Platelet larceny: spurious hypoxaemia due to extreme thrombocytosis

Rapid oxygen consumption by markedly increased numbers of hypermetabolic leukocytes in leukaemic patients resulting in the apparent diagnosis of hypoxaemia on arterial blood gas analyses is termed leukocyte larceny. In the present report, a case of polycythaemia vera, extreme thrombocytosis, normal leukocyte counts and arterial hypoxaemia in the absence of clinical, radiological or physiological evidence of lung disease is described. This pseudohypoxaemia case was established by pulse oximetry, as well as by incubation of a blood specimen with potassium cyanide, and became less significant after the use of cytoreductive agents showed a proportionate increase in arterial oxygen tension as platelet counts decreased on serial arterial blood gas analyses. The present case report demonstrates spurious hypoxaemia due to extreme thrombocytosis and shows that, beside significant leukocytosis, even markedly elevated platelet counts can cause larceny of arterial blood oxygen.

Efficacy of romiplostim in patients with chronic immune thrombocytopenic purpura: a double-blind randomised controlled trial

BACKGROUND

Chronic immune thrombocytopenic purpura (ITP) is characterised by accelerated platelet destruction and decreased platelet production. Short-term administration of the thrombopoiesis-stimulating protein, romiplostim, has been shown to increase platelet counts in most patients with chronic ITP. We assessed the long-term administration of romiplostim in splenectomised and non-splenectomised patients with ITP.

METHODS

In two parallel trials, 63 splenectomised and 62 non-splenectomised patients with ITP and a mean of three platelet counts 30x10(9)/L or less were randomly assigned 2:1 to subcutaneous injections of romiplostim (n=42 in splenectomised study and n=41 in non-splenectomised study) or placebo (n=21 in both studies) every week for 24 weeks. Doses of study drug were adjusted to maintain platelet counts of 50x10(9)/L to 200x10(9)/L. The primary objectives were to assess the efficacy of romiplostim as measured by a durable platelet response (platelet count > or =50x10(9)/L during 6 or more of the last 8 weeks of treatment) and treatment safety. Analysis was per protocol. These studies are registered with ClinicalTrials.gov, numbers NCT00102323 and NCT00102336.

FINDINGS

A durable platelet response was achieved by 16 of 42 splenectomised patients given romplostim versus none of 21 given placebo (difference in proportion of patients responding 38% [95% CI 23.4-52.8], p=0.0013), and by 25 of 41 non-splenectomised patients given romplostim versus one of 21 given placebo (56% [38.7-73.7], p<0.0001). The overall platelet response rate (either durable or transient platelet response) was noted in 88% (36/41) of non-splenectomised and 79% (33/42) of splenectomised patients given romiplostim compared with 14% (three of 21) of non-splenectomised and no splenectomised patients given placebo (p<0.0001). Patients given romiplostim achieved platelet counts of 50x10(9)/L or more on a mean of 13.8 (SE 0.9) weeks (mean 12.3 [1.2] weeks in splenectomised group vs 15.2 [1.2] weeks in non-splenectomised group) compared with 0.8 (0.4) weeks for those given placebo (0.2 [0.1] weeks vs 1.3 [0.8] weeks). 87% (20/23) of patients given romiplostim (12/12 splenectomised and eight of 11 non-splenectomised patients) reduced or discontinued concurrent therapy compared with 38% (six of 16) of those given placebo (one of six splenectomised and five of ten non-splenectomised patients). Adverse events were much the same in patients given romiplostim and placebo. No antibodies against romiplostim or thrombopoietin were detected.

INTERPRETATION

Romiplostim was well tolerated, and increased and maintained platelet counts in splenectomised and non-splenectomised patients with ITP. Many patients were able to reduce or discontinue other ITP medications. Stimulation of platelet production by romiplostim may provide a new therapeutic option for patients with ITP.

