ABSTRACT
Platelet antigens are of importance in several clinical situations and in population genetics. Data are scarce on allele frequencies in ethnic groups other than whites, Asians and African Americans. The frequencies of the alleles of the systems HPA-3 and HPA-5 were determined using the allele-specific restriction enzyme for five South American Amerindian populations and compared with those obtained for Afro-Americans, Japanese and whites from Brazil. The frequency of the HPA-3a allele among the Amerindians as a group did not differ from the values obtained for the other populations. However, differences were observed among the Amerindians, varying from 0.27 to 0.75, the highest frequency thus far observed for a population of Asian origin. Only the HPA-5a allele was found among 130 Amerindian chromosomes. The determination of gene frequencies of the HPA systems in different populations allows inference of gene flows and genetic constitution of populations and the estimation of the risk of platelet-specific alloimmunization.
Subject(s)
Alleles , Antigens, Human Platelet/genetics , Gene Frequency/genetics , Indians, South American/genetics , Brazil , DNA Restriction Enzymes/metabolism , Humans , Polymerase Chain ReactionABSTRACT
The HIV-1 variant that contains the GWG amino acid sequence in the crown of the principal neutralizing determinant (PND) has been detected in a few patients in Japan, France, and Brazil by direct sequencing. We describe for the first time the use of restriction fragment length polymorphism (RFLP) and limited DNA sequencing of the C2-V3 region of the HIV-1 envelope (env) gene to determine the prevalence of the variant in 75 HIV-1-infected Brazilian patients. Overall prevalence of the GWG sequence as indicated by RFLP was 57% (43 of 75). The prevalence in females (72%) was higher than that in males (32%) and newborns (40%). Two GFG sequences and 1 GLG sequence were also detected. This finding is relevant for the planning of vaccines and for studies of the epidemiology of HIV-1 in Brazil.
PIP: Most current HIV vaccine development research is focused on the third variable domain (V3) of the HIV-1 envelope gene product that contains the GWG amino acid sequence in the crown of the principal neutralizing determinant. Direct sequencing has detected this variant in patients in Japan, France, and Brazil. The present study used restriction fragment length polymorphism (RFLP) and limited DNA sequencing of the C2-V3 region of the HIV-1 envelope gene to determine the prevalence of the variant in 75 HIV-infected patients from Ribeirao Preto, Brazil. According to RFLP, the overall prevalence of the GWG sequence was 57% (72% in females, 32% in males, and 40% in newborns). Two GFG sequences and one GLG sequence were also detected, suggesting that the GWG variant could be the founder sequence. The gene dendrogram indicated the samples clustered together within the subtype B of the main group.
Subject(s)
HIV Envelope Protein gp120/genetics , HIV Infections/virology , HIV-1/classification , Peptide Fragments/genetics , Adult , Amino Acid Sequence , Base Sequence , Brazil/epidemiology , DNA, Viral/blood , DNA, Viral/chemistry , Deoxyribonucleases, Type II Site-Specific , Female , HIV Envelope Protein gp120/chemistry , HIV Infections/epidemiology , HIV Infections/transmission , HIV-1/genetics , Heterosexuality , Humans , Infant, Newborn , Infectious Disease Transmission, Vertical , Male , Molecular Sequence Data , Peptide Fragments/chemistry , Phylogeny , Polymorphism, Restriction Fragment Length , Prevalence , Substance Abuse, Intravenous/complicationsABSTRACT
The polymerase chain reaction (PCR) was evaluated for its ability to diagnose perinatal HIV-1 infection before the development of signs or symptoms of the disease in thirty-seven infants (median age of 5.5 days) born to HIV-1 infected women. Of 30 children with complete follow up (median of 25 months), 9 (30%) had serological and clinical features of HIV-1 infection and 21 (70%) were uninfected. Among the infected infants, 5/9 (56%) had positive neonatal PCR tests and 4/9 (44%) had negative PCR tests. None of the 21 uninfected children had positive PCR tests. The prognosis of HIV-1 disease in infected infants with a positive neonatal PCR positive test was similar to that of infected infants with a negative PCR test. In spite of not identifying all the infected infants, the PCR test is a useful tool for early diagnosis of HIV-1 perinatal infection, detecting infected newborns during gestation.
