Fetal Cytokine Balance, Erythropoietin and Thalassemia but Not Placental Malaria Contribute to Fetal Anemia Risk in Tanzania.

Fetal anemia is common in malaria-endemic areas and a risk factor for anemia as well as mortality during infancy. Placental malaria (PM) and red cell abnormalities have been proposed as possible etiologies, but the relationship between PM and fetal anemia has varied in earlier studies, and the role of red cell abnormalities has not been studied in malaria-endemic areas. In a Tanzanian birth cohort study designed to elucidate the pathogenesis of severe malaria in young infants, we performed a cross-sectional analysis of risk factors for fetal anemia. We determined PM status, newborn red cell abnormalities, and maternal and cord blood levels of iron regulatory proteins, erythropoietin (EPO), cytokines and cytokine receptors. We examined the relationship between these factors and fetal anemia. Fetal anemia was present in 46.2% of the neonates but was not related to PM. Maternal iron deficiency was common (81.6%), most frequent in multigravidae, and interacted with parity to modify risk of fetal anemia, but it was not directly related to risk. Among offspring of iron-deficient women, the odds of fetal anemia increased with fetal α+-thalassemia, as well as these patterns of cord blood cytokines: increased cord IL-6, decreased TNF-RI, and decreased sTfR. The EPO response to fetal anemia was low or absent and EPO levels were significantly decreased in newborns with the most severe anemia. This study from an area of high malaria transmission provides evidence that 1) fetal α+-thalassemia and cytokine balance, but not PM at delivery, are related to fetal anemia; 2) maternal iron deficiency increases the risk that other factors may cause fetal anemia; and 3) fetal anemia has a multifactorial etiology that may require a variety of interventions, although measures that reduce maternal iron deficiency may be generally beneficial.

The in-house monoclonal antibody against γ-globin chain; Thal N/B, accurately measured F cells in SEA-α thalassemia 1 trait.

The monoclonal antibody (mAb) against γ-globin chain clone Thal N/B was produced. It was aimed at measuring the quantity of HbF (α2γ2)-containing red blood cells or F cells by flow cytometry. However, it may cross-react with Hb Bart's (γ4) which is present in the SEA-α thalassemia 1 trait. We measured FC levels by flow cytometry using this in-house mAb for 100 blood samples. Prevalence of high FC trait in this cohort was 51%. Ten of 12 SEA-α thalassemia 1 trait were included in the 51% high FC individuals. Comparing FC levels in the 51 high FC individuals having and not having the SEA-α thalassemia 1 trait showed no difference of FC levels. It was concluded that Hb Bart's did not interfere with FC measurement by flow cytometry using the in-house Thal N/B mAb. Therefore, it can be used for measuring F cell levels in regions having a high prevalence of the SEA-α thalassemia 1 trait. The findings of this research should apply to other clones of anti-γ-globin chain mAb that are aimed for HbF/FC quantification.

[Preparation and identification of the polyclonal antibody against ATRX-C2193-2492].

Objective To prepare the polyclonal antibody against human alpha thalassemia/mental retardation syndrome X-linked (ATRX) C-terminal and study the distribution and expression of ATRX protein in human cervical cancer tissues. Methods The antiserum was obtained from the BALB/c mice immunized with 6His-ATRX-C2193-2492 protein and then purified by the saturated ammonium sulfate precipitation and affinity chromatography. The titer of anti-ATRX polyclonal antibody was determined by ELISA. Its specificity was identified by SDS-PAGE analysis and Western blotting. The expression and location of ATRX in human cervical tissues were analyzed by immunohistochemistry. Results The titer of the polyclonal antibody against 6His-ATRX-C2193-2492 protein was about 1:12 800. The antibody could recognize 6His-ATRX-C2193-2492 protein specifically. With the polyclonal antibody, the target protein was found mainly in the nucleus of para-carcinoma tissues, and it was also expressed in the nucleus of cervical cancer tissue cells, but the expression in the latter was obviously lower. Conclusion The polyclonal antibody against 6His-ATRX-C2193-2492 protein has been produced successfully and used to detect ATRX protein in human cervical cancer tissues.

Production and characterization of monoclonal antibodies against α-globin chain-containing human hemoglobins for detecting α-thalassemia disease.

