Polymerase Chain Reaction Using Sequence-specific Primers Research Articles

Serological and Molecular Characterization of Blood Group A2 in Pakistan

Objective: To determine the frequency of Blood Group A2 genotype among Group A Pakistani whole blood donors.
 Study Design: Cross-sectional study.
 Place and Duration of Study: Armed Forces Institute of Transfusion (AFIT), Rawalpindi Pakistan, from Jan 2019 to Jan 2020.
 Methodology: One thousand (1000) healthy and unrelated blood donors were selected. The blood samples were typed for ABO, and those of Blood Groups-A and AB were further subtyped with the help of anti-A1 lectin to categorize them as A1,non-A1, A1B and non-A1B Groups. Next, DNA of non-A1 samples was extracted, and a Polymerase Chain Reaction using sequence-specific primers (PCR-SSP) for type A2 was performed, followed by polyacrylamide gel electrophoresis (PAGE).
 Results: Among one thousand blood donors, 247(24.7%) were typed as Blood Group-A, 94(9.4%) as AB-Group, 339(33.9%) BGroup and 320(32%) O Group with variable strength of reaction with ABO antisera. A and AB Blood Groups were further subgrouped as A1 202(20.2%), A1B 77(7.7%), non-A1 45(4.5%) and non-A1B 17(1.7%). Anti-A1 antibodies were detected in 6(13.3%) of non-A1 samples. PCR of non-A1 samples showed 32(12.9%) to be genotypically A2, and the remaining 13(5.2%) were not A2 and were not further resolved.
 Conclusion: Blood Group A2 is not a rare Subgroup in our population. PCR-SSP is a more specific technique than anti-A1 lectin for establishing the Blood Group status of an individual.

Increased levels of anti-BSA antibodies in children with Down syndrome.

Autoimmune diabetes occurs more often in the first 2 years of life in children with Down syndrome (DS) compared with the general population. We previously observed increased frequencies of islet autoantibodies, including insulin autoantibodies (IAA), in children with DS. Assays for IAA using 125I-labelled insulin require competition to overcome cross reactivity with antibodies to the cow's milk protein, bovine serum albumin (BSA). 125I-IAA assay results suggested that levels of antibodies to BSA may also be increased in children with DS. The aim of this study therefore was to determine whether the levels of anti-BSA antibodies differed in children with DS compared with controls. Samples were available from two populations with DS: one from the UK, (UK DS cohort n=106, 58 male, median age 12.5 years) and one from Estonia (Estonian DS cohort: n=121, 65 male, median age 9.75 years). A UK control population was provided by sex and age-matched healthy siblings of probands participating in the Bart's Oxford (BOX) family study of type 1 diabetes. A competitive-displacement radiobinding assay (RBA) and a Dissociation Enhanced Lanthanide Fluoroimmunoassay (DELFIA) were developed to measure and confirm anti-BSA antibody levels. HLA class II genotype was analysed by PCR using sequence specific primers (PCR-SSP). Overall, levels of anti-BSA antibodies were increased in those with DS compared with controls (p<0.0001) but this was not HLA associated. Increased levels of anti-BSA antibodies may reflect a defect in immune maturation or increased gut permeability in children with DS, increasing their risk of developing autoimmunity.

Association of Ikir-Mismatching and Donor Akirs with Better Outcomes in Haploidentical Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia

