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Biomedical subjects

A Salama

Publications and source records attributed to A Salama.

At least 37 records · Page 2Linked to original sources
PubMed2004

Amlodipine-induced immune thrombocytopenia.

BACKGROUND AND OBJECTIVES: Drug-induced thrombocytopenia is a serious, but rare, side-effect of treatment with a number of drugs. In this report, we investigate the suspicion that amlodipine, a calcium-channel blocker, was responsible for immune thrombocytopenia in a 79-year-old patient. PATIENT AND METHODS: Our patient experienced two attacks of thrombocytopenic purpura after 10 years of treatment with amlodipine. Antibodies to platelets were tested by standard methods. RESULTS: Initially, the platelet count increased owing to treatment with prednisolone and intravenous immunoglobulin G, but decreased shortly after discontinuation of this treatment. The patient's serum was found to contain amlodipine-dependent antibodies to platelets, and he recovered after stopping the drug. CONCLUSIONS: Amlodipine can induce immune thrombocytopenia, which may strongly resemble autoimmune thrombocytopenia.

Aged↗
PubMed2004

Massive haemolysis after intramuscular diclofenac in a patient who apparently tolerated oral medication.

BACKGROUND AND OBJECTIVES: Administration of diclofenac may lead to immune haemolytic anaemia (IHA) owing to the presence of drug-dependent antibodies and/or autoantibodies. A relationship with oral or intramuscular drug administration is unknown. Here, we describe a patient who apparently tolerated oral diclofenac but developed severe IHA following intramuscular injection of the drug. PATIENTS AND METHODS: A 66-year-old-female was admitted to hospital because of jaundice and nausea, which were initially presumed to be manifestations of a postcholecystectomy syndrome. The patient soon developed haemolysis and renal failure. Although the symptoms and signs were suggestive of autoimmune haemolytic anaemia (AIHA), the patient had diclofenac-induced IHA. RESULTS: Serological testing, including detection of drug-dependent antibodies, was performed using standard techniques. The patient's serum was found to contain a highly reactive diclofenac-dependent red cell antibody of the immune complex type (titre 256 000). She recovered after 7 weeks of treatment with prednisolone, blood transfusions, haemodialysis and plasma exchange. CONCLUSIONS: Diclofenac-induced IHA should always be considered when a patient on diclofenac develops haemolysis.

Administration, Oral↗
PubMed2004

SERF: a new antigen in the Cromer blood group system.

The Cromer blood group system consists of eight high incidence and three low incidence antigens carried on decay-accelerating factor (DAF). This report describes the identification and characterization of a new Cromer high incidence antigen, named SERF. Sequence analyses of DNA from a Thai female whose serum contained the alloantibody to a high incidence antigen in the Cromer blood group system (anti-SERF) and from her two children were performed. Reverse transcriptase-polymerase chain reaction (RT-PCR) and sequence analysis on cDNA from the proband and PCR-restriction fragment length polymorphism analysis on DNA from Thais were also performed. To map the epitope, DAF deletion mutants were tested by immunoblotting with anti-SERF. Sequence analysis revealed a substitution of 647C>T in exon 5 DAF in the proband. The proband's two children and two of 100 Thais were heterozygotes 647C/T. Analysis using DAF deletion mutants revealed the antigenic determinant to be within short consensus repeat 3 (SCR3), which is encoded by exon 5. This study describes a novel high incidence antigen (SERF) in the Cromer blood group system characterized by the amino acid proline at position 182 in SCR3 of DAF. The SERF-negative proband has a substitution mutation that predicts for leucine at this position. SERF has been provisionally assigned the International Society of Blood Transfusion number 021.012 (CROM 12).

Base Sequence↗
PubMed2004

Description of a novel HLA-B allele, B*5613, identified during HLA-typing using sequence-specific oligonucleotide hybridization and sequence-specific amplification.

Here, we report on the characterization of a novel human leukocyte antigen (HLA)-B allele, B*5613. The allele was identified in an adult male from North Africa who was suffering from sickle cell anemia. HLA-B*5613 most closely matches to B*5601 differing only by a substitution of three nucleotides of codon 180. Due to this substitution, low-resolution HLA-typing using sequence-specific oligonucleotide hybridization or amplification using sequence-specific primers gave inconclusive results. DNA sequencing confirmed a variation of codon 180 (CTG-->GAC) resulting in an amino acid substitution Leu156Asp.

Base Sequence↗
PubMed2004

Tumor necrosis factor alpha enhances the adenoviral transduction of CD34+ hematopoietic progenitor cells.

