Red Cell Indices and Formulas Used in Differentiation of β-Thalassemia Trait from Iron Deficiency in Thai School Children

Red cell indices and formulas have been established as simple, fast, and inexpensive means for discrimination between the β-thalassemia (β-thal) trait and iron deficiency. However, there were no reports of the diagnostic reliability of different red cell indices and formulas in discrimination of β-thal trait from iron deficiency in the Thai population. The aim of this study was to examine the diagnostic accuracy of five red cell indices [red blood cell (RBC) count, mean corpuscular volume (MCV), mean corpuscular hemoglobin (Hb) (MCH), mean corpuscular Hb concentration (MCHC), and red cell distribution width (RDW)] and eight formulas (Sirdah, Green & King, RDW Index, Menzler, England & Fraser, Ehsani, Srivastava, and Shine & Lal). Their sensitivity, specificity, positive and negative prognostic value and efficiency, were analyzed in 77 Thai school children, 21 with the β-thal trait and 56 with iron deficiency. The Sirdah and Srivastava formulas proved to be the most reliable indexes as they had 100.0% sensitivity and negative predictive value, the highest efficiency (97.4%), and the highest Youden’s Index value (96.4%). Therefore, these formulas could be used in initial discrimination of the β-thal trait from iron deficiency in Thai school children.     

Production of a monoclonal antibody against a yeast secreted antigen of Penicillium marneffei

Monoclonal antibody against P. mameffei yeast secreted antigen was produced in order to develop a serological test for penicilliosis marneffei. The yeast form of P. marneffei was cultured in brain heart infusion broth at 37 degrees C for 7 days. A secreted antigen was prepared, partially purified from culture supernatant and subsequently immunized in a BALB/c mouse. Mouse monoclonal antibody was produced from immune spleen cells by a standard hybridoma technique. Specificity of the obtained monoclonal antibody was assessed with yeast secreted antigens for P. mameffei, C. alblicans, C. neoformans, and H. capsulatum by an indirect ELISA. Three of 46 hybrid clones (1 F1, 2G5, and 3G4) reacted positively with P mameffei secreted antigen. 1 F1 and 3G4 were cloned by two rounds of limiting dilution. Partially purified monoclonal antibody and rabbit polyclonal antibody against P. marneffei yeast secreted antigen were used to develop a double antibody sandwich ELISA to detect P. marneffei antigen in plasma or serum samples of 7 patients with penicilliosis marneffei and 5 healthy controls. The sandwich ELISA developed using monoclonal antibody as a capture antibody and rabbit polyclonal antibody as a detector was able to detect P. marneffei antigen in all the plasma and serum samples of penicilliosis marneffei patients, while negative in all the healthy controls. Thus, the monoclonal antibody produced in the present study appeared to be highly specific for P. marneffei and the double antibody sandwich ELISA developed using monoclonal and polyclonal antibodies against the yeast secreted antigen of P. marneffei showed a strong potential for the diagnosis of penicilliosis marneffei.     

Down modulation of TNF-alpha mRNA placental expression by AZT used for the prevention of HIV-1 mother-to-child transmission

Mechanisms of HIV-1 in utero mother-to-child transmission (MTCT) protection provided by AZT are not completely understood. The placental cytokine network is involved in the control of HIV-1 in utero transmission but the effect of AZT on this network is unknown. To evaluate the effects of AZT on placental cytokine expression, the chorionic villi from HIV-1 uninfected women term placentae were cultured with 0, 100, and 2,000 ng/ml AZT. Tissue fragments were harvested at days 1, 4, and 7 to determine the level of cytokine mRNA by real-time RT-PCR. The viability and morphology of the placental histocultures were monitored by the expression of beta-human chorionic gonadotropin (beta-hCG) gene, lipopolysaccharide (LPS) activation, and microscopic examination. AZT at 2,000 ng/ml significantly down-regulated TNF-alpha mRNA expression at day 1 and day 4, but had no effect on beta-hCG, stromal cell-derived factor 1 (SDF-1), and IL-10 gene expression. AZT did not induce any deleterious impact on placental tissue structure. Furthermore, activation of chorionic villi by LPS for 24 h up-regulated IL-10 and TNF-alpha mRNA expression. Down-regulation of TNF-alpha mRNA could represent a mechanism through which AZT can decrease the risk of HIV-1 MTCT, in addition to its direct effect on HIV-1 replication.     

Diagnosis of Compound Heterozygous Hb Tak/β-Thalassemia and HbD-Punjab/β-Thalassemia by HbA<Subscript>2</Subscript> Levels on Capillary Electrophoresis

A misdiagnosis of β-thalassemia carrier in samples with Hb Tak and HbD-Punjab, the β-variants, can be a cause of inappropriate genetic counseling thus having a new case of β-thalassemia major. A capillary electrophoresis (CE) is very efficient in separating and quantifying HbA₂. In this study, HbA₂ levels of samples which were doubted for compound heterozygous Hb Tak/β-thalassemia or heterozygous HbD-Punjab/β-thalassemia were measured and compared between CE and high performance liquid chromatography (HPLC). The molecular confirmation for Hb Tak, HbD-Punjab and β-thalassemia codons 17 (A > T), 41/42 (-TCTT), 71/72 (+A) and IVSI-nt1 (G > T) mutations and 3.4 kb deletion were also performed. Based on DNA analysis, 3 cases were diagnosed as compound heterozygous Hb Tak/β-thalassemia and one for HbD-Punjab/β-thalassemia. The elevated HbA₂ levels were found in all 4 samples with rages of 4.6–7.3% on CE while those were not found on HPLC. Thus, the elevated HbA₂ measured by CE can be used as a screening parameter for differentiating the homozygote of Hb Tak and HbD-Punjab from the compound heterozygote of these hemoglobinopathies and β-thalassemia.     