Objectives: Natural killer (NK) cells are the first donor-derived lymphocytes to be reconstituted after transplantation and play a critical role in improving transplantation outcomes. Their surface receptor, killer cell immunoglobulin like receptor (KIR), can trigger the alloreactivity of NK cells and have been shown to be protective for acute and chronic graft-versus-host disease (aGVHD, cGVHD) while retaining graft-versus-leukemia (GVL) effect. However, different results have been reported about KIR matching models and KIR alleles based on patient, donor and transplant characteristics, resulting in significant controversy about the best donor selection strategy. Here, we investigated the potential influence of KIR matching and KIR alleles on GVHD prophylaxis, overall survival (OS) and relapse rate (RR) of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) in acute myeloid leukemia (AML) patients. Methods：Data from 79 patients with AML treated with haplo-HSCT between May 2015 and May 2021 in the transplantation unit of the Fujian Medical University Union Hospital were retrospectively analyzed. The cohort included 49 male patients (62.0%) and 30 female (38.0%), with a median age of 25 years (1-68 years). KIR genotyping was performed by the PCR-SSO method. The amplicons were quantified on the Luminex 200 flow analyzer and analyzed using the Quick-Type for Lifecodes software for generating KIR data. HLA-A and -B alleles were typed by polymerase chain reaction using sequence-specific primers (PCR-SSP) (TBG, Taipei, Taiwan). HLA-C genotyping was determined by reverse hybridization with sequence specific oligonucleotides probes (rSSO) Line probe assay. Cox proportional hazards model and Kaplan-Meier survival curves were used for analysis. Results：At the time of transplantation, 49 cases (62.0%) were at CR1, while 30 (38.0%) were not. aGVHD occurred in 16 patients (20.3%) and recurrence arose in 10 patients (12.7%), 4 (5.1%) cases cGVHD was observed. After adjusting for age, disease-risk, disease-status, HLA-match, donor gender, conditioning regimen intensity and type of post-grafting GVHD prophylaxis, Cox regression analysis revealed that both KIR ligand-ligand mismatching (KLM) and KIR receptor-ligand matching (RLM) was associated with an decreased risk of aGVHD and relapse compared to KIR ligand-ligand matching and receptor-ligand matching group, respectively (aGVHD: KLM: p=0.047, RLM: p＜0.001; RR: KLM: p=0.049, RLM: p=0.017). Furthermore, RLM shows more accurate in prediction of relapse and aGVHD compared with KLM in both aGVHD and relapse. (aGHVD: p=0.009; RR: p=0.039). After taking activating KIR (aKIR) into consideration to compensate the defect of only inhibitory KIR (iKIR) dominant model, we found that patients with more donor activating KIRs can reach the lower incidence of aGVHD and relapse, and the benefit can gradually increase parallel with the increase in donor activating KIRs. (aGVHD：p=0.019；RR：p=0.037). Patients with both receptor-ligand mismatch and the most donor aKIRs can reach the lowest relapse, lowest incidence of aGVHD and best overall survival (OS). Conclusions: KIR-mismatch, both KLM and RLM significantly reduced the risk of aGVHD and relapse after halpo-HSCT in AML patients and RLM show more superiority in the prediction of HSCT outcome. The synergistic effects of receptor-ligand mismatch and more donor aKIRs can provide a better clinically applicable donor selection strategy to improve haplo-HSCT outcome in AML patients. DisclosuresHu: Astellas Pharma, Inc.: Research Funding.

Association between TNF-α, Interleukin-18 Polymorphisms and Risk of Hepatocellular Carcinoma in Egyptian patients.

Objective:To evaluate the association of gene polymorphisms of the SNP of TNF-α gene -238G>A and IL-18 gene-607C>A with the development of hepatocellular carcinoma among Egyptian patients. Methods:One hundred and fifty patients were allocated to this study; eighty patients with hepatocellular carcinoma (Group A), seventy cancer-free HCV age, and sex-matched patients (Group B). We analyzed two Single nucleotide polymorphisms (SNPs) (TNF-α-238G>A and IL-18-607C>A) by real-time polymerase chain reaction using sequence-specific primers (PCR-SSP). Results:Significant higher risk of HCC was associated with genotype IL-18–607AA (P<0.001), OR: 5(2.188-11.47), allele IL-18 -607⁄A (P=0.001), OR: 2.1(1.32-3.3). A significant association was found between the size of HFL in the HCC group and different genotypes of IL18 genes (P=0.013) where 62.5% of patients with tumor size >5 cm carried the risky (AA) genotype on the other hand the SNP of TNF-α gene -238G>A showed no statistically significant association between the two groups. Conclusion:The SNP -607C>A in the IL18 gene was associated with increased HCC risk in Egyptian patients suggesting its use as a potential diagnostic non-invasive tool that allows to identify a new group of HCC patients at an earlier stage.

