Aplastic anaemia

Aplastic anaemia is a rare haemopoietic stem-cell disorder that results in pancytopenia and hypocellular bone marrow. Although most cases are acquired, there are unusual inherited forms. The pathophysiology of acquired aplastic anaemia is immune mediated in most cases; autoreactive lymphocytes mediate the destruction of haemopoietic stem cells. Environmental exposures, such as to drugs, viruses, and toxins, are thought to trigger the aberrant immune response in some patients, but most cases are classified as idiopathic. Similarly to other autoimmune diseases, aplastic anaemia has a varied clinical course; some patients have mild symptoms that necessitate little or no therapy, whereas others present with life-threatening pancytopenia representing a medical emergency. Paroxysmal nocturnal haemoglobinuria and myelodysplastic syndrome commonly arise in patients with aplastic anaemia, showing a pathophysiological link between these disorders. Acquired aplastic anaemia can be effectively treated by allogeneic bone-marrow transplantation, immunosuppression (generally antithymocyte globulin and ciclosporin), and high-dose cyclophosphamide.

Aplastic Anemia: Management of Adult Patients

The primary therapeutic approach to acquired aplastic anemia (AA) in older adults differs from the primary approach used in children and younger adults because in the former group, the results of allogeneic bone marrow transplantation (BMT) are less favorable. With increasing age of the patients, immunosuppressive therapy with antithymocyte globulin (ATG) and cyclosporine (CsA) constitutes the primary treatment option and may be better than BMT. There are very few clinical clues as to the selection of patients likely to respond to immunosuppression. Repeated ATG/CsA cycles are often used as salvage regimens, but in refractory patients BMT may be the best treatment option, as the prognosis for non-responders is poor without definitive treatment. Conservative therapy such as intense immunosuppression is associated with a high relapse rate but does not impact the survival and overall prognosis. The inability to eliminate autoimmune T cell clones using current therapeutic strategies suggests that prolonged immunosuppressive maintenance therapy may be needed for a substantial proportion of patients. Late clonal complications of conservatively treated patients include evolution to myelodysplasia and paroxysmal nocturnal hemoglobinuria and may develop in 20% of the patients. However, BMT also has several sequelae including an increased frequency of solid tumors. Novel immunosuppressive and immunomodulatory agents and constantly improving results of allogeneic BMT will further improve the survival rate of adult patients with AA.

Fatal fulminant myocarditis caused by disseminated mucormycosis

Acute fulminant myocarditis is a critical clinical condition with sudden onset of severe congestive heart failure followed by severe haemodynamic deterioration. Instituting early left ventricular support may improve outcome and result in better long term survival. The case of an immunocompromised patient who developed acute fulminant myocarditis in the setting of disseminated mucormycosis is presented.

[Quantitative and functional changes of T helper cell subsets in the bone marrow of severe aplastic anemia patients]

OBJECTIVE

To evaluate the quantitative and functional changes of T helper (Th) cell subsets in the bone marrow of severe aplastic anemia (SAA) patients and the relationship between these changes and the patients hematopoietic function.

METHODS

By FACS, the quantity and ratio of Th1 and Th2 cells, the percentage of CD3(+)CD8(+) cells in the bone marrow were detected in 24 patients with SAA at active phase, 15 patients with SAA at recovery phase, and 16 normal controls. By radioimmunoassay, the serum levels of TNF-alpha, or IL-4 in 20 SAA patients at active phase, 12 at recovery phase and 16 normal controls were measured. The relationships between CD3(+)CD8(+) cells, TNF-alpha and Ret, ANC; and between Th1 cells and CD3(+)CD8(+) cells, TNF-alpha or Ret, ANC; between IL-4, balance of Th1/Th2 and Ret, ANC were evaluated.

RESULTS

The percentages of Th1 and Th2 cells, and ratio of Th1/Th2 in bone marrow of SAA patients at active phase were (4.87 +/- 2.64)%, (0.41 +/- 0.26)% and 21.22 +/- 5.07, respectively, being higher than those of normal controls [(0.42 +/- 0.30)% (P < 0.01), (0.24 +/- 0.17)% (P < 0.05) and (1.57 +/- 0.93) (P < 0.01), respectively] and all of them reduced to normal levels of SAA at recovery phase (P > 0.05). The percentage of CD3(+)CD8(+) cells significantly decreased from (32.32 +/- 8.69)% at active phase to (13.76 +/- 2.96)% at recovery phase (P < 0.01). The serum levels of TNF-alpha and IL-4 at active phase was (4.29 +/- 3.15) microg/L and (1.24 +/- 0.73) microg/L, respectively, being higher than those of normal controls (1.21 +/- 1.16) microg/L, (1.18 +/- 0.97) microg/L, but only the difference of TNF-alpha was statistically significant (P < 0.01). In recovery SAA patients, the serum levels of TNF-alpha significantly decreased to (1.46 +/- 1.41) microg/L (P < 0.01), and the levels of IL-4 increased markedly to (3.05 +/- 1.94) microg/L. The CD3(+)CD8(+) cells and TNF-alpha of patients negatively correlated with Ret (P < 0.05; P < 0.05) and ANC (P < 0.05; P < 0.05), Th1 cells correlated with CD3(+)CD8(+) cells and TNF-alpha positively (P < 0.01; P < 0.05), the Ret and ANC negatively (P < 0.01; P < 0.01), IL-4 and the balance of Th1/Th2 positively correlated with Ret and ANC (P < 0.05, P < 0.01; P < 0.01, P < 0.01).

CONCLUSION

The bone marrow failure in SAA might be caused not only by the increase of Th1 cells, Th1 type effector cells and cytokines, but also by insufficient compensation of Th2 cells and Th2 type cytokines, which shifted the balance of Th1/Th2 favorable to Th1.