Monoclonal antibodies against α-globin containing human Hbs, named AMS-Alpha1 and AMS-Alpha 2, were produced by the hybridoma technique using spleen cells enriched by the newly developed B lymphocyte enrichment protocol. These two monoclonal antibodies were of IgM class, reacting to only intact form of human Hbs A, A2, E, and F, which contain α-globin chain. By the indirect ELISA, the AMS-Alpha1 and AMS-Alpha 2 quantified less amount of α-globin chain containing hemoglobins in HbH disease than the SEA-α thalassemia 1 carriers and normal individuals. It was thus anticipated that these monoclonal antibodies can be used for detecting Hb Bart's hydrops fetalis in which no α-globin chain is produced.

Hydrops fetalis caused by homozygous alpha-thalassemia and Kidd antigen alloimmunization in a Chinese woman.

We report a case with hydrops fetalis resulting from homozygous alpha-thalassemia and alloimmune hemolytic anemia due to anti-JK3. This is one of the few cases with immune- and nonimmune-induced hydrops fetalis.

[Preparation and identification of monoclonal antibody against Homo sapiens hemoglobin alpha 2 (HBA2)].

This study was purposed to prepare and identify monoclonal antibodies (McAbs) against Homo sapiens hemoglobin alpha 2 (HBA2). Normal human fetal liver tissues were homogenized, and human liver nuclear proteins were isolated by centrifugation. The total human fetal liver nuclear proteins were used to immunize BALB/c mice for preparing McAbs by hybridoma technique. The McAbs specificity was identified by ELISA, Western blot, and immunohistochemistry. The antigen was identified by Uni-ZAP expression library screening. The results showed that one hybridoma cell line, AEE091, secreting specific McAb against HBA2 was established. The Ig subclass of this McAb was IgG1 (kappa). Data from immunohistochemistry assay showed that AEE091 could recognize human liver nuclear protein. Using AEE091 McAb, isolation of the protein antigen by IP revealed that AEE091 McAb could recognize 15 kD protein. Screening the Uni-ZAP XR pre-made liver cDNA library with AEE091 hybridoma cell supernatants demonstrated that AEE091 McAb specially reacted with HBA2. It is concluded that a hybridoma cell line stably secreting specific McAb against HBA2 is established. The specific McAb against HBA2 would be very useful for studying HBA2 function and screening thalassemia.

Nutritional iron status in children with alpha+ thalassemia and the sickle cell trait in a malaria endemic area on the coast of Kenya.

Although hemoglobinopathies such as alpha+ thalassemia and the sickle cell trait might contribute to anemia in African children, we hypothesized that they might also enhance iron absorption under circumstances of critical availability, and that this could attenuate their hematologic effects. We found no support for this hypothesis in a cohort of children living on the coast of Kenya.

[Influence of human genetic variants on resistance and immunity against malaria]. / Einfluss genetischer Varianten des Menschen auf Resistenz und Immunität gegen Malaria.

Certain human genetic variants occur on-ly in areas endemic for malaria. They protect against fatal malaria complications and cause inhibition of growth or development of malaria parasites in vitro. Among these are the haemoglobins (Hb) S and C, alpha-thalassaemias, glucose-6-phosphate dehydrogenase deficiency, as well as a deletion in the erythrocyte band 3 protein. Evidence for similar effects has been obtained for HbD and HbE, glycophorins A and C as well as for a number of immunologically relevant molecules such as human leukocyte antigens,tumour-necrosis-factor a and the inducible nitric oxide synthase. The findings indicate that malaria in endemic areas has caused a substantial selection of the human genome.

A human complement receptor 1 polymorphism that reduces Plasmodium falciparum rosetting confers protection against severe malaria.