Impact of Homozygous C4A Deficiency on Clinical Presentation of Systemic Lupus Erythematosus.

To investigate the association of C4A null allele (C4AQ0) with systemic lupus erythematosus (SLE) and determine the clinical presentation of SLE in relation to C4A null allele. Descriptive study. Armed Forces Institute of Pathology (AFIP), Rawalpindi, Immunology Department, from December 2018 to December 2019. Patients referred to AFIP, who fulfilled American College of Rheumatology (ACR) criteria of 1997 for diagnosis of SLE were included in the study. Approval from the Institutional Ethical Review Board was taken. C4A and C4B null alleles were determined in 66 SLE patients and 40 age- and gender-matched healthy controls by polymerase chain reaction (PCR) using sequence-specific primers (PCR-SSP). Various clinical features and laboratory findings in the SLE patients were analysed in relation with C4A null allele. The mean age of the study population was 30.56 ±10.08 years. C4A null allele was detected in 7 (10.6%) patients; whereas, C4B null allele was detected in only two (3%) patients. SLE patients with C4A null allele had increased incidence of arthritis (100%) and renal damage (85.7%); compared to those with normal C4A allele, 57.6% and 32%, respectively. Fisher's Exact test revealed strong association of C4A null allele with arthritis and renal damage, (p = 0.039 and 0.01, respectively). Homozygous absence of C4A alleles was encountered in 10.6% of Pakistani patients of SLE and is closely related with clinical features of arthritis and renal damage. Knowledge of C4A null allele in SLE patients at diagnosis can predict disease course. Key Words: SLE, C4A null alleles, C4AQ0, Homozygous C4A deficiency.

The association of HLA-DQB1*0602 but not HLA-DRB1*15 with obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a sleep breathing disorder with unclear multifactorial pathogenesis. This study aimed to investigate the association between OSA and two human leukocyte antigens (HLA) alleles; DQB1*0602 and DRB1*15. Forty patients with OSA and 40 control subjects were enrolled in the study. OSA diagnosis was made utilizing the Apnea-Hypopnea Index (AHI)≥5 in overnight polysomnography (PSG). AHI was also used to determine OSA severity. Controls were randomly selected from healthy volunteers who had a low risk for OSA, utilizing the Berlin Questionnaire. Polymerase chain reaction (PCR) using Sequence Specific Primers (PCR-SSPs) was used to determine the association between HLA (HLA-DQB1*0602 and HLA-DRB1*15) and OSA, then statistical analyses of the results were performed. HLA-DQB1*0602 allele was found in 85% of all OSA patients and 50% of controls (P< 0.001). In patients with severe OSA, HLA-DQB1*0602 was present in the 92.9% compared with 66.7% in non-severe OSA (P=0.05). HLA-DRB1*15 allele was found in 15% of OSA patients and 20% of controls, with no difference between the two groups (P=0.556). No statistical difference was found in HLA-DRB1*15 between severe and non-severe OSA (P=0.499). After adjusting for gender, HLA-DQB1*0602 allele was associated with increased odds of OSA (OR = 6.17, 95% CI 1.87-20.3, p = 0.003), but HLA-DRB1*15 allele was not associated with OSA (OR 0.45, 95% CI 0.12-1.73, p = 0.242). The presence of HLA-DQB1*0602 allele, but not HLA-DRB1*15 allele, was significantly associated with OSA.

Complement Component C3 Variant (R102G) and the Risk of Neovascular Age-Related Macular Degeneration in a Tunisian Population.