Effect of haematological alterations on thalassaemia investigation in HIV-1-infected Thai patients receiving antiretroviral therapy

Objectives

To evaluate the effect of haematological alterations resulting from antiretroviral therapy (ART) on the diagnosis of thalassaemia carriers in HIV‐1‐infected Thai patients.

Methods

Complete blood cell counts, osmotic fragility (OF) test and haemoglobin (Hb)‐A₂ values were measured in blood samples of 52 antiretroviral‐treated and 14 untreated HIV‐1‐infected patients. Data were analysed according to thalassaemia type and ART.

Results

Sixteen patients carried at least one of the investigated thalassaemia types and most of them (87.5%) received ART. Their red cell indices [mean corpuscular Hb (MCH), mean corpuscular Hb concentration (MCHC) and red blood cell distribution width (RDW)], OF test and Hb‐A₂ values were observed within the critical criteria of each thalassaemia type. Normocytic red cells were observed in α‐thalassaemia and Hb‐E trait. Among HIV‐1‐infected patients who are non‐thalassaemia carriers, higher values of Hb‐A₂, MCH, macrocytosis and lower red cell counts were observed in the treated group. Values of RDW, MCHC and OF test for treated and untreated groups were in the normal range. Five treated patients had Hb‐A₂ values within the critical criteria of β‐thalassaemia carriers but β‐thalassaemia gene mutations were not observed by polymerase chain reaction analysis.

Conclusions

ART can alter many haematological figures. Therefore, diagnosis of thalassaemia should be evaluated carefully in combination with those parameters.     

Coinheritance of Hb S [β6(A3)Glu→Val, GAG>GTG] with β0-thalassemia codon 17 (A>T) in a Thai patient

Hb S [β6(A3)Glu→Val, GAG>GTG] is a β-globin gene variant that has a very low incidence in the Thai population. Coinheritance of Hb S and β(0)-thalassemia (β-thal) can result in severe clinical conditions. This study reports the case of a Thai patient with a compound heterozygosity for Hb S and β(0)-thal codon 17 (A>T). His hemoglobin (Hb), hematocrit (packed cell volume, PCV), mean corpuscular volume (MCV) and mean corpuscular Hb (MCH) levels were all less than the lower limits, while red cell distribution width (RDW) was higher than the upper limit. Levels of Hbs S, F and A(2) detected by high performance liquid chromatography (HPLC) were comparable to those from capillary electrophoresis (CE). As Hb S has a similar electrophoretic mobility and the HPLC profile is also similar to those of Hb Tak [β147, Term→Thr (+AC)] and Hb D-Punjab [β121(GH4)Glu→Gln, GAA>CAA], DNA sequencing was then performed. This was to detect β(0)-thal, and to differentiate Hb S from the Hb Tak and Hb D-Punjab mutations. The β(0)-thal codon 17 and Hb S mutations were detected indicating that coinheritance of these two mutations can be found in the Thai population. Therefore, to provide proper clinical management and genetic counseling of this rare case, DNA analysis should be performed in all cases when a peak at the S-window is detected by HPLC or CE.     

Hb A2/E levels found in co-inheritance with the α-thalassemia-1 - -(SEA)/type deletion and either Hb E or β-thalassemia

The α-thalassemia-1 (α-thal-1) Southeast Asian (- -(SEA)) type deletion, β-thalassemia (β-thal) and Hb E [β26(B8)Glu→Lys, GAG>AAG] are the most common genetic disorders in Southeast Asian populations. Mean corpuscular volume (MCV) <80.0 fL with normal hemoglobin (Hb) is used for screening α- and β-thal, and a Hb E level of less than 25.0% is used for predicting α-thal-1 in Hb E trait. Thus, levels of Hb, MCV and Hb A(2)/E were reviewed and compared between the SEA type deletion co-inherited with β-thal trait (n = 61), with Hb E trait (n = 102) or homozygous Hb E (n = 13) and β-thal trait (n = 636), Hb E trait (n = 544) or homozygous Hb E (n = 83), respectively. When comparing the values of all three analyzed hematological parameters, only the - -(SEA)/β(E) values were shown to be significantly lower than those of Hb E trait. Furthermore, at a cut-off value of Hb A(2)/E of 21.54%, 95.0% of the - -(SEA)/β(E) had Hb A(2)/E levels lower than this cut-off value, while 94.0% of Hb E trait had Hb A(2)/E at higher levels. Accordingly, the Hb A(2)/E level at 21.54% is the best indicator for predicting co-inheritance of the α-thal-1 - -(SEA)/ deletion and Hb E trait.     

Quantification of hemoglobin Constant Spring in heterozygote and homozygote by a capillary electrophoresis method

Introduction: Capillary electrophoresis (CE) is a high‐resolution method for detection of hemoglobin Constant Spring (Hb CS). Methods: The levels of Hb CS quantified by CE were compared among three groups of samples including heterozygote and homozygote of Hb CS as well as Hb H‐CS disease classified by DNA molecular diagnosis. The mean corpuscular volume (MCV) of red blood cells was also analyzed among these three groups. Results: Mean ± SD of Hb CS level of the homozygote was not significantly different from that of the Hb H‐CS disease (1.9 ± 1.8 vs. 2.8 ± 1.3, P = 0.13), but it was significantly higher than that of the heterozygote (1.9 ± 1.8 vs. 0.4 ± 0.2, P = 0.007). The MCV <70 fL was found in Hb H‐CS disease only. Conclusion: CE is the preferable method for screening of heterozygote and homozygote of Hb CS. Moreover, in conjunction with a lower MCV (<70 fL), this approach provided a high resolution to identify Hb H‐CS disease.