Epidemiology of aplastic anaemia

Chromosomal Breakage in Fanconi Anemia and Consanguineous Marriages: A Social Dilemma for Developing Countries

Introduction A clear picture of the prevalence of Fanconi anemia is not known due to limited studies and research of the subject. This study will detect the frequency of positive chromosomal breakage in pediatric aplastic patients and provide the evidence-based guidelines which help in consideration of appropriate treatment and awareness to the society. Methods A total of 104 aplastic anemia patients were recruited of age <18 years whose samples were tested for chromosomal breakage with mitomycin C (MMC). History of consanguinity between parents were documented for all the patients referred to us. Result Out of 104 diagnosed aplastic anemia patients, 35 (33.7%) patients were found to be Fanconi positive. Mean age of all hypoplastic patients for aplastic anemia and Fanconi anemia was 10.7 ± 4.5 and 10.6 ± 3.5, respectively. Male preponderance was found to be higher (64, 61.5%) as compared to females (40, 38.5%) in aplastic patients. The male to female ratio was observed as 2.5:1 in Fanconi patients while 1.3:1 in non-Fanconi aplastic patients. Parental consanguinity was observed in 33 (94.2%) with Fanconi anemia. Conclusion Fanconi anemia accounts for significant number of patients with hypoplastic bone marrow, therefore consanguineous marriages should be avoided through mass education in Pakistan.

Efficacy of Chemotherapies and Stem Cell Transplantation for Systemic AL Amyloidosis: A Network Meta-Analysis

BACKGROUND/AIMS

The present Bayesian network meta-analysis (NMA) was to compare the efficacy of different chemotherapies and autologous stem cell transplantation (ASCT) in immunoglobulin light-chain (AL) amyloidosis.

METHODS

We systematically searched PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL) for studies compared the rates of hematological response (HR), complete response (CR), renal response, and cardiac response in AL amyloidosis patients.

RESULTS

There were three randomized controlled trials (RCTs) and thirteen observational controlled trials (OCTs) comprising 3,402 participants enrolled for the comparisons of seven treatments: melphalan + dexamethasone (MDex), high-dose melphalan followed by ASCT, bortezomib + melphalan + dexamethasone (BMDex), thalidomide + cyclophosphamide + dexamethasone (CTD), bortezomib + dexamethasone (BDex), bortezomib + cyclophosphamide + dexamethasone (CyBorD), cyclophosphamide + lenalidomide + dexamethasone (CLD). BMDex was ranked first in the aspect of both HR and CR, CTD induced the highest rate of renal response, and BDex was possibly the best treatment for the cardiac response.

CONCLUSION

Although more data about safety and cost are needed, BMDex was recommended as the most efficient treatment for AL amyloidosis patients for enhancing the response rate for HR and CR.

Pancytopenia of Unknown Cause in Adult Patients Admitted to a Tertiary Hospital in Ethiopia: Case series

Background

Over the past few years, we have witnessed a dramatic increase in the number of patients presenting with severe pancytopenia to Jimma University Hospital. We now present sociodemographic and clinical characteristics of adult patients admitted with pancytopenia of unknown cause to Jimma University Hospital during the period of March 2015 to June 2016. Complete blood count and other diagnostic tests were done for all patients to uncover underlying causes.

Result

Out of 65 cases admitted with pancytopenia during the specified period, 40 were excluded for various reasons. The rest 25 patients were included in this review. The mean age was 32.1 years (SD=14.9); 14 were younger than 30 years of age. The mean hemoglobin level, white cell count and platelet count were 48.6 g/L (SD=1.9), 1,918 /µL (SD=879.8) and 36,200 /µL (SD=26,131) respectively. The major presenting symptoms were generalized malaise and fever. No geographic or seasonal clustering of the cases was seen.

Conclusion

The number of cases with pancytopenia of unidentified cause seen at the hospital over the specified period is alarmingly high and deserves great attention. The hematologic alteration in most of the patients was found to be severe with poor clinical outcome. This calls for large scale community based investigation to uncover the root cause of the problem.

Haemotoxicity of busulphan, doxorubicin, cisplatin and cyclophosphamide in the female BALB/c mouse using a brief regimen of drug administration