Purpose To explore the association between the polymorphism (S/F) p.R102G in the complement component 3 (C3) gene and age-related macular degeneration (AMD) in a Tunisian population. Methods The molecular study was performed by polymerase chain reaction using sequence-specific primers (PCR-SSP) in 207 control subjects free of any eye disease (fundus normal) and 145 patients with exudative AMD. The CH50 activity and quantification of C3 and C4 have been made by technical home method and nephelometry, respectively. Results The prevalence of C3 GG genotype polymorphism was significantly higher in AMD patients compared to controls (OR: 2.41, IC 95% [1.90-3.05], p = 0.0007). However, no correlation was found between this allelic variant and the type of neovascularization. Similarly, there is no association between this polymorphism and the presence of functional and/or quantitative hypocomplementemia. Conclusions The C3 GG genotype of the gene could be a susceptibility factor for AMD in the Tunisian population. However, it does not seem to influence the clinical profile of the disease.

164-P: HLA DQB1 06:09 SIGNIFICANTLY INCREASES THE RISK OF MULTIPLE SCLEROSIS AMONGST PARSIS (ZOROASTRIANS) OF INDIA

The frequency of Multiple Sclerosis (MS) varies worldwide. Zoroastrians (Parsis) of Mumbai, India comprise a tiny inbred group who have shown a significantly higher prevalence of MS. DNA typing of HLA Class II DRB1 and DQB1 alleles was performed on 13 Parsi patients. DNA was extracted from blood samples of 13 MS Parsi patients (remitting relapsing) and 50 healthy Parsi controls. Low and high resolution HLA-DRB1 and DQB1 molecular typing was performed by polymerase chain reaction using sequence specific primers (PCR-SSP) (Olerup SSP, Qiagen). A statistically significant increase in HLA-DRB1∗15 xx (23% vs. 8%) and HLA-DQB1∗06 xx (26.9% vs 8%,) was detected in Parsi patients as compared to controls. High resolution typing of HLA-DQB1∗06 xx amongst them showed a significant increase in DQB1∗06:09 (11.53% vs. 2%) OR = 7.2; Chi square = 2.86; p value 0.05, CI (0.82-73.29).[ Table 1 ] Dean and Wadia studied MS patients amongst Asian immigrants in England. Five Parsis were found with definite MS in a community of 5000, as compared to 23 amongst 383,000 ethnic Indian immigrants. It has been of some concern that our genetic analysis is in a small number of patients, but such is the cohort available from this tiny community, which is now spread worldwide. Earlier clinical data has shown small affected populations can yield valuable information that may reflect on broader issues of genetic susceptibility. So a higher frequency of DRB1∗15 and DQB1∗06 in MS patients with a statistically significant increase in the DQB1∗06:09 allele is detected.

Establishment of an optimized PCR method using sequence-specific primers for screening multiple gene polymorphisms simultaneously

The present study aimed to explore the factors that affect polymerase chain reaction using sequence-specific primers (PCR-SSP) and to establish an optimized PCR-SSP method for detecting multiple gene polymorphisms simultaneously. The amplification system parameters, including the concentrations of Mg2+, dNTPs, pfu Taq, primers and control primers, were optimized using the designed PCR-SSP reactions. The resulting optimized reaction system was used to determine the melting temperature of the genomic DNA and the cycling parameters. The optimized PCR-SSP method was used to analyze the polymorphisms of the following genes: mutations -308A/G and -238G/A in TNF-α, -174G/C in IL-6 and C/T mutation at exon 188 of CYP2D6 *10B. The PCR-SSP amplification system was optimized; in a 20µl reaction system, the quantities of Mg2+, dNTPs, pfu Taq, primers, control primers and genomic DNA were 3.25µM, 0.5mM, 2.5units, 0.5µM, 0.2µM and 0.15µg, respectively. The cycling system comprised 5 start cycles and took 15min to melt a genomic DNA sample using a touchdown protocol. The optimized PCR-SSP is suitable for polymorphism analysis of polygenic SNPs in large genomic DNA samples and a number of different genes.

