Gene frequencies of the HPA-15 (Gov) platelet alloantigen system in Brazilians.

The HPA-15 (Gov) alloantigen is a biallelic co-dominant system on human platelets, and its allele HPA-15a and HPA-15b differ by an A-->C single nucleotide polymorphism at nucleotide 2108 of the coding sequence resulting in a Tyr682Ser substitution in the mature CD109 glycoprotein. Employing the polymerase chain reaction-restriction fragment length polymorphism technique, we determined the HPA-15 gene frequencies among 276 subjects of distinct Brazilian ethnic groups including, 15 Caucasians, 15 African Brazilians, 15 Orientals, 106 Amazon Xikrin Indians, 31 Amazon Gavioes Indians and 94 blood donors. The calculated HPA-15a and HPA-15b allele frequencies found in Caucasians (0.53/0.47), African Brazilians (0.57/0.43), Orientals (0.57/0.43) and Brazilian blood donors (0.52/0.48) did not differ significantly. However, the HPA-15a and HPA-15b gene frequencies of Xikrin Indians (0.78/0.22) were significantly different from that of all other groups (P < 0.01). The HPA-15a/a, HPA-15a/b and HPA-15b/b genotype frequencies observed in Gavioes Indians were significantly different from those seen in African Brazilians (P = 0.04) and blood donors (P = 0.017). The present data showed that the distribution of the HPA-15 (Gov) system alleles observed among the Brazilian population is quite similar to the distributions already reported among Asian, Canadian and European populations. Moreover, the data indicated differences in the frequency of the HPA-15 system between Amazon Indians and other distinct Brazilian ethnic groups suggesting that Amerindians would be at higher risk of HPA-15 alloimmunization in the need of receiving blood components collected from blood donors of other ethnic groups.

Urinary iron excretion induced by intravenous infusion of deferoxamine in beta-thalassemia homozygous patients.

The purpose of the present study was to identify noninvasive methods to evaluate the severity of iron overload in transfusion-dependent beta-thalassemia and the efficiency of intensive intravenous therapy as an additional tool for the treatment of iron-overloaded patients. Iron overload was evaluated for 26 beta-thalassemia homozygous patients, and 14 of them were submitted to intensive chelation therapy with high doses of intravenous deferoxamine (DF). Patients were classified into six groups of increasing clinical severity and were divided into compliant and non-compliant patients depending on their adherence to chronic chelation treatment. Several methods were used as indicators of iron overload. Total gain of transfusion iron, plasma ferritin, and urinary iron excretion in response to 20 to 60 mg/day subcutaneous DF for 8 to 12 h daily are useful to identify iron overload; however, urinary iron excretion in response to 9 g intravenous DF over 24 h and the increase of urinary iron excretion induced by high doses of the chelator are more reliable to identify different degrees of iron overload because of their correlation with the clinical grades of secondary hemochromatosis and the significant differences observed between the groups of compliant and non-compliant patients. Finally, the use of 3-9 g intravenous DF for 6-12 days led to a urinary iron excretion corresponding to 4.1 to 22.4% of the annual transfusion iron gain. Therefore, continuous intravenous DF at high doses may be an additional treatment for these patients, as a complement to the regular subcutaneous infusion at home, but requires individual planning and close monitoring of adverse reactions.

Urinary iron excretion induced by intravenous infusion of deferoxamine in ß-thalassemia homozygous patients

The purpose of the present study was to identify noninvasive methods to evaluate the severity of iron overload in transfusion-dependent ß-thalassemia and the efficiency of intensive intravenous therapy as an additional tool for the treatment of iron-overloaded patients. Iron overload was evaluated for 26 ß-thalassemia homozygous patients, and 14 of them were submitted to intensive chelation therapy with high doses of intravenous deferoxamine (DF). Patients were classified into six groups of increasing clinical severity and were divided into compliant and non-compliant patients depending on their adherence to chronic chelation treatment. Several methods were used as indicators of iron overload. Total gain of transfusion iron, plasma ferritin, and urinary iron excretion in response to 20 to 60 mg/day subcutaneous DF for 8 to 12 h daily are useful to identify iron overload; however, urinary iron excretion in response to 9 g intravenous DF over 24 h and the increase of urinary iron excretion induced by high doses of the chelator are more reliable to identify different degrees of iron overload because of their correlation with the clinical grades of secondary hemochromatosis and the significant differences observed between the groups of compliant and non-compliant patients. Finally, the use of 3-9 g intravenous DF for 6-12 days led to a urinary iron excretion corresponding to 4.1 to 22.4 percent of the annual transfusion iron gain. Therefore, continuous intravenous DF at high doses may be an additional treatment for these patients, as a complement to the regular subcutaneous infusion at home, but requires individual planning and close monitoring of adverse reactions

The frequency of blood-born viral infections in a population of multitransfused Brazilian patients.

The frequency of viral markers for hepatitis B (HBV) and C (HCV), human immunodeficiency virus-1 (HIV-1) and human T-lymphotropic virus-1 (HTLV-1) was evaluated in 32 Brazilian beta-thalassemia multitransfused patients. Additionally the serum concentrations of ferritin and alanine aspartate transaminase (ALAT) were determined. The results show a high prevalence of markers of infection by HBV (25.0%) and HCV (46.8%) and a low prevalence of markers for HIV-1 and HTLV-1. No correlations were demonstrated between the presence of the hepatitis markers and the number of units transfused or the serum concentrations of ferritin and ALAT.

PIP: In Brazil, clinicians followed 32 transfusion-dependent beta-thalassemia patients, 1-49 years old, at the Regional Blood Center and the Department of Hematology of University Hospital of the School of Medicine of Ribeirao Preto to determine the prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), HIV-1, and HTLV-1. They also measured serum levels of ferritin and alanine aspartate transaminase (ALAT) to examine liver iron content and liver damage, respectively. 46.8% tested positive for antibodies to HCV, which was much higher than that of voluntary blood donors of the Regional Blood Center (1.4%) or of other countries. Yet it was about the same as that of multitransfused patients in the UK (23.2%), Italy (92.9%), and Saudi Arabia (33.3%). 3 of these 15 patients also tested positive for HBV markers. 15.5% tested positive only for HBV markers. 37.5% had no hepatitis markers. Hepatitis-positive people were older than those who tested negative for hepatitis (15.2 years vs. 8.5 years; p .05). The number of units of blood transfused and the levels of ferritin and ALAT were not statistically different between the 2 groups (192.1-336 vs. 135.2 and 36.6-52.3 U/l vs. 36.7 U/l, respectively). 75% of the HCV positive patients received more than 100 units of packed red blood cells while only 42% did in the HCV negative group. 2 people tested positive for HIV-1 1 of whom also tested positive for anti-HBs-Ag and the other for HCV antibodies. The HIV-1 cases had become infected before the blood bank began screening for HIV-1 in 1987. None of the patients receiving blood from the center became infected with HIV-1, yet 60% of hemophiliacs treated at the hospital were HIV-1 infected. No one tested positive for HTLV-1, even though all 32 patients had received more than 6250 units of blood not screened for HTLV-1. This reflected the low incidence of HTLV-1 in the general population (0.05%). No one was positive for HBs-Ag or HBe-Ag.