Neonatal screening for hemoglobinopathies: results of a public health system in South Brazil.

AIM: The aim of this study was to estimate the prevalence of hemoglobinopathies in South Brazil. METHODS: Samples of dried blood spots collected by heel prick in neonates were evaluated by isoeletric focusing and/or high-performance liquid chromatography techniques. All variants were characterized at the molecular level. RESULTS: A total of 437,787 samples were evaluated. Among these, 6391 showed an abnormal hemoglobin pattern. These included 48 cases (0.01%) of sickle cell disorders (33 hemoglobin SS [Hb SS], 7 Hb SC, 7 Hb S/beta thalassemia, 1 Hb SD), 1 neonate who was homozygous for beta thalassemia, 6272 (1.4%) newborns who were heterozygous for Hb S, C, or D, and 71 (0.02%) neonates who were carriers for rare hemoglobin variants. Most of these rare variants were identified for the first time in Brazil. CONCLUSIONS: Comparing these results with those obtained in other Brazilian regions, we observe a highly heterogeneous distribution. This knowledge is useful in healthcare planning and allocation of resources, as well as identifying at-risk couples, which will assist with disease prevention.

Prevalence of common α-thalassemia determinants in south Brazil: Importance for the diagnosis of microcytic anemia.

Alpha thalassemia has not been systematically investigated in Brazil. In this study, 493 unrelated individuals from the southernmost Brazilian state of Rio Grande do Sul were screened for deletional forms of α-thalassemia. One hundred and one individuals had microcytic anemia (MCV < 80 fL) and a normal hemoglobin pattern (Hb A (2) < 3.5% and Hb F < 1%). The subjects were screened for - α(3.7) , - α(4.2) , - α(20.5) , - (SEA) and - (MED) deletions but only the - α(3.7) allele was detected. The - α(3.7) allele frequency in Brazilians of European and African ancestry was 0.02 and 0.12, respectively, whereas in individuals with microcytosis the frequency was 0.20. The prevalence of α-thalassemia was significantly higher in individuals with microcytosis than in healthy individuals (p = 0.001), regardless of their ethnic origin. There were also significant differences in the hematological parameters of individuals with - α(3.7) / αα, - α(3.7) /- α(3.7) and ß-thalassemia trait compared to healthy subjects. These data suggest that α-thalassemia is an important cause of microcytosis and mild anemia in Brazilians.

Prevalence of common α -thalassemia determinants in south Brazil: importance for the diagnosis of microcytic anemia

Alpha thalassemia has not been systematically investigated in Brazil. In this study, 493 unrelated individuals from the southernmost Brazilian state of Rio Grande do Sul were screened for deletional forms of α-thalassemia. One hundred and one individuals had microcytic anemia (MCV < 80 fL) and a normal hemoglobin pattern (Hb A2 < 3.5 percent and Hb F < 1 percent). The subjects were screened for -α3.7,-α4.2,-α20.5, -SEA and -MED deletions but only the -α3.7 allele was detected. The -α3.7 allele frequency in Brazilians of European and African ancestry was 0.02 and 0.12, respectively, whereas in individuals with microcytosis the frequency was 0.20. The prevalence of α-thalassemia was significantly higher in individuals with microcytosis than in healthy individuals (p = 0.001), regardless of their ethnic origin. There were also significant differences in the hematological parameters of individuals with -α3.7/αα, -α3.7/α3.7 and β-thalassemia trait compared to healthy subjects. These data suggest that α-thalassemia is an important cause of microcytosis and mild anemia in Brazilians.

Is steroid resistance related to multidrug resistance-I (MDR-I) in rheumatoid arthritis?

Both healthy ageing and rheumatoid arthritis (RA) are frequently associated with acquired steroid resistance. Here, we investigated the potential involvement of steroid resistance with multidrug resistance (MDR) and explored the impact of pathological ageing on lymphocyte sensitivity to glucocorticoids. Seventy-four RA patients and 26 healthy controls took part in this study. Peripheral blood mononuclear cells were isolated and T-cell sensitivity to glucocorticoids was measured in vitro. The functional activity of P-glycoprotein was analyzed by flow cytometry and ABCB1/MDR-1 gene polymorphisms were assessed in peripheral lymphocytes. Patients and controls had similar sensitivities to glucocorticoids. Only controls presented age-related immunological changes, including reduced T-cell proliferation and relative resistance to corticosterone. Patients had a higher percentage (72%) of lymphocytes actively extruding rhodamine 123 (Rh123(dim)) than controls (60%) in spite of similar P-glycoprotein activity. A higher percentage of Rh123(dim)+ lymphocytes was observed in patients who were more resistant to dexamethasone in vitro. The distribution of ABCB1 genotypes in RA patients did not differ significantly from that in controls and were not associated to steroid sensitiveness or disease activity. These data suggest that peripheral lymphocytes of arthritic patients are fully responsive to GCs in vitro in spite of displaying higher MDR activity.

Expression of mdr isoforms in mice during estrous cycle and under hormone stimulation

The multidrug resistance (MDR) phenotype is associated with the expression of P-glycoprotein (Pgp), coded by the multigenic mdr family. Mice present the isoforms mdr1 and mdr3, which are responsible for multidrug resistance, and mdr2, that is involved in the transport of phospholipids. mdr1 expression has more recently been associated also with the secretion of steroid hormones. This work presents an RT-PCR analysis of the expression of mdr isoforms, in several organs of mice during different phases of the estrous cycle. Additionally, females were ovariectomized, submitted to different hormone treatments, and their uterus was analyzed for the expression of mdr isoforms. The results show that in the adrenal gland and ovaries mdr1 is the main isoform during proestrus, and that progesterone or a combination of progesterone and estrogen induce the expression of all mdr isoforms in the uterus of ovariectomized females. We suggest that the functions of mdr1 and mdr3 are overlapping, that mdr3 may be the more efficient isoform in the detoxification function, and that mdr1 may be more closely related to the secretion of steroid hormones.