Prospects for new leprosy diagnostic tools, a narrative review considering ELISA and PCR assays

Abstract

Slit skin smear and histopathological examinations are currently the main laboratory tools used to aid the diagnosis of leprosy. However, their sensitivity is low, and many cases are not detected. New methodologies have been studied to develop more accurate tests. This narrative review aims to raise attention to the results of molecular (polymerase chain reaction) and serological (Enzyme-Linked Immunosorbent Assay) tests applied to the diagnosis of leprosy, and to summarize the available information about the former. Original scientific articles published in indexed international journals, whose study involved aspects of the diagnosis and classification of leprosy cases or home contacts, were selected. The data were extracted independently using a standardized method that dictated the inclusion of the following information: diagnosis in Paucibacillary and Multibacillary cases and in household contacts; sample number; sample type; study design; studied variables; statistical analysis employed; main results; and limitations identified. In clinical practice, the results from molecular and serological tests are assessed separately, with moderate sensitivity and specificity. However, an integrated study of these methodologies has been suggested for greater accuracy in diagnosis.

Diagnosis and Treatment of Leprosy in Taiwan during the COVID-19 Pandemic: A Retrospective Study in a Tertiaty Center

“…The following sequences, including gene regions encoding M. leprae 18-, 36-, and 65-kDa antigens, 16S rRNA subunit, and M. leprae-specific repetitive sequences (RLEP), are used for PCR [16]. RLEP is the preferred target because of its high copy number; however, 16S rRNA shows higher specificity [17]. Specimens fixed in 10% neutral buffered formalin or 50% or 70% ethanol are commonly used for PCR detection of M. leprae DNA.…”

Leprosy: A Review of Epidemiology, Clinical Diagnosis, and Management

“…Over the past 30 years, PCR methods have been developed to amplify various gene targets in M. leprae. PCR techniques have been used to detect possible environmental sources for the dissemination of M. leprae as well as the aerosol route of infection by means of nasal carriage [74][75][76][77].…”

“…PCR is typically used to support the clinical diagnosis of leprosy. However, PCR is an expensive and laboratory-intensive technique, and most endemic countries cannot routinely perform it [ 74 , 75 ].…”

Susceptibility and resistance in leprosy: Studies in the mouse model

“…A top priority in leprosy research is the implementation of a fieldfriendly diagnostic test for detection of early leprosy, 114 and the development and assessment of such a test is an area of intense research. [115][116][117] To aid in this endeavor, animal models have been used to screen immune responsiveness to various M. leprae antigens with a goal of providing an interface between the production of these test antigens and their evaluation in human field trials. Lahiri et al 118 humans.…”