Screening for the carriers of thalassemias and abnormal hemoglobins at the community level

Thalassemia and abnormal hemoglobins are common genetic disorders in Southeast Asia. Thalassemia is not only an important public health problem but also a socio-economic problem of many countries in the region. The approach to deal with the thalassemic problem is to prevent and control births of the new cases. This requires an accurate identification of couple at high risk to have a thalassemic child. The diagnosis of thalassemia carriers need several tests that are not practical for screening the population at large. In this study we used two simple laboratory tests to screen for potential thalassemia carriers and hemoglobin E individuals. Three-hundred pregnant women and 40 spouses were recruited in this study. The methods were the red cell osmotic fragility (OF) screening test with 0.36% NaCl and the dichlorophenolindophenol (DCIP) precipitation test to detect Hb E and unstable hemoglobins. Standard methods for red cell indices, hemoglobin analysis and detection of alpha-thalassemia by immunological method were also performed to confirm genotypes of thalassemia. The results showed that 98 women (32.7%) were carriers of thalassemias and hemoglobin E. The number of false positive by OF test was 3.2% and by DCIP test was 0.6%. Sensitivity and specificity of OF test were 89.5% and 93.3%, respectively whereas those of DCIP test were 100%. Of the 40 couples investigated, one was found to be at risk of having beta-thalassemia/Hb E fetus. Screening techniques including one tube osmotic fragility and DCIP precipitation tests are sensitive and specific for the detection of thalassemia and unstable hemoglobins such as Hb E. The techniques are also simple, economic, rapid, and give minimal false negative result.

Clinical manifestation of beta-thalassemia/hemoglobin E disease

PURPOSE

To review the clinical manifestation and changes in hematologic parameters of patients with beta-thalassemia/hemoglobin (Hb) E.

MATERIALS AND METHODS

Retrospective analysis of the clinical manifestation of 378 patients with beta-thalassemia/Hb E attending the hematology clinic at Siriraj Hospital between 1957 and 1982.

RESULTS

A wide spectrum of clinical phenotypes has been observed. Most patients show clinical symptoms by 10 years of age. The majority of patients survive with or without occasional transfusion. Splenectomy was performed in 26.5% of patients. Patients come to the hospital because of anemia, fever, abdominal mass, and jaundice. Gastrointestinal tract disturbances are the most common presenting symptoms (34.6%), especially abdominal pain (10%) and cholecystitis (5.1%). Respiratory tract infections were found in 21.8% of patients and cardiovascular complications, including congestive heart failure, occurred in 11.9%. Other less common symptoms and complications included bone pain, chronic leg ulcers, paraplegia and hypertension-associated convulsions, and cerebral hemorrhage after multiple blood transfusion. Patients usually die between 20 to 40 years of age (67%), mainly from congestive heart failure and septicemia. Septicemia was often caused by Gram-negative bacteria.

CONCLUSION

These clinical features observed in patients with beta-thalassemia/Hb E are probably the results of chronic anemia and iron overload. The study of the life history and clinical courses of patients with beta-thalassemia/Hb E should provide important information for the better management of these patients.

Standardization on laboratory diagnosis of thalassemia and abnormal hemoglobin

Thalassemia is one of the most common single gene disorders. The geographic distribution of thalassemia and abnormal hemoglobin has been known for many years. A worldwide significant spread of these abnormal genes, especially from Southeast Asia, occurred in the last two decades. This has resulted in a dramatic increase of Hb E disorders and various Southeast Asian thalassemia genotypes, which means that requests for hemoglobinopathy investigations are likely to increase in many laboratories worldwide. Hemoglobinopathy screening and diagnosis may need to be undertaken antenatally, neonatally and in certain hematological situations. The introduction of automation for hemoglobinopathy screening, including the automated cell counting and HPLC system, is an important advance in technology for hematology laboratories. The instruments need to be calibrated and standardized to get an accurate data for interpretation. Internal and external control samples are also needed. Combination of test results is usually required to achieve a proper diagnosis, which in turn, provide a self-check for each laboratory test.

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.

