ABSTRACT
AIMS: To evaluate the potential use of synthetic oligonucleotides as a standard curve for proviral load (PVL) of human T-cell leukaemia virus type 1 (HTLV-1) quantification in peripheral blood mononuclear cells (PBMC) of HTLV-1-infected individuals by quantitative real-time polymerase chain reaction (qPCR) analysis. METHODS AND RESULTS: Synthetic oligonucleotides based on HTLV-1 genome were customized to use as a standard curve. Twelve anti-HTLV-1-positive samples with known HTLV-1 PVL, previously quantified by qPCR assay using TARL-2 cells as a conventional standard curve, were submitted to the new protocol. The proviral quantification levels had a high concordance with qPCR results using a conventional standard curve. The results demonstrate that the conventional standard curve can be replaced by a synthetic standard curve due to its ability to quantification based on the linearity and qPCR efficiency and similar results with a validated qPCR assay using a conventional standard curve. CONCLUSIONS: Synthetic oligonucleotides standard curves could be a very useful tool on HTLV-1 diagnosis and absolute HTLV-1 PVL quantification. SIGNIFICANCE AND IMPACT OF THE STUDY: HTLV-1 PVL determination using synthetic oligonucleotides standard curve by qPCR could be a helpful alternative for the laboratories that monitor infected patients as an important prognostic factor in HTLV-1-associated diseases progression. Also, it can decrease costs and overcome the biological limitations of the plasmid curve.
Subject(s)
HTLV-I Infections/diagnosis , Human T-lymphotropic virus 1/isolation & purification , Proviruses/isolation & purification , Real-Time Polymerase Chain Reaction/methods , Viral Load/methods , Adult , DNA, Viral/genetics , Disease Progression , Genome, Viral/genetics , HTLV-I Infections/blood , HTLV-I Infections/virology , Human T-lymphotropic virus 1/genetics , Humans , Leukocytes, Mononuclear/virology , Middle Aged , Oligonucleotides/chemical synthesis , Oligonucleotides/genetics , Prognosis , Proviruses/genetics , Real-Time Polymerase Chain Reaction/standards , Viral Load/standardsABSTRACT
BACKGROUND: Due to environmental and social conditions inherent to incarceration, tuberculosis (TB) and hepatitis B virus (HBV) are major diseases among prison inmates. OBJECTIVE: To determine overall and occult HBV infection (OBI) prevalence rates, risk factors and genotype distribution among inmates with active TB. STUDY DESIGN: A cross-sectional study was conducted among 216 inmates with active TB recruited at the largest prisons in Campo Grande, Mato Grosso do Sul, Central Brazil. The participants were interviewed and tested for the presence of serological markers for HBV infection. RESULTS: The overall prevalence of HBV infection (total hepatitis B core antibodies) was 10.2% (95%CI 6.2-14.2). HBV surface antigen (HBsAg) prevalence was 1.4% (3/216). HBV DNA was detected in all three HBsAg-positive samples and in 10.5% (2/19) of the anti-HBc-positive samples (OBI), giving a HBV-TB co-infection prevalence of 2.3% (5/216). A multivariate analysis of risk factors showed that history of sharing cutting instruments, length of incarceration and homosexual sex were associated with HBV infection. CONCLUSION: Our findings indicate that HBV remains an important public health concern among prison inmates and active TB-HBV co-infection needs to be addressed for effective treatment.
