24 research outputs found

    Neutrophil-Specific Antigens: Immunobiology, Genetics and Roles in Clinical Disorders

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    Neutrophils are the most abundant nucleated cells in blood circulation and play important roles in the innate and adaptive immune responses. Neutrophil-specific antigens, only expressed on neutrophils, are glycoproteins originally identified in studies on neonatal neutropenia due to fetal-maternal incompatibility and autoimmune neutropenia of infancy. The most investigated neutrophil–specific antigens are the NA and NB antigens that their incompatibilities also cause transfusion-induced febrile reactions and acute lung injury, a potentially fatal reaction, and in bone marrow transplantation, causing graft rejection. NA antigens are members of the immunoglobulin superfamily and are low-affinity Fc-receptors FcγRIIIb (CD16b). Fc receptors connect the F(ab), the antigen-binding fragment of the antibody molecules, to neutrophils and lead them to recognize and phagocytize the targeted antigens. The NB (CD177) antigen belongs to the urokinase-type Plasminogen Activator Receptor Superfamily (uPAR, CD59, Ly6), but its specific functions have not been fully determined. It is known, however, that NB antigen binds proteinase-3 (PR3 to the neutrophil membrane), a serine protease. In clinical studies, it was also demonstrated that NB expression is highly elevated in Polycythemia Vera and is unexpectedly expressed in some cancer tissues. Neutrophil-specific antigens are examples of antigens that have important biological and clinical activities beyond antigenicity

    Transfusion of Target Antigens to Pre-Immunized Recipients:A New Mechanism in Transfusion-Related Acute Lung Injury

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    Transfusion-related lung injury (TRALI) is a serious side effect of blood transfusion. Exclusion of antibody carriers from the donor pool has significantly decreased the number of cases, but TRALI remains the leading cause of transfusion-related morbidity and mortality in industrialized countries. Here, we show that proteins released from donor cells during processing of blood components are capable of inducing a new type of reverse TRALI when transfused to preimmunized recipients. First, we show that soluble neutrophil surface protein CD177 in complex with proteinase 3 (sCD177/PR3) is not only present in human plasma but also in packed red blood cell (PRBC) supernatant. Filtration or storage enhances the concentration of sCD177/PR3 in PRBCs. Second, we show that sCD177/PR3 specifically binds to PECAM-1 on stimulated (but not on unstimulated) endothelial cells (ECs). Third, we provide evidence that the sCD177/PR3/PECAM-1 complex is functional. In the presence of monoclonal or human antibodies against CD177 or PR3, ECs produce reactive oxygen species and become apoptotic. Albumin flux through an EC monolayer increases significantly whenever antibodies and the cognate antigens are present. Finally, we describe a clinical case in which anti-CD177 present in a transfusion recipient precipitated TRALI after the transfusion of CD177-positive, but not CD177-negative, PRBCs. In conclusion, we introduce a new TRALI mechanism based on the specific binding of transfused, soluble antigens to activated ECs in preimmunized recipients. We suggest that further studies and clinical work-up of TRALI should also include antibody investigation of the recipient

    Screening of common CYP1B1 mutations in Iranian POAG patients using a microarray-based PrASE protocol

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    Purpose: The gene coding cytochrome P4501B1 (CYP1B1) has been shown to be a major cause of primary congenital glaucoma in the Iranian population. More recently it was shown to also be important in juvenile-onset open angle glaucoma (JOAG). We aimed to further investigate the role of CYP1B1 in a larger cohort of primary open angle glaucoma (POAG) patients which included late-onset patients. We also aimed to set up a microarray based protocol for mutation screening with an intent of using the protocol in a future population level screening program. Methods: Sixty three POAG patients, nine affected family members, and thirty three previously genotyped primary congenital glaucoma (PCG) patients were included in the study. Clinical examination included slit lamp biomicroscopy, IOP measurement, gonioscopic evaluation, fundus examination, and measurement of perimetry. G61E, R368H, R390H, and R469W were screened by a protocol that included multiplexed allele specific amplification in the presence of a protease (PrASE), use of sequence tagged primers, and hybridization to generic arrays on microarray slides. The entire coding sequences of CYP1B1 and myocilin (MYOC) genes were sequenced in all individuals assessed by the microarray assay to carry a mutation. Intragenic single nucleotide polymorphism (SNP) haplotpes were determined for mutated alleles. Results: Genotypes assessed by the array-based PrASE methodology were in 100 concordance with sequencing results. Seven mutation carrying POAG patients (11.1) were identified, and their distribution was quite skewed between the juvenile-onset individuals (5/21) as compared to late-onset cases (2/42). Four of the seven mutation carrying Iranian patients harbored two mutated alleles. CYP1B1 mutated alleles in Iranian PCG and POAG patients shared common haplotypes. MYOC mutations were not observed in any of the patients. Conclusions: The PrASE approach allowed reliable simultaneous genotyping of many individuals. It can be an appropriate tool for screening common mutations in large sample sizes. The results suggest that CYP1B1 is implicated in POAG among Iranians, notably in the juvenile-onset form. Contrary to POAG patients studied in other populations, many mutation harboring Iranian patients carry two mutated alleles. We propose an explanation for this observation. © 2008 Molecular Vision

    In vitro analysis of anti-HPA-1a dependent platelet phagocytosis and its inhibition using a new whole blood phagocytosis assay (WHOPPA)