Molecular characterisation of the monocytic cell line THP‐1 demonstrates a discrepancy with the documented HLA type

Molecular characterisation of the monocytic cell line THP‐1 demonstrates a discrepancy with the documented HLA type

Geno‐ and phenotyping and immunogenicity of HNA‐3

Alloantibodies directed against the human neutrophil alloantigen (HNA)-3a are frequently implicated in severe and fatal transfusion-related acute lung injury (TRALI). The HNA-3a/3b system results from a single-nucleotide exchange (461G>A; Arg154Gln) in the choline transporter-like protein 2 gene. Genotyping may allow identification of blood donors at risk to develop HNA-3a antibodies. A polymerase chain reaction using sequence-specific primers (PCR-SSP) for genotyping of HNA-3a and -3b alleles was designed. Results of genotyping and phenotyping were compared in 40 randomly selected individuals and in blood donors and recipients of six TRALI cases associated with HNA-3a antibodies. Phenotyping was performed by granulocyte immunofluorescence and granulocyte agglutination using typing sera for HNA-3a and two recently found HNA-3b-reactive sera. Immunogenicity of HNA-3a was determined by the rate of HNA-3a alloantibodies in HNA-3b homozygous parous women. Genotyping and phenotyping results correlated to 100% and were in accordance with alloantibody formation and binding in HNA-3a antibody associated TRALI cases. Gene frequencies of HNA-3a and -3b were 0.792 and 0.207 in the German population with 64.1% homozygous individuals for the HNA-3a allele, 5.5% for the HNA-3b allele, and 30.4% heterozygous individuals, in accordance with the Hardy-Weinberg equilibrium and the gene frequencies of 0.819 and 0.181 reported in 1964. Immunization rates were estimated to be of 7% for HNA-3a and 0.5% for HNA-3b. The PCR-SSP method allows reliable determination of the HNA-3a and -3b genotypes; approximately 7% of HNA-3b homozygous women develop antibodies when exposed to the HNA-3a antigen during pregnancy.

Application of real-time PCR and melting curve analysis in rapid Diego blood group genotyping

Abstract The paucity of appropriate reagents for serologic typing of the Diego blood group antigens has prompted the development of a real-time PCR and melting curve analysis for Diego blood group genotyping. In this study, we phenotyped 4326 donor blood samples for Dia using semiautomated equipment. All 157 Di(a+) samples were then genotyped by PCR using sequence-specific primers (PCR-SSP) for DI*02 because of anti-Dib scarcity. Of the 4326 samples, we simultaneously tested 160 samples for Dia and Dib by serology, and for DI*01 and DI*02 by PCR-SSP and by real-time PCR. We used the same primers for Diego genotyping by real-time PCR and PCR-SSP. Melting curve profiles obtained using the dissociation software of the real-time PCR apparatus enabled the discrimination of Diego alleles. Of the total samples tested, 4169 blood donors, 96.4 percent (95% confidence interval [CI], 95.8–96.9%), were homozygous for DI*02 and 157, 3.6 percent (95% CI, 3.1–4.2%), were heterozygous DI*01/02. No blood donor was found to be homozygous for DI*01 in this study. The calculated DI*01 and DI*02 allele frequencies were 0.0181 (95% CI, 0.0173–0.0189) and 0.9819 (95% CI, 0.9791–0.9847), respectively, showing a good fit for the Hardy-Weinberg equilibrium. There was full concordance among Diego phenotype results and Diego genotype results by PCR-SSP and real-time PCR. DI*01 and DI*02 allele determination with SYBR Green I and thermal cycler technology are useful methods for Diego determination. The real-time PCR with SYBR Green I melting temperature protocol can be used as a rapid screening tool for DI*01 and DI*02 blood group genotyping. Immunohematology 2010;26:66–70.

Recipient's Killer Cell Immunoglobulin-like Receptor Genotype and Human Leukocyte Antigen C Ligand Influence the Clinical Outcome following Living Donor Liver Transplantation

