The Common H202D Variant in GDF-15 Does Not Affect Its Bioactivity but Can Significantly Interfere with Measurement...

Area of Science:

• Biochemistry
• Molecular Biology
• Clinical Diagnostics

Background:

• Growing interest in growth differentiation factor 15 (GDF-15) measurement for cachexia-related disorders.
• Investigating the impact of a common GDF-15 pro-peptide variant (Histidine to Aspartate at position 202) on immunoassay detection.

Purpose of the Study:

• To determine if the GDF-15 H202D variant interferes with detection by three common immunoassays.
• To compare the performance of different immunoassays in quantifying GDF-15 variants.

Main Methods:

• Synthetic GDF-15 homodimers (HH, HD, DD) were serially diluted and measured using Roche Elecsys®, R&D Quantikine™ ELISA, and MSD R&D DuoSet® immunoassays.
• GDF-15 concentrations in 173 genotyped participants were measured using Roche and MSD assays.
• Comparative statistical analyses included Bland-Altman plots and Passing-Bablok regression; bioactivity was assessed in HEK293S-SRF-RET/GFRAL cells.

Main Results:

• Roche assay detected H- and D-containing GDF-15 peptides similarly.
• R&D reagents (Quantikine and DuoSet) underreported GDF-15 in the presence of the D variant, with DD dimers showing ~45% recovery and HD dimers ~62-78%.
• In human serum, R&D assay reported 4% lower for HH, 36% lower for HD, and 61% lower for DD GDF-15 compared to Roche assay.

Conclusions:

• The D variant of GDF-15 significantly affects its measurement by commonly used immunoassays.
• This finding has critical implications for interpreting GDF-15 levels in research and clinical settings.
• Bioactivity of HH and DD GDF-15 peptides was found to be indistinguishable.