Excessive production of tumor necrosis factor-alpha by bone marrow T lymphocytes is essential in causing bone marrow failure in patients with aplastic anemia

Aplastic anemia (AA) is regarded as an immunological disorder because of the clinical effect of immunosuppressive therapy. Recent studies have reported that cytokines play an important role in the development of AA. In the present study, we measured levels of T-cell derived intracellular cytokine production in peripheral blood and bone marrow (BM) of patients with AA. We demonstrated that BM lymphocytes, particularly CD4(+) and CD8(+) T cells, in patients with AA produced significantly higher amounts of tumor necrosis factor-alpha (TNF-alpha), compared with lymphocytes in normal controls. We have previously reported that expression of TNF receptor (R)1 and TNFR2 in the CD34(+) CD38(-) and CD34(+) CD38(+) fractions of patients with AA is significantly higher than those in normal control. These results indicate that BM stem cells in patients with AA may possess high sensitivity to TNF-alpha. This in turn suggests that TNF-alpha affects hematopoiesis at an earlier stage in AA patients than in normal controls. We strongly support the hypothesis that a simultaneous increase in TNF-alpha production by BM lymphocytes and sensitivity of stem cells to TNF-alpha leads to BM failure in AA.

Marrow Failure

New discoveries in cell biology, molecular biology and genetics have unveiled some of the pathophysiological mysteries of some of the bone marrow failure syndromes. Many of these discoveries have revealed why these syndromes show so much clinical overlap and some hold the potential for influencing the development of new therapies. In children and adults with pancytopenia and hypoplastic bone marrows proper differential diagnosis requires that some attention be directed toward defining molecular and cellular pathogenetic mechanisms because, once identified, some of these mechanisms will clearly suggest rational therapeutic approaches, treatment options that should be avoided, or both.

In Section I, Drs. Jeffrey Lipton and Grover Bagby review the approach to diagnosis and management of patients with the inherited bone marrow failure syndromes, Fanconi anemia, dyskeratosis congenita, Diamond-Blackfan anemia, and the Shwachman-Diamond syndrome. Extraordinary progress has been made in identifying the genes bearing pathogenetically relevant mutations in these disorders, but slower progress has been made in defining the precise functions of the proteins these genes encode in normal cells, in part because it is increasingly obvious that the proteins are multifunctional. In practice, it is clear that in patients with dyskeratosis congenita and Fanconi anemia, the diagnosis must be considered not only in children but in adults as well.

In Section II, Dr. Elaine Sloand outlines a very practical and evidence-based approach to diagnosis and management of acquired hypoplastic states emphasizing overlap between non-clonal and clonal hematopoiesis is such conditions. The pathogenesis of T lymphocyte–mediated marrow failure is presented as a clear-cut rationale for use of immunosuppressive therapy and stem cell transplantation. Practical management of patients with refractory disease with and without evidence of clonal evolution (either paroxysmal nocturnal hemoglobinuria [PNH] or myelodysplasia [MDS]) is presented.

In Section III, the challenge of hypoplastic MDS is reviewed by Dr. Charles Schiffer. After reviewing the most up-to-date classification scheme, therapeutic options are reviewed, focusing largely on agents that have most recently shown some promising activity, including DNA demethylating agents, thalidomide and CC5013, arsenic trioxide, and immunosuppressive therapy. Here are also outlined the rationale and the indications for choosing allogeneic bone marrow transplantation, the only therapy with known curative potential.

Acquired aplastic anemia

Acquired aplastic anemia (AA) is a disorder characterized by a profound deficit of hematopoietic stem and progenitor cells, bone marrow hypocellularity, and peripheral blood pancytopenia. It primarily affects children, young adults, and those over 60 years of age. The majority of cases are idiopathic; however, idiosyncratic reactions to some drugs, chemicals, and viruses have been implicated in its etiology. An autoimmune T-cell reaction likely causes the stem cell depletion, but the precise mechanism, as well as the eliciting and target antigens, is unknown. Symptoms vary from severe life-threatening cytopenias to moderate or non-severe disease that does not require transfusion support. The peripheral blood typically exhibits pancytopenia, reticulocytopenia, and normocytic or macrocytic erythrocytes. The bone marrow is hypocellular and may exhibit dysplasia of the erythrocyte precursors. First line treatment for severe AA consists of hematopoietic stem cell transplantation in young patients with HLA identical siblings, while immunosuppression therapy is used for older patients and for those of any age who lack a HLA matched donor. Patients with AA have an increased risk of developing paroxysmal nocturnal hemoglobinuria (PNH), myelodysplastic syndrome (MDS), or acute leukemia. Further elucidation of the pathophysiology of this disease will result in a better understanding of the interrelationship among AA, PNH, and MDS, and may lead to novel targeted therapies.

Clinical presentation of parvovirus B19 infection in children with aplastic crisis

The records of 22 children with parvovirus B19-induced aplastic crisis were reviewed. The group consisted of 16 children with sickle cell hemoglobinopathies and 6 with hereditary spherocytosis. Children presented to the hospital 0.5 to 8 days (mean, 2.4 days) after the onset of symptoms. The children with sickle-cell disease presented earlier (mean, 1.4 days) than did children with hereditary spherocytosis (mean, 5 days; P = 0.02. Fever was the most common symptom, occurring in 73% of children. Rash did not occur in either group. Reticulocyte counts began to rise 1 week after onset of illness associated with a rise in parvovirus B19-specific IgG antibody. These data suggest that parvovirus B19 infection in children with sickle-cell hemoglobinopathies and heredity spherocytosis differs from infection in normal children.

Hematopoietic management in oncology practice. Part 2. Erythropoietic factors

As the major regulator of erythropoiesis in man, erythropoietin inhibits the programmed cell death of committed erythroid precursors. In cancer patients, a relative erythropoietin deficiency is coupled with a decreased responsiveness to the substance mediated by the effects of inflammatory cytokines on the marrow and on ferrokinetics, leading to a high incidence of anemia. Two recombinant human erythropoietin (rhEPO) preparations--epoetin alfa (Epogen, Procrit) and epoetin beta (Marogen)--as well as a modified erythropoietic compound (darbepoetin alfa [Aranesp]) are in clinical use. Part 2 of this two-part series on hematopoietic agents reviews the use of these erythropoietic factors and their effect on the anemia that develops in cancer patients. Thrombopoietic factors and progenitor cell-mobilizing factors are also briefly addressed.