The purpose of this study was to improve the transduction efficiency of adenoviral vectors (Ad) in human CD34+ hematopoietic progenitor cells. CD34+ cells from cord blood or mobilized peripheral blood were incubated with tumor necrosis factor-alpha (TNF-alpha). After removal of free TNF-alpha, the cells were infected with an Ad encoding green fluorescent protein (GFP). One day later, viable cells were counted and analyzed for GFP and CD34 by flow cytometry. To visualize vectoral trafficking, CD34+ cells were incubated with fluorophore-conjugated Ad. Plating efficiencies of hematopoietic progenitors before and after transduction were evaluated by methylcellulose assays. Pretreatment with TNF-alpha increased the transduction efficiency more than twofold (39.2% versus 15.5%) in a dose-dependent manner and strongly improved the survival of GFP-positive CD34+ cells. Time course experiments showed that TNF-alpha incubation times as short as 10 minutes were still effective. Neutralizing antibodies to TNF receptor II and RGD peptides diminished the TNF-alpha-dependent increase in transduction efficiency. No TNF-alpha-dependent increase in adenoviral receptors (coxsackie-adenovirus receptor, alphavbeta3-integrin) occurred. Analysis of viral binding demonstrated a significantly higher incidence of local concentrations of Ad along the cell surface (caps) in virus-positive cells of the TNF-alpha-treated group. Plating efficiency, especially the formation of granulocyte-macrophage colony forming units, was enhanced by TNF-alpha pretreatment. We conclude that brief incubation with TNF-alpha before addition of the Ad significantly increased the Ad transduction efficiency in CD34+ cells, and improved post-transduction survival of progenitors of the granulocyte-macrophage lineage. This finding correlates with increased Ad capping at the cell surface and suggests an alteration of Ad trafficking.

Adenoviridae↗
PubMed2003

Immune hemolysis-serological and clinical aspects.

The differential diagnosis of anemia must consider immune hemolytic anemias as a frequent cause. Whereas detection of anti-red blood cell (RBC) alloantibodies frequently induced by immunogenic stimuli (transfusion, pregnancy) is performed by routine serology, diagnosing autoimmune hemolytic anemias or drug-induced hemolytic anemias remains a challenge, usually requiring close collaboration of a number of disciplines. Positive direct antiglobulin test (Coombs' test) represents a central criterion in diagnosing immune hemolytic anemias, leading to further detailed analyses. The most-severe type of immune-mediated hemolysis is acute intravascular hemolysis after ABO incompatible RBC transfusion. This review highlights underlying biochemical aspects, immunohematological diagnostics, and the clinical relevance of RBC allo- and autoantibodies, including paroxysmal nocturnal hemoglobinemia and drug-induced hemolysis. Finally, current and partly experimental therapeutic strategies of immune hemolytic anemias are summarized.

ABO Blood-Group System↗
PubMed2003

Frequencies of alpha4 A3061G variants and identification of three new variants of the human integrin alpha4-subunit.

Human integrin alpha4beta1 (VLA-4) is thought to play a key role in immune responses. Only two variants of alpha4-subunit (alpha4-tex and alpha4-mas) have been described until now, and the information regarding these variants is scanty. In this study, we measured the frequency of both variants in healthy blood donors (n=252). Surprisingly, the frequency of alpha4-mas (3061G, 0.31) was lower than that of alpha4-tex (3061A, 0.69). In addition, we sequenced and analyzed the mRNA of the entire alpha4-subunit in eight unselected healthy blood donors. These studies revealed three new variants, including a C to A transversion at position 269 in the promoter region of exon 1 (accession no. AJ504733); a G to A transversion at position 2273 in exon 16 (accession no. AJ510246, AJ510247), and a T to C exchange at position 3311 in exon 26 (accession no. AJ510248, AJ510249). None of these variants led to amino acid (AA) substitutions. Interestingly, homozygosity of the new variant 269A was not found.

Adolescent↗
PubMed2003

Comparison of two leukapheresis programs for computerized collection of blood progenitor cells on a new cell separator.

