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

Comparable outcomes with low-dose and standard-dose horse anti-thymocyte globulin in the treatment of severe aplastic anemia

BACKGROUND

The standard dose (SD) of horse anti-thymocyte globulin (hATG) ATGAM (Pfizer, USA) or its biosimilar thymogam (Bharat Serum, India) for the treatment of Aplastic Anemia (AA) is 40 mg/kg/day for 4 days in combination with cyclosporine. Data on the impact of hATG dose on long-term outcomes are limited. Here, we describe our comparative experience using 25 mg/kg/day (low-dose [LD]) hATG for 4 days with SD for the treatment of AA.

METHODS

We retrospectively studied patients with AA (age > 12 years) who received two doses of hATG combined with cyclosporine. Among 93 AA patients who received hATG, 62 (66.7%) and 31 (33.3%) patients received LD and SD hATG with cyclosporine, respectively. Among these,seventeen(18.2%) patients also received eltrombopag with hATG and cyclosporine. Overall response rates [complete response (CR) and partial response (PR)] of LD and SD hATG groups at 3 months (50% vs. 48.4%; p = 0.88), 6 months (63.8% vs. 71.4%; p = 0.67), and 12 months (69.6% vs. 79.2%; p = 0.167) were comparable. The mean (Standard Deviation) 5-year Kaplan-Meier estimate of overall survival and event-free survival was 82.1 (4.6)% and 70.9 (5.5)% for the study population. The mean (standard deviation) 5-year Kaplan-Meier estimate of overall survival and event-free survival of those who received LD hATG versus SD hATG dose was 82.9 (5·3)% versus 74.8 (10·3)% (P = 0·439), and 75.2 (6.2)% versus 61.4(11.2)% (P = 0·441).

CONCLUSION

Our study revealed that the response rates of patients with AA and LD were similar to those of patients with SD to hATG combined with cyclosporine in a real-world setting.

An Investigation of Selected Socio-Demographic Factors with Aplastic Anemia in Pakistan: A Case-Control Study

Introduction

In Pakistan, the incidence rate of aplastic anemia is 3.5 cases/million. The associated risk factors are exposure to pesticides, chemicals, and some drugs. The link between aplastic anemia and socio-demographic factors is debatable.

Purpose

We conducted this study to investigate the role of socio-economic and -demographic factors with aplastic anemia.

Methodology

A total of 191 lab-confirmed incident cases of aplastic anemia were identified from the tertiary hospital of Karachi-Pakistan in between 2015 and 2018. Age and gender-matched 694 controls were randomly selected from the same institute admitted or visited for other non-neoplastic conditions. Socio-demographic and exposure information was gathered using a data collection form. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were computed for selected socio-demographic factors.

Results

Among socio-demographic factors, significant associations of aplastic anemia risk emerged for illiteracy (aOR: 2.3; 1.5; 3.5) occupation (any type) (aOR: 2.1; 1.7; 2.5), living in rural environments (aOR: 2.9; 1.9; 4.2). The odds of aplastic anemia increased with the age group 31–50 years (aOR: 1.8; 1.7; 3.5) and >50 years (aOR: 2.5; 2.1; 4.2). We observed no association of income with the risk of aplastic anemia.

Conclusion

This study highlights the importance of socio-demographic factors as a risk factor for the development of aplastic anemia in the population of Pakistan. In order to reduce disease incidence, health education program and use of personal protective equipment and organization of screening camps in high-risk population is warranted.

Epidemiology of aplastic anemia: a study of 1324 cases

Objective: Prevalence of aplastic anemia (AA) is high in the Asian population. This study was done to explore the etiology and association of AA with various socio-economic and environmental factors.Study design and setting: Study included 1324 consecutive AA cases registered at Armed Forces Bone Marrow Transplant Centre Rawalpindi, Pakistan, from March 2001 to August 2016. The study questionnaire was completed through an interview. It included patients' socio-demographic details, personal and family medical history, environmental attributes and clinico-hematological features.Results: The median age of patients was 20 years, 997 were male and 327 female. Distribution of non-severe, severe and very severe AA was 230 (17.4%); 598 (45.2%) and 496 (37.4%), respectively. The majority of patients were from low (n = 761, 57.5%) or middle socioeconomic class (n = 543, 41%). Consanguinity among patients (n = 806, 61%) was slightly higher than the national statistics. History of chemical exposures included fertilizers (n = 116, 8.7%), pesticides (n = 56, 4.2%) and industrial chemicals (n = 37, 2.8%). PNH clone was found in 63 of AA patients. After excluding 298 patients undergoing HSCT and 660 deaths/lost to follow-up, disease evolution was observed in 38(10.4%) patients out of 366 evaluable patients. These included PNH = 18, MDS = 11 and AML = 9.Discussion: Due to lack of funding and adequate human resource at the center, age and sex-matched controls could not be included. Other limitations were a lack of molecular testing to exclude the possibility of inherited bone marrow failure syndromes on a genetic basis.Conclusion: Younger age, male predominance and higher consanguinity point toward genetic factors in AA etiology among the South Asian population.