New insights into the physiology and treatment of acquired myelodysplastic syndromes and aplastic pancytopenia

MDS are a diverse group of primary and secondary bone marrow disorders that are characterized by cytopenias in blood, prominent dysplastic features in blood or bone marrow, and normal or hypercellular bone marrow. MDS in cats are typically associated with FeLV infection. Dogs with MDS-RC and MDS-Er seem to respond to erythropoietin administration and have prolonged survival. Dogs with MDS-EB respond poorly to present treatments, and survival is short. Prognosis and probability of progression to acute myelogenous leukemia can be predicted based on the percentage of myeloblasts in bone marrow. Several experimental therapeutic modalities in human beings have been described that may be useful in treating MDS-EB in dogs and cats. Aplastic pancytopenia is a relatively rare disorder in dogs and cats. Causes include Ehrlichia spp, Parvovirus, and FeLV infections; sepsis; chronic renal failure; drug and toxin exposure; and idiopathic causes. Diagnosis is based on identification of multiple cytopenias in the blood and hypoplastic/aplastic bone marrow, with the marrow space replaced by adipose tissue. Treatment and outcome are dependent on determining the underlying cause of the bone marrow failure.

Hematopoietic stem cells in aplastic anemia

Profound cytopenia involving all blood lineages, a hallmark of aplastic anemia (AA), can result in devastating morbidity and high mortality. Although various etiologies and distinct pathophysiologic mechanisms may be involved, a profound defect in the stem cell compartment is a unifying feature in most patients with AA. As a stem cell disease, AA is very instructive and provides insights into the function and quantity of normal hematopoietic stem cells and their ability to regenerate. Pathophysiologically, understanding of AA may reveal mechanisms as to the evolution of other related bone marrow failure syndromes such as paroxysmal nocturnal hemoglobinuria and myelodysplasia-clonal diseases of hematopoiesis associated with defective stem cells. Conversely, constitutional forms of AA occurring in association with Fanconi anemia and dyskeratosis congenita demonstrate the role of specific genes and pathways in the dysfunction of the stem cells leading to the failure of the stem cell compartment. The acquired mechanisms resulting in depletion of stem cells in AA may involve fundamental pathways such as apoptosis and senescence as well as exhaustion of proliferative capacity or excessive differentiation. Inherent in the paucity of the bone marrow in AA, the study of the stem cells in AA has been very difficult due to their natural rarity and disease-specific contraction of the stem cell pool. Despite these scientific challenges, laboratory studies and systematic clinical observation provide valuable information of significance beyond its specific application to AA.

Aplastic anemia complicating systemic lupus erythematosus: successful management with cyclosporine

Anemia is common with connective tissue disorders, but pancytopenia is rare. We report a 22-year-old female who presented with menorrhagia, seizures, anemia, leukocytosis, thrombocytopenia, pericardial effusion, positive ANA, and evidence of vasculitis on CT head scan and was diagnosed with systemic lupus erythematosus (SLE). After 7 months of remission, she was readmitted with menorrhagia and pancytopenia. Investigations revealed aplastic anemia. She survived on transfusion support for 6 weeks, during which period she received methylprednisolone and cyclophosphamide pulses, and phenytoin was omitted but to no avail. Cyclosporine (300 mg/day) was started and the aplastic anemia responded. After 4 months of therapy, the cyclosporine was gradually tapered over the next 2 months. The patient has been on 10 mg/day of prednisolone for the last 6 months. Aplastic anemia is rare in SLE and the response to immunosuppressants is variable, but here is a success story.

Pathophysiology and treatment of aplastic anemia

Aplastic anemia (AA) is a rare hematological disease characterized by peripheral blood pancytopenia and a hypocellular bone marrow in which normal hematopoietic tissue is replaced by fatty marrow. There is strong in vitro and in vivo evidence suggesting an immunologic mechanism for hematopoietic suppression in the majority of patients with AA. Interferon-gamma and tumor necrosis factor-alpha are considered as soluble mediators of bone marrow (BM) suppression in AA. The events triggering the aberrant immune response are less clear but some viruses and drug metabolites may lead to autoimmune destruction of hematopoietic cells. Patients with severe AA who are younger than 35 to 45 years and who have an HLA-identical sibling donor have a 60-80% chance of being cured by allogeneic BM transplantation. In patients surviving more than two years, chronic graftversus-host disease is the major cause of morbidity and mortality and a solid-tumor malignancy may develop in a few patients. Patients without HLA-identical BM donors and patients older than 35 to 45 years are candidates for combined immunosuppressive treatment with antithymocyte globulin, methylpredisolone and cyclosporine, leading to hematological responses in 70-80% of patients. One has to consider, however, that a significant proportion of these patients will develop further clonal hematological disorders such as paroxysmal nocturnal hemoglobinuria and myelodysplastic syndrome.

Recent insights into the pathophysiology of paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a unique clonal stem cell disorder characterized by intravascular hemolysis, thrombotic events and bone marrow failure. There has been accelerated progress in understanding the mechanisms underlying the clinical features of the disease over the last decade. The development of PNH requires not only a somatic mutation of the phospatidylinositol glycan complementation class A (PIG-A) gene, but also a survival advantage of the PNH clone ('dual pathogenesis' theory). There is increasing evidence that negative selection against the non-mutated cells rather than positive selection of the PIG-A gene mutant cells is responsible for the dominance of the PNH clone. In this review, we summarize the important advances in the understanding of PNH, but we also concentrate on the presence of PNH clones in other hematological disorders, including aplastic anemia (AA), myelodysplastic syndromes (MDS), acute leukemias, and myeloproliferative and lymphoproliferative syndromes. The fuller comprehension of the pathophysiology of PNH may have wider implications than for PNH itself, as indicated by the presence of PNH clones in these hematological malignancies, and by the therapeutic implications of this fact, as already described in patients with AA and MDS.