Purpose: The design of this study was to determine the most influential factor(s) on post-transplant immunological consequences, particularly with regard to the role of killer cell immunoglobulin-like receptors (KIRs) and their ligands (type Ⅰ human leukocyte antigen (HLA)) in unstable liver function. Methods: Retrospectively collected data from 319 recipients undergoing adult living donor liver transplantation (LDLT) using a right lobe graft between January 2002 and August 2008 were analyzed. Patients were categorized according to the serum alanine transaminase (ALT) pattern; stable ALT pattern was defined as ALT pattern during 3 months post-transplantation, except for initial 2 weeks post-transplantation, in which 2 times or less additional elevation(s) of serum alanine transaminase (ALT) (≥80 IU/L) were observed. When a serum ALT pattern showed fluctuating and/or unpredictable nature, it was defined as an unstable pattern. In addition, genetic information of KIRs and HLA-C allotypes received from 68 recipients and 59 donors was analyzed by way of polymerase chain reaction using sequence-specific primers (PCR-SSP) to determine the factor(s) influencing a serum ALT pattern. Results: Among 319 LDLT recipients included in this study, the actual incidences of AR and unstable ALT pattern were 13.4% (43/319) and 42.3% (135/319), respectively. Unstable ALT pattern correlated with poorer survival following LDLT than stable pattern (P＜0.000). Genetically, unstable ALT pattern was related to recipients carrying KIR2DL2(＋)/KIR2DS2(＋) combined with the heterogeneous HLA-C allotype (HLA-C1/C2), (relative risks 45.0, 95% confidence interval 2.160∼937.321; P=0.013). Conclusion: This study indicates that, when performing LDLT, pretransplant determination of recipient’s KIRs and HLA-C allotypes may be beneficial in coping with post-transplant immunological circumstances.

Allele frequencies of the human platelet antigen-1 in the Egyptian population

BackgroundThe human platelet alloantigen system HPA-1 in the Egyptian population was examined by polymerase chain reaction using sequence-specific primers (PCR-SSP). The objectives of this study were to evaluate the allele frequency of HPA-1a and -1b in healthy Egyptian individuals and compare these with the international literature. Human platelet antigen (HPA) systems are associated with alloimmunization and organ transplantation rejection as well as the development of cardiovascular disease. Of the various HPA systems, HPA-1 specifically has been considered to be the most important antigenic system implicated in the Caucasian population. No study has yet examined this system in the Egyptian populations, however. We therefore investigated the allele frequency of the HPA-1 system in the Egyptian population.FindingsTo determine the allele frequency of the HPA-1a and -1b, we tested genomic DNAs from 206 healthy, unrelated Egyptian individuals using PCR-SSP. Our results showed that the 1a/1a genotype was the most predominant (59.22%) followed by 1a/1b (34.95%) and 1b/1b (5.83%) with allele frequencies for 1a and 1b of 0.77 and 0.23, respectively, in the population.ConclusionAs compared with other geographic groups, a relatively high allele frequency of the HPA-1b in the Egyptian population may indicate a higher risk of alloimmunization. This study is the first to investigate the allele frequency of the HPA-1 system in the Egyptian population and serves as an outline for future clinical research associated with platelet disorders in this group.

Increased activating killer immunoglobulin-like receptor genes and decreased specific HLA-C alleles in couples with recurrent spontaneous abortion

Accumulating evidence indicates natural killer (NK) cells play crucial roles in successful pregnancy. To investigate whether the killer cell immunoglobulin-like receptor (KIR) gene polymorphism and the corresponding specific HLA ligands in parent couples possessing a susceptibility to unexplained recurrent spontaneous abortion (RSA), we searched 73 pairs of childless couples with three or more abortions characterized as unexplained RSA and 68 pairs of healthy control couples. Peripheral blood was drawn to obtain genomic DNA which was used for a polymerase chain reaction using sequence-specific primers (PCR-SSP) in order to determine whether 15 selected KIR genes and two groups of HLA-C alleles were present. Our result showed that gene frequency of KIR2DS1 was higher in patients with RSA compared to that of control subjects ( P = 0.029). Increased numbers of activating KIR genes was observed in patients ( P = 0.041). Women who possessed more than two activating KIR genes were found more frequently in patients than those in control subjects ( P = 0.018). From a cohort of husband and wife couples, the women with a KIR2DS1 gene, and with a decreased group 2 HLA-C allele for the homologous inhibitory receptor KIR2DL1, had a tendency to fall into the RSA group ( P = 0.004). The results suggest that a genetic variation at the KIR locus influences the susceptibility to unexplained RSA in the Chinese Han population. Moreover, decreased ligands for inhibitory KIRs could potentially lower the threshold for NK cell activation, mediated through activating receptors, thereby contributing to pathogenesis of RSA.

