MALDI MS profiling of serum extracts to identify Galactomannan Enzyme Immunoassay False Positivity via Immunoglobulin Products

  • The clinical application of MALDI MS is growing as a result of it’s ease of use, low cost per test and ability to identify biomarkers from body fluids which correlate with disease. We report a clinical scenario where MALDI MS profiling is used to investigate the origin of false positive Galactomannan enzyme immunoassay (EIA) results in a clinical laboratory.
  • Therapeutic immunoglobulins (IVIG) are used as replacement or immunomodulatory therapy, but can transmit clinically important molecules (Ramsey et al., 2016). Indications for their use include replacement therapy in antibody-deficiency syndromes.
  • Patients in these groups are at increased risk of invasive fungal disease (IFD) with Aspergillus fumigatus.
  • Galactomannan antigen (GM) is a component of the cell wall of Aspergillus fumigatus and several other clinically important fungi. The Galactomannan enzyme immunoassay (GM-EIA) is used largely as a screening test for early detection of invasive aspergillosis in at-risk patients. Several immunodominant glycoproteins in Aspergillus fumigatus have been identified previously via immunoblot, but with the use of Aspergillus fumigatus anti-cell wall antibody (Haynes et al., 1990). These glycoprotein masses are described.
  • Some patients were found to become positive for the GM-EIA screening test following IVIG administration, although aspergillus culture, pan-fungal and aspergillus specific PCR were negative. The testing of the IVIG vials produced a similar pattern.
  • A false-positive GM-EIA result can be interpreted as an early biomarker of invasive aspergillosis or other invasive fungal infection leading to further investigation or treatment.
  • Here, the development of a MALDI-based assay to confirm a false-positive GM-EIA result was investigated.


*Not available in the U.S.

Content Type:
Paper
Document Number:
PO-CON1762E
Product Type:
Mass Spectrometry, Life Science Lab Instruments, MALDI-TOF Mass Spectrometry
Keywords:
Clinical research, Forensics, Healthcare, Clinical research, MALDI-8020
Language:
English
File Name:
ego317098.pdf
File Size:
479kb

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For Research Use Only. Not for use in diagnostic procedures.

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