Aplastic anaemia: a review

Aplastic anaemia is featured by bone marrow hypocellularity and peripheral pancytopenia and is a potentially fatal disease. In recent years, insight in it pathogenesis has increased. It appears that activated autoreactive T lymphocytes induce apoptosis of haematopoietic stem cells resulting in a hypocellular bone marrow. Nowadays, it can be treated by stem cell transplantation or immunosuppressive therapy. This review focuses on the pathophysiology and treatment of aplastic anaemia.

Membranous nephropathy after allogeneic hematopoietic stem cell transplantation in a patient with aplastic anemia: a case report

Nephrotic syndrome has been described as one of the clinical forms of chronic graft-versus-host disease (cGVHD), but a limited number of cases have been described. We experienced a young female patient with nephrotic syndrome developed 22 months after allogeneic hematopoietic stem cell transplantation (HSCT) for severe aplastic anemia. She had been well after successful management for gut-limited cGVHD until she developed a clinical nephrotic syndrome with hypoalbuminemia of 2.0 g/dL and 24-hr urine protein of 6.88 g/dL. On physical examination and laboratory findings, there was no other evidence of cGVHD. Clinical and renal biopsy findings were consistent with cGVHD-related membranous nephropathy, and immunosuppressive agents with cyclosporine and prednisone were prescribed. After 3 month of treatment, the proteinuria decreased to normal range; and the patient from nephrotic syndrome nearly recovered. We recommend cGVHD-related glomerulonephritis should be considered in all patients with hypoalbuminemia following allogeneic HSCT, even if there is no other evidence of clinical GVHD.

Aplastic anemia associated with interferon beta-1a

Subcutaneous interferon beta-1a is a recognized treatment of relapsing multiple sclerosis, and it may delay the onset of definite multiple sclerosis in patients with a first clinical demyelinating episode. Interferon beta-1a exerts beneficial effects on cognitive functioning via both short-term and long-term mechanisms. The beneficial effect is thought to be a result of immune modulation, with inhibition of leukocyte proliferation and antigen presentation and an increased amount of interleukins. The systemic side effects of interferon beta-1a are flu-like syndrome and development of neutralizing antibodies, the clinical significance of which is not known. There have been concerns about the rare development of an acute demyelinating disease after interferon beta-1a therapy as a result of upregulation of inflammatory mediators. In the clinical trials, there is evidence of development of mild anemia with a hemoglobin level below 10 g/dL only in 3% of the patients. There has been no reported case of development of aplastic anemia in patients being treated with interferon beta-1a. Described here is a case of development of aplastic anemia with interferon beta-1a in a patient with multiple sclerosis. Our patient underwent a complete hematologic evaluation to rule out other causes of aplastic anemia. Association with interferon beta-1a was highly suspected.

Severe aplastic anemia and allogeneic hematopoietic stem cell transplantation

Aplastic anemia is a form of bone marrow failure that ranges in severity from mild to severe. In all cases, some degree of pancytopenia is present. The cause usually is unknown, although many drugs and viruses are associated with the disease. The pathophysiology of aplastic anemia involves either a stem cell defect or injury or an immunologically mediated hematopoietic cell destruction, which may operate in concert with abnormalities in programmed cell death. Excellent clinical care and research have dramatically improved patient survival, with 70% to 90% of sibling hematopoietic stem cell transplant recipients surviving long term. Patients with mild or moderate disease may not require immediate treatment. If and when these patients require treatment, the mainstay of therapy is immunosuppression. The initial drug regimen includes antithymocyte globulin, often in combination with cyclosporine A, followed by moderate-dose steroids and cyclophosphamide. Nurses assess and monitor patients and their progress, recognizing medication adverse effects. Nurses educate patients about their disease and its treatment, and provide necessary emotional support. Severe aplastic anemia is treated with allogeneic hematopoietic stem cell transplantation. This therapy involves complex nursing challenges. The patient goes through an extensive pretransplantation workup. Donor selection and harvesting of hematopoietic stem cells are preludes to an intensive preparative regimen. This preparative or conditioning regimen and the need for long-term immunosuppression are the reasons for many of the acute complications and adverse events that may follow the hematopoietic stem cell transplantation. Nurses must be vigilant in assessing and monitoring patients for toxicities and long-term complications that may affect almost any organ system.

Acquired aplastic anemia

In aplastic anemia, hematopoiesis fails: Blood cell counts are extremely low, and the bone marrow appears empty. The pathophysiology of aplastic anemia is now believed to be immune-mediated, with active destruction of blood-forming cells by lymphocytes. The aberrant immune response may be triggered by environmental exposures, such as to chemicals and drugs or viral infections and, perhaps, endogenous antigens generated by genetically altered bone marrow cells. In patients with post-hepatitis aplastic anemia, antibodies to the known hepatitis viruses are absent; the unknown infectious agent may be more common in developing countries, where aplastic anemia occurs more frequently than it does in the West. The syndrome paroxysmal nocturnal hemoglobinuria (PNH) is intimately related to aplastic anemia because many patients with bone marrow failure have an increased population of abnormal cells. In PNH, an entire class of proteins is not displayed on the cell surface because of an acquired X-chromosome gene mutation. The PNH cells may have a selective advantage in resisting immune attack. In contrast, the disease myelodysplasia can be confused with aplasia and can also evolve from aplastic anemia. The occurrence of cytogenetic abnormalities in patients years after presentation implies that genomic instability is a feature of this immune-mediated disease. Aplastic anemia can be effectively treated by stem-cell transplantation or immunosuppressive therapy. Transplantation is curative but is best used for younger patients who have histocompatible sibling donors. Antithymocyte globulin and cyclosporine restore hematopoiesis in approximately two thirds of patients. However, recovery of blood cell count is often incomplete, recurrent pancytopenia requires retreatment, and some patients develop late complications (especially myelodysplasia).