Many anticancer drugs are myelotoxic and cause bone marrow depression; however, generally, the marrow/blood returns to normal after treatment. Nevertheless, after the administration of some anti-neoplastic agents (e.g. busulphan, BU) under conditions as yet undefined, the marrow may begin a return towards normal, but normality may not be achieved, and late-stage/residual marrow injury may be evident. The present studies were conducted to develop a short-term mouse model (a 'screen') to identify late-stage/residual marrow injury using a brief regimen of drug administration. Female BALB/c mice were treated with BU, doxorubicin (DOX), cisplatin (CISPLAT) or cyclophosphamide (CYCLOPHOS) on days 1, 3 and 5. In 'preliminary studies', a maximum tolerated dose (MTD) for each drug was determined for use in 'main studies'. In main studies, mice were treated with vehicle (control), low and high (the MTD) dose levels of each agent. Necropsies were performed, and blood parameters and femoral/humeral nucleated marrow cell counts (FNCC/HNCC) were assessed on six occasions (from days 1 to 60/61 post-dosing). Late-stage/residual changes were apparent in BU-treated mice at day 61 post-dosing: RBC, Hb and haematocrit were reduced, mean cell volume/mean cell haemoglobin were increased and platelet and FNCC counts were decreased. Mice given DOX, CISPLAT and CYCLOPHOS, in general, showed no clear late-stage/residual effects (day 60/61). It was concluded that a brief regimen of drug administration, at an MTD, with assessment at day 60/61 post-dosing was a suitable short-term method/screen in the mouse for detecting late-stage/residual marrow injury for BU, a drug shown to exhibit these effects in man.

Further development of a model of chronic bone marrow aplasia in the busulphan-treated mouse

Aplastic anaemia (AA) in man is an often fatal disease characterized by pancytopenia of the peripheral blood and aplasia of the bone marrow. AA is a toxic effect of many drugs and chemicals (e.g. chloramphenicol, azathioprine, phenylbutazone, gold salts, penicillamine and benzene). However, there are no widely used or convenient animal models of drug-induced AA. Recently, we reported a new model of chronic bone marrow aplasia (CBMA = AA) in the busulphan (BU)-treated mouse: eight doses of BU (10.50 mg/kg) were administered to female BALB/c mice over a period of 23 days; CBMA was evident at day 91/112 post-dosing with significantly reduced erythrocytes, platelets, leucocytes and nucleated bone marrow cell counts. However, mortality was high (49.3%). We have now carried out a study to modify the BU-dosing regime to induce CBMA without high mortality, and investigated the patterns of cellular responses in the blood and marrow in the post-dosing period. Mice (n = 64/65) were dosed 10 times with BU at 0 (vehicle control), 8.25, 9.0 and 9.75 mg/kg over 21 days and autopsied at day 1, 23, 42, 71, 84, 106 and 127 post-dosing (n = 7-15); blood and marrow samples were examined. BU induced a predictable bone marrow depression at day 1 post-dosing; at day 23/42 post-dosing, parameters were returning towards normal during a period of recovery. At day 71, 84, 106 and 127 post-dosing, a stabilized, late-stage, nondose-related CBMA was evident in BU-treated mice, with decreased erythrocytes, platelets and marrow cell counts, and increased MCV. At day 127 post-dosing, five BU-treated mice showed evidence of lymphoma. In this study, mortality was low, ranging from 3.1% (8.25 mg/kg BU) to 12.3% (9.75 mg/kg BU). It is concluded that BU at 9.0 mg/kg (or 9.25 mg/kg) is an appropriate dose level to administer (10 times over 21 days) to induce CBMA at approximately day 50-120 post-dosing.

A third course of anti-thymocyte globulin in aplastic anaemia is only beneficial in previous responders

This retrospective study evaluated the outcome of 18 patients with aplastic anaemia treated with a third course of anti-thymocyte globulin (ATG)-containing immunosuppressive therapy (IST). Of the 18 patients, seven had responded to one of the previous courses of ATG and 11 were refractory to both the previous courses. Self-limiting grade >/=3 liver toxicity was observed in three patients. Two patients had to discontinue ATG because of severe systemic side effects. The incidence and manifestations of serum sickness did not appear to be different during the three courses. All of the seven patients that previously responded to one of the courses responded to a third course. In contrast, of 11 patients refractory to the previous courses, only two had a transient partial response. The 3-yr event-free survival for the patients who had responded to one of the previous courses of ATG was significantly superior to that of patients refractory to both the previous courses of ATG (83% vs. 0%, P = 0.0001). For aplastic anaemia patients, a third course of ATG-containing IST is a reasonable option in previous responders. Patients refractory to previous two courses of ATG have a much lower response rate and may be suitable candidates for novel therapeutic options.

