Rheumatic immune-related adverse events in patients on anti-PD-1 inhibitors: Fasciitis with myositis syndrome as a new complication of immunotherapy

Immune checkpoint inhibitor–induced inflammatory arthritis as a model of autoimmune arthritis

“…Thus far, most reports are from small case series or single‐center cohort studies and the assays used to detect seropositivity are not uniform between studies. Despite these limitations, aggregation of the data from multiple studies reveals a low rate of seropositivity among patients developing IA following treatment with ICI therapy with 5.5% (12/217; range 0%‐36%) positive for RF and 5% (11/217; range 0%‐11%) positive for ACPAs . In a study comparing ICI‐IA patients to ethnically matched counterparts with RA, 7.7% of ICI‐IA patients were positive for RF or ACPAs, whereas 64.6% of RA patients were positive for ACPAs and 56.7% positive for RF, with 49.3% being positive for both .…”

“…While ANA is not specific for a particular subgroup, it does correlate with an increased incidence of JIA‐associated uveitis, particularly iridocyclitis . Aggregate analysis of ANA positivity in patients with ICI‐IA, as defined by a titer greater than 1:40, from several published studies revealed that 15.3% (32/209; range 0%‐89%) of patients were positive for ANA . In addition, antibodies against specific nuclear antigens, dsDNA, Ro, and La (usually seen in patients with systemic lupus erythematosus or Sjögren's syndrome), have been detected in ICI‐IA patients .…”

“…In another study, the SE allele HLA DRB1*01:01 was found in two out of nine patients who had inflammatory arthritis after treatment with an ICI; however, comparison to a control population was not reported . Interestingly, several studies have shown that SpA‐associated HLA‐B27 alleles do not appear to confer increased risk for ICI‐IA, as almost all patients who developed ICI‐IA were HLA‐B27‐negative . The genetic studies performed thus far show that SE alleles, but not HLA‐B27 alleles, associate with ICI‐IA.…”

“…Despite these limitations, aggregation of the data from multiple studies reveals a low rate of seropositivity among patients developing IA following treatment with ICI therapy with 5.5% (12/217; range 0%-36%) positive for RF and 5% (11/217; range 0%-11%) positive for ACPAs. 30,31,33,36,[57][58][59]66,[109][110][111][112][113][114][115] In a study comparing ICI-IA patients to ethnically matched counterparts with RA, 7.7% of ICI-IA patients were positive for RF or ACPAs, whereas 64.6% of RA patients were positive for ACPAs and 56.7% positive for RF, with 49.3% being positive for both. 116 Although these results indicate that the prevalence of seropositivity in ICI-IA is much lower than in RA, it is unknown if seropositivity is increased in patients who develop RA-like disease following ICI therapy.…”

“…128 Aggregate analysis of ANA positivity in patients with ICI-IA, as defined by a titer greater than 1:40, from several published studies revealed that 15.3% (32/209; range 0%-89%) of patients were positive for ANA. 30,31,36,[57][58][59]66,[109][110][111][112][113][114][115] In addition, antibodies against specific nuclear antigens, dsDNA, Ro, and La (usually seen in patients with systemic lupus erythematosus or Sjögren's syndrome), have been detected in ICI-IA patients. 31,36,112 Although ICI-IA develops in a subset of adult patients treated with ICI therapy, it is possible that the pathogenesis and development of this disease may more closely parallel the development of JIA rather than adult RA or SpA.…”