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    Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a serious bleeding condition mostly caused by the reaction between maternal anti-HPA-1a antibodies and fetal platelets. This reaction leads to Fc-dependent platelet phagocytosis. Although several serological methods have been developed to identify maternal antibodies, a reliable laboratory parameter as a prognostic tool for FNAIT severity is still lacking. In this study, we developed whole blood platelet phagocytosis assay (WHOPPA), a flow cytometry-based phagocytosis assay that uses a pH-sensitive fluorescent dye (pHrodo-SE) to analyze anti-HPA-1a-dependent platelet phagocytosis in whole blood. WHOPPA revealed a high phagocytosis rate for the anti-HPA-1a opsonized platelets by monocytes but not by neutrophils. Analysis of different monocyte populations showed that all monocyte subsets, including classical (CD14++CD16−), intermediate (CD14++CD16+), and nonclassical (CD14+CD16++) monocytes, were able to engulf opsonized platelets. A unique monocyte subset, termed shifted monocytes (CD14+CD16−), showed the highest phagocytosis rate and was detected after platelet engulfment. FcγR inhibition tests revealed that except for FcγRIIa, FcγRI and FcγRIII on monocytes were responsible for the phagocytosis of anti-HPA-1a opsonized platelets. Analysis of anti-HPA-1a antibodies from FNAIT cases (n = 7) showed the phagocytosis of HPA-1aa but not of HPA-1bb platelets by monocytes. The phagocytosis rate was highly correlated with bound antibodies measured by flow cytometry (p < 0001; r = 0.9214) and MAIPA assay (p < 0.001; r = 0.7692). The phagocytosis rates were equal for type I and II anti-HPA-1a antibodies recognizing the plexin–semaphoring–integrin (PSI) domain and PSI/epidermal growth factor 1 domain of β3 integrin, respectively. By contrast, type III anti-HPA-1a antibodies reacting with αvβ3 integrin did not induce platelet phagocytosis. Furthermore, effector-silenced mAbs against HPA-1a inhibited the phagocytosis of anti-HPA-1a opsonized platelets. In conclusion, WHOPPA is a reliable in vitro platelet phagocytosis assay that mimics the phagocytosis of anti-HPA-1a opsonized platelets in whole blood. This assay allows to prove platelet phagocytosis ex vivo and evaluate the inhibitory capacity of different inhibitors as therapeutically strategies for the prevention of fetal thrombocytopenia in FNAIT in the future

    Comparison of the Effectiveness of Play Therapy and Storytelling on the Improvement of Attention Deficit/Hyperactivity Disorder Symptoms in Students

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    Background and Objectives: Attention deficit/hyperactivity disorder is associated with many problems and several treatments have been proposed for the treatment of children with this disorder. The present study was carried out with the purpose of determining the effectiveness of play therapy and storytelling on the improvement of the symptoms of hyperactivity disorder/attention deficit disorder in students. &nbsp; Methods: The research method was pretest and posttest design with control group. At first, the Conners scale was implemented on 450 female students (age range, 7-12 years) in the schools of Semnan city. Then, 45 students who obtained the highest score based on the Conners scale, were voluntarily selected. In the following, these 45 students were randomly and equally assigned to two experimental groups of experimental (play therapy and storytelling) and control. Data analysis was performed using multivariate analysis of variance (MANOVA) and univariate variance analysis. &nbsp; Results: According to the results of MANOVA test, there was a significant difference between the experimental and control groups in the variables of hyperactivity, conduct, attention deficit, and anxiety [p&ge;0.005, F=(35.4)=17.22]. The results of the univariate ANOVA indicated that there was a significant difference between all studied variables, except for inactivity between the groups (p<0.005). &nbsp; Conclusion: The results of this study revealed that play therapy and storytelling have a positive effect on the improvement of attention deficit/hyperactivity disorder, thus, applying these methods can have beneficial results for students. &nbsp

    Speech Intelligibility in Persian Children with Down Syndrome

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    Objectives: One of the most effective methods to describe speech disorders is the measurement of speech intelligibility. The speech intelligibility indicates the extent of acoustic signals that correctly speaker produces and hearer receives. The purpose of this study was to investigate the speech intelligibility in the Persian children with Down syndrome, age range was 3 to 5 years, who had spoken Persian. Methods: this cross- sectional study investigates 12 children (6 girls and 6 boys) with Down syndrome who had referred to speech therapy clinic in Hamadan city and 12 normal children (6 girls and 6 boys) who went to the kindergarten in Hamadan city. The pictures of speech intelligibility test (in Persian language) were used to collect speech samples of participants. The participant&rsquo;s voice was recorded by voice recorder and was investigated in two age groups. Results: The results of this study indicated the means of speech intelligibility was 92.25 for normal children and 35.08 for children with Down syndrome. The correlation between age and speech intelligibility for normal children was 0.866 and for children with Down syndrome was 0.352. The mean of speech intelligibility 2 for normal boys was 93 and for normal girls 91.5 and for boys with Down syndrome 34.66 and for girls with Down syndrome 35.5. Discussion: The difference between normal children and children with Down syndrome was Significant. One of the factors that affects speech intelligibility for children with Down syndrome is difficulty with voluntarily programming, combining, organizing, and sequencing the movements necessary for speech