Erythropoietic protoporphyria: altered phenotype after bone marrow transplantation for myelogenous leukemia in a patient heteroallelic for ferrochelatase gene mutations

Acute myelogenous leukemia occurred in a 47-year-old woman whose 25-year history of cutaneous photosensitivity had been undiagnosed until abnormally high erythrocyte, plasma, and fecal protoporphyrin levels were discovered during evaluation for her hematologic disorder. She was found to be heteroallelic for ferrochelatase gene mutations, bearing a novel missense mutation caused by a C185-->G (Pro62-->Arg) transversion in exon 2 of one allele, and a previously described g-->a transition at the +5 position of the exon 1 donor site of the other allele, confirming a diagnosis of erythropoietic protoporphyria. Successful bone marrow transplantation from her brother, who is a mildly affected bearer of the second mutation, resulted in remission of the leukemia and in conversion of the protoporphyria phenotype of the recipient to one resembling that of the donor.

Epoetin treatment of anemia associated with cancer therapy: a systematic review and meta-analysis of controlled clinical trials

Epoetin treatment offers an attractive but costly alternative to red blood cell transfusion for managing anemia associated with cancer therapy. The goal of this review is to facilitate more efficient use of epoetin by 1) quantifying the effects of epoetin on the likelihood of transfusion and on quality of life in patients with cancer treatment-related anemia and 2) evaluating whether outcomes are superior when epoetin treatment is initiated at higher hemoglobin thresholds. Two independent reviewers followed a prospective protocol for identifying studies. Outcomes data were combined with the use of a random-effects meta-analysis model. Double-blind, randomized, controlled trials that minimized patient exclusions were defined as higher quality for sensitivity analysis; randomized but unblinded trials and trials with excessive exclusions were included in the meta-analysis but were defined as lower quality. Twenty-two trials (n = 1927) met inclusion criteria, and 12 (n = 1390) could be combined for estimation of odds of transfusion. Epoetin decreased the percentage of patients transfused by 9%-45% in adults with mean baseline hemoglobin concentrations of 10 g/dL or less (seven trials; n = 1080), by 7%-47% in those with hemoglobin concentrations greater than 10 g/dL but less than 12 g/dL (seven trials; n = 431), and by 7%-39% in those with hemoglobin concentrations of 12 g/dL or higher (five trials; n = 308). In sensitivity analysis, the combined odds ratio for transfusion in epoetin-treated patients as compared with controls was 0.45 (95% confidence interval [CI] = 0.33 to 0.62) in higher quality studies and 0.14 (95% CI = 0.06 to 0.31) in lower quality studies. The number of patients needed to treat to prevent one transfusion is 4.4 for all studies, 5.2 for higher quality studies, and 2.6 for lower quality studies. Only studies with mean baseline hemoglobin concentrations of 10 g/dL or less reported statistically significant effects of epoetin treatment on quality of life; quality-of-life data were insufficient for meta-analysis. No studies addressed epoetin's effects on anemia-related symptoms. We conclude that epoetin reduces the odds of transfusion for cancer patients undergoing therapy. Evidence is insufficient to determine whether initiating epoetin earlier spares more patients from transfusion or results in better quality of life than waiting until hemoglobin concentrations decline to nearly 10 g/dL.

An evidence-based analysis of the effect of busulfan, hydroxyurea, interferon, and allogeneic bone marrow transplantation in treating the chronic phase of chronic myeloid leukemia: developed for the American Society of Hematology

