The retrovirus human T lymphotropic virus type 1 (HTLV-1) promotes spastic paraparesis, adult T cell leukaemia and other diseases. Recently, some human microRNAs (miRNAs) have been described as important factors in host-virus interactions. This study compared miRNA expression in control individuals, asymptomatic HTLV-1 carriers and HTLV-1 associated myelopathy (HAM)/tropical spastic paraparesis patients. The proviral load and Tax protein expression were measured in order to characterize the patients. hsa-miR-125b expression was significantly higher in patients than in controls (p = 0.0285) or in the HAM group (p = 0.0312). Therefore, our findings suggest that miR-125b expression can be used to elucidate the mechanisms of viral replication and pathogenic processes.

A soroprevalência e a distribuição geográfica do HTLV-1/2 entre os doadores de sangue são extremamente importantes para os serviços de transfusão. Neste trabalho, foi determinada a soroprevalência da infecção pelo HTLV-1/2 entre os doadores de sangue de primeira vez da cidade de Ribeirão Preto e região. No período de Janeiro de 2000 a Dezembro de 2010, 1.038.489 doações de sangue foram obtidas sendo 301.470 doações de primeira vez. Todas as amostras foram avaliadas com testes sorológicos para HTLV-1/2 usando ensaio imunoenzimático (EIA). Adicionalmente, a frequência de coinfecção com o vírus da hepatite B (HBV), vírus da hepatite C (HCV), vírus da imunodeficiência humana (HIV), doença de Chagas (CD) e sífilis também foi determinada. Adicionalmente, foi utilizada uma reação de PCR in-house como teste confirmatório para HTLV-1/2. Um total de 296 (0,1%) doadores de primeira vez foram sorologicamente reativos para HTLV-1/2. O PCR confirmatório de 63 amostras mostrou que 28 eram HTLV-1 positivas, 13 HTLV-2 positivas, 19 negativas e três indeterminadas. Em relação às taxas de coinfecção com HTLV1/2, a maior prevalência foi com HBV (51,3%) e HCV (35,9%), mas a coinfecção com HIV, CD e sífilis também foram detectadas. O número real de indivíduos infectados pelo HTLV-1 e a taxa de coinfecção na população é subestimado e estudos epidemiológicos como esse são muito informativos.

The seroprevalence and geographic distribution of HTLV-1/2 among blood donors are extremely important to transfusion services. We evaluated the seroprevalence of HTLV-1/2 infection among first-time blood donor candidates in Ribeirão Preto city and region. From January 2000 to December 2010, 1,038,489 blood donations were obtained and 301,470 were first-time blood donations. All samples were screened with serological tests for HTLV-1/2 using enzyme immunoassay (EIA). In addition, the frequency of coinfection with hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), Chagas disease (CD) and syphilis was also determined. In-house PCR was used as confirmatory test for HTLV-1/2. A total of 296 (0.1%) first-time donors were serologically reactive for HTLV-1/2. Confirmatory PCR of 63 samples showed that 28 were HTLV-1 positive, 13 HTLV-2 positive, 19 negative and three indeterminate. Regarding HTLV coinfection rates, the most prevalent was with HBV (51.3%) and HCV (35.9%), but coinfection with HIV, CD and syphilis was also detected. The real number of HTLV-infected individual and coinfection rate in the population is underestimated and epidemiological studies like ours are very informative.

Complement receptor 1 (CR1) gene polymorphisms that are associated with Knops blood group antigens may influence the binding of Plasmodium parasites to erythrocytes, thereby affecting susceptibility to malaria. The aim of this study was to evaluate the genotype and allele and haplotype frequencies of single-nucleotide polymorphisms (SNPs) of Knops blood group antigens and examine their association with susceptibility to malaria in an endemic area of Brazil. One hundred and twenty-six individuals from the Brazilian Amazon were studied. The CR1-genomic fragment was amplified by PCR and six SNPs and haplotypes were identified after DNA sequence analysis. Allele and haplotype frequencies revealed that the Kn b allele and H8 haplotype were possibly associated with susceptibility to Plasmodium falciparum. The odds ratios were reasonably high, suggesting a potentially important association between two Knops blood antigens (Kn b and KAM+) that confer susceptibility to P. falciparum in individuals from the Brazilian Amazon.