Reliability of hemoglobin A2 value as measured by the Premier Resolution system for screening of β-thalassemia carriers

OBJECTIVES

Accurate quantification of hemoglobin (Hb) A2 is vital for diagnosing β-thalassemia carriers. This study aimed to assess the precision and diagnostic utility of HbA2 measurements using the new high-performance liquid chromatography (HPLC) method, Premier Resolution, in comparison to capillary electrophoresis (CE).

METHODS

We analyzed 418 samples, previously identified as A2A by CE, using Premier Resolution-HPLC. We compared the results, established correlations, and determined an optimal HbA2 cutoff value for β-thalassemia screening. Additionally, we prospectively evaluated the chosen cutoff value in 632 samples. Mutations in the β- and α-globin genes were identified using polymerase chain reaction (PCR) techniques and DNA sequencing.

RESULTS

HbA2 levels were consistently higher with Premier Resolution, yet there was a significant correlation with CE in all samples (bias, -0.33; r, 0.991), β-thalassemia (bias, -0.27; r, 0.927), and non-β-thalassemia carriers (bias, -0.36; r, 0.928). An HbA2 cutoff value of ≥4.0 % for β-thalassemia screening achieved 100 % sensitivity and 99.6 % specificity. Further validation yielded sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 97.3 , 99.8, 97.3, 99.8, and 99.7 %, respectively. We also identified a rare β-Hb variant, Hb La Desirade [HBB:c.389C>T], associated with β-thalassemia and co-inherited with a single α-globin gene.

CONCLUSIONS

The Premier Resolution HPLC is a reliable and accurate method for routine β-thalassemia carrier screening, aligning with existing CE methods.

Molecular understanding of unusual HbE-β+-thalassemia with Hb phenotype similar to HbE heterozygote: simple and rapid differentiation using HbE levels

BACKGROUND

Low HbF expression in HbE-β+-thalassemia may lead to misdiagnosis of HbE heterozygosity. We aimed to characterize the β- and α-globin genes and the modifying factors related to HbF expression in patients with an Hb phenotype similar to that of HbE heterozygotes. Furthermore, screening tools for differentiating HbE-β+-thalassemia from HbE heterozygotes have been investigated.

PARTICIPANTS AND METHODS

A total of 2133 participants with HbE and HbA with varying HbF levels were recruited. Polymerase chain reaction-based DNA analysis and sequencing were performed to characterize β- and α-globin genes. DNA polymorphism at position -158 nt 5' to Gγ-globin was performed by XmnI restriction digestion. Receiver operating characteristic (ROC) curves were constructed using the area under the curve (AUC). Cutoff values of HbA2, HbE, and HbF levels for the differentiation of HbE-β+-thalassemia from HbE heterozygotes were determined.

RESULTS

Five β+-thalassemia mutations trans to βE-gene (β-87(C>A), β-31(A>G), β-28(A>G), β19(A>G), and β126(T>G)) were identified in 79 patients. Among these, 54 presented with low HbF levels, and 25 presented with high HbF levels. ROC curve analysis revealed an excellent AUC of 1.000 (95% confidence interval:1.000-1.000) for HbE levels, and a cut-off point of ≥35.0% had 100.0% sensitivity, specificity, and Youden's index for differentiating HbE-β+-thalassemia from HbE heterozygotes. The proportion of α-thalassemia mutations was 46.3 and 8.0% among HbE-β+-thalassemia patients with low and high HbF levels, respectively. Two rare α-thalassemia mutations (Cap +14(C>G) and initiation codon (ATG>-TG)) of α2-globin genes were identified. The genotype and allele of the polymorphism at -158 nt 5' to Gγ-globin was found to be negatively associated with HbF expression.

CONCLUSIONS

HbE-β+-thalassemia cannot be disregarded until appropriate DNA analysis is performed, and the detection of α-thalassemia mutations should always be performed under these conditions. An HbE level ≥35.0% may indicate screening of samples for DNA analysis for HbE-β+-thalassemia diagnosis.

Hemoglobin profile and molecular characteristics of the complex interaction of hemoglobin Doi-Saket [α9(A7) asn > lys, HBA2:c.30C > a], a novel α2α1 hybrid globin variant, with hemoglobin E [β26(B8) Glu > lys, HBB:c.79G > A] and deletional α+-thalassemia in a Thai family

BACKGROUND

An increasing number of α-hemoglobin (Hb) variants is causing various clinical symptoms; therefore, accurate identification of these Hb variants is important.

