Temporal small arterial inflammation is common in patients with giant cell arteritis

Giant cell arteritis (GCA) primarily involves medium-to-large arteries. Small-vessel inflammation is a recognized phenomenon occurring in association with GCA. However, its significance is poorly elucidated. Histologic sections and medical records of105 temporal artery specimens were retrospectively reviewed between 2008 and 2017 to examine associated clinical manifestations and laboratory data including antinuclear antibody and p-antineutrophilic cytoplasmic antibody titers. Immunohistochemical staining for CD4 and CD8 was performed in select cases to assess the nature of the inflammatory response. Seventy-eight patients meeting the diagnostic criteria of temporal arteritis were included in the analysis. Twenty-eight specimens demonstrated temporal arteritis with small arterial inflammation (SAI), and 50 specimens showed temporal arteritis without SAI. Eight (28.6%) of 28 patients with SAI presented with jaw claudication, whereas 5 (17.9%) were febrile at presentation. In contrast, in 50 patients without SAI, jaw claudication and fever were seen in 11 and 2 cases, respectively (P = .01 and P = .0047, respectively). No statistically significant difference was noted between other symptoms and laboratory indices between the 2 groups. Elevated p-antineutrophilic cytoplasmic antibody titers in GCA may be associated with concomitant polymyalgia rheumatica or treatment-resistant disease. We also identified a higher count of CD4 and CD8 T cells in SAI cases, although the ratio of CD4/CD8 T lymphocytes was within normal limits. In conclusion, simultaneous involvement of arterioles and medium- to large-sized arteries is common in GCA and may be associated with treatment-refractory disease. Documentation of small arterial involvement in GCA will help the clinicians to manage the disease more effectively.