Association between histological features in temporal artery biopsies and clinical features of patients with giant cell arteritis.

BACKGROUND: In most cases of giant cell arteritis (GCA) the diagnosis is confirmed by temporal artery biopsy. Aside from the diagnostic purpose, histological parameters may serve as prognostic markers.
OBJECTIVES: To review positive temporal artery biopsies ofGCA in an attempt to correlate various histological parameters with clinical features, disease complications and outcome.
METHODS: Positive biopsies from 65 GCA patients were randomly selected for review by a single pathologist. In each biopsy the following parameters were scored: intensity and location of the inflammatory infiltrate, presence of giant cells and other cell types, fragmentation and calcification of the internal elastic lamina, intimal thickening, and presence of luminal thrombus. Clinical data were obtained from the patients' charts. Intensity of the initial systemic inflammatory reaction (ISIR) at the time of diagnosis was scored by the presence of five parameters: fever, anemia, thrombocytosis, leukocytosis, and sedimentation rate >100 mm/hr.
RESULTS: In cases with bilateral positive biopsy (n=27), there was good correlation between the two sides regarding intensity of inflammation (r= 0.65, P< 0.001), location of the infiltrate (r= 0.7, P< 0.001), degree of intimal thickening (r= 0.54, P 0.001), and presence of giant cells (r= 0.83, P< 0.001). The rate of corticosteroid discontinuation tended to be quicker in patients with inflammatory infiltrates confined mainly to the adventitia, but other histological parameters did not affect this rate.
CONCLUSIONS: Inflammatory infiltrates confined to the adventitia were associated with more neuro-ophthalmic ischemic manifestations, weak/moderate ISIR at the time of diagnosis, and faster rate of corticosteroid discontinuation. No association was found between other temporal artery biopsy histological parameters and clinical features of GCA patients.