Treatment of myelodysplastic syndrome with low-dose human granulocyte colony-stimulating factor: a multicenter study

The objective of this study was to determine the hematopoietic effects and toxicity of low-dose granulocyte colony-stimulating factor (G-CSF) in myelodysplastic syndrome (MDS) patients with neutropenia. Recombinant human G-CSF (Lenograstim) was administered by daily subcutaneous injection with an initial dosage of 0.5 microg/kg per day for 2 weeks. Patients not responding to the initial dosage received the escalated dosage, 1 to 2 microg/kg per day for 2 weeks. Eligibility criteria were the following: French-American-British disease classification subtype refractory anemia (RA), refractory anemia with ringed sideroblasts (RARS), or refractory anemia with excess blasts (RAEB) with an absolute neutrophil count (ANC) of <1.5 x 10(9)/L. Criteria indicating response to treatment were ANC of >1.5 x 10(9)/L and doubling of ANC on at least 2 occasions. Thirty-two MDS patients were recruited from 6 university hospitals. Eighteen patients had RA, 4 had RARS, and 10 had RAEB. Median age was 56.4 years (range, 28-87 years). Twenty-six patients (81.2%) had an increase in ANC from a median of 0.94+/-0.35 x 10(9)/L to 4.24+/-3.78 x 10(9)/L. Three of 6 patients who did not respond to the initial dosage responded to the escalated dosage of 1 microg/kg per day. Eighteen (81.8%) of 22 patients with RA or RARS responded compared with 8 (80%) of 10 patients with RAEB. The response rates in patients with ANCs of <0.5 x 10(9)/L. 0.5 to <1.0 x 10(9)/L, and 1.0 to 1.5 x 10(9)/L were 80%, 70%, and 88.2%, respectively. The side effects were minimal. No significant changes in hemoglobin levels or platelet counts were observed. In conclusion, low-dose G-CSF administered by subcutaneous injection is well tolerated and effective in improving neutropenia in MDS 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.

Agranulocytosis in Bangkok, Thailand: a predominantly drug-induced disease with an unusually low incidence. Aplastic Anemia Study Group

Agranulocytosis, a syndrome characterized by a marked reduction in circulating granulocytes, is strongly associated with medical drug use in Europe and the United States. Unregulated use of common pharmaceutical agents in developing countries has been suspected of causing large numbers of cases of agranulocytosis and deaths, especially among children. To elucidate the incidence and etiology of agranulocytosis in Thailand, a population-based case-control study of symptomatic agranulocytosis that resulted in hospital admission was conducted in Bangkok from 1990 to 1994. An attempt was also made to study the disease in Khonkaen (in northeastern Thailand) and Songkla (in southern Thailand), but there were insufficient cases in the latter regions, and the analysis was confined to subjects from Bangkok. In that region, the overall incidence of agranulocytosis was 0.8 per million per year; there were no deaths. As expected, the incidence was higher in females (0.9 per million), and it increased with age (4.3 per million beyond age 60). Among 25 cases and 529 controls the relative risk estimate for a combined category of all suspect drugs was 9.2 (95% confidence interval = 3.9-21), and the proportion of cases that could be attributed to drug use was 68%. For individual drugs and drug classes the data were sparse; within these limitations, the strongest association appeared to be with antithyroid drugs. One case and three controls were exposed to dipyrone, a drug known to cause agranulocytosis; with such scanty data the risk could not be evaluated. Exposure to pesticides or solvents was not associated with an increased risk. This is the first formal epidemiologic study of agranulocytosis in a developing country. As in the West, most cases are attributable to medical drug use. However, the incidence of agranulocytosis in Bangkok, and apparently, in Thailand as a whole, is unusually low, and the disease does not pose a public health risk.

Myelodysplastic syndromes in Thailand: a retrospective pathologic and clinical analysis of 117 cases

To gain more insight into the understanding of myelodysplastic syndromes (MDS) as they occur in Thailand, a retrospective clinicopathologic analysis was conducted in patients (age > 15 years) diagnosed as MDS from January 1992 to December 1996 at the five major medical centers in various geographic regions of the country. The central reviewers independently examined the bone marrow and peripheral blood smears of all the patients and classify the disease according to the French-British-American (FAB) classification. There were a total of 117 eligible patients. The median age of the patients was 56 years (range 16-86). The male:female ratio was 1:1. Thirty-two percent of the patients were younger than 40 years. The frequency of the FAB subtypes was RA/RARS, 54.7; RAEB, 23.1; CMML, 9.4; and RAEB-T, 12.8%. Anemia was the most common symptom presenting in 84.6% of the patients. In the 34 patients in whom the cytogenetics in the bone marrow were analysed, 44.1% revealed abnormalities. Of these, monosomy 7 and trisomy 8 were the most common aberration, each being detected in 26.7% of the patients. Transfusions were the main therapeutic modality in 80% of the patients. Kaplan-Meier analysis revealed a 5 year survival rate of 29% for the whole group with a median survival of 24 months. Twenty-five percent of the patients had progressed to acute myelogenous leukemia (AML) with a median time to disease-progression of 23 months. The median survival for RA/RARS, RAEB, CMML and RAEB-T were 58.4, 19.9, 10.7 and 8.7 months, respectively (P < 0.001). The stepwise Cox regression analysis revealed the percentage of blasts in the bone marrow as the only parameter significantly associated with survival and disease progression. On comparison with data from other countries, the age of Thai patients with MDS is considerably lower than the western population but is comparable to other asian countries. The distribution of the FAB subtypes and the survival of the patients are similar. The major prognostic features, however, lie in the percentage of blasts in the bone marrow rather than the degree of the observed cytopenia.