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.

Ethnic prevalence of anemia and predictors of anemia among chronic kidney disease patients at a tertiary hospital in Johannesburg, South Africa

INTRODUCTION

Anemia is a complication of chronic kidney disease (CKD) that can greatly impact on its prognosis. However, the risk factors for anemia, including the influence of ethnicity, are not well established among the CKD population in Johannesburg.

METHODS

This was a cross-sectional study of 353 adult CKD patients attending the renal outpatient clinic of the Charlotte Maxeke Johannesburg Academic Hospital (Johannesburg, South Africa) from June 1, 2016 to December 30, 2016. Sociodemographic and clinical characteristics were obtained using a proforma. Blood samples were collected for serum electrolytes and hematological parameters. Predictors of low hemoglobin and iron deficiency anemia (IDA) were evaluated using multivariable binary logistic regression.

RESULTS

The mean age and prevalence of anemia among the CKD participants were 55.3±15.0 years and 43.18% (95% CI: 38.1%-48.4%), respectively. Blacks had the highest prevalence of anemia (46.9%), while Indians/Asians had the lowest (18.2%). Although the odds of anemia was 3.8-fold higher (odds ratio =3.8, P-value =0.059) among CKD stage V participants as compared to CKD stage I, the relationship between anemia and stages of CKD was non-linear. Diabetes mellitus (odds ratio =2.31, P-value =0.005) had a strong association with anemia among the CKD participants.

CONCLUSION

Almost half of the CKD participants were anemic, and the odds of anemia did not increase linearly with increasing severity of CKD. There was a marked ethnic disparity in anemia prevalence. Our study highlights the need for risk-based management of anemia among CKD patients.

Environmental determinants of aplastic anemia in Pakistan: a case-control study

Aim

Aplastic anemia (AA) affects the Asian population two to three fold more than people in other regions. Besides the host genetics and socioeconomic status, several other environmental exposures have been linked with an AA etiology. We aimed to examine the association of various environmental exposures with AA occurrence among Pakistani individuals.

Subjects and methods

A case-control study was conducted in Karachi, Pakistan, where cases (diagnosed AA patients) were selected from the National Institute of Blood Disease and Bone Marrow Transplantation (NIBD), while for each case, a single control (who was free of AA and visited the outpatient department of the same hospital for the treatment of minor ailments) was selected matched by age and sex. A total of 428 participants were included in this study with equal proportions of cases and controls. Information related to disease characteristics, sociodemographics and exposure to chemicals was collected through a survey questionnaire, laboratory investigations and medical records. Descriptive results were reported as frequencies and proportions, adjusted odds ratios with 95 % confidence intervals and population attributable risk (PAR) as percentage.

Results

Among study participants (n = 428), AA was significantly associated with various environmental exposures. Participants residing in rural settings (OR = 2.29, 95 % CI 1.12–4.67, p-value < 0.01) and those who reported exposure to pesticides (OR = 3.58, 95 % CI 1.27–10.10, p-value 0.01; PAR = 18.16 %) were significantly more likely to report AA. Participants with a formal education were significantly less likely to have AA (OR = 0.27, 95 % CI 0.10–0.71, p-value < 0.01).

Conclusions

This study observed a significant association of aplastic anemia with a lower socioeconomic profile, and certain environmental exposures among the Pakistani population. The evidence may be helpful in understanding the pathophysiology of aplastic anemia in the context of environmental exposures.

