Prognostic Biomarker Found for Post-Chemotherapeutic Relapse in Visceral Leishmaniasis
By LabMedica International staff writers Posted on 05 Nov 2014 |
The effective clinical management, chemotherapy and control of the transmission of visceral leishmaniasis (VL) are largely dependent on early and unequivocal diagnosis as without effective chemotherapy symptomatic VL is usually fatal.
The most sensitive and specific method to detect the causative agent of VL is microscopic examination of invasive spleen aspirates; bone marrow and lymph node aspirates provide similar high specificity but lesser sensitivity although more user-friendly point-of-care (POC) diagnostics have been developed based on antibody detection.
Scientists at the London School of Hygiene and Tropical Medicine (UK) and their international colleagues collected plasma samples after 2007 from active VL, cured, relapsed, post-kala-azar dermal leishmaniasis (PKDL) and asymptomatic groups from the endemic region of Bihar state (north-eastern India), and control subjects from a region where VL is not endemic. Serum samples were also collected in 2011 and 2013, from active VL, treated, relapsed, PKDL, and endemic controls in eastern Sudan.
Leishmania donovani specific enzyme-linked immunosorbent assays (ELISA) were performed and human immunoglobulin G (IgG) isotype responses were determined. The ELISAs were read at 490 nm on a Spectra Max 190 microplate reader (Molecular Devices; Sunnyvale, CA, USA), the MRX II plate reader, (Dynex Technologies; Chantilly, USA). Prototype L. donovani antigen-specific IgG1 immunochromatographic rapid diagnostic tests (RDTs) were developed and consisted of a cassette with a nitrocellulose membrane, a sample pad, a conjugate pad and an absorbent pad, backed with a plastic strip.
For the Indian VL sera, consistent with the known IgG1 half-life, IgG1 levels had not decreased significantly at day 30 after the start of treatment, but were dramatically decreased by six months compared to day 0 or day 15 after the start of treatment. Similarly, Sudanese sera taken soon after treatment did not show a significant change in the IgG1 levels. The two prototype lateral flow immunochromatographic rapid diagnostic tests that were developed to detect IgG1 levels following VL treatment showed that in more than 80% of the relapsed VL patients, they were IgG1 positive; while in at least 80% of the cured VL patients were IgG1 negative.
The authors concluded that six months after treatment of active VL, elevated levels of specific IgG1 were associated with treatment failure and relapse, whereas no IgG1 or low levels were detected in cured VL patients. A lateral flow RDT was successfully developed to detect anti-Leishmania IgG1 as a potential biomarker of post-chemotherapeutic relapse.
Related Links:
London School of Hygiene and Tropical Medicine
Molecular Devices
Dynex Technologies
The most sensitive and specific method to detect the causative agent of VL is microscopic examination of invasive spleen aspirates; bone marrow and lymph node aspirates provide similar high specificity but lesser sensitivity although more user-friendly point-of-care (POC) diagnostics have been developed based on antibody detection.
Scientists at the London School of Hygiene and Tropical Medicine (UK) and their international colleagues collected plasma samples after 2007 from active VL, cured, relapsed, post-kala-azar dermal leishmaniasis (PKDL) and asymptomatic groups from the endemic region of Bihar state (north-eastern India), and control subjects from a region where VL is not endemic. Serum samples were also collected in 2011 and 2013, from active VL, treated, relapsed, PKDL, and endemic controls in eastern Sudan.
Leishmania donovani specific enzyme-linked immunosorbent assays (ELISA) were performed and human immunoglobulin G (IgG) isotype responses were determined. The ELISAs were read at 490 nm on a Spectra Max 190 microplate reader (Molecular Devices; Sunnyvale, CA, USA), the MRX II plate reader, (Dynex Technologies; Chantilly, USA). Prototype L. donovani antigen-specific IgG1 immunochromatographic rapid diagnostic tests (RDTs) were developed and consisted of a cassette with a nitrocellulose membrane, a sample pad, a conjugate pad and an absorbent pad, backed with a plastic strip.
For the Indian VL sera, consistent with the known IgG1 half-life, IgG1 levels had not decreased significantly at day 30 after the start of treatment, but were dramatically decreased by six months compared to day 0 or day 15 after the start of treatment. Similarly, Sudanese sera taken soon after treatment did not show a significant change in the IgG1 levels. The two prototype lateral flow immunochromatographic rapid diagnostic tests that were developed to detect IgG1 levels following VL treatment showed that in more than 80% of the relapsed VL patients, they were IgG1 positive; while in at least 80% of the cured VL patients were IgG1 negative.
The authors concluded that six months after treatment of active VL, elevated levels of specific IgG1 were associated with treatment failure and relapse, whereas no IgG1 or low levels were detected in cured VL patients. A lateral flow RDT was successfully developed to detect anti-Leishmania IgG1 as a potential biomarker of post-chemotherapeutic relapse.
Related Links:
London School of Hygiene and Tropical Medicine
Molecular Devices
Dynex Technologies
Read the full article by registering today, it's FREE!
Register now for FREE to LabMedica.com and get complete access to news and events that shape the world of Clinical Laboratory Medicine.
- Free digital version edition of LabMedica International sent by email on regular basis
- Free print version of LabMedica International magazine (available only outside USA and Canada).
- Free and unlimited access to back issues of LabMedica International in digital format
- Free LabMedica International Newsletter sent every week containing the latest news
- Free breaking news sent via email
- Free access to Events Calendar
- Free access to LinkXpress new product services
- REGISTRATION IS FREE AND EASY!
Sign in: Registered website members
Sign in: Registered magazine subscribers
Latest Microbiology News
- Integrated Solution Ushers New Era of Automated Tuberculosis Testing
- Automated Sepsis Test System Enables Rapid Diagnosis for Patients with Severe Bloodstream Infections
- Enhanced Rapid Syndromic Molecular Diagnostic Solution Detects Broad Range of Infectious Diseases
- Clinical Decision Support Software a Game-Changer in Antimicrobial Resistance Battle
- New CE-Marked Hepatitis Assays to Help Diagnose Infections Earlier
- 1 Hour, Direct-From-Blood Multiplex PCR Test Identifies 95% of Sepsis-Causing Pathogens
- Mouth Bacteria Test Could Predict Colon Cancer Progression
- Unique Metabolic Signature Could Enable Sepsis Diagnosis within One Hour of Blood Collection
- Groundbreaking Diagnostic Platform Provides AST Results With Unprecedented Speed
- Simple Blood Test Combined With Personalized Risk Model Improves Sepsis Diagnosis
- Blood Analysis Predicts Sepsis and Organ Failure in Children
- TB Blood Test Could Detect Millions of Silent Spreaders
- New Blood Test Cuts Diagnosis Time for Nontuberculous Mycobacteria Infections from Months to Hours
- New Tuberculosis Test to Expand Testing Access in Low- and Middle-Income Countries
- Rapid Test Diagnoses Tropical Disease within Hours for Faster Antibiotics Treatment
- Rapid Molecular Testing Enables Faster, More Targeted Antibiotic Treatment for Pneumonia