Malignant lymphoma in Thailand: changes in the frequency of malignant lymphoma determined from a histopathologic and immunophenotypic analysis of 425 cases at Siriraj Hospital

BACKGROUND

Analysis of malignant lymphoma in a single institution at different periods of time can determine the changing status of the disease in the region.

METHODS

To compare with the large series of 1095 lymphoma cases reported between 1957-1971 at Siriraj Hospital, the largest hospital in Thailand, a similar study was performed through histopathologic evaluation of 425 lymphoma cases diagnosed consecutively at the same institution between August 1993 and October 1995. Phenotypic analysis was performed by paraffin section-immunoperoxidase studies.

RESULTS

A striking increase in lymphoma cases was noted from 73 cases/year in the first series to 189 cases/year in the second series (an increase of 158.9%). Lymphoma occurred in all age groups, with a peak incidence at the seventh decade of life. The male to female ratio decreased from 2:1 in 1957-1971 to 1.3:1 in the more recent series. The incidence of Hodgkin's disease (HD) was found to have decreased from 28.9% to 8.5%. There were 36 cases (8.5%) of HD and 389 cases (91.5%) of non-Hodgkin's lymphoma (NHL) reported in the second series. The subtypes of HD included 16 cases of mixed cellularity, 13 cases of nodular sclerosis, 6 cases of lymphocyte depletion, and 1 case of lymphocyte predominance. According to the Working Formulation, the 389 NHL cases included low grade (14.1%), intermediate grade (57.3%), high grade (11.3%), and miscellaneous groups (17.2%). They were classified as small lymphocytic (9.5%), follicular (11.1%), diffuse (50.9%), immunoblastic (4.1%), small noncleaved (4.4%), lymphoblastic (2.8%), anaplastic large cell (9.0%), mycosis fungoides (1.8%), hairy cell leukemia (0.3%), true histiocytic (0.5%), and extramedullary plasmacytoma (1.0%). The immunophenotypes of the 359 NHL cases available for paraffin section-immunoperoxidase studies were B-cell (71.0%), T-cell (24.5%), histiocyte (0.6%), and undetermined phenotypes (3.9%).

CONCLUSIONS

The incidence of malignant lymphoma is increasing in Thailand, with a high frequency of intermediate to high grade NHL of B-cell phenotype reported.

Prenatal and postnatal diagnoses of thalassemias and hemoglobinopathies by HPLC

The conventional approach to qualitative and quantitative analyses of hemoglobin (Hb) molecules for the diagnoses of hemoglobinopathies requires a combination of tests. We used an automated HPLC (VARIANT) system to study alpha-thalassemia and beta-thalassemia syndromes in Thailand. The beta-thalassemia short program is applicable to the diagnosis of alpha-thalassemia and beta-thalassemia disorders, including Hb H, EA Bart's disease, and EF Bart's disease, in adults, newborns, and fetuses. The system cannot quantify accurately certain Hb molecules, such as Hb H and Hb Bart's. The alpha-thalassemia short program was therefore developed and used to quantify Hb Bart's to detect alpha-thalassemia genotypes in cord blood. This automated HPLC system is an alternative approach to the diagnosis of complicated thalassemia syndromes in Thailand and Southeast Asia.

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.

Relation of haemolytic anaemia and erythrocyte-bound IgG in alpha- and beta-thalassaemic syndromes

There has been evidence that IgG-mediated phagocytosis plays some part in destruction of erythroid cells and subsequent anaemia in thalassaemia. In this study using direct immunofluorescence and flow cytometry, erythrocyte-bound IgG was studied in 53 and 33 beta-thal/Hb E and Hb H patients, respectively. The mean percentages of IgG-positive erythrocytes in both nonsplenectomized (4.4%) and splenectomized (24%) beta-thal/Hb E patients were significantly higher than that in normal subjects (1.0%); p < 0.05 and < 0.001, respectively. Splenectomized beta-thal/Hb E patients had significantly higher percentages of IgG-positive erythrocytes than the nonsplenectomized patients (p < 0.001). The mean percentages of IgG-positive erythrocytes in Hb H patients were comparable to those from normal controls. However, patients with alpha-thal 1/Hb CS had significantly higher IgG-positive erythrocytes than those with alpha-thal 1/alpha-thal 2 (p = 0.008). Splenectomized Hb H patients also had higher IgG-positive erythrocytes than nonsplenectomized Hb H patients (p < 0.039). During haemolytic crisis in some Hb H patients, high percentages of IgG-positive erythrocytes were also demonstrated. This study demonstrates the presence of increased IgG on erythrocytes in patients with beta-thal/Hb E and in those with Hb H disease following splenectomy or in haemolytic crisis.