Because there are differing opinions regarding treatment of patients in the chronic phase of chronic myeloid leukemia (CML), the American Society of Hematology convened an expert panel to review and document evidence-based benefits and harms of treatment of CML with busulfan (BUS), hydroxyurea (HU), recombinant interferon-alpha (rIFN-alpha), and bone marrow transplantation (BMT). The primary measure for defining efficacy was survival. Analysis indicated a survival advantage for HU over BUS. Observational studies of rIFN-alpha suffer from numerous biases including sample size, variations in study populations, definitions of hematologic and cytogenetic remissions, and dose. That rIFN-alpha is more efficacious than chemotherapy is demonstrated by 6 prospective randomized trials. For patients with favorable clinical features in chronic phase, compared to HU and BUS, rIFN-alpha improves survival by a median of about 20 months. Most evidence suggests that rIFN-alpha is most effective when combined with other drugs and when given during the earliest stage of the chronic phase. Adding cytarabine to rIFN-alpha adds further survival benefit but increases toxicity. Limitations for evaluating the long-term benefits of allogeneic BMT include the retrospective nature of most studies, incomplete documentation of the clinical characteristics of the patients, paucity of the details on patient selection, lack of control groups, and limitations of survival calculations. Survival curves for BMT show that at least half of the patients transplanted remain alive 5 to 10 years after treatment, whereas similar curves for rIFN-alpha show a continuous relapse rate over time with the curves crossing at about 7 to 8 years. Estimates of long-term survival may be confounded by the selection biases mentioned and the analytic methods used. The magnitude of the incremental increase in benefit with BMT must be weighed against the potential serious harm and death that may accompany the procedure in the short term. The best results with BMT have been obtained when it is performed within 1 to 2 years from diagnosis. Since each treatment option involves tradeoffs between benefit and harm, patient choice must be based on the examination of facts presented in an unbiased fashion. Newly diagnosed younger patients and older patients who are candidates for BMT should also be offered information about IFN-based regimens, the tradeoffs involved, and, if possible, share in the treatment decision. Hopefully this analysis will provide the stimulus for evaluation of other important aspects of CML.

2',5'-Oligoadenylate-antisense chimeras cause RNase L to selectively degrade bcr/abl mRNA in chronic myelogenous leukemia cells

We report an RNA targeting strategy, which selectively degrades bcr/abl mRNA in chronic myelogenous leukemia (CML) cells. A 2', 5'-tetraadenylate activator (2-5A) of RNase L was chemically linked to oligonucleotide antisense directed against either the fusion site or against the translation start sequence in bcr/abl mRNA. Selective degradation of the targeted RNA sequences was demonstrated in assays with purified RNase L and decreases of p210(bcr/abl) kinase activity levels were obtained in the CML cell line, K562. Furthermore, the 2-5A-antisense chimeras suppressed growth of K562, while having substantially reduced effects on the promyelocytic leukemia cell line, HL60. Findings were extended to primary CML cells isolated from bone marrow of patients. The 2-5A-antisense treatments both suppressed proliferation of the leukemia cells and selectively depleted levels of bcr/abl mRNA without affecting levels of beta-actin mRNA, determined by reverse transcriptase-polymerase chain reaction (RT-PCR). The specificity of this approach was further shown with control oligonucleotides, such as chimeras containing an inactive dimeric form of 2-5A, antisense lacking 2-5A, or chimeras with altered sequences including several mismatched nucleotides. The control oligonucleotides had either reduced or no effect on CML cell growth and bcr/abl mRNA levels. These findings show that CML cell growth can be selectively suppressed by targeting bcr/abl mRNA with 2-5A-antisense for decay by RNase L and suggest that these compounds should be further explored for their potential as ex vivo purging agents of autologous hematopoietic stem cell transplants from CML patients.

Hematologic complications of rheumatic disease therapies

Hematologic side effects of rheumatic disease therapies are generally mild and reversible; however, the clinician must be alert for potential profound and life-threatening toxicities. A knowledge of the toxicity patterns for the individual drugs is necessary to anticipate potential complications. Management of acute leukemias and lymphomas arising in patients with connective tissue disorders is particularly challenging. Further data are needed to define the best treatment options and thus enrollment in clinical trials is encouraged for these patients.