Enrichment of individual KIR2DL4 sequences from genomic DNA using long‐template PCR and allele‐specific hybridization to magnetic bead‐bound oligonucleotide probes

DNA enrichment by allele-specific hybridization (DEASH) was used as a means to isolate individual alleles of the killer cell immunoglobulin-like receptor (KIR2DL4) gene from heterozygous genomic DNA. Using long-template polymerase chain reaction (LT-PCR), the complete KIR2DL4 gene was amplified from a cell line that had previously been characterized for its KIR gene content by PCR using sequence-specific primers (PCR-SSP). The whole gene amplicons were sequenced and we identified two heterozygous positions in accordance with the predictions of the PCR-SSP. The amplicons were then hybridized to allele-specific, biotinylated oligonucleotide probes and through binding to streptavidin-coated beads, the targeted alleles were enriched. A second PCR amplified only the exonic regions of the enriched allele, and these were then sequenced in full. We show DEASH to be capable of enriching single alleles from a heterozygous PCR product, and through sequencing the enriched DNA, we are able to produce complete coding sequences of the KIR2DL4 alleles in accordance with the typing predicted by PCR-SSP.

No Significant Benefit of Marrow and Blood HLA-Haploidentical Stem Cell Transplantations Given by Mothers with Long-Term Fetomaternal Microchimerism.

Non-T-cell-depleted maternal HLA-haploidentical hematopoietic stem cell transplantations(SCT) have been reported feasible based on the hypothesis that long-term fetomaternal microchimerism(FMC) is linked with hyporesponsiveness to inherited paternal antigens(IPAS),but the hypothesis is still in debate due to lack of direct evidence. To determine whether the existence of such microchimerism affect the outcome of maternal HLA-haploidentical SCT, we investigated the outcomes of 18 patients (median age 19) with hematologic malignancies (ALL 8, AML 6, CML 3, NHL 1) who underwent haploidentical SCT from mothers with the same regime from July 2003 to January 2005. Donor was treated with granulocyte colony stimulating factor subcutaneously at a dose of 300μg per day for 5 days before bone marrow harvesting. Leukaphereses were performed using a continuous-flow blood cell separator if CD34+ cells in the bone marrow harvest were less than 4.0×106 cells/kg. Patients with CML or AML in CR received 7.5Gy TBI based standard-intensity regimen combined with cyclophosphamide plus cytarabine. The remaining received non-TBI standard-intensity regimen consisting of cytarabine, busulfan and cyclophosphamide. Antithymocyte globulin(ATG) at a dosage of 2.5mg/kg/day on days −5 to −3 was given as an additional immunosuppressive measure in all patients. To prevent GVHD, patients also received cyclosporin at a dose of 3mg/kg/day as a continuous infusion from day −10, 30mg/kg/day mycophenolate mofetil starting on day −10, and short-term methotrexate administered on days 1, 3, 6, 11 at doses of 15, 10, 10, and 10mg/m2. Among all these patients, microchimerism were confirmed with nested polymerase chain reaction using sequence-specific primers(PCR-SSP) typing for HLA in 10 donor-recipient pairs. In the 2 categories as to whether the microchimeric status of the donor is positive or negative, they had similar characteristics in the background factors such as recipient sex, type of conditioning regime, stem cell source, and disparity of HLA except recipients of positive group had more CML. Engraftment was obtained in all patients. As of august 1, 2005, 5 patients died (1 of relapse, 4 of complication), other 13 patients were alive and free of disease. The 2-year overall survival for the whole cohort was 58%. Although there was a survival advantage for pairs with microchimerism over pairs without it, the influence on outcome was not statistically significant (P=0.9, log-rank test). The cumulative incidences of grade Ò/Ô acute graft-versus-host disease (GVHD) were 39% (95%CI, 17%–64%). Also no significant difference was observed between the two groups. Extensive chronic GVHD developed in 5 of 13 patients who could be evaluated. These results indicate maternal HLA-haploidentical hematopoietic SCT is a acceptable option for patients who lack immediate access to a conventional stem cell source, but the presence of fetomaternal microchimerism may not correlate to the existence of immunological tolerance between mother and offspring.