Quantitative and qualitative assessment of reactive hematopoietic bone marrow in aplastic anemia using MR spectroscopy with variable echo times

OBJECTIVE

To assess quantitative and qualitative differences in water components between normal bone marrow and reactive hematopoietic marrow in aplastic anemia using magnetic resonance (MR) spectroscopy with variable echo times (TEs).

DESIGN

Water content, T2 value of the water component, and signal change in water related to TE were assessed in normal bone marrow and reactive hematopoietic bone marrow by a stimulated echo acquisition mode with TEs of 30, 45, 60, and 90 ms.

PATIENTS

Six patients with aplastic anemia (13-84 years) and seven normal volunteers (25-38 years) were examined.

RESULTS AND CONCLUSION

Reactive hematopoietic marrow showed significantly higher water content than normal bone marrow. The T2 value of water components tended to be longer in reactive hematopoietic marrow. Water signal ratio related to TE was significantly higher in reactive hematopoietic marrow. These results suggest a quantitative and qualitative difference in water components between normal and reactive hematopoietic bone marrow.

Epidemiological features of aplastic anaemia in Pakistan

OBJECTIVE

To complete the data on the demographic features of patients diagnosed to have aplastic anemia at a single institution over a 7.5 years period.

METHODS

Demographic information was retrieved from the patients medical records retrospectively as well as prospectively of those patients who presented with features of aplastic anaemia. Their diagnosis was confirmed by performing a complete blood count and bone marrow trephine.

RESULTS

One hundred and forty four patients were diagnosed to have aplastic anemia; there were 106 males and 38 females. Their ages ranged from 2 to 75 years, with a median of 17 years, 112 (77.7%) patients were below the age of 30 years. Severe aplastic anemia (SAA) was seen in 74 (51.4%), very severe (VSAA) in 24 (16.7%) and non-severe aplastic anemia (NSAA) in 46 (31.9%) patients. No obvious cause could be established for 74.3%. Thirteen patients admitted using drugs known to cause AA and one was a radiographer (9%). Out of 44 patients tested, 7 (15.9%) were found to have either hepatitis B virus markers or antibody to hepatitis C at the time of diagnosis of AA. However it was difficult to establish a cause and effect relationship with either drugs or viruses.

CONCLUSION

Aplastic anaemia is found to occur mostly in young males. The most common type was idiopathic severe aplastic anaemia.

Toxic epidermal necrolysis in a patient with severe aplastic anemia treated with cyclosporin A and G-CSF

Toxic epidermal necrolysis (TEN) and severe aplastic anemia (SAA) are rare nonpredictable side effects of several drugs. To our knowledge there are no reports on the coexistence of these two disorders. This study presents a 23 year-old man with TEN diagnosed 6 days after treatment with aminophenazone, paracetamol and phenoxymethylpenicillin. The resolution of the skin disorder was observed after few days of treatment with G-CSF and cyclosporin A. In contrast, SAA only partially responded to treatment with these agents.

[Apoptosis of bone marrow cells aplastic anemia patients treated with cyclosporin A]

OBJECTIVE

To evaluate the effects of cyclosporin A (CsA) on the apoptosis of bone marrow cells of aplastic anemia (AA) patients.

METHODS

The apoptosis of and Fas antigen expression on the bone marrow mononuclear cells (MNC) in 25 AA patients and 10 normal controls were assayed by TUNEL and FACS, respectively.

RESULT

The percentage of CD(34)(+) cells was decreased significantly in AA patients than in normal controls (P < 0.05), and so did the percentage of CD(34)(+)Fas(+) cells (P < 0.05). The percentage of apoptotic cells in AA patients was higher than that of controls (P < 0.01). After the patients were treated with CsA for 2 months, the percentage of apoptotic cells was decreased (P < 0.01). The percentage of CD(34)(+)Fas(+) cells was positively correlated with that of apoptotic cells in AA patients.

CONCLUSION

Fas is involved in the apoptosis of CD(34)(+) cells of AA patients. CsA could reduce the percentage of apoptosis of bone marrow cells in AA patients.

Prospects for nutritional interventions in the clinical management of Fanconi anemia

The evidence associating Fanconi anemia (FA) phenotype to in-vitro and ex-vivo oxidative stress is reviewed. A cancer-prone genetic disease, FA is characterized by delayed bone marrow failure with a progression to aplastic anemia. It is diagnosed by excess chromosomal instability induced by two clastogens, either diepoxybutane (DEB) or mitomycin C (MMC). Clinical symptoms vary in a broad range including a life-threatening hematological impairment, and an extended set of developmental abnormalities, growth retardation and skin pigmentation. Cancer-proneness in FA results in excess incidence of non-lymphoblastic leukemias, and of some defined solid tumors. The relationships of oxidative stress with FA phenotype rely on a consistent body of evidence that includes: (1) excess formation of DNA oxidative damage (both in vitro and in vivo); (2) cellular protection by hypoxia, low molecular-weight antioxidants, antioxidant enzymes, and thioredoxin overexpression; (3) impaired expression and/or activity of antioxidant enzymes, and (4) the redox-dependent action mechanisms of MMC and DEB. This evidence points to a re-appraisal of FA phenotype, suggesting a causative role for oxidative stress in disease progression towards malignancies and/or bone marrow depletion. A well-established literature reporting epidemiological and experimental data provides the nutritional bases for cancer control. Thus, the present state-of-the-art in the related fields of oxidative stress, nutrition, cancer-proneness and FA phenotype, altogether implies the need to undertake the most appropriate efforts to counteract oxidative stress in the clinical management of FA patients.