OBJECTIVE

This study aimed to describe the molecular and hematological characteristics of novel Hb Doi-Saket that gives rise to a typical α+-thalassemia phenotype in carriers with and without other hemoglobinopathies.

MATERIALS AND METHODS

Biological samples from a proband and his family members were analyzed. Hematological profiles were analyzed using a standard automated cell counter. Hb was analyzed by capillary electrophoresis and high-performance liquid chromatography. Mutations and globin haplotype were identified by DNA analysis. Novel diagnostic tools based on allele-specific polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism were developed.

RESULTS

Hb analysis showed a major abnormal Hb fraction, moving slower than HbA, and a minor Hb fraction alongside HbA2 in the proband, his father, and son. DNA analysis of the α-globin gene identified the -α3.7 deletion and in cis the C > A mutation on codon 9 of the α2α1 gene, corresponding to Hb Doi-Saket [α9(A7) Asn > Lys]. This mutation could be identified using newly developed allele-specific PCR-based assays. The Hb Doi-Saket al.lele was significantly associated with haplotype [- + M + + 0 -]. Interaction of αDoi-Saket with βE globin chains led to a new Hb variant (HbE Doi-Saket). Phenotypic expression was clinically silent in heterozygotes and might present slight microcytosis.

CONCLUSIONS

Hb Doi-Saket emphasizes a great diversity present in α-globin gene. The mutation in this family from Thailand was linked to -α3.7 and caused mild microcytosis in the carriers. The combination of this variant with deletions in α genes might cause a severe clinical phenotype. Different methods of separation can provide useful information in diagnosis, and a complete molecular approach is needed for confirmation before considering patient management.

Effective screening of hemoglobin Constant Spring and hemoglobin Paksé with several forms of α- and β-thalassemia in an area with a high prevalence and heterogeneity of thalassemia using capillary electrophoresis

Background and aims

We aimed to evaluate the efficiency of identification and quantification of hemoglobin (Hb) Constant Spring (CS) and Hb Paksé by capillary electrophoresis (CE).

Materials and methods

Blood samples collected from 2057 patients were used for identifying and quantifying Hb by CE. Molecular analysis of α- and β-thalassemia, Hb CS, and Hb Paksé was performed.

Results

Hb CS and Hb Paksé were identified in 573 samples (27.86%) with diverse genotypes. Thirty-eight samples (6.6%) showed no Hb CS peak. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of Hb CS by CE were 93.37, 95.96, 89.92, 97.40, and 95.24%, respectively. The amount of Hb CS in those carrying Hb CS was 0.2-6.5% which showed an increasing trend according to the number of defective α-globin genes, in contrast to Hb A2 levels, which decreased. Hb CS level ≥1.0% accurately excluded heterozygotes and that of ≥2.0% could identify homozygotes.

Conclusion

CE has the high potential for identifying and quantifying Hb CS and Hb Paksé, especially in an area with a high prevalence of thalassemia. Hb CS levels can be used as a potential marker to distinguish the genotype of individuals carrying Hb CS.

Microbicide Containing Ellagic Acid Can Inhibit HIV-1 Infection

OBJECTIVES

Ellagic acid (EA) has a wide range of biological effects. The purpose of this study was to investigate the in vitro effects of EA on HIV-1 replication, viral enzyme activity and cytokine secretion by infected cells.

METHODS

The anti-HIV-1 activity of EA in solution was determined in vitro using the infection of TZM-bl cells by the nano luciferase-secreting R5-tropic JRCSF strain of HIV-1, which allows for the quantification of viral growth by measuring nano luciferase in the culture supernatants. The effect of EA on the cytokine secretion of TZM-bl cells was determined by a multiplexed bead array after 48 h of HIV-1 exposure. The antiviral effect of EA in the gel formulation (Ellagel), as would be used for vaginal application, was investigated by the inhibition of infection of UC87.CD4.CCR5 cells with R5-tropic pBaLEnv-recombinant HIV-1.