Assessment of iron status among preschool children (6 to 59 months) with and without malaria in Western Province, Kenya

Introduction

Iron deficiency is a major public health concern. Globally, iron deficiency ranks number 9 and is responsible for about 60% of all anemia cases among preschool children. In Africa iron deficiency is 43-52% while in Kenya, children under 5 years constitute the largest burden with 69% of them being deficient. There is limited iron deficiency data in Kenya. This study determined haemoglobin levels, serum ferritin levels, nutritional status and P.falciparum malaria infection in preschool children.

Methods

A household cross sectional study was undertaken among 125 preschoolers in Western province, drawn from 37 clusters. Systematic random sampling was used for sample selection. Data was collected using pretested structured questionnaires, entered in Microsoft package. Data analysis was done in Statistical package for social science (SPSS) version 20 using bivariate and multivariate logistic regression and differences were considered significant at P < 0.05.

Results

The prevalence of iron deficiency (Serum ferritin <12mg/l), anaemia (Hb < 110g/l) and plasmodium falciparum malaria were 20.8%, 25% and 6.8% respectively. There was a significant association between iron deficiency and anaemia (OR = 3.43, 95% CI: 1.33-8.84, p = 0.008). A preschool child with anaemia was 3.43 times likely to be iron deficient compared to a preschool child who was not anaemic.

Conclusion

Iron deficiency, anaemia and plasmodium falciparum malaria was prevalent among preschool children. The findings revealed a significant association between iron deficiency and anaemia. Therefore effective interventions to improve iron status will have large health benefits by greatly reducing anaemia in preschool children.

Relationship between socioeconomic status and anemia prevalence in adolescent girls based on the fourth and fifth Korea National Health and Nutrition Examination Surveys

BACKGROUND/OBJECTIVES

We studied the relationship between socioeconomic status (SES), represented by household income, and the prevalence of anemia and iron deficiency anemia (IDA) among adolescent girls in Korea.

SUBJECTS/METHODS

The samples were based on the data from a four-year (2008-2011) collection for the Korea National Health and Nutrition Examination Survey (1312 girls, age 10-18 years). The survey included demographic, anthropometric, biochemical and nutritional parameters. A multiple regression analysis after adjusting for age, body mass index (BMI), red blood cell count, white blood cell count and red meat intake was performed. Anemia was defined as hemoglobin level lower than 11.5 g/dl for ages 10-11 years and 12.0 g/dl for ages 12-14 years. Iron deficiency was defined as serum ferritin level below 15 μg/l.

RESULTS

The prevalences of anemia and IDA in Korean girls were 5.3 and 4.2%, respectively. Girls with anemia were older, taller, weighed more, had higher BMI, had higher portion of menarche experience and consumed less red meat than girls without anemia. Girls with higher income had lower anemia prevalence and consumed more iron and vitamins. Logistic regression analysis showed a decreasing trend in anemia prevalence as household income increased. Correlation analysis demonstrated that there is a relationship between household income and serum hemoglobin and ferritin levels (P=0.003 and P=0.026, respectively).

CONCLUSIONS

Higher SES leads to lower prevalence of anemia and IDA in Korean adolescent girls. This may be due to the fact that higher SES individuals consume more iron and vitamin C.

Association between anaemia, iron deficiency anaemia, neglected parasitic infections and socioeconomic factors in rural children of West Malaysia

BACKGROUND

Given that micronutrient deficiency, neglected intestinal parasitic infections (IPIs) and poor socioeconomic status are closely linked, we conducted a cross-sectional study to assess the relationship between IPIs and nutritional status of children living in remote and rural areas in West Malaysia.

METHODS/FINDINGS

A total of 550 children participated, comprising 520 (94.5%) school children aged 7 to 12 years old, 30 (5.5%) young children aged 1 to 6 years old, 254 (46.2%) boys and 296 (53.8%) girls. Of the 550 children, 26.2% were anaemic, 54.9% iron deficient and 16.9% had iron deficiency anaemia (IDA). The overall prevalence of helminths was 76.5% comprising Trichuris trichiura (71.5%), Ascaris lumbricoides (41.6%) and hookworm infection (13.5%). It was observed that iron deficiency was significantly higher in girls (p = 0.032) compared to boys. Univariate analysis demonstrated that low level of mother's education (OR = 2.52; 95% CI = 1.38-4.60; p = 0.002), non working parents (OR = 2.18; 95% CI = 2.06-2.31; p = 0.013), low household income (OR = 2.02; 95% CI = 1.14-3.59; p = 0.015), T. trichiura (OR = 2.15; 95% CI = 1.21-3.81; p = 0.008) and A. lumbricoides infections (OR = 1.63; 95% CI = 1.04-2.55; p = 0.032) were significantly associated with the high prevalence of IDA. Multivariate analysis confirmed that low level of mother's education (OR = 1.48; 95 CI% = 1.33-2.58; p<0.001) was a significant predictor for IDA in these children.