Human platelet antigen genotyping by using sequence‐specific primers and the particle gel agglutination assay

Polymerase chain reaction using sequence-specific primers (PCR-SSP) is currently the most widely used technique for human platelet antigen (HPA) genotyping. Here, we describe a novel particle gel-agglutination technique for simplified visualization of the amplified products. Biotinylated primers were used to amplify HPA-1, -2, -3, -4, -5, -6, and -15, and the PCR products were incubated with streptavidin particles. Fluorescein isothiocyanate (FITC)-labelled primers [amplifying a fragment of the human growth hormone (HGH) gene] and anti-FITC-coated particles were used as internal controls. Agglutination of the particles in or on top of the gel indicated specific amplification. A total of 100 samples from blood donors was tested by using this new technique and a standard PCR-SSP protocol. The use of biotinylated sequence-specific primers resulted in PCR products that agglutinated streptavidin particles, and the FITC-labelled HGH primers led to agglutination of anti-FITC-coated particles. Negative reactions were clearly distinguishable from positive reactions. The results of the particle gel agglutination method were in concordance with those of the electrophoretic visualization in all cases tested. The new particle agglutination method is reliable and easy to use.

FCGR3B polymorphism in three ethnic Chinese populations

Abstract FcγRIIIb receptor is expressed primarily on neutrophils as three polymorphic antigens (HNA-1a, HNA-1b, and HNA-1c) that are encoded by alleles FCGR3B*1, FCGR3B*2, and FCGR3B*3, respectively. These antigens play an important role in immune neutropenia; their absence predisposes individuals who lack them to life-threatening infections. This study investigated the FCGR3B gene frequencies in three ethnic Chinese populations: Han, She, and Tajik. FCGR3B*1, FCGR3B*2, and FCGR3B*3 were genotyped by PCR using sequence specific primers (PCR-SSP). The results showed the gene frequencies were 0.55 for FCGR3B*1 and 0.45 for FCGR3B*2 in 177 Han individuals, 0.69 for FCGR3B*1 and 0.31 for FCGR3B*2 in 87 She individuals, and 0.35 for FCGR3B*1 and 0.65 for FCGR3B*2 in 99 Tajik individuals, respectively. The FCGR3Bnull genotype was not found, but the FCGR3B*3 allele was identified in only three individuals in the Tajik population. DNA clone and sequencing confirmed that these individuals had the C⇒A mutation at position 266 on exon 3. This study found that the gene frequencies in Han and She ethnic groups were similar to those previously reported in the Asian population, but the FCGR3B allele frequencies in the Tajik population were more similar to that of Caucasians. Immunohematology 2005;21:25–28.

A modified PCR-SSP method for the identification of ABO blood group antigens.

The ABO blood group antigens are carbohydrate molecules synthesized by the glycosyltransferases encoded by the ABO gene on chromosome 9. Kidney transplantation across the ABO barrier generally leads to rapid humoral graft rejection due to the presence of naturally occurring antibodies to the A and B antigens. We have developed a method for ABO typing our cadaveric organ donors by the polymerase chain reaction using sequence-specific primers (PCR-SSP). The method uses 12 primers in eight PCR mixtures and is performed under the same conditions as our routine HLA-A, B, C PCR-SSP typing. The PCR-SSP-based types of 166 regular blood donors and 148 cadaveric organ donors all showed total concordance with their serologically assigned ABO groups. Six individuals possessing the ABO A subgroups (A3, Ax and Aend) all typed as A1 by PCR-SSP, as expected. PCR-SSP is an appropriate method for ABO typing of cadaveric organ donors and, importantly, enables both ABO and HLA typing to be performed on the same DNA material.