Parasitized red blood cells (RBCs) from children suffering from severe malaria often adhere to complement receptor 1 (CR1) on uninfected RBCs to form clumps of cells known as "rosettes." Despite a well documented association between rosetting and severe malaria, it is controversial whether rosetting is a cause or a correlate of parasite virulence. CR1-deficient RBC show greatly reduced rosetting; therefore, we hypothesized that, if rosetting is a direct cause of malaria pathology, CR1-deficient individuals should be protected against severe disease. In this study, we show that RBC CR1 deficiency occurs in up to 80% of healthy individuals from the malaria-endemic regions of Papua New Guinea. This RBC CR1 deficiency is associated with polymorphisms in the CR1 gene and, unexpectedly, with alpha-thalassemia, a common genetic disorder in Melanesian populations. Analysis of a case-control study demonstrated that the CR1 polymorphisms and alpha-thalassemia independently confer protection against severe malaria. We have therefore identified CR1 as a new malaria resistance gene and provided compelling evidence that rosetting is an important parasite virulence phenotype that should be a target for drug and vaccine development.

Hydrops fetalis caused by homozygous alpha-thalassemia and Rh antigen alloimmunization: report of a survivor and literature review.

Hematologic causes of hydrops fetalis include homozygous alpha-thalassemia and immune hemolytic anemias. We report the case of a boy with hydrops fetalis who had homozygous alpha-thalassemia and alloimmune hemolytic anemia due to anti-E and anti-C blood group antibodies. He received intrauterine red blood cell transfusions and postnatal chronic transfusion with iron chelation therapy. A non-myeloablative sibling stem cell transplant failed. He is now 5 years and 6 months of age, hypothyroid with short stature, but in overall good health. He is one of the oldest reported homozygous alpha-thalassemia survivors and, to our knowledge, the only survivor with immune- and nonimmune-induced hydrops fetalis.

Alloimmunization and erythrocyte autoimmunization in transfusion-dependent thalassemia patients of predominantly asian descent.

The development of hemolytic alloantibodies and erythrocyte autoantibodies complicates transfusion therapy in thalassemia patients. The frequency, causes, and prevention of this phenomena among 64 transfused thalassemia patients (75% Asian) were evaluated. The effect of red blood cell (RBC) phenotypic differences between donors (mostly white) and Asian recipients on the frequency of alloimmunization was determined. Additional transfusion and patient immune factors were examined. 14 (22%) of 64 patients (75% Asian) became alloimmunized. A mismatched RBC phenotype between the white population, comprising the majority of the donor pool, and that of the Asian recipients, was found for K, c, S, and Fyb antigens, which accounts for 38% of the alloantibodies among Asian patients. Patients who had a splenectomy had a higher rate of alloimmunization than patients who did not have a splenectomy (36% vs 12.8%; P =.06). Erythrocyte autoantibodies, as determined by a positive Coombs test, developed in 25% or 16 of the 64 patients, thereby causing severe hemolytic anemia in 3 of 16 patients. Of these 16, 11 antibodies were typed immunoglobulin G [IgG], and 5 were typed IgM. Autoimmunization was associated with alloimmunization and with the absence of spleen (44% and 56%, respectively). Transfused RBCs had abnormal deformability profiles, more prominent in the patients without a spleen, which possibly stimulated antibody production. Transfusion of phenotypically matched blood for the Rh and Kell (leukodepleted in 92%) systems compared to blood phenotypically matched for the standard ABO-D system (leukodepleted in 60%) proved to be effective in preventing alloimmunization (2.8% vs 33%; P =.0005). Alloimmunization and autoimmunization are common, serious complications in Asian thalassemia patients, who are affected by donor-recipient RBC antigen mismatch and immunological factors.

Brief communication: Resistance to Falciparum malaria in alpha-thalassemia, oxidative stress, and hemoglobin oxidation.

A recent survey conducted on Vanuatu Island suggests that resistance to Plasmodium falciparum in alpha-thalassemic individuals may have an immunological basis. This study is important since it seems to undermine the current idea that red-cell genetic defects give protection against falciparum malaria by reducing intraerythrocytic growth and development of the parasite. However, the mechanisms underlying these clinical and genetic observations are not yet fully understood. Based on a review of the relevant literature, we first show that the model based on the interaction between hemoglobin (Hb) and membrane components may provide a molecular basis for the involvement of the immune response in genetic adaptation to malaria. Second, we discuss the main evolutionary implications of the model. Finally, we suggest two approaches by which anthropological studies could provide a useful way of testing the model: 1) analysis of the interactions of malaria-resistance genes with genetic polymorphisms which affect the erythrocyte redox status and 2) study of the antimalarial effects of natural products (introduced as a part of a diet or for traditional antimalarial therapy) capable of interfering with the Hb/membrane interaction.

