PMC8141761_01
- Summary of laboratory studies and radiography: Trends in CRP, CD20+ B-cells, anti-IFNgamma antibody levels, and changes in magnetic resonance imaging (MRI) of the pelvis pre- and post-bortezomib. C-reactive protein (solid red line) and CD20+ B-cells (solid blue line) changes over time and their relationship to rituximab (blue bars) and bortezomib (red bar) initiation. The vertical, red-dotted line represents time of clinical disease relapse (top-left). Anti-IFNgamma autoantibody titers were highest on initial diagnosis as depicted by an increased fluorescence intensity throughout multiple Log10 dilutions (squares - top right). These titers decreased with rituximab but overall remained elevated pre-bortezomib (triangles). They decreased further after bortezomib was added to the rituximab regimen (circles). See supplementary materials for detailed methodology. Representative image of MRI pelvis post-contrast demonstrates significant soft tissue inflammation throughout the left obturator internus and pelvic sidewall (arrowheads) and the left biceps femoris (arrows) prior to bortezomib despite multiple antimycobacterial antibiotics and rituximab (bottom-left). Repeat MRI pelvis with contrast after one year of bortezomib shows resolution of soft tissue inflammation in these areas (bottom-right).
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She continued to have slow clinical and radiologic improvement throughout the subsequent 6-8 months of treatment (Fig. 1).
STAT-1 phosphorylation assay: Functional STAT-1 phosphorylation (pSTAT-1) flow assay using stimulation with different concentrations of IFNgamma. Healthy control cells in the presence of 10% healthy control plasma shows maximal STAT-1 phosphorylation at 100 U/mL (not shown). Patient plasma (7/21/14) prior to rituximab blocks STAT-1 phosphorylation in healthy control cells at the highest dose of 50,000 U/mL IFNgamma. In 8/22/18 after treatment with rituximab, partial STAT-1 phosphorylation is present at 40,000 U/mL IFNgamma and is fully restored at 50,000 U/mL IFNgamma. Repeat assay on 8/11/20 after completing one-year of bortezomib combined with rituximab, STAT-1 phosphorylation is restored, but only at IFNgamma concentrations of 30,000 U/mL and above, indicating significant and continued pSTAT1 blockade compared to healthy control plasma.
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There was a small further decrease in her anti-IFNgamma autoantibody titers over this time with detectable improvements in STAT-1 phosphorylation (Fig. 2).