The role of occupational and environmental exposures in the aetiology of acquired severe aplastic anaemia: a case control investigation

Aplastic anaemia is a rare but serious disorder with a high morbidity and mortality rate. The causes of aplastic anaemia are, for the most part, unknown. We report on the hypothesis that aplastic anaemia may be caused by occupational and/or environmental exposures to certain chemicals. The UK Aplastic Anaemia Study was an interview-based case-control study covering the whole of Great Britain. Those patients diagnosed between 1 July 1993 and 20 October 1997, aged < or =75 years and born and diagnosed in the UK were eligible for the study. Two hundred eligible cases of aplastic anaemia were compared with 387 age- and sex-matched controls. A number of occupational exposures showed increases in risk. In a multivariate model of these exposures the odds ratios (ORs) for solvents/degreasing agents, pesticides and radiation were >2 and statistically significant. Reported chemical treatment of houses within 5 years of diagnosis had a significantly raised risk for adults [OR = 2.51, 95% confidence interval (CI) 1.02-12.01], particularly for woodworm treatment (OR = 5.1, 95% CI 1.5-17.4). This study identified significant risks associated with self-reported exposure to solvents, radiation and pesticides in the workplace. Self-reported chemical treatment of houses was also associated with an increased risk of developing aplastic anaemia, in keeping with previous literature.

Acquired aplastic anemia in children: incidence, prognosis and treatment options

Acquired aplastic anemia is a rare disease. The incidence ranges from two to six new cases per 1 million inhabitants per annum. Bone marrow transplantation (BMT) in case of available human leucocyte antigen (HLA)-identical sibling and immunosuppressive therapy are the main therapeutic modalities currently used in pediatric patients. In large cooperative studies carried out in Europe, overall survival was not significantly different in children with aplastic anemia treated with allogeneic BMT from an HLA-identical sibling (85%) and those treated with immunosuppressive therapy (83%). Survival was significantly worse for patients treated with BMT from an alternative source (26%; p < 0.00001) versus immunosuppressive therapy. Based on these results, therapeutic strategies recommended for aplastic anemia are allogeneic BMT as a first-line therapy for children with an HLA-identical sibling, and immunosuppressive therapy in patients without. In children who do not respond, alternative therapies include BMT from unrelated or mismatched family donors and, more recently, the use of hematopoietic growth factors. Therapeutic choice in childhood severe aplastic anemia should also take into account the possible late effects, such as growth failure and other endocrine problems, that are peculiar to pediatric patients, as well as the risk of malignancies occurring mostly when irradiation is given as part of the conditioning regimen before BMT. As aplastic anemia is such a rare disease, improvements in current treatment strategies can only be achieved by joint efforts between treatment centers. Therefore, patients should be referred to experienced centers early in the course of the disease in order to offer the patient the best therapeutic options presently available.

A new model of busulphan-induced chronic bone marrow aplasia in the female BALB/c mouse

Aplastic anaemia (AA) is characterized by hypocellular marrow, pancytopenia, and risk of severe anaemia, haemorrhage and infection. AA is often idiopathic, but frequently occurs after exposure to drugs/chemicals. However, the pathogenesis of AA is not clearly understood, and there are no convenient animal models of drug-induced AA. We have evaluated regimens of busulphan (BU) administration in the mouse to produce a model of chronic bone marrow aplasia showing features of human AA. Mice were given 8 doses of BU at 0, 5.25 and 10.50 mg/kg over 23 days; marrow and blood samples were examined at 1, 19, 49, 91 and 112 days after dosing. At day 1 post dosing, in mice treated at 10.50 mg/kg, nucleated marrow cells, CFU-GM and Erythroid-CFU were reduced. Similarly, peripheral blood erythrocytes, leucocytes, platelets and reticulocytes were reduced. At day 19 and 49 post dosing, there was a trend for parameters to return towards normal. However, at day 91 and 112 post dosing, values remained significantly depressed, with a stabilized chronic bone marrow aplasia. At day 91 and 112 post dosing, marrow cell counts, CFU-GM and Erythroid-CFU were decreased; marrow nucleated cell apoptosis and c-kit+ cell apoptosis were increased; peripheral blood erythrocyte, leucocyte, and platelet counts were reduced. We conclude that this is a model of chronic bone marrow aplasia which has many interesting features of AA. The model is convenient to use and has potential in several areas, particularly for investigations on mechanisms of AA pathogenesis in man.

Aplastic anemia in Brazil: incidence and risk factors

This study is the first large-scale epidemiological investigation of acquired aplastic anemia (AAA) in South America. The objective was to estimate the incidence and to identify risk factors for AAA in Brazil. A national case-control study was conducted to investigate the risk factors for the disease. One hundred twenty-five cases and 129 controls were included. Multiple logistic regression was used in the estimation of odds ratios (OR) to control confounding. The size of Brazil made it unfeasible to estimate the incidence of AAA in the whole country, and we limited the calculation to the state of Parana. The annual incidence of AAA in Parana was 2.4 cases/10(6) inhabitants. There was no positive association between chloramphenicol use and AAA (OR 0.4; 95% CI: 0.1-2.9). The OR of AAA associated with household pesticides that include organophosphates in their composition was 2.7 (1.0-8.4). The OR for the usage of unspecified thinner and/or acetone for at least 7 days was 3.0 (1.2-7.3). Cases of AAA in Brazil seem to be associated with some factors traditionally related to this disease, such as certain solvents and the incidence is similar to what has been reported from Europe.

