A preliminary study of the distribution of blood group systems in Thai blood donors determined by the gel test.

Two hundred blood samples obtained from volunteer blood donors at the Blood Bank, Army Institute of Pathology were studied for red cell groupings in the ABO, Rh, MNSs, Duffy, Lewis. P. Kell, Lutheran and Kidd Systems. Each sample was tested by the gel test using five cards; the ABO-Rh card, Diaclon Rh sub groups + K card, Antigen profile I card (P, Le(a), Le(b), Lu(a), Lu(b)), Antigen profile II card (k, Kp(a), Kp(b), Jk(a), Jk(b)) and Antigen profile III card (M, N, S, s, Fy(a), Fy(b)). For the ABO System, group O is the most common (40.5%) followed by group B (30.5%), group A (20.5%) and group AB (8.5%). The most common Rh gene complex was CCDee (51.5%), which was similar to other studies. The incidence of MMss and MNss gene complexes were the most common in the MNSs System. Fy(a) is very common as in other Asians. In the Lewis System, the incidence of Le (a-b-) was 23.5%, which is consistent with other findings in the Thai population. Sixty (30%) were positive with anti-P1. For the Kell System, only kk and Kp(b) positive types were observed in this study, as well as Lu (a-b+) in the Lutheran System. Jk (a-b-) was not found, which is considered a rare phenotype among Thai people. This study reveals the blood group distribution in 200 Thai volunteers using the gel test. Because of its simplicity and efficacy, this test is practical in population studies. Moreover, it is useful for mass screening and application in emergency situations.

HLA class II alleles in Japanese patients with non-Hodgkin's lymphoma.

The distribution of HLA-DRB1 alleles and DQB1 alleles in 30 Japanese patients with non-Hodgkin's lymphoma (NHL) was analyzed using polymerase chain reaction with the sequence-specific primer (PCR-SSP) method, and the association between the disease and the presence of certain HLA class II alleles was investigated. The frequencies of HLA-DRB1*0803, DRB1*0802 and DRB1*1502 were increased while those of DRB1*1501 and DRB1*0405 were decreased. On the other hand, the incidence of HLA-DQB1 alleles was similar to that in the normal population. However, none of these HLA class II alleles showed significant positive or negative associations with NHL. In addition, when allele frequencies of NHL Japanese patients were compared to Thai patients, only DRB1*0803 was significantly increased in Japanese patients. These results indicate that DRB1*0803 may not contribute to NHL susceptibility in the Japanese population. However, further studies with larger numbers of NHL Japanese patients are needed to confirm our preliminary findings.

Comparison of the RPHA and EIA techniques for the detection of HBs antigen among pregnant Thai women.

Five hundred serum samples obtained from pregnant women attending an antenatal clinic in Bangkok were tested for HBsAg by reverse passive hemagglutination assay (RPHA) and enzyme immunoassay (EIA). It was found that 21 (4.2%) and 28 (5.6%) of the sera were positive by RPHA and EIA, respectively. The sensitivity and specificity of the RPHA were 75% and 100%, respectively, when using EIA as the standard method. The RPHA positive predictive value was 100% and the negative predictive value was 98.5%. Accuracy was 98.6%. This study showed that the RPHA was simple and required inexpensive equipment, making it suitable for mass screening. However, the possibility of false negative readings due to low levels of HBsAg should be kept in mind, especially in the blood transfusion practice.

HLA class I antibodies in thalassemic patients.

This study was undertaken to demonstrate the prevalence of HLA class I antibodies among 62 polytransfused patients. The diagnosis included beta-thalassemia major, beta-thalassemia/Hb E disease and severe Hb H disease. Their ages ranged from 1 year to 23 years with the mean age of 10.7 years. The number of packed red cell transfusions ranged from 3 to 235 with the mean of 60 episodes per patient. The standard microlymphocytotoxicity test was performed using 50 panels of lymphocytes which specifically identified the majority of HLA class I antibodies. 31/62 cases (50%) were positive for HLA class I antibodies. The detection of single or multiple antibodies depended upon the number of blood transfusions and the patients' ages. These antibodies were induced by the leukocytes present in the transfused packed red cells. Therefore, leukocyte-reduced packed red cells prepared by either additional inverted centrifrugation or leukocyte filter is suggested for the routine blood bank service.

A comparative study of three techniques for eluting red cell antibodies.

Sixty-seven eluates obtained from the heat, ether and acid elution techniques were tested with the specific red blood cells (RBCs) and were compared according to their reactivities using the indirect antiglobulin test (IAT). It was found that the ether elution technique was superior in eluting Rh antibodies except for anti-e while the acid elution technique was superior in eluting Miltenberger (Mi(a)) antibodies (P < 0.05). The heat elution technique gave the lowest reactivity among the three techniques. In conclusion, the reactivities of the eluates obtained from the acid elution technique were overall comparable to those from the ether elution technique. The acid elution technique is practical for routine use in most blood banks because it is less time consuming and reduces the risk of exposing hazardous chemicals.