BACKGROUND: Peripheral blood progenitor cells (PBPCs) can be collected on various cell separators. Two leukapheresis programs (LP-MNC and LP-PBSC-Lym) were evaluated for computerized collection of PBPCs on a new cell separator. STUDY DESIGN AND METHODS: Leukapheresis assisted by the LP-MNC or LP-PBSC-Lym software was performed for the harvesting of PBPCs in 52 oncology patients after chemotherapy plus G-CSF treatment and in 18 healthy subjects after G-CSF mobilization alone. RESULTS: A total of 38 components from 33 donors via LP-MNC and 43 components from 37 donors via LP-PBSC-Lym were collected with a median of one (range, one to two) standard-volume leukapheresis procedures (9.2-13.3 L) per donor. There were no significant differences between the two groups concerning median counts of WBCs, CD34+ cells, CD34+ cell yields per harvest, and CD34+ cell yields of cumulative harvests. The blood cell counts after leukapheresis revealed that the LP-MNC resulted in significantly higher platelet loss than LP-PBSC-Lym (p = 0.024): 35.9 percent (range, 19.2%-66.1%) versus 29.7 percent (11.6%-52.3%). Regarding the CD34+ cell collection efficiency, the LP-MNC program was significantly better than the LP-PBSC-Lym program (p < 0.001): 77.5 percent (range, 35.5%-98.9%) versus 58.3 percent (range, 20.4%-98.9%). However, concentrates collected by the LP-PBSC-Lym program had significantly higher percentages of MNCs (p < 0.001) and CD34+ cells (p = 0.028) than harvests with the LP-MNC program: 90 percent (range, 69%-99%) versus 70 percent (range, 35%-98%) and 1.2 percent (range, 0.2%-7.3%) versus 0.7 percent (range, 0.2%-6.0%), respectively. No leukapheresis-related serious adverse events were seen, and time for hematopoietic engraftment was equivalent to data published in the literature. CONCLUSION: The LP-MNC program shows a significantly better CD34+ cell collection efficiency than the LP-PBSC-Lym program. However, collections with the LP-MNC program result in PBPC components with a lower MNC and CD34+ cell concentrations and a higher apheresis-related loss of patient's platelets.

Antigens, CD34↗
PubMed2002

Characterization of autoantibodies from patients with Goodpasture's disease using a resonant mirror biosensor.

Goodpasture's disease is characterized by the binding of IgG autoantibodies to the glomerular basement membrane, leading to glomerular inflammation. The autoantigen has been identified as the noncollagenous domain of the alpha3 chain of type IV collagen (alpha3(IV)NC1). We have used the IAsys resonant mirror biosensor to analyse the extent and affinity of binding of anti-GBM antibodies from sera of patients to purified alpha3(IV) NC1. alpha3(IV) NC1 monomers were immobilized to a carboxylate cuvette, with the simultaneous use of a control well. The binding of serum from patients with Goodpasture's disease (n = 12), normal controls (n = 14) and disease controls with vasculitis (n = 14) was analysed. Antibody binding was detected in sera from all patients with Goodpasture's disease but not from controls. IAsys measurements of binding correlated with antibody levels assessed by the standardized ELISA used for clinical assays. Both ELISA and biosensor measurements showed declining antibody levels in serial serum samples from treated patients; however, the biosensor detected antibody recrudescence when ELISA remained negative. Autoantibodies from patients' serum had average affinity constants (Kd) of 6.5 x 10-11M to 52.07 x 10-10M, as determined by an inhibition assay, indicating high affinity. Sips analysis showed that the antibody response was relatively homogeneous (values of 0.46-1). Biosensor techniques can therefore be used to detect and characterize anti-GBM antibodies in serum from patients, with high sensitivity and without need for antibody purification. This technique may be useful in diagnosis and monitoring of patients with Goodpasture's disease, and may be applicable to other autoantibody mediated diseases.

Adolescent↗
PubMed2002

Heparin-induced thrombocytopenia: detection of antiheparin/PF4 antibodies by means of heparin/PF4-coated beads and flow cytometry.

A total of 70 serum samples from heparin-induced thrombocytopenia (HIT II) patients, non-HIT patients and healthy subjects, respectively, were studied for the presence of antiheparin/PF4 antibodies. Two enzyme-linked immunosorbent assay (ELISA) assays were compared with the particle gel immunoassay (PaGIA). Beads of the PaGIA kit were also used to evaluate the feasibility of flow cytometric detection of antiheparin/PF4 antibodies in patient samples. Experiments have shown that all samples found positive by ELISA and PaGIA, were also positive when analysed by flow cytometry by an indirect test using the high-density particles coated with heparin/PF4 complexes and a second step fluorescein isothiocyanate (FITC) antihuman immunoglobulin (Ig)G reagent. The procedure was easy to perform, repetitive and beads were promptly visualized by physical parameters, with a very low background. In conclusion, the results of this study suggest that flow cytometry is a reliable method for the detection of antiheparin/PF4 antibodies.

