Human herpesvirus 8 (HHV-8) seroprevalences were determined in two isolated Amazon Amerindian tribes, according to age, gender and familial aggregation. Plasma and serum samples obtained from 982 Amazon Amerindians (664 Tiriyó and 318 Waiampi) were tested for antibodies against lytic and latent HHV-8 antigens by using 'in-house' immunofluorescence assays. Overall, HHV-8 seroprevalence was 56?8 % (57?4 % in the Tiriyó tribe and 55?7 % in the Waiampi tribe). Seroprevalence was independent of gender and increased linearly with age: it was 35?0 % among children aged 2-9 years, 51?4 % in adolescents (10-19 years), 72?9 % in adults and 82?3 % in adults aged >50 years. Interestingly, 44?4 % of children under 2 years of age were HHV-8-seropositive. No significant differences in seroprevalence between tribes and age groups were detected. It is concluded that HHV-8 is hyperendemic in Brazilian Amazon Amerindians, with vertical and horizontal transmission during childhood, familial transmission and sexual contact in adulthood contributing to this high prevalence in these isolated populations.

The GATA box single nucleotide polymorphism (SNP) at position -33 (T>C) in Blacks silences the expression of FY*B in erythrocytes, and the substitution 265 C>T, together with 298 G>A, weakens the Fy(b) antigen (Fy(x)). Individuals with these phenotypes/genotypes who receive Fy(b+) blood are unlikely to be alloimmunized to Fy(b) because, in the presence of 265 T, the Fy(b) antigen is expressed, and in the case of -33 C, other tissues express Duffy protein and probably the Fy(b) antigen. We studied samples from 361 blood donors (182 of African ancestry and 179 of Caucasian ancestry) by haemagglutination and polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP). Forty Caucasian and 130 donors of African ancestry were serologically Fy(b-); among these, the majority of the donors of African ancestry had FY*B with the GATA SNP, while the majority of Caucasians typing Fy(b-) had FY*B with 265 T/298 A SNPs. Six of the Fy(b-) donors (three Africans and three Caucasians) had both GATA and 265/298 SNPs, and six donors of Caucasian ancestry apparently had a GATA SNP. Samples from two donors - one African and one Caucasian with an unusual MspA1I-RFLP pattern - were sequenced and found to have a novel SNP (145 G>T) co-existent with 265 C>T and 298 G>A SNPs. These findings highlight the importance of establishing the incidence and nature of molecular events that impact on Duffy expression in different populations.

Our data show that polymorphisms in the CD177 are associated with variations in the HNA-2 expression and may be the cause of atypical expressions.

The effects of long-term aspirin for the treatment of sickle cell disease were compared with placebo in a double-blind trial completed by 29 patients. Each patient was submitted to a 5-month period of treatment with aspirin (median dose 31 mg/kg/ day) and an equivalent period with placebo. No clinical or laboratory differences were observed between the two phases, including the frequency of painful crises and infectious episodes, hemoglobin concentration, PCV, reticuloyctes, Hb F, bilirubin, irreversibly sickled cells, filterability of red cell, sickling in vitro and hypoxia-induced potassium loss.

In this study we have determined the frequency of β^s haplotypes in a Brazilian sickle cell disease population from Sao Paulo, Brazil, by analyzing sequence variations in the immediate 5’ flanking and second intervening sequence (IVSII) regions of the γ globin genes. This association between sequence differences and β^s haplotype backgrounds was determined by screening genomic DNA samples using dot blot analysis of polymerase chain reaction products. We studied 148 β^s chromosomes, and found that haplotype 20 (CAR or Bantu) significantly predominated in this population. This is in agreement with the findings of the historical Portuguese Atlantic slave trade from Africa to South America.