Hepatitis C infection among survivors of childhood cancer

Preliminary reports have suggested that survivors of childhood cancer and aplastic anemia who are infected with the hepatitis C virus (HCV) have a low risk for progression to significant liver disease. Among our surviving patients who were transfused between 1961 and March 1992, 77 (6.6% of surviving patients tested thus far) have evidence of HCV infection, whereas 4 surviving patients who were transfused after March 1992 are HCV-infected. One patient chronically infected with HCV died of liver failure, and 2 patients died of hepatocellular carcinoma. To characterize the risk for these and other complications, 65 patients are enrolled in a longitudinal study of HCV infection, of whom 58 (89.2%) had circulating HCV RNA at the time of protocol enrollment, with genotypes 1A and 1B most commonly isolated. Most enrolled patients have few or no symptoms, carry out normal activities, and have normal liver function. To date, 35 patients have undergone liver biopsy for abnormal liver function since the diagnosis of primary malignancy; central pathology review shows 28 (80%) have chronic active hepatitis, 25 (71%) have fibrosis, and 3 (9%) have cirrhosis. These preliminary data suggest that though most survivors of childhood cancer who are infected with HCV are clinically well, some are at risk for clinically significant liver disease. Identification of other HCV-infected patients and prospective monitoring of this cohort are ongoing to determine the risk for, and to identify factors associated with the progression of, liver disease.

Utility of blasts with a clear halo around the nucleolus as a predictive indicator for disease progression in patients with myelodysplastic syndromes and aplastic anemia

This study was designed to evaluate the utility of blasts with a clear halo around their nucleoli (BCHN) as a predictive indicator of disease progression in myelodysplastic syndromes (MDSs) and aplastic anemia (AA). Bone marrow aspirates from 75 patients with MDSs and 18 with AA were fixed in 95% ethanol solution or 10% neutral formalin and stained with the Papanicolaou method. BCHNs were detected in 57 of 75 patients with MDSs and in 10 of 18 AA patients. Disease progression was restrictedly observed in 17 patients with MDSs who had BCHNs at onset and in 1 patient with AA. The proportion of BCHNs increased with disease progression in these 16 of 17 patients with MDSs. The presence of BCHNs at onset and the increase in proportion of BCHNs during the clinical course of MDSs were significant indications for predicting disease progression.

N-RAS gene mutation in patients with aplastic anemia and aplastic anemia/ paroxysmal nocturnal hemoglobinuria during evolution to clonal disease

Long-term survivors of aplastic anemia (AA) have a high incidence of clonal disorders, in particular paroxysmal nocturnal hemoglobinuria (PNH), myelodysplastic syndromes (MDS), and acute nonlymphocytic leukemia. To investigate the potential involvement of N-RAS gene mutations in the predisposition to leukemic evolution, a subset of patients at potentially increased risk for clonal disease was selected based on evidence of existing clonal evolution. Nine patients showed a monoclonal pattern of X-chromosome inactivation, 18 demonstrated a PNH clone, and in 3 MDS developed during the course of this study. No mutations were detected during the aplastic phase of disease; 2 of 3 patients with MDS after AA also showed no mutations. However, in 1 patient in whom the disease transformed from AA/PNH to MDS, a mutation of GGT --> GAT at N-RAS codon 13 became detectable, whereas the PNH mutation disappeared. The authors conclude that N-RAS mutations are not an early event preceding transformation of AA or AA/PNH to leukemia. In a subset of patients, RAS mutations may occur at the time of evolution to MDS, but preexisting RAS mutations do not explain the propensity of AA to leukemogenesis. Although PNH is also associated with leukemia, this may arise in the non-PNH cells, indicating that PIG-A gene mutation is not per se oncogenic. (Blood. 2000;95:646-650)

Hematopoietic growth factors in the pathogenesis and for the treatment of aplastic anemia

The production and release of hematopoietic growth factors from bone marrow stromas established in vitro from patients with aplastic anemia is normal or increased. Addition of hematopoietic growth factors to aplastic anemia bone marrow cells results in only modest increases in colony growth, with the exception of granulocyte colony-stimulating factor (G-CSF), which corrects their impaired cloning efficiency to normal. Most clinical data on the use of hematopoietic growth factors in aplastic anemia have derived from uncontrolled and small single-arm studies or case reports. Sustained trilineage hematologic responses have not been observed when hematopoietic growth factors have been used alone or in combination. Serious side effects have been reported for most of the hematopoietic growth factors in patients with aplastic anemia, with the exception of G-CSF. There is a major concern that they may further increase the risk of clonal disorders such as myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Hematopoietic growth factors should not be used alone in newly diagnosed patients as specific treatment for aplastic anemia, and their use in combination with immunosuppressive therapy should be confined to multicenter, prospective randomized studies.

Use of granulocyte colony-stimulating factor for treatment of aplastic anemia

Over the last ten years, recombinant human granulocyte colony-stimulating factor (rh G-CSF) has been widely used in the treatment of aplastic anemia (AA). It has been shown to facilitate the recovery of neutrophil count and useful for complicated bacterial or fungal infections. However, recent randomized clinical trials showed that the addition of rh G-CSF to immunosuppressive therapy had no clinical benefit for the prophylaxis of severe infections. These results suggested that rh G-CSF should be used for the treatment of infectious complications, not for the prophylaxis of infections in patients with AA.

Clonal evolution of aplastic anaemia to myelodysplasia/acute myeloid leukaemia and paroxysmal nocturnal haemoglobinuria

Aplastic anaemia (AA) is a non-malignant haemopoietic disorder characterised by peripheral blood pancytopenia and a hypocellular bone marrow. Successful management of acquired AA including treatment with immunosuppressive agents, mainly antithymocyte globulin (ATG) and cyclosporin or allogeneic haemopoietic stem cell transplantation, has resulted in long-term survival of many patients. The later evolution of complicating clonal disorders such as paroxysmal nocturnal haemoglobinuria, myelodysplasia and acute myeloid leukaemia in patients treated with immunosuppressive therapy may be a manifestation of the natural history of the aplasia, the development of which may or may not be increased by immunosuppressive therapy. A persistent, profound deficiency and/or defect in the stem cell compartment, despite haematological recovery after immunosuppressive therapy, may create an unstable situation which predisposes to later clonal disorders. A review of the progression of AA to clonal disorders is now outlined.

