Leprosy or leprosy is a serious health problem in Indonesia, even in Brazil. Therefore we need a better diagnostic tool with high specifications and sensitivity. The use of phenolic glycolipid (PGL) -1 is a good diagnostic tool, but it has limitations. Recently, the combination of natural disaccharide octyl (NDO) and IDRI diagnostic leprosy (LID) -1 or NDO-LID has become a promising diagnostic tool because it has high specifications and sensitivity and can even detect leprosy before clinical symptoms appear.
Leprosy is a chronic disease caused by Mycobacterium leprae. This disease mainly attacks the skin and peripheral nerves. Previously, to diagnose leprosy based only on clinical symptoms, bacilloscopy, and histopathology. Examination of skin smears and histopathology has several limitations, namely not being able to detect leprosy before the number of bacteria is more than 104 and the technique is difficult to do. Over time and the development of technology, diagnostic tools have been found that can detect Mycobacterium leprae infection before clinical symptoms appear. Some tests that have this ability is the immunohistochemical test, relatively inexpensive serology, and PCR.
At present research is directed at specific molecules of Mycobacterium leprae for early diagnosis and treatment. One of the molecules used is phenolic glycolipid I (PGL-1) which was discovered in the early 1980s. Immunoglobulin M (IgM) will be produced against PGL-1. PGL-1 antibody examination has a sensitivity of 77% and a specificity of 93% in multibacillary type patients. However, research has found the limitation of PGL-1 is that it has a high false-positive value in endemic areas. PGL-1 antibodies will also last a long time in the body’s tissues, stimulating IgM production even without living bacteria. Therefore, its presence does not always indicate active leprosy infection.
The latest discovery found an antigen found in the Mycobacterium leprae nucleus known as IDRI diagnostic leprosy (LID) -1. Based on LID-1 research can diagnose multibacillary type leprosy and several types of pausibacillary. It has been proven that LID-1 can be an early diagnosis tool for leprosy because LID-1 can diagnose leprosy before clinical symptoms appear. Antibodies against LID-1 appear before one year of clinical diagnosis. When LID-1 is combined with natural disaccharide octyl (NDO) it forms an NDO-LID 1 conjugate is able in diagnosing leprosy early and becomes more sensitive to the type of papalbacillary. The NDO-LID 1 rapid test is available in the market. This test works to detect IgM antibodies against NDO and IgG antibodies against LID-1. Research shows that the NDO-LID 1 test is better than PGL-1 because in NDO-LID 1 it can detect IgM and IgG. Research shows that IgG and IgM levels are related to patient bacterial load. Subjects who had lower yields were also suspected of having a lower bacterial load.
A 2017 study conducted on eight multibacillary type leprosy patients who had not or had received multi-drug therapy for less than six months at the RSUD Dr. Soetomo had his blood drawn for testing using NDO-LID serology. Three antibodies will be detected in this study, namely IgM, IgG, and a combination of IgAMG antibodies against NDO-LID. This study found that anti-NDO-LID IgAMG levels were higher than IgM and IgG levels. The level also correlates well with the clinical and histopathological results of the subject. Through this research, IgAMG has a higher sensitivity than IgM and IgG. Although this study was conducted in multibacillary patients, it is possible that if carried out in patibacillary patients it would give the same results.
The importance of early diagnosis of leprosy patients makes researchers competing to find diagnostic tools that have high specificity and sensitivity and can detect leprosy before the onset of clinical symptoms. Apart from that, diagnostic tools must also be affordable and techniques to do so must also be easy. The NDO-LID serology test is one that might meet these criteria. An initial study proves that IgAMG anti-NDO-LID levels are higher than IgM and IgG. Therefore detection of IgAMG levels might increase the sensitivity of the NDO-LID test, which still requires further study with a larger sample size.
Author: Prof. Dr. dr. Cita Rosita Sigit Prakoeswa, SpKK, FINS-DV, FAADV
Details of the research available at:
Journal title : Immunoglobulin AMG Anti Natural Disaccharide Octyl – Leprosy IDRI Diagnostic (NDO-LID) Serologic Test for Leprosy Diagnosis: A Pilot Study
Rumondor, B., Prakoeswa, A., Trianita, M., Iswahyudi, I., Herwanto, N., Listiawan, M. Y., Agusni, I., Izumi, S., Duthie, M., & Sigit Prakoeswa, C. R.
Department of Dermatology and Venereology, Faculty of Medicine, Universitas Airlangga / Dr. Soetomo General Hospital, Surabaya, Indonesia