Hematopoietic progenitor cells in the blood and bone marrow in various hematologic disorders

Hematopoietic progenitor cells are present in the blood and the bone marrow. Changes in the numbers of hematopoietic progenitor cells reflect alteration of pluripotent stem cells. We discuss such changes in common hematologic diseases including aplastic anemia, paroxysmal nocturnal hemoglobinuria (PNH) and thalassemia. In aplastic anemia, the numbers of burst forming units-erythroid (BFU-E) and colony-forming units-granulocyte-macrophage (CFU-GM) are much decreased; the decrease still exists after recovery from therapy. In PNH, the numbers of progenitor cells are low, even in the presence of marrow hypercellularity. In thalassemia, the numbers of progenitor cells are much increased; more pronounced in splenectomized patients.

Aplastic anaemia: management

Acquired, idiosyncratic aplastic anaemia (AA) is a rare but potentially fatal haematological disorder. Severe AA constitutes an acute medical emergency, and supportive therapy is needed to prevent overwhelming sepsis or a life threatening haemorrhage. Specific therapy for the disease includes the choice between allogeneic stem cell transplantation (SCT) from an HLA-identical sibling or immunosuppressive therapy with anti-thymocyte globulin (ATG) and cyclosporin A (CSA). Long-term cure rates of 75-90% are now achieved following HLA (human leukocyte antigen) identical sibling bone marrow transplant. The use of donors other than HLA-id siblings for transplantation in AA remains experimental. Transplantation offers the patient a chance of cure, whilst treatment with immunosuppressive therapy carries a long-term risk of relapse and clonal transformation. The haemopoietic growth factors, apart from granulocyte colony stimulating factor (G-CSF), have been shown to be potentially toxic when given to patients with AA. A short course of G-CSF may be useful to help treat severe infection, but its longer-term use with ATG and CSA remains controversial. Results from immunosuppressive treatment continue to improve with time, as a result of the additional use of CSA with ATG, the use of repeat courses of ATG for non-responders and improvements in the supportive care of patients.

Study of the association between cytochromes P450 2D6 and 2E1 genotypes and the risk of drug and chemical induced idiosyncratic aplastic anaemia

A genetic susceptibility to drug or chemical toxicity may provide a basis for an increased risk of idiosyncratic aplastic anaemia (AA). The cytochrome P450 enzymes are responsible for the metabolism of many drugs, some of which have been linked to AA. Mutations in the cytochrome P450 CYP2D6 gene result in absent or impaired enzyme activity in about 7% of Caucasians, whereas a specific mutation in the 5'-regulatory region of the CYP2E1 gene causes overexpression of the gene. We evaluated the frequency of allelic variants of CYP2D6 and CYP2E1 using allele-specific PCR amplification and restriction enzyme analysis of blood mononuclear cell DNA among 54 Caucasian AA patients. CYP2D6 and CYP2E1 were chosen because of the link between AA and the antipsychotic drug remoxipride (CYP2D6 substrate) and benzene (CYP2E1 substrate), respectively. Results were compared with 53 controls matched for age, sex and ethnicity. The percentage of AA patients homozygous for the CYP2D6*3, CYP2D6*4 alleles (poor metabolizer phenotype) and the CYP2E1 mutant allele (overexpression) was 0%, 4% and 0%, respectively, and the percentage of heterozygotes was 2%, 28% and 15%, respectively. For normal controls the corresponding results for homozygous mutants were 0%, 4% and 0% and for heterozygotes 4%, 25% and 6%, respectively. We concluded that there were no major differences in the frequencies of the genetic polymorphisms between this series of AA patients and controls, but due to the low number of cases with the poor metabolizer phenotype and those with a history of drug exposure, the power of the study was too low to disprove an interaction.

An association of aplastic anaemia in Thailand with low socioeconomic status. Aplastic Anemia Study Group

The relationship of socioeconomic status to the risk of aplastic anaemia was evaluated in a case-control study conducted in Bangkok and two rural regions of Thailand (Khonkaen and Songkla). Among 152 cases and 921 controls there were significant trends of increasing risk with decreasing years of education (P = 0.01) and total household income (P = 0.0001), after control for confounding. The relative risk estimate for those with monthly incomes of < 1500 baht (about $60 U.S.) was 3.9 (95% confidence interval 2.1-7.3) compared to those with monthly incomes of at least 5000 baht (about $200). The pattern of increasing risk with decreasing income was observed in all three regions, with significant trends in Bangkok (P = 0.004) and Khonkaen (P = 0.003). This finding may partly explain the high incidence of aplastic anaemia in Thailand. Low socioeconomic status may be a surrogate for one or more environmental factors that could cause aplastic anaemia, such as infectious pathogens or toxic exposures.