Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are inflammatory rheumatic diseases common in people over the age of 50 years. Seasonal influenza vaccination (IV) is strongly recommended in this population, among whom it is considered to be effective and well tolerated. IV-induced GCA or PMR are thought to be exceptional.
We retrieved all post-IV cases from an inception cohort of patients with newly diagnosed GCA. We also included two patients with post-IV PMR and reviewed all published reports of post-IV GCA or PMR, with selection of cases demonstrating disease onset within 1 month following IV. We compared the results of HLA-DRB1 typing, performed in seven patients with post-IV GCA or PMR, with those of 11 GCA patients with familial aggregation and 16 randomly selected GCA patients without a reported trigger.
Of 358 GCA recruited since 2002, 10 (2.8%) qualified for post-IV GCA, of whom two also showed familial aggregation. Thirty-two patients (19 with GCA and 13 with PMR) including our patients were reviewed; their mean age was 71.8 ± 7.4 years and the M/F ratio was 0.8. Six patients (19%) had a history of PMR. Patients with post-IV GCA/PMR had the DRB1*13:01 haplotype more frequently compared to those with familial GCA (5/7 vs. 2/11, p = 0.048) or with GCA without a known trigger (3/16, p = 0.026). Post-IV PMR generally appeared self-limited, whereas post-IV GCA often displayed a more protracted course (chronic relapsing disease in one-third of the patients).
Post-IV onset of GCA/PMR is not an exceptional occurrence and may be part of the spectrum of the autoimmune syndrome induced by adjuvants (ASIA). IV can trigger GCA or PMR, especially in persons at higher spontaneous risk, such as those with a personal or familial history of GCA/PMR. Whether the presence of the DRB1*13:01 allele further increases the risk of post-IV GCA/PMR through a stronger vaccine-induced immune reaction deserves further investigation. Unlike PMR, GCA can be a serious complication of IV.