Hydroxyurea increases hemoglobin F levels and improves the effectiveness of erythropoiesis in beta-thalassemia/hemoglobin E disease

Hydroxyurea (HU) is one of several agents that have been shown to enhance hemoglobin (Hb) F levels in patients with sickle cell disease and may be useful as a therapy for beta-globinopathies. However, limited information exists on the effects of HU in patients with thalassemia. Accordingly, we examined the hematologic effects of orally administered HU in 13 patients with beta-thalassemia/Hb E, including four patients who had been splenectomized. These patients were treated with escalating doses (final range, 10 to 20 mg/kg/d) for 5 months and were observed in the outpatient hematology clinic every 2 to 4 weeks. Complete blood counts including reticulocyte counts, amounts of Hb E and Hb F, G gamma:A gamma and alpha:non-alpha globin biosynthetic ratios were evaluated before and during treatment. Almost all patients responded with an average increase of 33% in Hb F levels, from a mean (+/- SD) of 42% +/- 11% to 56% +/- 8% (P < .0001), and a reciprocal decline in the percentage of Hb E from 59% +/- 9% to 49% +/- 8% (P < .001). Reticulocytosis was decreased from a mean (+/- SD) of 18.0% +/- 15.6% to 11.7% +/- 9.1% (P < .05); there was also a slight (10%) but statistically significant increase in hemoglobin levels and an improved balance in alpha:non-alpha globin chains ratios. The side effects were minimal in most patients, although these patients tended to tolerate a lower dose of HU before significant myelosuppression than has been our previous experience in sickle cell disease. One splenectomized patient died of sepsis during the trial. We conclude that increased Hb F production in beta-thalassemia/Hb E patients, with an improvement in the alpha:non-alpha globin ratios and, probably, the effectiveness of erythropoiesis, can be achieved using HU. Longer trials of HU in this population, including at other doses and in combination with other agents, appear warranted.

Collection of cord blood stem cells for transplantation in thalassemic patients

Thalassemia is widely distributed throughout the world and is one of the major public health problems. The use of bone marrow transplantation, the only curative therapy for thalassemia, is limited because less than 30% of the patients have unaffected and HLA-identical siblings as donors. Cord blood stem cells, an alternative source of stem cells for transplantation, have been successfully transplanted into patients with several diseases after myeloablative therapy. Twenty cord blood samples from unaffected neonates whose siblings had severe thalassemia were collected. The median volume was 80 ml. The median number of cells and colony forming units-granulocyte-macrophage in cord blood was 9.2 x 10(8) and 3.4 x 10(5), respectively. Four of 20 cord blood samples had HLA-matched to the affected siblings. One patient underwent cord blood transplantation with success; one patient is waiting for transplantation.

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.

Glomerulonephritis in beta-thalassemia Hb-E disease: clinical manifestations, histopathologic studies and outcome

We presented 8 patients with beta-thal/Hb E with glomerular diseases. Diverse glomerular lesions were seen, but diffuse endocapillary glomerulonephritis was the most common. The clinical manifestations of acute glomerulonephritis in beta-thal/Hb E differed from typical cases in the older age group, female preponderance, longer duration of edema, less hypertension, marked proteinuria, hypoalbuminemia and hypertriglyceridemia and also a longer period of recovery but their outcome was still favorable despite many risk factors of renal injury. Renal biopsy was necessary in doubtful cases to detect the correct diagnosis and give proper management. The association and mechanism of glomerulonephritis in these patients require further prospective study.

