgia recurred. As compared with asymptomatic ET patients and control subjects erythromelalgia was characterized by significantly higher beta-TG and TM levels but no significant differences were detected in either F1 + 2 or TDP levels. Treatment of erythromelalgia with aspirin resulted in disappearance of erythromelalgic signs and symptoms, which was paralleled by a significant decrease of beta-TG and TM levels. Histopathologic and immunohistochemical analysis of biopsies derived from erythromelalgic skin areas of 2 ET patients showed that erythromelalgic thrombi stained positively for von Willebrand factor opposed to only a weak fibrin staining. Our data suggest that erythromelalgia is caused by the intravascular activation and aggregation of platelets with subsequent sludging or occlusion of the acral arterial microvasculature. The generation of thrombin appears not to be essential for the formation of these platelet thrombi, thereby giving a plausible explanation for the inefficacy of coumadin derivatives and heparin in the prevention and treatment of erythromelalgia in essential thrombocythemia.

Hereditary protein S deficiency and venous thrombo-embolism. A study in three Dutch families.

Protein S, a vitamin K-dependent coagulation factor, is involved in the regulation of the anticoagulant activity of activated protein C. Using an immunoradiometric assay for total protein S in plasma we identified 14 patients (7 male and 7 female) in three unrelated Dutch families as fulfilling the criteria for an isolated protein S deficiency. In 9 patients who were not receiving oral anticoagulant treatment the mean total protein S antigen concentration was 0.50 +/- 0.08 U/ml (+/- S.D.) and the calculated free protein S concentration was 0.15 +/- 0.01 U/ml (+/- S.D.). In the five patients who were on oral anticoagulant treatment the mean total protein S antigen was 0.23 +/- 0.05 U/ml (+/- S.D.). Seven of the 14 patients had a history of venous thromboembolism occurring at a mean age of 25 years and often without an apparent cause. Protein S deficiency is inherited as an autosomal dominant trait.

Multiple myeloma and acute megakaryoblast leukemia in spent phase polycythemia vera.

The spontaneous and simultaneous occurrence of multiple myeloma and megakaryoblast leukemia with myelodysplastic features in a case of spent phase polycythemia vera is well documented. In support of the morphologic characteristics of the bone marrow, immunocytologic studies show proliferation of monoclonal plasma cells and megakaryoblasts. The cytogenetic findings of 20q- and unbalanced t(1;7) are consistent with myelodysplastic and leukemic transformation of the bone marrow. These transformations expand observations on variable and spontaneous lineage commitments as the consequence of alterations of the hematopoietic stem cell clone. These data are in support of the changing insights in hematopoiesis as a process of ordered commitment of the stem cell with sequential lineage potentials.

Philadelphia chromosome-positive thrombocythemia and megakaryoblast leukemia.

A case of well-documented and -illustrated megakaryoblastic transformation is described in a patient with thrombocythemia passing through a stage of myelofibrosis without features of chronic granulocytic leukemia. Immunocytologic studies with the use of conventional and monoclonal antibodies against platelet membrane glycoproteins and electron microscopic investigations, demonstrating bull's-eye granules and platelet peroxidase positivity, proved the megakaryocytic differentiation of the blast cells. From the onset of the disease as well as during the megakaryoblastic transformation, the Philadelphia (Ph1) karyotype, 46XX t(9:22) (q34:q11), was found in peripheral blood and bone marrow cells as the only clonal abnormality. Southern blot analysis of DNA extracted from the blast cells revealed a rearrangement within the bcr on chromosome 22 similar to findings in chronic granulocytic leukemia. The presentation with excessive small and abnormal megakaryocytes in the initial and subsequent bone marrow and the rapid progressive myelofibrosis and splenomegaly differentiate the Ph1 chromosome-positive thrombocythemia from the chronic myeloproliferation of thrombocythemia in its primary form or associated with polycythemia vera.

Renal AA amyloidosis in a patient with Bence Jones proteinuria and ankylosing spondylitis.

A patient with a 10 year history of monoclonal gammopathy of undetermined significance and Bence Jones proteinuria, and a 44 year history of ankylosing spondylitis, developed a nephrotic syndrome secondary to renal amyloidosis. Clinically the amyloidosis was ascribed to Bence Jones proteinuria rather than to the burnt out ankylosing spondylitis. However, histochemical and immunofluorescence staining techniques used to type the amyloid fibrils showed AA amyloidosis, implicating ankylosing spondylitis rather than monoclonal gammopathy as the underlying cause of the patient's systemic amyloidosis and consequent nephrotic syndrome. It is recommended that immunostaining of amyloid become a routine procedure to detect occult or apparently inactive disease.