Effects of Infliximab on FDG Uptake and Small Fiber Neuropathy Symptoms in Sarcoidosis Patients

Abstract

<b>Introduction:</b> Small fiber neuropathy (SFN) presents amongst others in sarcoidosis&nbsp;and has&nbsp;a high impact on quality of life. Although treatment of the underlying disease of SFN is advised for the past decades, little research has been performed to investigate SFN improvement as consequence of sarcoidosis treatment. <b>Aims and objectives:</b> This retrospective study investigates treatment effects of Infliximab on SFN symptoms. <b>Methods:</b> The Small Fiber Neuropathy Screening List (SFNSL) was used to identify changes in SFN symptoms during Infliximab treatment. Maximal standardized uptake value (SUVmax) from Fluordeoxyglucose Positron Emission Tomography (FDG-PET) was used as a measure for inflammatory activity. To investigate the effects of Infliximab on inflammatory activity, a subdivision was made based on the degree of SFNSL change. Three groups are defined as improved, stable and worsened SFNSL-score. <b>Results:</b> 95 sarcoidosis patients were eligible for analysis. SUVmax decreased significantly during Infliximab treatment. When looking at the groups with improved (n=38) and stable (n=34) SFNSL-score, sarcoidosis activity also decreases significantly. However, the group who showed worsened SFNSL-score (n=23), did not show improvement of inflammatory response. <b>Conclusion:</b> In 40% of patients with active inflammatory sarcoidosis defined by FDG-PET, Infliximab treatment showed an improvement of the SFNSL-score. Furthermore, in patients with worsening of SFNSL symptoms no improvement of inflammatory response was seen. These data could open a discussion about whether persistent inflammation in sarcoidosis can be&nbsp;detrimental to symptoms of SFN.