Cyclical neutropenia and other periodic hematological disorders: a review of mechanisms and mathematical models

Although all blood cells are derived from hematopoietic stem cells, the regulation of this production system is only partially understood. Negative feedback control mediated by erythropoietin and thrombopoietin regulates erythrocyte and platelet production, respectively, but the regulation of leukocyte levels is less well understood. The local regulatory mechanisms within the hematopoietic stem cells are also not well characterized at this point. Because of their dynamic character, cyclical neutropenia and other periodic hematological disorders offer a rare opportunity to more fully understand the nature of these regulatory processes. We review the salient clinical and laboratory features of cyclical neutropenia (and the less common disorders periodic chronic myelogenous leukemia, periodic auto-immune hemolytic anemia, polycythemia vera, aplastic anemia, and cyclical thrombocytopenia) and the insight into these diseases afforded by mathematical modeling. We argue that the available evidence indicates that the locus of the defect in most of these dynamic diseases is at the stem cell level (auto-immune hemolytic anemia and cyclical thrombocytopenia seem to be the exceptions). Abnormal responses to growth factors or accelerated cell loss through apoptosis may play an important role in the genesis of these disorders.

Management of patients with hematologic malignancies and aplastic anemia who are refractory to platelet transfusions

Patients with hematologic malignancies or aplastic anemia may have reduced responses to platelet transfusions after multiple transfusions of standard red blood cells or platelet components. This situation, conventionally described as 'refractoriness' to platelet transfusions, may result from immune or non-immune causes. Non-immune causes include fever, infections, hypersplenism, disseminated intravascular coagulation, antibiotics, or veno-occlusive disease. Immune causes include platelet-reactive alloantibodies, which are typically antibodies to human leukocyte antigens (HLA) or, less commonly, antibodies to human platelet antigens (HPA). Transfused HLA-matched platelets often have satisfactory posttransfusion survivals, but few transfusion services have the donor and logistical resources to sustain a prolonged course of platelet transfusions requiring four-antigen matches. The availability of commercially marketed kits for crossmatching samples of potential donors' platelets with a recipient's serum has facilitated donor-recipient matching. Also, platelet crossmatching may be used to select a suitable unit of from several candidates platelets that have been identified to be partial HLA matches. The high likelihood of decreased efficacy of platelet transfusions in HLA-alloimmunized recipients makes avoidance of exposure to HLA-bearing leukocytes a priority. This goal is facilitated by lowering transfusion 'triggers' for cellular blood components, particularly for prophylactic platelet transfusions, by reducing the leukocyte content of components by leukocyte-reduction filters and, possibly by ultraviolet-B irradiation of leukocyte-containing products.

[Paroxysmal nocturnal hemoglobinuria and its association with aplastic anemia]

Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired clonal disorder of haematopoiesis. Clinically it is characterized by intravascular haemolysis, venous thrombosis and often by bone marrow hypoplasia. Haemolysis and thrombosis develop as a consequence of deficiency of several proteins on the cell membrane of the affected clone of blood elements. This is caused by somatic mutations in the PIG-A gene, which encodes an enzyme involved in the biosynthesis of glycosylphosphatidylinositol (GPI) anchor. Spectrum of mutations in the PIG-A gene is different to that observed in other genes. The mutations are mainly small deletions and insertions causing frameshift; large deletions are rare. Recently, however, a 88 base pairs direct tandem repeat insertion has been reported in a patient with PNH developed on the background of aplastic anaemia (AA). The peculiar pattern of the PIG-A gene mutations and the finding that more than one mutated clone is commonly present in patients with PNH might suggest that some form of hypermutability, caused by decreased DNA stability, deficient repair or increased generation of mutagens, might underline PNH. As most mutations cause cell death, it would explain the hypoplastic nature of the disorder and its association with AA. Other models of pathogenesis of PNH are also discussed.

[Study on the improvement of bone marrow microenvironment by ligustrazine in immune-induced aplastic anemia mice]

OBJECTIVE

To explore the effects of ligustrazine on bone marrow microenvironment and its mechanism in aplastic anemia (AA).

METHODS

Each immune-induced AA mouse was gastric fed by 4 mg ligustrazine twice a day. On the 10th day, the ulnar bone marrow partial pressure of oxygen (PbO2) was determined in vivo by a PO2 sensory needle. Then the histological features, fibroblastic colony forming unit (CFU-F) yields and the adhesive function of stromal cells of the bone marrow were assayed in vitro.

RESULTS

The PbO2 in ligustrazine-treated group was 10.32 +/- 1.27 kPa, while in AA group was 4.32 +/- 2.86 kPa (P < 0.001). In AA group, the microvessels were expanded, broken and being stasis. The percentage of hematopoietic tissue volume was 24.9% +/- 9.6% and the CFU-F yields was 12.5 +/- 7.3/2 x 10(6) BMNC. The microvessels in ligustrazine group were more clear and intact, not being broken and had no stasis. The percentage of hematopoietic tissue volume was 52.8% +/- 15.6% and the CFU-F yields was 31.5 +/- 10.6/2 x 10(6) BMNC. In ligustrazine group, the adhesive function of stromal cell layer cultured with bone marrow nucleated cells from normal mice was 72.7% +/- 7.8%, which was not different from that in normal group (73.4% +/- 3.4%), but much higher than that in AA group (56.2% +/- 9.8%, P < 0.01).