RESULTS

EA in solutions of up to 100 µM was not toxic to TZM-bl cells. EA added either 1 h before or 4 h after HIV-1 exposure suppressed the replication of R5-tropic HIV-1 in TZM-bl cells in a dose-dependent manner, with up to 69% inhibition at 50 µM. EA-containing solutions also exhibited a dose-dependent inhibitory effect on HIV-1 replication in U87 cells. When EA was formulated as a gel, Ellagel containing 25 µM and 50 µM EA inhibited HIV-1 replication in U87 cells by 56% and 84%, respectively. In assays of specific HIV-1 enzyme activity, Ellagel inhibited HIV-1 integrase but not protease. EA did not significantly modulate cytokine secretion.

CONCLUSIONS

We conclude that EA either in solution or in a gel form inhibits HIV infection without adverse effects on target cells. Thus, gel containing EA can be tested as a new microbicide against HIV infection.

Hb Athens-Georgia (beta 40(C6) Arg > Lys, HBB:c.122G > A) with a single α-globin gene (Hb H disease) in a Thai family: molecular, hematological, and diagnostic aspects

Interaction of structural hemoglobin (Hb) variants with α- or β-globin defects are occasional in Southeast Asia. Herein we provide the first description of Hb Athens-Georgia (Hb A-Ga) in association with deletional Hb H disease, a novel combination previously undescribed in the population. Hematological, Hb and DNA analysis, and β-globin haplotype analyses were performed in seven participants from one ethnic Thai family. Hemoglobin analysis by capillary electrophoresis revealed an abnormal Hb fraction in the proband, his father and grandmother (I-2). DNA sequencing revealed that the G > A substitution at codon 40 of the β-globin gene was identical to the Hb A-Ga (HBB:c.122G > A). Interestingly, α-thal-1 (SEA deletion) and α-thal-2 (-α^3.7 deletion) were identified in the proband resulting in Hb H disease, while α-thal-1 was identified in the father, and no α-thal was observed in I-2. Hematological analysis indicated that the proband (β^A-Ga/β^A, -^SEA/-α^3.7) had moderate anemia and was markedly hypochromic with microcytic red blood cells (RBCs). The father (β^A-Ga/β^A, -^SEA/αα) presented mild microcytic anemia, while normal hematology was observed in the I-2 who was heterozygous for Hb Athens-Georgia (β^A-Ga/β^A, αα/αα). The relative level of Hb A-Ga was distinctly reduced according to the degree of α-globin defects. The developed allele-specific PCR method can successfully be used for confirmation of Hb A-Ga. The Thai Hb A-Ga allele associated with a β-haplotype [+ - - - - - +]. These findings were in accordance with the previous conclusion that this variant is a non-pathological β-Hb variant.

Molecular Characterization and Hematological Aspects of Hb E-Myanmar [β26(B8)Glu→Lys and β65(E9)Lys→Asn, HBB: c.[79G>A;198G>C]): A Novel β-Thalassemic Hemoglobin Variant

Hb E [β26(B8)Glu→Lys, GAG>AAG, HBB: c.79G>A] is an inherited thalassemic β-globin variant that favors the Hb E-β-thalassemia (β-thal) syndrome when interacting with the β-thal gene. However, hemoglobin (Hb) variants carrying Hb E in combination with another variant on the same β gene are rare. We recently studied a 29-year-old pregnant woman, initially diagnosed as a β-thal carrier. Hemoglobin and DNA analysis were performed by high performance liquid chromatography (HPLC) and DNA sequencing. Hematological data revealed no anemia or altered red blood cell (RBC) parameters. Hemoglobin HPLC showed Hb A and Hb A₂ but no Hb E or abnormal Hb peaks, with a markedly elevated Hb A₂ level (6.4%) reaching the accepted range (4.0-10.0%) for β-thal trait. DNA analysis identified a GAG>AAG transition at codon 26 of the β-globin gene that is responsible for Hb E, and an AAG>AAC mutation at codon 65 in cis on the β-globin chain resulting in a lysine to asparagine substitution. These two mutations led to the formation of a novel variant, namely Hb E-Myanmar, β26(B8)Glu→Lys and β65(E9)Lys→Asn, HBB: c.[79G>A;198G>C]. Moreover, a heterozygous α-thalassemia-2 (α-thal-2) [-α^3.7 (rightward)] deletion was also observed. Hb E-Myanmar is a doubly substituted β-globin variant, which has not been previously described. This variant did not have any clinical or hematological abnormalities, and the genetic mechanism resulting in this variant is discussed. The new simultaneous allele-specific polymerase chain reaction (ASPCR) was developed for rapid detection of these two mutations within the same β-globin chain.

