Therapeutic plasma exchange for peripheral neuropathy associated with trisulfated heparan disaccharide IgM antibodies: A case series of 17 patients

Abstract Background Small fiber neuropathy (SFN) can be associated with autoantibodies, including those of IgM class with specificity for the trisulfated heparan disaccharide (TS‐HDS) antigen. We hypothesized that, as an IgM autoantibody‐mediated disorder, TS‐HDS‐associated SFN symptoms may be reduced with therapeutic plasma exchange (TPE). Study methods This was an observational analysis of all patients referred for TPE from 2018 to 2020 following laboratory confirmation of SFN with TS‐HDS autoantibodies; a loading course of 3 to 5 procedures over 2 weeks was completed, with some patients returning for monthly procedures. The following data were collected: demographics, symptoms and duration, TS‐HDS levels, skin biopsy results, reported responses to TPE, and TPE‐associated adverse events. Results Of the 17 subjects, 12 (71%) were female and the mean age was 57.5 years (range 27‐94). The most common reported symptom was lower extremity paresthesia (88% of subjects). The mean number of TPE procedures completed per subject was 9 (range 3‐18), with 71% (12/17) reporting symptomatic improvement or slowed disease progression. About 15% of procedures were associated with an adverse event, with vasovagal reactions being the most common; 53% of patients had at least one adverse event. Conclusions Given a reported symptomatic response rate of more than 70%, TPE may be a treatment option for individuals with autoimmune‐mediated SFN associated with increased titers of TS‐HDS IgM autoantibodies. Since TPE‐associated adverse events appear common in this population, close monitoring during procedures is warranted.