The benefit of the direct antiglobulin test using gel technique in ABO hemolytic disease of the newborn.

The direct antiglobulin test (DAT) using the gel technique was included in the investigation of infants with hyperbilirubinemia in the first week of life. Twelve cases were preterm and 48 cases were full term infants. The patients were divided into 2 groups: the study group comprised 22 cases of blood group A or B infants born to blood group O mothers; the control group comprised 38 cases of ABO blood groups compatible with those of their mothers. The mean +/- SD (39 +/- 26 hours) of the age at the onset of hyperbilirubinemia induced by ABO hemolytic disease of the newborn (HDN) was significantly earlier than that due to other causes. The positive rate of DAT in the ABO incompatible group was similar by both the conventional technique and the gel technique, 54.5% and 50% respectively. However, the scores by the gel technique were higher than those of the conventional technique. The gel technique is simple, reliable, involves less technical error and requires a small amount of blood sample. The grading system is clear-cut, especially grade 1 + or weak positive as compared to the conventional technique which requires examination under a microscope. Therefore, the DAT using the gel technique is beneficial to the diagnosis of ABO HDN. It should be included in the investigation of infants with hyperbilirubinemia especially in case of suspected ABO HDN.

Clinical phenotypes and genotypes diagnosis of thalassemia in children.

Thalassemia is a relatively common hemolytic anemia in Southeast Asia. Alpha and beta thalassemia, hemoglobin (Hb) E, and Hb Constant Spring (CS) are prevalent in Thailand. Different gene combinations lead to over 60 thalassemic syndromes. One hundred and forty-nine thalassemia families were retrospectively studied. They were 4 homozygous beta-thalassemia (beta-thal/ beta-thal), 79 beta-thal/Hb E, 22 Hb H disease, 32 Hb with Hb CS, and 6 AE Bart's disease. The first clinical manifestation and hematologic data including hemoglobin electrophoresis were analysed. Most homozygous beta-thalassemia and beta-thal/Hb E presented with anemia (100% vs 81%), hepatomegaly (40% vs 21%), and splenomegaly (20% vs 27%). In Hb H disease and Hb H with Hb CS, the clinical findings were anemia (74% vs 79%), hepatomegaly (9% vs 8%), splenomegaly (9% vs 13%), jaundice (24% vs 13%), and fever (18% vs 25%). The 317 hematologic data and hemoglobin types of the patients, their parents and relative were also analyzed. These findings can be used as reference values for childhood thalassemia and heterozygous states.

Prenatal diagnosis of Hb Bart's hydrops fetalis by PCR technique: Pramongkutklao experience.

Hb Bart's hydrops fetalis is very common in Southeast Asia, especially in Thailand. As the mother of such an infant may suffer from toxemia of pregnancy, ante- or post-partum hemorrhage as well as the psychological burden for carrying a nonviable fetus to term, so prenatal diagnosis is indicated and the family should be given the choice of early termination of the pregnancy. Seven high risk pregnancies with Hb Bart's hydrops fetalis (homozygous alpha-thalassemia 1) were studied. Amniocentesis was done at 16-33 weeks of gestation. DNA analysis was performed by polymerase chain reaction (PCR) using 2 techniques, 1) three nucleotide primers and 2) four nucleotide primers. After either therapeutic abortion or birth, heart blood or cord blood was drawn to confirm the diagnosis by Hb electrophoresis and DNA analysis. Of 7 high risk fetuses, 3 were recognized as Hb Bart's hydrops fetalis, 2 showed the alpha-thal 1 trait, 1 showed alpha-thal 2 trait and 1 was a normal fetus. The technique was entirely suitable for prenatal diagnosis of Hb Bart's hydrops fetalis. This technique was a rapid, simple non-radioactive method, less expensive and available in most PCR laboratories.

High transfusion in children with beta-thalassemia/Hb E: clinical and laboratory assessment of 18 cases.

Between 1990-1992, 18 patients with beta-thalassemia/Hb E age between 2-13 years (mean 7.4 +/- 3 years) were examined. Three patients were splenectomized and the rest were nonsplenectomized. They were divided into 3 groups. Group A:5 nonsplenectomized and 3 splenectomized patients had high transfusion rates with subcutaneous desferrioxamine injections. Five patients in group B received only high transfusion whereas in 5 patients in group C the levels pretransfusion Hb were maintained between 6-7 g/dl. The mean blood consumption in the nonsplenectomized groups were 220 +/- 25.3, 221 +/- 59 and 175.4 +/- 45.4 ml/kg/year in groups A, B and C, respectively. In group A, the mean blood requirement was 40% higher in the nonsplenectomized group. In the high transfusion regimen the spleen size did not increase and serum aspartate aminotransferase showed a striking fall in the majority of cases. The absolute increases in serum ferritin were 843.2 +/- 395, 861 +/- 252 and 1,262 +/- 440 ng/ml in groups A, B and C, respectively. These data demonstrated that high transfusion with desferrioxamine injection could improve the clinical well being of the patients.