Relation of haemolytic anaemia and erythrocyte-bound IgG in alpha- and beta-thalassaemic syndromes.

There has been evidence that IgG-mediated phagocytosis plays some part in destruction of erythroid cells and subsequent anaemia in thalassaemia. In this study using direct immunofluorescence and flow cytometry, erythrocyte-bound IgG was studied in 53 and 33 beta-thal/Hb E and Hb H patients, respectively. The mean percentages of IgG-positive erythrocytes in both nonsplenectomized (4.4%) and splenectomized (24%) beta-thal/Hb E patients were significantly higher than that in normal subjects (1.0%); p < 0.05 and < 0.001, respectively. Splenectomized beta-thal/Hb E patients had significantly higher percentages of IgG-positive erythrocytes than the nonsplenectomized patients (p < 0.001). The mean percentages of IgG-positive erythrocytes in Hb H patients were comparable to those from normal controls. However, patients with alpha-thal 1/Hb CS had significantly higher IgG-positive erythrocytes than those with alpha-thal 1/alpha-thal 2 (p = 0.008). Splenectomized Hb H patients also had higher IgG-positive erythrocytes than nonsplenectomized Hb H patients (p < 0.039). During haemolytic crisis in some Hb H patients, high percentages of IgG-positive erythrocytes were also demonstrated. This study demonstrates the presence of increased IgG on erythrocytes in patients with beta-thal/Hb E and in those with Hb H disease following splenectomy or in haemolytic crisis.

Prenatal diagnosis of Hb Bart's hydrops fetalis in West Malaysia: the identification of the alpha thal 1 defect by PCR based strategies.

Haemoglobin Bart's hydrops fetalis is the result of complete absence of functional alpha-globin genes where the fetus is homozygous for the alpha 0-thal gene. Prenatal diagnosis can be made by analysis of fetal DNA from chorionic villus, amniotic cells and fetal blood. Earlier studies for analysing genomic DNA needed digestion with restriction enzymes and hybridisation to radiolabelled probes which took 2 weeks. We have used the polymerase chain reaction (PCR) and non-radioactive primers to identify specific target sequences with results available within 1-3 days for the diagnosis of haemoglobin Bart's syndrome. With fetal blood samples, complete absence of alpha-chain synthesis is confirmed by globin chain electrophoresis on cellulose acetate pH 6.0.

Production of monoclonal and polyclonal antibodies against various haemoglobins for the detection of thalassaemias.

The thalassaemias are a major group of genetic disorders in Southeast Asia that affect the production of the alpha-globin chain (alpha-thalassaemia) or the beta-globin chain (beta-thalassaemia) of the haemoglobin. As a result of defective globin chain synthesis, individuals with this disorder show varying degrees of anaemia due to ineffective erythropoiesis and haemolysis. The presence of abnormal haemoglobins in thalassaemia patients has enabled the detection of thalassaemia using immunological methods which have certain advantages over the conventional diagnostic methods. This paper reviews the application of various types of antibodies against the different types of haemoglobins used for the detection of thalassaemia. The developed antibodies include the polyclonal antibodies against Hb Bart's and Hb H; monoclonal antibodies (mab) against Hb H, used in a sandwich enzyme-linked immunosorbent assay (ELISA), for detecting carriers of (--SEA/) deletion and deletions involving the complete zeta-alpha-globin gene cluster, such as (--alpha FIL/), (--alpha THAI/) and (--HW/), which are the common deletional alpha-thalassaemias in Southeast Asians; mab against zeta-globin chains used in an immunocytological test, for the detection of adult carriers of (--SEA/) deletion except for (alpha 20.5/), (--alpha FIL/) and (--alpha THAI/) (this simple test is useful in identifying couples at risk of conceiving foetuses afflicted with the Hb Bart's hydrops foetalis syndrome due to homozygous alpha-thalassaemia); mab against Hb A2 and beta- and gamma-globin chains used for the quantitation of Hb A2 in beta-thalassaemia and the diagnosis of beta-thalassaemia major in foetuses respectively; other mabs produced to date include those specific to haemoglobins D-Los Angeles, J-Baltimore, O-Arab and J-Paris-I.