CONCLUSION

It is crucial that a comprehensive primary health care programme for these communities that includes periodic de-worming, nutrition supplement, improved household economy, education, sanitation status and personal hygiene are taken into consideration to improve the nutritional status of these children.

Drugs in the aetiology of agranulocytosis and aplastic anaemia

Agranulocytosis and aplastic anaemia are rare but serious conditions known to be caused by numerous drugs. Most of what is known or suspected about the aetiology is based on case reports, with only a few formal epidemiological studies that provide quantitative estimates of risk. Updated results have been obtained from a combined analysis of data from 3 case-control studies that used similar methods: the International Agranulocytosis and Aplastic Anemia Study (IAAAS), conducted in Israel and Europe; a study conducted in the northeast US; and a study conducted in Thailand. Totals of 362 cases of agranulocytosis, 454 cases of aplastic anaemia and 6458 controls were included in the analyses. The IAAAS and Thai study were population-based, providing estimates of the incidence of the 2 dyscrasias. The overall annual incidence of agranulocytosis in the ambulatory population was 3.4/10(6) in the IAAAS and 0.8/10(6) in Thailand; by contrast the incidence of aplastic anaemia was 2.0/10(6) in the IAAAS and 4.1/10(6) in Thailand. A total of 21 compounds were significantly associated with an increased risk of agranulocytosis in the IAAAS and US studies. Excess risks ranged from 0.06 to 13 cases/10(6) users/wk; the most strongly associated drugs were procainamide, anti-thyroid drugs and sulphasalazine. An association with drugs that had previously been suspected was also seen in Thailand. The overall aetiologic fractions of agranulocytosis due to drug use were 62% in the IAAAS, 72% in the US and 70% in Thailand. Eleven drugs were significantly associated with an increased risk of aplastic anaemia, with excess risks ranging from 1.4 to 60 cases/10(6) users in a 5-month period. The most strongly associated drugs were penicillamine, gold and carbamazepine. Aetiologic fractions were 27% in the IAAAS, 17% in the US and 2% in Thailand, which paralleled the prevalence of use of associated drugs in the 3 populations. The present results confirm that agranulocytosis is largely a drug-induced disease, with similar proportions accounted for in 3 disparate geographic regions. By contrast, although many of the expected associations were observed for aplastic anaemia, most of the aetiology is not explained by drugs. For all associated drugs, the excess risks are sufficiently low that blood dyscrasias should not figure prominently in the balancing of risks and benefits.

Incidence and non-drug aetiologies of aplastic anaemia in Thailand. The Thai Aplastic Anaemia Study Group

A population-based, case-control study of aplastic anaemia has been conducted in Thailand since 1989. Up to December 1994, the overall annual incidence was 3.9/10(6) in Bangkok, 5.0/10(6) in Khonkaen and 3.0/10(6) in Songkla. In Bangkok, the incidence peaked in 2 age groups (at 15-24 yr and > or = 60 yr), whereas in Khonkaen and Songkla there was a consistent increase in incidence with increasing age. The results of case-control analyses for non-drug risk factors indicate a strong inverse association with socio-economic status present in all 3 areas; a strong association with grain farming in the 2 rural areas that does not appear to be explained by pesticides; an association with occupational exposure to solvents in Bangkok; and a positive association with hepatitis A seropositivity.

Unexpected case of aplastic anemia in a patient with glioblastoma multiforme treated with Temozolomide

We report the case of a 30-year-old woman with glioblastoma multiforme (GBM) treated with surgery followed by concomitant Temozolomide (TMZ) and external beam radiation, which she tolerated well without any interruptions. However, when she was being evaluated for adjuvant Temozolomide, she developed progressive decline in leukocyte counts and platelet counts and subsequently, febrile neutropenia with bleeding manifestations. A bone marrow aspiration and biopsy done showed a gross hypocellular bone marrow with very few erythriod and myeloid cells and no suggestion of progenitor cells, consistent with aplastic anemia.

