Israel Medical Association Journal

Giant cell arteritis (GCA) is considered to be a T cell-dependent disease. Autoantibodies have not consistently been found in GCA. The exception is antiphospholipid antibodies (APLA), which were found in 30–80% of GCA cases. Recently, efforts have been made to seek autoantibodies in GCA using newer methods of detection: serological identification of antigens by recombinant cDNA expression cloning, and a proteomic approach. In these studies, lamin C (a nuclear envelope antigen) was recognized by antibodies in 32% of GCA sera and none of the controls. Other autoantigenic proteins were also identified: lamin A, vinculin (a cytoskeleton antigen), and annexin 5 (an endothelial protein). In a recent study, 92% of 36 patients with GCA and/or polymyalgia rheumatica (PMR) had autoantibodies to a human ferritin peptide (the heavy chain N-terminal); 89% had antibodies to bacterial ferritin peptide of Staphylococcus epidermidis. The significance of these findings needs to be studied further. GCA may be a part of the newly described ASIA syndrome (autoimmune syndrome induced by adjuvants). A recent study from Italy reported 10 cases of GCA/PMR within 3 months of influenza vaccination. These comprised 50% of all cases of GCA/PMR diagnosed during the 6 year period of the study. Another 11 cases of GCA following influenza vaccinations were reported. GCA pathogenesis involves all branches of the immune system, including antigen-presenting cells, T cells and B cells, and autoantibody formation is not uncommon. GCA etiology remains unknown, but may be associated with exposure to bacterial or viral antigens.  

 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 biopsiese of GCA 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.