Anti-zeta antibody screening for alpha-thalassemia using dried filter paper blood.

The most common alpha-thalassemia in Southeast Asian or Southern Chinese populations is the (--SEA) double alpha-globin deletion. Couples heterozygous for (--SEA) have 25% risk for hydrops fetalis from loss of all four alpha-globin genes. The (--SEA) deletion spares the embryonic zeta-globin genes and causes traces of zeta-peptide to persist throughout life. A colorimetric monoclonal anti-zeta antibody test for raised zeta-peptide has detected the (--SEA) deletion in liquid blood samples, but not deletions of the entire alpha-globin region with loss of the zeta-globin genes. Eluates from dried blood spots had the same anti-zeta antibody color reaction as whole blood, even after storage at 4 degrees C for up to 77 days. The anti-zeta antibody test was positive in 24 of 91 microcytic samples (mean corpuscular hemoglobin < 24 pg), including four with iron deficiency; it was negative in 26 provisionally diagnosed alpha-thalassemia-1 heterozygotes and all 32 nonmicrocytic samples. Southern blot analysis and a specific SEA-polymerase chain reaction test confirmed that 18 anti-zeta antibody-positive samples and 1 anti-zeta antibody-negative sample had the (--SEA) deletion. Two anti-zeta antibody-negative microcytic samples had the (--Fil) total alpha-globin region deletion, 2 had single alpha-gene deletions, 22 others may also have had a total alpha-region deletion. Hence specificity was very high and sensitivity was 95%. The anti-zeta antibody test can detect the (--SEA) deletion in dried blood samples, even after prolonged storage. This simple inexpensive test can conveniently screen samples collected at a distance from a central laboratory.

A prospective study of the influence of alpha thalassaemia on morbidity from malaria and immune responses to defined Plasmodium falciparum antigens in Gambian children.

The protective effect of alpha thalassaemia (-alpha/alpha alpha) against morbidity from falciparum malaria was assessed in a prospective study of rural Gambian children. The gene frequency for single alpha-globin gene deletions was 0.12. Malariometric indices measured during cross-sectional surveys and morbidity from malaria determined by weekly surveillance were similar in children with alpha thalassaemia and in those with a normal alpha-globin genotype. However, the small number of children who carried both alpha thalassaemia and the sickle cell trait had fewer clinical episodes of malaria than children with the sickle cell trait alone. Specific antibody responses and cell-mediated immune responses in vitro to defined Plasmodium falciparum antigens were measured in children participating in the study. In general, there was no evidence of an increased prevalence or intensity of humoral or cell-mediated immune responses to the malaria antigens studied in children heterozygous for alpha thalassaemia compared with children with a normal alpha-globin genotype.

Erythroblast- and erythrocyte-bound antibodies in alpha and beta thalassaemia syndromes.

Thirty-five Thai patients with various alpha-thalassaemia (alpha-thal 1/alpha-thal 2, alpha-thal 1/HbCS, HbCS/HbCS) and beta-thalassaemia (beta-thal/HbE, severe and mild form, HbE/HbE) syndromes were examined for the presence of immunoglobulins and C3d on o-tolidine positive erythroblasts in the bone marrow, and for the amounts of IgG of some specificities bound to circulating erythrocytes. In mild, but not in severe beta-thal/HbE and in alpha-thalassaemia, the percentages of Ig-positive erythroblasts were significantly higher than in controls and correlated well with the percentage of IgG-positive erythroblasts. By contrast, the percentages of IgM and C3d positive erythroblasts were low and similar in thalassaemic and control marrows. A substantial proportion of thalassaemic patients showed more erythrocyte-bound IgG than controls, but statistically significant elevations were seen only in severe beta-thal/HbE. Within a particular syndrome erythrocyte-bound IgG was more abundant in splenectomized than non-splenectomized subjects. It showed specificity for spectrin in some beta-thalassaemic patients and for band 3 protein in several individuals with alpha- or beta-thalassaemia. The results suggest that IgG antibodies play a role in the haemolysis of thalassaemia and that they are likely to be involved in the ineffective erythropoiesis in at least some of the syndromes studied.