Molecular Characterization of β- and α-Globin Gene Mutations in Individuals with Borderline Hb A2 Levels

Elevated Hb A₂ level (≥4.0%) is considered to be reliable parameter to identify β-thalassemia (β-thal) carriers. However, some β-thal carriers have been misdiagnosed as their Hb A₂ levels are below 4.0%. In addition, coinheritance of α-thalassemia (α-thal) and β-thal might affect Hb A₂ levels. Therefore, the aim of this study was to investigate the mutations of β- and α-globin genes in individuals with borderline Hb A₂ levels in Thailand. Three hundred samples from individuals with Hb A₂ levels of 3.5-3.9% were collected for molecular diagnosis of β-globin gene mutations. In addition, the α⁰-thal, α⁺-thal, Hb Constant Spring (Hb CS, HBA2: c.427T>C), and Hb Paksé (HBA2: c.429A>T) diagnostics were also performed. Sixteen samples (5.33%) had β-globin gene mutations, and codon 41/42 (-TTCT) (HBB: c.126_129delCTTT) was the most prevalent mutation. Ninety-eight samples (32.67%) had α-globin gene mutations including four Hb H (β4)-Hb CS disease, two Hb H disease, 13 heterozygous α⁰-thal, 11 homozygous α⁺-thal, two α⁺-thal/Hb CS, one α⁺-thal/Hb Paksé, 61 heterozygous α⁺-thal, and four Hb CS. Furthermore, seven cases of β-thal carriers coinheriting α-thal were observed, and five of them carried Hb H disease. High prevalence of both α- and β-thal in subjects with borderline Hb A₂ levels suggested that molecular diagnosis of α- and β-thal should be performed, especially in a high prevalence area of thalasssemia carriers, for accurate diagnosis and genetic counseling to prevent and control new severe thalassemia cases. Moreover, β-thal carriers who coinherited Hb H disease might have reduced Hb A₂ levels, leading to a misdiagnosis of β-thal in analysis programs.

Molecular spectrum of Hb H disease and characterization of rare deletional α-thalassemia found in Thailand

Hb H diseases with the clinical features of thalassemia are found in many parts of the world, including Southeast Asia and southern China. There are limitations in molecular data from the population of Thailand, which includes multiple ethnic groups. Here, we characterized the molecular basis of the disease among a large cohort from this region. A total of 479 unrelated Thai patients with Hb H disease were studied. Mutations of the α-globin gene were characterized by conventional gap-PCR and rare genotypes were identified by MLPA analysis and direct DNA sequencing. The molecular characterization showed five common Hb H genotypes (472/479; 98.54%), including three deletional types (-^SEA/-α^3.7; n = 312), (-^SEA/-α^4.2; n = 26), (-^THAI/-α^3.7; n = 1) and two non-deletional types (-^SEA/α^CSα; n = 131), (-^SEA/α^Pakséα; n = 2). Herein, we firstly report a rare genotype of Hb H disease with (-^SA/-α^3.7; n = 1) that has not been documented in Thailand, and rare genotypes related to (-^SEA/-α^16.6; n = 1), and (-^SEA/α^QSα; n = 3) as well. The remaining two cases could not be characterized. The hematological parameters demonstrated that the clinical phenotype of non-deletional Hb H diseases is more severe than the deletional type of α⁺-thalassemia. The molecular spectrum of α-thalassemia is useful for prevention and thalassemia control and genetic counseling for couples at risk in this region.

Ellagic acid inhibits HIV-1 infection in vitro: Potential role as a novel microbicide

OBJECTIVE

To investigate the in vitro effects of ellagic acid on HIV-1 replication.

