H. H. and Fudenberg's research while affiliated with UCSF University of California, San Francisco and other places

... The possibility that autoantibodies from patients with RA may actually play a role in the disease process had previously been raised following the analysis of RhF derived from synovial tissue in RA patients. As well as being class-switched, as shown by Kunkel et al. [22], sequence analysis revealed different structural and functional properties from RhF in normal individuals [23]. This was interpreted to suggest that parent RhF B-cells may be dysregulated and hence produce the 'wrong type' of RhF, which may have pathogenic properties. ...

Reference:

Response to Rituximab: Has the Original Hypothesis Been Confirmed?

... [30] Moreover, a previous study suggested that rheumatoid factor, which is a diagnostic feature of rheumatoid arthritis, may lead to immune complex-mediated vasculitis and eventually result in Bell's palsy due to disruption of the blood supply to the nerve itself. [22] Rheumatoid factor may also be identified in systemic lupus erythematosus, sarcoidosis, and scleroderma [31][32][33] ; however, the evidence presented for the occurrence of Bell's palsy following these autoimmune disorders is limited. In other words, this autoimmune-mediated vasculopathy may yield an increased risk for Bell's palsy in patients with rheumatoid arthritis; however, the impact of autoimmunity on Bell's palsy remains unknown. ...

Reference:

The association between Bell's palsy and rheumatoid arthritis: A longitudinal study