Antithrombotic, anticoagulant, and thrombolytic agents

There are a growing number of clinical indications for the use of antithrombotic, anticoagulant, and thrombolytic agents. Clinicians must recognize that these patients require multidisciplinary treatment and coordination of care, and an assessment of the patient's level of anticoagulation is imperative to ensure values that may preclude problematic bleeding during dental procedures, yet maintain therapeutic anticoagulation.

High-dose busulfan and cyclophosphamide followed by autologous bone marrow transplantation and/or peripheral blood progenitor cell rescue for metastatic breast cancer

High doses of combination alkylating agents have shown promise in the treatment of breast cancer but are complicated by significant toxicity. Busulfan and cyclophosphamide (BuCy) is a high-dose combination alkylating agent regimen that is well-tolerated when given for hematologic malignancy. We prospectively studied the effects of BuCy followed by autologous bone marrow transplant (ABMT) or peripheral blood progenitor cell (PBPC) rescue in 21 patients with metastatic breast cancer who had responded to either standard chemotherapy or radiotherapy. The mean patient age was 44 years. Nine patients were either estrogen- or progesterone-receptor positive, ten were negative, and two were unknown. Fourteen patients had local recurrence, ten had bone metastases, six had visceral disease, and two had a nonlocal soft tissue recurrence. Busulfan 16 mg/kg and cyclophosphamide 120 mg/kg (BuCy2) was given and followed by either ABMT, PBPC rescue, or both. Grade III to IV extramyeloid toxicity occurred in 6 (29%) patients. One patient died of hepatic venoocclusive disease but there was no other treatment-related mortality. Pulmonary infiltrates with hypoxia of uncertain origin developed in 2 patients after discharge. Of the 10 patients with measurable disease, 4 had complete responses, and 3 had partial responses to high-dose therapy for a total response rate of 70%. The estimated 2-year disease-free survival is 25% (95% CI = 6% to 44%). Our study found BuCy to be a well-tolerated preparative regimen for ABMT in the treatment of patients with metastatic breast cancer.

G-CSF primed peripheral blood progenitor cells in autologous bone marrow transplantation: parameters affecting bone marrow engraftment

G-CSF and GM-CSF enhance the rate of neutrophil engraftment in autologous bone marrow transplantation (ABMT) without significantly affecting platelet engraftment. Peripheral blood progenitor cells (PBPC) may enhance rates of engraftment of both neutrophils and platelets. We treated 49 patients undergoing ABMT with a course of G-CSF to obtain PBPC and infused these cells post-transplant with G-CSF in an attempt to determine factors which might correlate with enhanced BM engraftment. Forty-nine patients with Hodgkin's disease, non-Hodgkin's lymphoma or breast cancer undergoing unpurged ABMT were studied. G-CSF priming consisted of an outpatient 8 day course of 5 micrograms/kg/day followed by three leukaphereses (on day 5, 7 and 8) to collect PBPC. Patients then received a chemotherapeutic BMT preparative regimen followed by an infusion of PBPC, autologous BM and the reinstitution of G-CSF (16 micrograms/kg/day). BM engraftment was rapid. The median time to achieve 0.5 x 10(9)/l neutrophils was 10 days compared with a historical BMT control patient population receiving the same preparative regimens of 19 days (p = 0.001). Time to achieve a platelet count of 20 x 10(9)/l was 16 days compared with a historical control of 22 days (p = 0.001). Neutrophil engraftment occurred in all patients by day +14. Marrow engraftment correlated with the total number of CD34+ cells infused as well as the total number of mononuclear cells infused but not the total number of CD34+/CD33- cells infused. The amount of total blood volume pheresed significantly correlated with yield of total mononuclear cells. Prior exposure to radiation therapy negatively correlated with progenitor cell yield.(ABSTRACT TRUNCATED AT 250 WORDS)

Precursor Langerhans cell histiocytosis. An unusual histiocytic proliferation in a patient with persistent non-Hodgkin lymphoma and terminal acute monocytic leukemia

BACKGROUND

Langerhans cell precursors are considered to be identical to their mature counterparts except for the lack of Birbeck granules. Proliferations composed of such histiocytes appear to be uncommon.