Significance of blood coagulation and platelet profiles in relation to pulmonary thrombosis in beta-thalassemia/Hb E

In beta-Thalassemia hemoglobin E (beta-thal Hb E), hypoxemia with abnormal lung function was described and postmortem examination in these patients showed organized pulmonary trombi with thickened arterial wall, particularly in post-splenectomized cases. Coagulation and platelet profiles were studied in 58 beta-thal Hb E patients. In 35 cases with intact spleen, the fibrinolytic activity was significantly decreased with high antithrombin III activity, while coagulation tests revealed mild abnormality. The platelet aggregation to ADP, adrenaline, collagen and ristocretin were defective and platelet 5-hydroxytryptamine content was lower than normal. Twenty-three patients who had been splenectomized for 5-18 years, decreased fibrinolytic activity and high antithrombin III activity were also observed. The coagulation profiles and platelet aggregation in response to ADP, adrenaline and collagen showed better results. Fourteen cases exhibited thrombocytosis and their thrombin generation was in the hypercoagulable range. Platelet aggregation in response to ristocetin remained defective and platelet 5-hydroxytryptamine content was lower than in cases with intact spleens. Defective aggregation to ristocetin would indicate abnormal von Willebrand's factor (vWF). Decreased fibrinolysis should very likely have a role in the occurrence of thrombosis and the better hemostatic profiles in post-splenectomized cases would contribute to the more frequent thrombotic incidence in these cases.

Effect of pyrexia in the formation of intraerythrocytic inclusion bodies and vacuoles in haemolytic crisis of haemoglobin H disease

Clinical aspects and in vivo formation of inclusion bodies and vacuoles in red cells of patients with haemoglobin H disease were studied and compared during steady state and after pyrexia of acute infections. During period of pyrexia, there were haemolytic crises with significant drops of the steady-state haemoglobin levels of 8.6 +/- 0.9 g/dl to 5.6 +/- 1.7 g/dl. The phenomenon was observed with splenic enlargement and significant increase of inclusion body formation. The findings suggested that inclusion body formation in red cells during pyrexia of acute infections played an important role in haemolytic crisis of haemoglobin H disease, probably by causing these cells to be sequestered and destroyed in the spleen.

Fatal arteritis due to Pythium insidiosum infection in patients with thalassaemia

Six thalassaemic patients had a distinct clinical syndrome characterized by progressive ischemia of the lower extremities, with ascending arteritis and thrombosis of the main arteries of the lower limbs. With periodic acid Schiff and Gomori's methenamine silver staining a large number of hyphae were revealed in the arterial wall and the outer part of the thrombus. Pythium insidiosum was isolated from 3 patients. The clinical course of the disease was progressive gangrene of the extremities and the patients invariably died when the infectious process reached the bifurcation of the aorta. There is no effective antimicrobial agent for the syndrome and radical amputation was the only method to ensure survival of the patients. P. insidiosum infection should be considered in thalassaemic patients with leg ulcers or arterial occlusion of the lower limbs.

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.

High-dose intravenous immunoglobulin in the management of immune hemolysis in patients with thalassemic disease: factors which determine refractoriness

We report our experience with high dose intravenous immunoglobulin (IVIg) in 3 thalassemic patients who had evidence of possible immune hemolysis. In 2 patients who had serious sepsis, their responses to IVIg were only partial and transient. The other patient who had marked splenomegaly had no evidence of response to IVIg. Both serious infections and large spleen may hamper the effect of IVIg and should be considered before IVIg is to be used in thalassemia.

Incidence of aplastic anemia in Bangkok. The Aplastic Anemia Study Group

The annual incidence of aplastic anemia in metropolitan Bangkok, Thailand, and its five suburban provinces was prospectively determined. All patients first diagnosed during the period from January through December 1989 who met specific clinical and pathologic criteria were included. Thirty-two cases were identified, yielding an overall incidence of 3.7 per million. The incidence rates for the age groups 0 through 24, 25 through 59, and over 60 years were 4.3, 3.2, and 2.1 per million, respectively; the highest rate, 7.2 per million, was found for individuals aged 15 to 24 years. The male-to-female ratio was 1.9. The incidence of aplastic anemia in Bangkok is higher than that reported in recent European studies. The peak rate in young persons is almost fourfold higher than in comparable recent western studies and suggests an environmental etiology peculiar to Thailand.