Pattern of haematological diseases diagnosed by bone marrow examination in Yemen: a developing country experience

There is lack of information about the relative prevalence of haematological disorders in Yemen and other Middle East countries. The aim of this study was to evaluate the pattern of haematological diseases diagnosed by bone marrow examination in Yemen considering the limited diagnostic facilities. At the referral haematology centre in Yemen, between November 1999 and November 2005, 785 patients >14 years old were evaluated by bone marrow examination. Relevant investigations were performed when needed. A total of 627 patients had haematological disorders other than lymphoma, and their data were analysed. There were 273 females and 354 males. A total of 159 patients had Acute myeloid leukaemia, 75 had acute lymphocytic leukaemia, 87 had chronic myeloid leukaemia, 36 chronic lymphocytic leukaemia, eight had multiple myeloma, 13 myelodysplastic syndromes, seven myelofibrosis, seven polycythaemia vera, three primary thrombocythaemia, two hairy cell leukaemia, two metastases, 36 aplastic anaemia, 29 immune thrombocytopenic purpura (ITP), nine autoimmune haemolytic anaemia, three pernicious anaemia, 65 iron deficiency anaemia, 57 megaloblastic anaemia and malaria, 18 mixed deficiencies, and 11 patients had visceral leishmaniasis. Sex- and age-related distribution of the various disorders was also presented. In conclusion, the leukaemias were the most frequently encountered diagnosis followed by iron deficiency anaemia, megaloblastic anaemia and malaria, aplastic anaemia and ITP respectively. The other haematological disorders were less common. These findings are comparable with that seen in other developing and developed countries.

The epidemiology of aplastic anemia in Thailand

Aplastic anemia has been linked to environmental exposures, from chemicals and medical drugs to infectious agents. The disease occurs more frequently in Asia than in the West, with incidence rates 2- to 3-fold higher. We report updated results of an epidemiologic study conducted in Thailand from 1989 to 2002, in which 541 patients and 2261 controls were enrolled. Exposures were determined by in-person interview. We observed significantly elevated relative risk estimates for benzene (3.5) and other solvents (2.0) and for sulfonamides (5.6), thiazides (3.8), and mebendazole (3.0). Chloramphenicol use was infrequent, and no significant association was observed. Agricultural pesticides were implicated in Khonkaen (northeastern Thailand). There were significant associations with organophosphates (2.1), DDT (6.7), and carbamates (7.4). We found significant risks for farmers exposed to ducks and geese (3.7) and a borderline association with animal fertilizer (2.1). There was a significant association in Khonkaen with drinking other than bottled or distilled water (2.8). Nonmedical needle exposure was associated in Bangkok and Khonkaen combined (3.8). Most striking was the large etiologic fraction in a rural region accounted for by animal exposures and drinking of water from sources such as wells, rural taps, and rainwater, consistent with an infectious etiology for many cases of aplastic anemia in Thailand.

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.

Lack of known hepatitis virus in hepatitis-associated aplastic anemia and outcome after bone marrow transplantation

Viral infection has been shown to induce aplastic anemia, unidentified types of hepatitis being the most common cause for aplastic anemia-associated viral hepatitis. The survival rate for this group of patients after bone marrow transplantation with stem cells from an HLA-matched sibling is not well known. The aim of this study was to determine the prevalence of hepatitis G virus (HGV) and transfusion transmitted virus (TTV) infection in non-A, non-B, non-C hepatitis associated-aplastic anemia (HAAA) patients, and to define the role of bone marrow transplantation (BMT) as a therapeutic modality for this disease. Sixty-eight patients (43 males and 25 females) with aplastic anemia, underwent allogeneic BMT at the Hadassah University Hospital between 1981 and 1997. Onset of hepatitis was defined as jaundice and elevated alanine aminotransaminase (ALT) levels. Onset of aplastic anemia was defined as the first date on which varying degrees of pancytopenia occurred: hemoglobin level below 10 g/dl, WBC below 2 x 10(9)/l and low platelet count 10 x 10(10)/l. Serial serum samples from HAAA patients were assayed for virological and/or serological markers of hepatitis A, B, C, D, E, G viruses, TTV and parvovirus B19. Seventeen of the 68 patients with aplastic anemia (25%) suffered from hepatitis, 12 males and five females, ages 5 to 36 years. The mean interval between onset of hepatitis and first indication of aplastic anemia was 62 days (range 14-225 days). The development of aplastic anemia was unrelated to age, sex or severity of hepatitis. Ten of the 17 patients (59%) achieved complete ALT recovery prior to the diagnosis of aplastic anemia. Serum samples were available for 15 patients; none had evidence of acute or active hepatitis A, B, C, D, E, G and TTV virus infection at the time of diagnosis. Parvovirus B19 DNA sequences were not detectable in 10 of 12 tested cases; two positive results were detected in serum samples obtained after blood transfusion, making the analysis of these positive results difficult. All 17 patients underwent BMT. The mean post-BMT follow-up period was 38 months (range 1 day-123 months), five patients (30%) died 1 to 160 days post BMT, and 12 (70%) are alive 31 to 123 months after BMT. Relapsing hepatitis was not observed in any of the patients. In conclusion, HAAA is a disease of the young and the etiologic agent associated with HAAA remains unknown. HGV, TTV and parvovirus B19 sequences were not detected in any of the HAAA cases. The survival rate after BMT with stem cells from an HLA-matched sibling is similar to that for patients with non-hepatitis-associated aplastic anemia.