METHODS

Standard immunophenotypic, molecular genetic, and DNA content studies were used to characterize various hematopoietic disorders, including a proliferation of precursor Langerhans cells, which arose sequentially in a patient.

RESULTS

The patient studied initially had a low-grade, B-cell, non-Hodgkin lymphoma and subsequently had an unusual histiocytic proliferation (precursor Langerhans cell histiocytosis) in cutaneous and lymph node sites. The patient eventually died of acute myelogenous leukemia (FAB, M5).

CONCLUSIONS

A larger series is required to determine the significance of the precursor Langerhans cell phenotype, particularly with respect to the development of acute myelogenous leukemia.

Incidence of mixed chimerism using busulfan/cyclophosphamide containing regimens in allogeneic bone marrow transplantation

The incidence of mixed chimerism (MC) following allogeneic bone marrow transplantation (allo-BMT) is in part a measure of the marrow ablative effect of preparative regimens. Although the incidence of MC has been reported for many patients treated with total body irradiation (TBI), limited data for busulfan/cyclophosphamide (BU/CY) recipients have been examined. We performed restriction fragment length polymorphism (RFLP) analysis on 68 peripheral blood samples from 26 patients treated with BU/CY prior to allo-BMT for chronic myelogenous leukemia or acute myeloid leukemia. MC was detected in four of 26 patients for an overall incidence of 15.4%. Three of four MC patients are alive with no evidence of disease at 263 to 795 days post-transplantation. A fourth patient is alive at day 501 but developed CNS relapse at day 274. The level of recipient origin cells was less than 10% in all samples and detectable MC was transitory with an RFLP pattern that reverted to full chimerism. These results are comparable to those reported for TBI-containing regimens in patients receiving non-T cell-depleted bone marrow. The efficacy of BU/CY in conjunction with a T cell depletion still requires exploration.

Pseudo-gamma heavy chain (IgG4 lambda) deposition disease

Two patients with Ig deposition disease presented with acute renal failure, moderate proteinuria, and hematuria. A plasmacytoid lymphocytic infiltrate was identified in bone marrow that produced IgG4 lambda and free lambda light chains. One patient developed an anaplastic plasmacytoma (secreting only lambda light chains) 1 yr after renal biopsy. Renal biopsy in both patients demonstrated a nodular intercapillary glomerulopathy and electron dense granular deposits, associated with a linear pattern of IgG4 heavy chain deposition in vascular, tubular, and glomerular basement membranes (VBM, TBM, and GBM). In one patient this entrapped IgG4 was unassociated with detectable kappa or lambda light chains. In the second patient, lambda light chains (1+) were detected only in the GBM, but IgG4 (4+) was identified in GBM/TBM. Neither circulating (peripheral blood and bone marrow serum) nor cellular free gamma chains were present. We propose the term "pseudo-gamma heavy chain deposition disease" for the process.

Efficacy of intensive plasmapheresis in thrombotic thrombocytopenic purpura

Forty-one patients with thrombotic thrombocytopenic purpura were treated at the Hospital of the University of Pennsylvania, Philadelphia, between 1975 and 1985. Initially, early splenectomy was performed. However, since 1981, more intensive plasma exchange therapy (increase in frequency and size of exchange) has been used as the primary modality of treatment for this disorder. A reduction of the mortality rate over time has been observed. For the period 1975 to 1980, the mortality rate was 41% (seven of 17). In contrast, for the period 1981 to 1985, the mortality rate decreased to 17% (four of 24). These observations support the concept that the initial management of thrombotic thrombocytopenic purpura with intensive daily plasma exchange is associated with improved survival. The role of platelet inhibitors and corticosteroids needs yet to be defined.