Cytochemical stainings in acute promyelocytic leukemia: chloroacetate esterase reaction as a prognostic index

Cytochemical studies including peroxidase, sudan black B and esterases were used for staining peripheral blood and bone marrow smears from 42 patients with acute promyelocytic leukemia. The most sensitive methods were sudan black B (mean 98%, range 81-100%) and peroxidase (mean 92% range 70-100%). Naphthol AS-D chloroacetate esterase activity was less sensitive and was positive in only 49.4 per cent (range 2-100%). All of the population of leukemic cells contained less than 3 per cent of alpha-naphthyl acetate esterase staining. For stability tests of the storage specimens compared to fresh stains, there was no difference in naphthol AS-D chloroacetate esterase (mean 45% vs 49% P greater than 0.7) and sudan black B (mean 74% vs 98% P greater than 0.3), but the enzyme activity was significantly decreased in peroxidase staining (mean 42% vs 92% P greater than 0.05). When the patients were divided into 2 groups according to the degree of AS-D chloroacetate esterase activity, those with lower activity had a higher number of white blood cells, promyelocytes and shorter survival compared to those with higher activity. Therefore, naphthol AS-D chloroacetate esterase may be useful as a prognostic index.

Severe hyperbilirubinemia in glucose-6-phosphate dehydrogenase deficient patients during viral hepatitis

Nine G-6-PD subjects developed acute hemolysis and severe hyperbilirubinemia (up to 61.1 mg/dl) following viral hepatitis. All except one had fever at presentation. Neutrophilic leukocytosis was a common feature. Elevation of both alanine aminotransferase (SGPT) and extremely high level of aspartate aminotransferase (SGOT) were prominent. Three developed acute renal failure. All patients survived, one after peritoneal dialysis. Recognition of the clinical picture is essential to prevent serious complications and for successful management.

Abnormalities of hematopoietic progenitor cells in patients with aplastic anemia after hematologic recovery

Hematopoietic progenitor cells were studied in 11 patients with aplastic anemia who had hematologic recovery after androgen therapy. The mean numbers of colonies derived from erythroid and granulocyte-macrophage progenitor cells (BFU-E and CFU-GM) were markedly decreased compared to normal controls. Cell-mediated suppression of colony growth as detected by coculture studies was observed in 5 patients; 4 patients for CFU-GM and one for both CFU-GM and BFU-E. It is thus concluded that the pool of hematopoietic stem cells in patients after hematologic recovery is still not fully reconstituted. In addition, this impaired reconstitution appears due in some cases to cell mediated suppression of progenitor colony growth.

Dark green pit viper (Trimeresurus popeorum) bite: clinical and serial coagulation profiles in 51 cases

Trimeresurus popeorum, a dark green pit viper, is commonly found in Southeast Asia. This study describes the clinical picture and blood studies of 51 patients bitten by this snake. Affected limbs were swollen; and hemorrhagic blebs in fingers and toes were found in 12 patients. Lymphangitis was observed in 4 instances. Six individuals exhibited hypofibrinogenemia of 0-84 mg/dl, and 2 cases developed thrombocytopenia and bleeding. The presence of venom in the blood of these patients was demonstrated. Positive fibrin degradation products of 40-320 micrograms/ml were observed in 6 cases with hypofibrinogenemia, and in 8 other cases. Nineteen patients had short euglobulin lysis times of 51.8 +/- 24.7 min. Hyperfibrinogenemia of 626.7 +/- 288.9 mg/dl was found in 18 cases. Apart from bleeding, there were no systemic symptoms. Hypofibrinogenemia became normal in 3-12 days. The clinical course in all patients was uneventful, and none received antivenin.

Glucose intolerance, hyperinsulinemia and insulin resistance in aplastic anemia

Oral glucose tolerance tests were conducted in 29 patients with aplastic anemia and 20 nondiabetic controls. Seventeen were men and 12 were women, ranging in age from 15 to 67 years. Based on the results of oral glucose tolerance test, the patients were divided into three groups: 14 previously treated cases with normal glucose tolerance; eight previously treated cases with abnormal glucose tolerance, of whom six had diabetes and two had impaired glucose tolerance; and seven newly diagnosed cases with normal glucose tolerance. Hyperinsulinemia and insulin resistance were observed in all patients. Multivariate analyses show that sex, age, body mass index, previous androgen and corticosteroid therapy, previous blood transfusion, initial hemoglobin and white blood cell and serum ferritin concentrations were not significantly related to hyperinsulinemia as expressed by the integrated insulin area under the curve of glucose tolerance test. Patients in the second group who had abnormal glucose tolerance had a delay in insulin secretion in response to glucose, indicating a deterioration of insulin reserve in the beta cells. Patients in this group were significantly older at the time of diagnosis than those in the first group. No other determinants of the development of abnormal glucose tolerance were demonstrated.