Adult↗
PubMed2002

Acute haemolytic transfusion reactions due to weak antibodies that in vitro did not seem to be clinically significant.

BACKGROUND AND OBJECTIVES: In the present article, we report on two patients with acute haemolytic transfusion reactions (AHTRs), and whom we were unable to transfuse, owing to alloantibodies that in vitro did not seem to be clinically significant. MATERIALS AND METHODS: The patients were a 67-year-old male and a 64-year-old female, both of whom developed antibodies to red blood cells (RBCs) after repeat blood transfusions. Serological analyses were carried out using standard techniques. RESULTS: Both patients developed an AHTR of the intravascular type following blood transfusions. Serological re-examination revealed weakly reactive alloantibodies with anti-JMH specificity in one patient, and with unclear specificity in the second. Rechallenging the patients with 15-30 ml of packed RBCs caused AHTRs, and blood transfusion became impossible in both cases. CONCLUSION: Weak alloantibodies that in vitro do not seem to be clinically significant may cause severe AHTRs.

Acute Disease↗
PubMed2002

Rapid detection of autoantibodies to dsDNA with the particle gel immunoassay (ID-PaGIA).

OBJECTIVE: To describe a new particle agglutination test for the detection of autoantibodies to double stranded DNA (dsDNA). PATIENTS AND METHODS: Serum samples were collected from 40 unselected healthy blood donors and 200 patients with systemic lupus erythematosus (SLE) or a positive antinuclear antibody screen, or both. The samples were tested in the presence of red high density polystyrene particles coated with purified human dsDNA using the gel technique (Micro Typing System, ID-PaGIA, particle gel immunoassay). The results were compared with those obtained by the two standard anti-dsDNA antibody detection methods, Crithidia luciliae immunofluorescence test (CLIF) and enzyme linked immunosorbent assay (ELISA). RESULTS: The three anti-dsDNA assays exhibited an overall agreement of 87% and significant correlation with each other (p<0.0001). In the SLE group (n=71), 45 patients (63%) were found to be positive by ID-PaGIA compared with only 11/129 (9%) patients in the non-SLE group. Thus the ID-PaGIA had a sensitivity of 63%, and a specificity of 92% for SLE. In comparison, the standard detection methods showed sensitivities of 62% (CLIF) and 70% (ELISA) and specificities of 99% (CLIF) and 84% (ELISA) for SLE. Anti-dsDNA reactivity in the agglutination assay correlated closely with the quantities of antibody obtained by CLIF (r=0.81, p<0.0001) and ELISA (r=0.73, p<0.0001). CONCLUSIONS: The new particle gel agglutination test is a sensitive and specific immunoassay. It is a simple test procedure that might be well suited as a rapid screening method.

Agglutination Tests↗
PubMed2001

Interleukin-6 is a major effector molecule of short-term G-CSF treatment inducing bone metabolism and an acute-phase response.

OBJECTIVE: The biological steps leading to hematopoietic progenitor cell (HPC) mobilization from the bone marrow to the peripheral blood compartment during G-CSF treatment are still poorly defined. In this study, we investigated G-CSF-mediated secretion of cytokines as potential mediators. MATERIALS AND METHODS: Plasma and urine samples from G-CSF-mobilized donors for HPC transplantation were collected before and during mobilization therapy. Interleukin-6 (IL-6), alkaline phosphatase (ALP), bone-specific ALP (bone ALP), C-reactive protein (CRP), lipopolysaccharide binding protein (LPB), CD34+ cells and urinary deoxypyridinoline (DPD) concentrations were measured and statistically correlated. RESULTS: IL-6 was highly elevated at days 4 and 5 of G-CSF treatment. G-CSF administration led to elevation of IL-6 parallel to the appearance of CD34+ cells in the peripheral blood. Major metabolic changes such as high bone ALP plasma concentration and urinary excretion of deoxypyridinoline (DPD), indicating stimulation of bone metabolism, were observed. Elevated concentrations of CRP and LPB indicated an acute-phase response. Furthermore, CRP concentrations correlated significantly with the percentage of mobilized CD34+ cells. CONCLUSION: Based on these findings, we propose IL-6 as a major physiological effector molecule of G-CSF treatment that induces bone metabolism and an acute-phase reaction along with mobilization of CD34+ cells in the peripheral blood. IL-6 may be responsible for osteopenia observed during short- and long-term G-CSF treatment. These observations may also have implications for G-CSF treatment of patients with plasmocytoma.

Acute-Phase Reaction↗
PubMed2001

Rapid detection of antibodies to immunoglobulin A molecules by using the particle gel immunoassay.

