Rheumatic immune-related adverse events secondary to anti–programmed death-1 antibodies and preliminary analysis on the impact of corticosteroids on anti-tumour response: A case series

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 .…”

“…While this could be due to the low frequency of ICI‐IA as an irAE, it has been suggested that underreporting of IA symptoms may be a factor for why there are so few cases of ICI‐IA described . In practice, milder or non–life‐threatening irAEs, such as arthritis, may be overlooked or omitted from reports, and examining physicians may not refer such patients to rheumatologists . Diagnoses in retrospective studies are also difficult, as there is often very little information about immunology, pathology, or radiology reports .…”

“…Similar to SpA, patients with ICI-IA have been primarily found to be seronegative for RF and ACPA, 30,31,36,[57][58][59][109][110][111][112] and an indepth analysis of other serologies has not been performed. 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. 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.…”