Emergency splenectomy in adult idiopathic thrombocytopenic purpura. A report of seven cases

Seven adult patients with idiopathic thrombocytopenic purpura underwent emergency splenectomy. Six were female and one was a male, aged 16 to 61 years. All of them had a life-threatening episode. Six patients had progressive intracranial bleeding and one had postsurgical intra-abdominal bleeding. All patients were saved by surgery, except one for whom operation was delayed. There was no postoperative bleeding or surgical complication. Immediate splenectomy should be the treatment of choice in any patient with idiopathic thrombocytopenic purpura complicated by life-threatening hemorrhage.

Studies on the pathogenesis of aplastic anemia in Thailand: evidence of immune-mediated mechanism

The pathogenesis of aplastic anemia in Thailand was studied by using in vitro progenitor cells culture. In 37 patients who had active disease, the numbers of colonies derived from erythroid and granulocyte-macrophage progenitor cells (BFU-E and CFU-GM) were markedly decreased both in the blood and bone marrow as compared to normal controls. Co-culture of patients' cells with normal blood cells was performed in order to verify an immunologically mediated mechanism. In 8 of 26 patients, there were very low numbers of colonies both BFU-E and CFU-GM in the blood and bone marrow with significant suppression of colony formation in co-culture. Suppressor cells may have caused the aplasia in these patients. The rest had low colony formation and no suppression in co-culture. These patients may have absent or defective stem cells. None had normal colony formation. Therefore, aplastic anemia in Thailand may result mostly from defects involving the stem cells. Only some patients had cell mediated suppression of hematopoiesis as detected by co-culture.

Serious complications following treatment of chronic idiopathic thrombocytopenic purpura

Six patients had serious complications as consequences of treatment of idiopathic thrombocytopenic purpura. Five had splenectomy-related complications, one of them developed fatal intra-abdominal bleeding. Three patients acquired operation-related serious infection, two of them died. Serious neutropenia after vinblastine-loaded platelets occurred in one patient leading to pseudomonas septicaemia and panophthalmitis with permanent vision loss of left eye. Recurrence thrombocytopenia occurred in every case during serious complications. Early detection by awareness of the possibility of serious complications can reduce morbidity and mortality occurring after therapy of idiopathic thrombocytopenic purpura.

Methylprednisolone therapy in aplastic anaemia: correlation of in vitro tests and lymphocyte subsets with clinical response

20 patients with aplastic anaemia were treated with methylprednisolone 1 g/d for 3 d followed by prednisolone 60 mg on alternate days. At 3 months after therapy, 7 of 20 patients (35%) showed recovery, 2 had died and 11 were non-responders. Only newly diagnosed patients were responders. Results of in vitro tests were correlated with clinical response. The first test was designed to determine whether removing various subpopulation of cells would increase the numbers of progenitor cells. In the second test blood cells were collected at 1 month after starting treatment and assayed for progenitor cells. Data from both tests did not correlate with the response to therapy. Lymphocyte subsets were measured in the blood before and at 1 month after treatment. The absolute numbers of OKT3+, OKT4+ and OKT8+ cells were significantly decreased compared to the normal population. The number of HNK1+ cells was also decreased but no significant difference was observed. Responders had a higher number of HNK1+ cells compared to non-responders. No significant differences of OKT3+, OKT4+ and OKT8+ cells among responders and non-responders were observed. Therefore a high number of HNK1+ cells prior to therapy may identify patients responding to the treatment.

