Quantitative PCR for leprosy diagnosis and monitoring in household contacts: A follow-up study, 2011-2018.

Household contacts (HHC) of leprosy patients exhibit high-risk of developing leprosy and contact tracing is helpful for early diagnosis. From 2011 to 2018,2,437 HHC were examined in a clinic in Rio de Janeiro, Brazil and 16S qPCR was used for diagnosis and monitoring of contacts. Fifty-four HHCs were clinically diagnosed with leprosy at intake. Another 25 exhibited leprosy-like skin lesions at intake, 8 of which were confirmed as having leprosy (50% of which were qPCR positive) and 17 of which were diagnosed with other skin diseases (6% qPCR positive). In skin biopsies, qPCR presented a sensitivity of 0.50 and specificity of 0.94. Furthermore, 955 healthy HHCs were followed-up for at least 3 years and skin scrapings were collected from earlobes for qPCR detection. Positive qPCR indicated a non-significant relative risk of 2.52 of developing the disease. During follow-up, those who progressed towards leprosy exhibited 20% qPCR positivity, compared to 9% of those who remained healthy. Disease-free survival rates indicated that age had a significant impact on disease progression, where patients over 60 had a greater chance of developing leprosy [HR = 32.4 (3.6-290.3)]. Contact tracing combined with qPCR may assist in early diagnosis and age is a risk factor for leprosy progression.

Quantitative polymerase chain reaction in paucibacillary leprosy diagnosis: A follow-up study.

OBJECTIVE: The diagnosis of paucibacillary (PB) leprosy cases remains a challenge because of the absence of a confirmatory laboratory method. While quantitative polymerase chain reaction (qPCR) has been shown to provide reliable sensitivity and specificity in PB diagnoses, a thorough investigation of its efficacy in clinical practice has not yet been published. The present study evaluated patients with suspected leprosy skin lesions by using qPCR to identify PB individuals in the Leprosy Outpatient clinic at the Oswaldo Cruz Foundation in Rio de Janeiro, Brazil. METHODS: One hundred seventy-two suspected PB cases were included in the study. The patients were evaluated by a dermatologist at three different times. The clinical dermato-neurological examination and collected samples were performed on the first visit. On the second visit, the results of the histopathological analysis and PCR assay (DNA-based Mycobacterium leprae qPCR-targeting 16S gene) results were analyzed, and a decision regarding multi-drug therapy was made. A year later, the patients were re-examined, and the consensus diagnosis was established. RESULTS: In 58% (100/172) of cases, a conclusive diagnosis via histopathological analysis was not possible; however, 30% (30/100) of these cases had a positive PCR. One hundred ten patients (110/172) attended the third visit. The analysis showed that while the sensitivity of the histopathological test was very low (35%), a qPCR alone was more effective for identifying leprosy, with 57% sensitivity. CONCLUSION: The use of qPCR in suspected PB cases with an inconclusive histology improved the sensitivity of leprosy diagnoses.

Ser49Gly polymorphism in the ß-adrenergic receptor 1 gene in a population sample from Rio de Janeiro state, Brazil, stratified by self-identified skin color and genetic ancestry.

Cardiovascular diseases (CVD) have the highest worldwide mortality rate of any type of disease. In recent years, genetic research regarding CVD has been conducted using association studies, in which the presence of a genetic polymorphism associated with a specific cell signaling pathway in a lower or in a higher frequency among patients may be interpreted as a possible causal factor. Genetic polymorphisms that occur in the ß-adrenergic receptor 1 (ß-ADR1) can result in significant changes in its function that may result in physiopathologies. Ambiguous categorizations, such as skin color and self-reported ethnicity have been used in pharmacogenetic studies as phenotypic proxies for ancestry; however, admixed populations present a particular challenge to the effectiveness of this approach. The main objective of the present study was to estimate the diversity and the frequency of the Ser49Gly polymorphism of the ß-ADR1 gene in a sample of 188 male individuals from the population of Rio de Janeiro. The Ser49Gly frequencies were analyzed by two forms of sample stratification: The phenotypic criterion of black or non-black skin color, and African or non-African ancestry, defined using Y-chromosome single nucleotide polymorphisms and autosomal indel markers. These results were used to evaluate whether marker-based ancestry criteria and/or skin color were associated with the frequency of the Ser49Gly polymorphisms in the heterogeneous Rio de Janeiro/Brazilian population. The DNA fragments of interest were amplified by polymerase chain reaction with specific primers for the Ser49Gly marker, and genotyping reactions were performed by restriction with the enzyme Eco0109I. Heterozygosity values ranging from 0.25 to 0.50 and 0.20 to 0.41 were found for the groups stratified by ancestry and skin color, respectively. Using the Hardy-Weinberg equilibrium at the ser49Gly marker, it was found that there was no significant deviation in the genotype distribution of the whole Rio de Janeiro sample or the stratified sample. Analysis of the allelic distribution in the Rio de Janeiro population sample revealed frequencies of 80.30 and 19.70% for the wild-type (Ser49) and mutated (Gly49) alleles, respectively. Significant differences were observed in the allele frequencies of the Ser49Gly marker between the self-defined black and non-black phenotype, and the African and non-African descendant genotype population samples. A significant difference was also observed between blacks and African-descendant individuals, with a lesser degree of genetic differentiation. The results presented in the present study suggest that the Ser49Gly marker has a distribution that is influenced by an ancestral component, due to the increased prevalence of the Gly49 polymorphism in the black and African descendant populations of the Rio de Janeiro state. This evidence, in combination with clinical studies, may contribute to a detailed analysis of the pattern of susceptibility to CVD involved in ß-ADR1 receptor mechanism failure.