Context. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is increasingly used to assess extension and response to treatment of IgG4 Related type 1 autoimmune pancreatitis (IgG4RD-AIP) but clear correlations between 18F-FDG uptake and disease activity have not been established yet. Objective. To correlate the intensity and distribution of 18-Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) uptake with validated clinical, serological and immunological biomarkers of IgG4-related disease (IgG4RD) activity. Methods. Twenty patients with active IgG4RD underwent a baseline 18F-FDG PET/CT. Ten patients repeated 18F-FDG PET/CT after immunosuppressive treatments. 18F-FDG tissue uptake was measured using the standardized uptake value corrected for the partial volume effect (PVC-SUV). Disease activity was assessed by means of clinical parameters [IgG4RD Responder Index (RI)], serological (ESR and CRP) and immunological (serum IgG4 and circulating plasmablasts) biomarkers. The enhanced liver fibrosis score was exploited as a biomarker for fibroblast activation. Results. Thirteen (65%) patients had IgG4RD AIP. All patients had active IgG4-RD [median IgG4-RD RI = 9 (normal<3)]. Serum IgG4 and plasmablasts were elevated in 85% of patients. Circulating plasmablasts positively correlated with PVC-SUV (P=0.027). No statistically significant correlation was found between PVC-SUV and IgG4-RD RI, ESR, CRP, serum IgG4 or enhanced liver fibrosis score (P>0.05). Clinical response to immunosuppressive therapies was associated with a consensual reduction of circulating plasmablasts and PVC-SUV (P<0.05 compared to baseline) Conclusions. 18 F-FDG uptake of IgG4RD lesions and of IgG4RD-AIP reflects immunological perturbations of the B cell compartment rather than fibroblast activation and extracellular matrix deposition. 18 F-FDG uptake faithfully mirrors IgG4RD activity.
Quantitative measurement of 18F-FDG PET/CT uptake reflects the expansion of circula-ting plasmablasts in IgG4-related type 1 au-toimmune pancreatitis and other organs
DELLA TORRE E;Marco Lanzillotta;Paolo Giorgio Arcidiacono;Massimo Falconi;Lorenzo Dagna
2017-01-01
Abstract
Context. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is increasingly used to assess extension and response to treatment of IgG4 Related type 1 autoimmune pancreatitis (IgG4RD-AIP) but clear correlations between 18F-FDG uptake and disease activity have not been established yet. Objective. To correlate the intensity and distribution of 18-Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) uptake with validated clinical, serological and immunological biomarkers of IgG4-related disease (IgG4RD) activity. Methods. Twenty patients with active IgG4RD underwent a baseline 18F-FDG PET/CT. Ten patients repeated 18F-FDG PET/CT after immunosuppressive treatments. 18F-FDG tissue uptake was measured using the standardized uptake value corrected for the partial volume effect (PVC-SUV). Disease activity was assessed by means of clinical parameters [IgG4RD Responder Index (RI)], serological (ESR and CRP) and immunological (serum IgG4 and circulating plasmablasts) biomarkers. The enhanced liver fibrosis score was exploited as a biomarker for fibroblast activation. Results. Thirteen (65%) patients had IgG4RD AIP. All patients had active IgG4-RD [median IgG4-RD RI = 9 (normal<3)]. Serum IgG4 and plasmablasts were elevated in 85% of patients. Circulating plasmablasts positively correlated with PVC-SUV (P=0.027). No statistically significant correlation was found between PVC-SUV and IgG4-RD RI, ESR, CRP, serum IgG4 or enhanced liver fibrosis score (P>0.05). Clinical response to immunosuppressive therapies was associated with a consensual reduction of circulating plasmablasts and PVC-SUV (P<0.05 compared to baseline) Conclusions. 18 F-FDG uptake of IgG4RD lesions and of IgG4RD-AIP reflects immunological perturbations of the B cell compartment rather than fibroblast activation and extracellular matrix deposition. 18 F-FDG uptake faithfully mirrors IgG4RD activity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