CONCLUSION

Ligustrazine can promote the rehabilitation of bone marrow microvessels in AA mice, increasing the oxygen supply for bone marrow microenvironment, promoting the growth of stromal cells and strengthening their adhesive function. Ligustrazine enbances the bone marrow hematopoietic cells proliferation by improving their microenvironment.

Long-term outcome of autoimmune disease following allogeneic bone marrow transplantation

OBJECTIVE

To investigate the long-term outcome of autoimmune disease following allogeneic bone marrow transplantation (BMT), and its relationship to hemopoietic chimerism.

METHODS

Three previously described patients with rheumatoid arthritis (RA) who underwent allogeneic BMT for therapy-related severe aplastic anemia and 1 new patient with psoriasis who received BMT for chronic myeloid leukemia (CML) were followed up. Molecular studies were performed to assess hemopoietic and immune reconstitution in 3 cases.

RESULTS

In 2 of the RA patients, the RA remained in remission without treatment, with nonprogressive disease, 11 and 13 years after BMT. The third patient with RA had a relapse 2 years after BMT, although the previously aggressive disease subsequently ran an attenuated course with treatment-free remission for the last 11 years. Comparison with other cases of RA suggests that graft-versus-host disease may influence the long-term outcome, perhaps through ongoing inhibition of the immune system. In the patient with psoriasis, BMT was followed by remission, but the psoriatic rash recurred and arthropathy developed 12 months later. The psoriasis and arthropathy remained active 4.5 years post-BMT, although the CML remained in remission. Molecular studies in the 2 patients whose RA remained in continued remission and in the patient with psoriasis that relapsed confirmed complete donor hemopoietic reconstitution.

CONCLUSION

Long-term followup of autoimmune disease after allogeneic transplantation confirmed cure of the autoimmune disease in some, but eventual relapse in others. The occurrence of relapse despite complete donor hemopoietic reconstitution is evidence for the development of de novo, as opposed to persistent, disease, and is possibly related to intrinsic susceptibility of the transplanted stem cells or to host factors. There may be a relationship between remission of autoimmune disease and graft-versus-host reaction. These findings have relevance for the evolving application of stem cell transplantation as a therapy for autoimmune diseases.

Impaired liver function tests in patients treated with antithymocyte globulin: implication for liver transplantation

Antithymocyte globulin (ATG) is traditionally used as a conventional immunosuppression agent in various pathological states including severe aplastic anaemia (SAA), graft versus host disease (GVHD), and for the prevention and treatment of graft rejection and GVHD post bone marrow and liver transplantation. We reviewed the liver functions of 16 haematological patients with no previous liver disorders who received ATG as part of their pre-bone marrow transplantation (BMT) conditioning regimen, and the liver function tests of five SAA patients who received ATG as part of their treatment. Liver functions were evaluated at day -1 pre-, and days +3 and +10 post-ATG treatment. All patients had normal liver functions before treatment. In the haematological patients, the mean serum lactic dehydrogenase (LDH) levels increased from 408.7 +/- 37.7 U/l pre-treatment to 1394.4 +/- 488.7 U/l 3 days post-treatment (n = 16; p < 0.029), and then declined to 561.4 +/- 61.3 U/l 10 days post-treatment (n = 16; p < 0.043). The mean alanine aminotransferase (ALT) levels increased from 51.9 +/- 11.3 U to 184.6 +/- 74.6 U (n = 16; p < 0.036), and then declined to 121.9 +/- 61.3 U (n = 16; NS). The mean aspartate amino transferase (AST) levels increased from 31.2 + 5.7 U to 152.0 +/- 67.0 U (n = 16; p < 0.44) and then declined to 46.0 +/- 14 (n = 16; p < 0.049). The mean tau-glutamyltransferase (GTP) levels increased from 93.0 +/- 34 to 188.0 +/- 36 (n = 16; p < 0.02), and were 168.0 +/- 37.0 at day +10 (n = 16; NS). The mean bilirubin levels increased from 18.0 +/- 1.9 microM l(-1) to 22.7 +/- 2.8 (n = 16); NS), at day +3 and to 31.9 +/- 6.9 at day +10 (n = 16; NS). In contrast, no significant changes in liver function tests were demonstrated in the SAA patients treated with ATG. The possible pathophysiologic mechanisms and the clinical implications for liver transplantation are discussed.

Inactivation of the Fanconi anemia group C gene augments interferon-gamma-induced apoptotic responses in hematopoietic cells

Hematopoietic progenitor cells (HPC) from mice nullizygous at the Fanconi anemia (FA) group C locus (FAC -/-) are hypersensitive to the mitotic inhibitory effects of interferon (IFN-gamma). We tested the hypothesis that HPC from the bone marrow of Fanconi group C children are similarly hypersensitive and that the fas pathway is involved in affecting programmed cell death in response to low doses of IFN-gamma. In normal human and murine HPC, IFN-gamma primed the fas pathway and induced both fas and interferon response factor-1 (IRF-1) gene expression. These IFN-gamma-induced apoptotic responses in HPC from the marrow of a child with FA of the C group (FA-C) and in FAC -/- mice occurred at significantly lower IFN doses (by an order of magnitude) than did the apoptotic responses of normal HPC. Treatment of FA-C CD34+ cells with low doses of recombinant IFN-gamma, inhibited growth of colony forming unit granulocyte-macrophage and burst-forming unit erythroid, while treatment with blocking antibodies to fas augmented clonal growth and abrogated the clonal inhibitory effect of IFN-gamma. Transfer of the normal FAC gene into FA-C B-cell lines prevented mitomycin C-induced apoptosis, but did not suppress fas expression or inhibit the primed fas pathway. However, the kinetics of Stat1-phosphate decay in IFN-gamma-treated cells was prolonged in mutant cells and was normalized by transduction of the normal FAC gene. Therefore, the normal FAC protein serves, in part, to modulate IFN-gamma signals. HPC bearing inactivating mutations of FAC fail to normally modulate IFN-gamma signals and, as a result, undergo apoptosis executed through the fas pathway.