BACKGROUND AND OBJECTIVES: Antibodies to immunoglobulin A (IgA) molecules are thought to be frequently responsible for anaphylactic reactions in transfusion medicine, but practical tests for the detection of antibodies to IgA are not yet available. MATERIAL AND METHODS: Red, high-density polystyrene beads were coated with purified IgA molecules and then used to test serum samples collected from unselected healthy blood donors (n = 105) and patients with common variable immunodeficiency and/or IgA deficiency (n = 44). For testing, the standard gel-agglutination technique (ID-Micro Typing System) was employed. RESULTS: None of the normal serum samples were reactive with IgA-coated beads and samples from only 10 patients were positive (titre range 1 : 2 to 1 : 256). Only one out of all patients studied had a history of an anaphylactic reaction and this was related to the administration of Rh(D) prophylaxis (anti-D immunoglobulin). The beads did not show non-specific agglutination and could be used repeatedly for longer than 6 months. The results were reproducible in all patients tested. CONCLUSION: The new test allows a specific and rapid detection of antibodies to IgA molecules. In order to evaluate the clinical relevance of the test, analysis is required of a wider range of antibodies that produce anaphylactic reactions.

Adult↗
PubMed2001

Donor-derived alloantibodies and passenger lymphocyte syndrome in two of four patients who received different organs from the same donor.

BACKGROUND: Reported here is the occurrence of RBC alloimmunization in two of four patients who received different organs from an immunized donor. STUDY DESIGN AND METHODS: The donor, a 58-year-old woman, was group O D+, K-, and Fy(a-). Initially, her serum contained only a K antibody. After blood transfusion, a second antibody (anti-Fy(a)) could also be identified. The liver was given to a group O D+, K-, Fy(a+) patient; the pancreas and one kidney to a group O D+, K-, Fy(a+) patient; the heart to a group A D+, K-, Fy(a-) patient; and the other kidney to a group B D+, K-, Fy(a+) patient. RBC grouping and antibody screening were performed by standard techniques. Lymphoid microchimerism in the peripheral blood of the recipients was analyzed by flow cytometry and nested PCR. RESULTS: None of the recipients had irregular RBC alloantibodies at the time of transplantation. After the transplant, anti-K became detectable in the serum of the liver recipient, and anti-Fy(a) could be eluted from the RBCs of the liver recipient and the pancreas-kidney recipient. The latter patient also developed mild hemolysis, and his Hb dropped to 8 g per dL on posttransplant Day 9. Donor-derived lymphocytes were detectable by flow cytometry in the peripheral blood of the liver recipient and the pancreas-kidney recipient until Days 8 and 63, respectively, whereas no lymphoid chimerism could be demonstrated in the heart recipient. PCR chimerism analyses were positive in all three recipients over the whole observation period of 97 postoperative days. CONCLUSION: The amount of cotransplanted lymphoid tissue may correlate with the extent of peripheral lymphoid microchimerism and the antibody-formation capacity in solid organ transplantation.

Adult↗
PubMed2001

Increased RBC autoantibody production in pregnancy.

BACKGROUND: Autoimmunization against RBCs is generally believed to occur very rarely during pregnancy and to represent a high risk for those affected. The occurrence of benign RBC autoantibodies in pregnancy is reported. STUDY DESIGN AND METHODS: The incidence of autoantibodies to RBCs in unselected pregnant and nonpregnant women were compared by the new standard gel hemagglutination method. RESULTS: Data from a total of 22,782 pregnant and 12,903 nonpregnant women were analyzed. The antibody screen test was positive in 547 (2.40%) of the pregnant women. The positive test results were related to passive anti-D in 341 cases (1.50%), to clinically relevant alloantibodies in 43 cases (0.19%), to clinically irrelevant antibodies in 138 cases (0.61%), to autoantibodies in 23 cases (0.1%), and to autoantibodies plus alloantibodies in 2 cases (0.01%). In the cases of alloantibodies and/or autoantibodies, the DAT was invariably positive with anti-C3d and less commonly so with anti-IgG. The autoantibodies were first detected during pregnancy, they predominantly reacted with enzyme-treated RBCs, and none of the affected women or their infants appear to have developed clinically significant hemolysis. In the control group consisting of nonpregnant female blood donors, there were 3 cases (0.02%) of clinically insignificant IgG autoantibodies. CONCLUSION: There is an increase in autoimmunization against RBCs during pregnancy. The resultant autoantibodies do not appear to cause significant RBC destruction. Further studies are required for precise characterization of this phenomenon.

Adult↗