METHODS

Anti-HIV-1 activity of ellagic acid was determined in vitro using X4-tropic HIV-1_NPO3 and R5-tropic pBaL Env-recombinant virus. Anti-HIV-1_NPO3 activity of ellagic acid was investigated at a multiplicity of infection (MOI) of 0.01. Anti-HIV-1 integrase and protease activities of ellagic acid were tested using in vitro integration and proteolytic cleavage assays.

RESULTS

Ellagic acid, added either before or after HIV-1_NPO3 exposure, suppressed replication of the virus in C8166 cells up to 34%. Ellagic acid showed an anti-integrase IC₅₀ of 8.7 μM. No cytotoxicity of ellagic acid at concentrations ranging from 12.5 to 100 μM was observed.

CONCLUSION

We conclude that ellagic acid can inhibit HIV-1 infection without cytotoxicity. Thus, it may be a new effective agent that has potential to be developed as a novel microbicide against HIV-1.

Vaginal innate immune mediators are modulated by a water extract of Houttuynia cordata Thunb

Background

Vaginal epithelial cells (VECs) produce antimicrobial peptides including human β-defensin 2 (hBD2) and secretory leukocyte protease inhibitor (SLPI), as well as cytokines and chemokines that play vital roles in mucosal innate immunity of the female reproductive tract. Houttuynia cordata Thunb (H. cordata), a herbal plant found in Asia, possesses various activities including antimicrobial activity and anti-inflammation. As inflammation and infection are commonly found in female reproductive tract, we aimed to investigate the effects of H. cordata water extract in modulating innate immune factors produced by VECs.

Methods

Primary human VECs were cultured and treated with H. cordata at a concentration ranging from 25–200 μg/ml for 6 or 18 h. After treatment, the cells and culture supernatants were harvested. The expression of hBD2 and SLPI mRNA was evaluated by quantitative real-time reverse transcription PCR. Levels of secreted hBD2 and SLPI as well as cytokines and chemokines in the supernatants were measured by ELISA and Luminex assay, respectively. Cytotoxicity of the extract on VECs was assessed by CellTiter-Blue Cell Viability Assay.

Results

H. cordata did not cause measurable toxicity on VECs after exposure for 18 h. The expression of hBD2 and SLPI mRNA as well as the secreted hBD2 protein were increased in response to H. cordata exposure for 18 h when compared to the untreated controls. However, treatment with the extract for 6 h had only slight effects on the mRNA expression of hBD2 and SLPI. The secretion of IL-2 and IL-6 proteins by VECs was also increased, while the secretion of CCL5 was decreased after treatment with the extract for 18 h. Treatment with H. cordata extract had some effects on the secretion of IL-4, IL-8, CCL2, and TNF-α, but not statistically significant.

Conclusions

H. cordata water extract modulates the expression of antimicrobial peptides and cytokines produced by VECs, which play an important role in the mucosal innate immunity in the female reproductive tract. Our findings suggest that H. cordata may have immunomodulatory effects on the vaginal mucosa. Further studies should be performed in vivo to determine if it can enhance mucosal immune defenses against microbial pathogens.

Houttuynia cordata modulates oral innate immune mediators: potential role of herbal plant on oral health

OBJECTIVE

Epithelial cells play an active role in oral innate immunity by producing various immune mediators. Houttuynia cordata Thunb (H. cordata), a herbal plant found in Asia, possesses many activities. However, its impacts on oral innate immunity have never been reported. The aim of this study was to determine the effects of H. cordata extract on the expression of innate immune mediators produced by oral epithelial cells.

MATERIALS AND METHODS

Primary gingival epithelial cells (GECs) were treated with various concentrations of the extract for 18 h. The gene expression of hBD2, SLPI, cytokines, and chemokines was measured using quantitative real-time RT-PCR. The secreted proteins in the culture supernatants were detected by ELISA or Luminex assay. Cytotoxicity of the extract was assessed using CellTiter-Blue Assay.

RESULTS

H. cordata significantly induced the expression of hBD2, SLPI, IL-8, and CCL20 in a dose-dependent manner without cytotoxicity. The secreted hBD2 and SLPI proteins were modulated, and the levels of IL-2, IL-6, IL-8, and IFN-γ were significantly induced by the extract.

CONCLUSIONS

Our data indicated that H. cordata can modulate oral innate immune mediators. These findings may lead to the development of new topical agents from H. cordata for the prevention and treatment of immune-mediated oral diseases.