Corticosteroids therapy in paroxysmal nocturnal hemoglobinuria

We evaluated the efficacy of alternate day, high dose prednisolone for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). Nineteen patients were included. Thirteen were men and six were women, aged between 13-56 years. Eleven patients improved, eight with good response and three with fair response. Eight patients were non-responders. Responders had gradual improvement in the hemoglobin level, but none achieved a normal hemoglobin level. Age at diagnosis, sex, initial hemoglobin, white count, and percentage of a positive Ham's test had no apparent bearing on treatment outcome. A prolonged interval from diagnosis to prednisolone treatment decreased the chance of a favorable hematologic response to therapy. Age at the treatment in non-responders was higher than responders. Responders had higher numbers of colonies derived from BFU-E and CFU-GM both in the blood and bone marrow than non-responders although the differences did not achieve statistical significance. These data indicate that alternate day, high dose prednisolone therapy is effective in some patients with PNH.

Growth of mixed erythroid-granulocytic colonies in culture derived from bone marrow of patients with paroxysmal nocturnal hemoglobinuria without addition of exogenous stimulator

Hematopoietic progenitor cell cultures were studied in 16 patients with paroxysmal nocturnal hemoglobinuria (PNH). Both erythroid and granulocyte-macrophage progenitors in the blood and bone marrow decreased despite hypercellular marrow. In eight out of 16 patients, mixed erythroid-granulocytic colonies were observed in the bone marrow cultures without erythropoietin and colony-stimulating factor. Removal of monocytes and T-lymphocytes before culture failed to abrogate spontaneous mixed-colony formation. Conditioned media prepared from blood and bone marrow of PNH patients could not promote the growth of mixed colonies in normal individuals. The autonomous, spontaneous mixed-colony formation in patients with PNH is an abnormality of PNH stem cells not described previously.

Methylprednisolone treatment in aplastic anaemia

Twenty patients with aplastic anaemia were treated with a short term bolus of methylprednisolone. Seven patients were refractory to anabolic steroids and were observed in very long follow-up periods of 14-104 months. Thirteen patients had never been treated. The latter group also received anabolic steroids. Five out of 20 patients responded to the treatment while the remaining patients did not or died. Responders among patients refractory to anabolic steroids had shorter duration of disease compared to non-responders. No recurrence of aplasia was observed in all responders.

Identification of different types of lymphoblasts in patients with acute lymphoblastic leukemia

Identification of different types of lymphoblasts in acute lymphoblastic leukemia were studied with light microscopy, SEM and TEM.

Homozygous haemoglobin Constant Spring: a need for revision of concept

Twenty-two patients with mild haemolytic anaemia and haemoglobin (Hb) Constant Spring (CS) of around 6% were studied because they were suspected of having homozygous Hb CS. Family studies revealed Hb CS trait in both parents of eight patients, supporting that they were homozygous for Hb CS. The other patients were included because they had clinical and haematological features similar to the diagnosed cases of homozygous Hb CS. Heterozygosity and homozygosity for Hb CS are clearly distinguishable in that the former is asymptomatic but the latter is associated with overt haemolytic anaemia, and the levels of Hb CS in the two conditions of less than 1% and around 6%, respectively, do not overlap. The findings in homozygous Hb CS contradict prediction. There are four alpha-structural genes per normal human diploid genome. Hb CS trait is believed to be almost equivalent to alpha-thalassaemia 2 or a loss of one alpha-gene because HB CS, and alpha-variant, is barely or not detectable. Homozygosity for Hb CS has thus been predicted to be equivalent to alpha-thalassaemia 1 or a loss of two genes. The latter is asymptomatic and associated with microcytic-hypochromic red cells. However, Hb CS homozygosity presents with mild overt haemolytic anaemia and normal sized red cells. Pathogenesis associated with Hb CS inheritance is more complex than originally believed. There is a possibility that the unstable alpha CS mRNAs precipitate and aggregate leading to pathology of red cells and to the basophilic stippling appearance, so striking in this syndrome.

Plasminogen levels in subjects with eosinophilia

Plasminogen determinations were performed in 98 normal volunteers and 50 subjects with eosinophilia. There was no significant difference in the plasminogen levels between these two groups. Since, increased eosinophils in the bone marrow of those eosinophilic subjects were also demonstrated. This observation should raise a question as to whether the eosinophils would really be the site of systemic plasminogen synthesis.