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.

Use of household pesticides and the risk of aplastic anaemia in Thailand. The Aplastic Anemia Study Group

BACKGROUND

Aplastic anaemia is a severe blood dyscrasia that is more common in Thailand than in Western countries. Its a etiology remains poorly understood.

METHODS

A case-control study was conducted in Bangkok and two rural regions of Thailand. The effect of household pesticides was evaluated among 253 incident cases of aplastic anaemia and 1174 hospital controls.

RESULTS

A total of 54% of the cases and 61% of the controls were exposed 1-6 months previously. For most individual household pesticides and for groups classified according to chemical type (organophosphates, pyrethrins, and organochlorines), the relative risk (RR) estimates approximated 1.0; upper 95% confidence limits were below 2.0 for many comparisons. A significant association was observed for exposure to combination products containing dichlorvos and propoxur, with an overall RR estimate of 1.7 (95% confidence interval [CI]: 1.1-2.6); the estimate for regular use was 1.6 (95% CI: 0.9-2.9).

CONCLUSIONS

The absence of a higher risk for the regular use of dichlorvos/propoxur reduces the credibility of the apparent association, which could well have been an artefact of multiple comparisons. We conclude that most household pesticides used in Thailand do not appear to increase the risk of aplastic anaemia.

Low drug attributability of aplastic anemia in Thailand. The Aplastic Anemia Study Group

From 1989 to 1994, a population-based, case-control study of aplastic anemia was conducted in Thailand, including the regions of Bangkok, Khonkaen in the northeast, and Songkla in the south. An annual incidence in Bangkok of 3.7 cases per million population, about twice as high as in Western countries, has been reported. To evaluate the etiologic role of drugs, 253 subjects were compared with 1,174 hospital controls. With multivariate adjustment for confounding, a significant association was identified for exposure 2 to 6 months before admission to thiazide diuretics (relative risk estimate 7.7; 1.5 to 40). There were crude associations with sulfonamides (relative risk estimate, 7.9; P = 0.004) and mebendazole (6.3; P = 0.03) (there were insufficient data for multivariate adjustment). Excess risks for the three drugs were in the range of 9 to 12 cases per million users. There was no significant association with chloramphenicol, although the multivariate relative-risk estimate was elevated (2.7; 0.7 to 10). Other drugs that have been reported to increase the risk of aplastic anemia, such as nonsteroidal anti-inflammatory drugs and anticonvulsants, were not commonly used. There were no associations with commonly used drugs, including benzodiazepines, antihistamines, oral contraceptives, and herbal preparations. For all associated drugs, the overall etiologic fraction (the proportion of cases attributable to an exposure) was 5%, compared with 25% in Europe and Israel. Drugs are uncommon causes of aplastic anemia in Thailand, and their use does not explain the relatively high incidence of the disease in that country.

Association of seropositivity for hepatitis viruses and aplastic anemia in Thailand

Aplastic anemia is more common in the Orient than in western countries, with an incidence in Thailand that is 2- to 3-fold higher than in Europe. Aplastic anemia after hepatitis is a well characterized clinical entity, and clinical hepatitis is also prevalent in the Far East. We performed a prospective case-control study to determine risk factors for aplastic anemia in Bangkok and two rural regions during 1989 to 1994. A total of 375 cases were identified, along with 1,174 hospital controls matched for age and sex. Historical data were collected by trained interviewers. Sera from a subset of cases (N = 177) and controls (N = 183) were tested for antibodies to hepatitis viruses A, B, and C and hepatitis B surface antigen. There was no evidence of association of aplastic anemia with hepatitis B or hepatitis C. Previous exposure to hepatitis A, as determined by immunoglobulin G (IgG) seropositivity, was significantly associated with aplastic anemia: the relative risk adjusted for confounding was 2.9 (95% confidence interval 1.2-6.7). The same association also existed for persons under age 25 years, in whom the prevalence of hepatitis A IgG was lower than in the total population. However, no patients showed evidence of recent infection with hepatitis A (immunoglobulin M [IgM] seropositivity). These results indicate that exposure to a hepatitis virus is a risk indicator for aplastic anemia in Thailand, and while itself unlikely to be etiologic, hepatitis A may be a surrogate marker for another enteric microbial agent.

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.

Outcomes of pregnancy in adult idiopathic thrombocytopenic purpura

The outcomes of 39 pregnancies in 36 idiopathic thrombocytopenic purpura (ITP) patients were analysed. Among the 36 pregnant patients, 23 had active ITP (platelet count < 100,000 per mm3), 12 had inactive ITP, during pregnancies, while one patient had active and inactive ITP during each of her two pregnancies. Maternal bleeding during delivery occurred more commonly in thrombocytopenic patients and was more frequent by cesarean section than by vaginal delivery. There was a 56 per cent incidence of neonatal thrombocytopenia. Maternal platelet count had no predictive value for neonatal thrombocytopenia. There was no serious bleeding among neonates born from thrombocytopenic mothers. In our experience, vaginal delivery was a relatively safe procedure for delivering small neonates from multiparous ITP mothers. Cesarean section should be used to deliver relatively big neonates especially from primigravida ITP mothers and splenectomy should be done at the same time.