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.

Regional patterns in the incidence of aplastic anemia in Thailand. The Aplastic Anemia Study Group

The annual incidence of aplastic anemia has been determined in a rigorous and standardized epidemiologic study conducted in Thailand. A total of 374 cases were identified over a period of 3-6 years in three geographically defined and distinct regions of the country; Bangkok, Khonkaen in the northeast, and Songkla in the south. The incidence was 3.9 cases per million persons in Bangkok, 3.0 per million in Songkla, and 5.0 per million in Khonkaen. These rates are as high or higher than in any region of Europe or Israel as reported in the International Agranulocytosis and Aplastic Anemia Study, in which the methods and case definition were the same. Rates were stable over the course of the study. There were marked differences in incidence between northern and southern rural regions of Thailand, and among Bangkok suburbs. These differences, together with an unusual peak in the incidence among young people in Bangkok, suggest the possibility of occupational and environmental factors in the etiology of aplastic anemia.

Aplastic anemia in rural Thailand: its association with grain farming and agricultural pesticide exposure. Aplastic Anemia Study Group

OBJECTIVES

A population-based case-control study was conducted to elucidate the incidence and etiology of aplastic anemia in Thailand.

METHODS

Case patients and hospital control patients were enrolled in three regions from 1989 to 1994; data were collected by interview.

RESULTS

Forty-six percent of 81 case patients and 19% of 295 control patients from Khonkaen were grain farmers (estimated relative risk [RR] = 2.7, 95% confidence interval [CI] = 1.4, 5.2). Sixteen percent of case patients and 6% of control patients used agricultural pesticides (estimated RR = 2.7, 95% CI = 1.1, 6.6). The association with grain farming remained among those not exposed to pesticides. In Songkla, 16% of 43 case patients and 2% of 181 control patients were grain farmers (crude RR estimate = 11, 95% CI = 3.4, 35).

CONCLUSIONS

The relation of aplastic anemia to grain farming may partly explain the high incidence of aplastic anemia in Thailand.

Practical aspects in the diagnosis and management of aplastic anemia

Aplastic anemia may result from several pathogenic mechanisms, the most common is idiopathic. The current definitive treatments for aplastic anemia are bone marrow transplantation (BMT) or immunosuppressive (IS) therapy. The benefits of each are comparable. However, certain subsets of patients derive superior benefit from one or the other. Bone marrow transplantation is the initial treatment of choice for young patients (< 20 years old). It results in the complete reconstitution of hematopoiesis, whereas autologous hematopoietic remissions after IS therapy are more susceptible to relapse. Survival rates after BMT, in patients between the ages of 20 and 40, are comparable to those reported for IS therapy. Better survival rates after BMT have been achieved with improved conditioning regimens and graft-versus-host disease prophylaxis. For patients older than 40, the treatment of choice is IS. Long-term complications of IS therapy include recurrence and development of clonal myeloid disorders. Long-term complications after BMT include graft-versus-host disease and secondary neoplasms. The IS regimen includes the combination of antithymocyte globulin and cyclosporin A. The addition of growth factor to the IS regimen seems promising; however, their use on their own is not recommended. Androgens have been shown to be inferior in the treatment of aplastic anemia. The role of BMT from an unrelated donor is being investigated.