Temporal Small-Vessel Inflammation in Patients with Giant Cell Arteritis: Clinical Course and Preliminary Immunohistopathologic Characterization

The Clinical Significance of Small Vessel Vasculitis on Temporal Artery Biopsies

BACKGROUND

Giant cell arteritis (GCA) is the most common type of systemic vasculitis in the elderly. Untreated, it can lead to irreversible blindness. Its diagnosis relies on a temporal artery biopsy (TAB). However, a proportion of patients have small vessel vasculitis (SVV) on biopsy; the prognosis of which remains unclear. The aim of this study is to compare the clinical presentation and long-term outcomes of those with SVV with negative and positive biopsies to determine whether long-term corticosteroid therapy can be avoided in these patients.

METHODS

Post hoc analysis of patients with suspected GCA who underwent TAB and fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scan as part of a prospective GCA and PET cohort. Patients were divided in to 3 groups based on TAB result: positive (inflammation in the main artery wall), negative (no inflammation), and SVV (isolated vasa vasorum or periadventitial SVV). Clinical, serological, and PET/CT data of patients with SVV were compared with those with positive and those with negative biopsies.

RESULTS

For the 58 eligible patients recruited between May 2016 and December 2017, 11 had SVV, 12 had positive, and 35 had negative biopsies. Patients with SVV had similar clinical, serological, and PET/CT findings to those with negative biopsies. Compared with those with positive biopsies, patients with SVV had lower erythrocyte sedimentation rate (25 vs 78 mm/hour; P = 0.02), platelet count (296 vs 385 ×109/L; P = 0.03), and a lower median total vascular score on PET/CT scan (1.0 vs 13.5; P = 0.01). Median prednisone dose was lower (4.8 vs 11.7 mg; P = 0.015) and fewer were on steroid-sparing agents (20% vs 67%; P = 0.043) at 6 months. The percentage of patients with a clinical diagnosis of GCA was similar between those with SVV (3/11, 27.3%) and those with negative biopsies (5/35, 14.3%; P = 0.374).

CONCLUSIONS

Patients with SVV on TAB had similar clinical features, PET/CT findings, and 6-month outcomes to those with negative biopsies. Small vessel vasculitis can be treated as equivalent to a negative biopsy when being considered for diagnosis and treatment of GCA.

Necessity of Temporal Artery Biopsy for Giant Cell Arteritis: A Systematic Review

Temporal artery biopsy (TAB) is currently the gold standard procedure to diagnose giant cell arteritis. Despite low sensitivity, TAB is routinely performed even if a clinical diagnosis has already been made. The objective of this study was to determine the usefulness of TAB for giant cell arteritis management.

Methods

We performed a systematic review to identify studies that compared steroid treatment between TAB+ and TAB- patients. EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials were searched from inception until April 4, 2020. Titles, abstracts, and full texts were reviewed by two independent reviewers and conflicts resolved by consensus. Studies reporting TAB result and steroid treatment were included. Information pertaining to steroid treatment was compared between TAB+ and TAB- groups. Steroid duration was compared by grouping patients in a less than 6 month group, a 6-24 month group, and a more than 24 month group.

Results

An estimated 5288 abstracts were screened and 13 studies involving 1355 patients were included. Rate of prebiopsy steroid treatment was higher in TAB+ patients compared with TAB- patients [93% versus 63% (P < 0.001)]. The TAB+ group was more likely to be started on steroids prebiopsy [28% versus 8% (P < 0.001)]. TAB+ and TAB- patients had similar steroid duration for all groups [<6-month group 17% versus 19% (P-0.596), the 6-24-month group 16% versus 19% (P-0.596), and the >24-month group 66% versus 63% (P-0.642)].

Conclusion

TAB results have minimal impact on treatment, and the utility should be reconsidered when a clinical diagnosis of giant cell arteritis is possible.

The Immunopathology of Giant Cell Arteritis Across Disease Spectra

Giant cell arteritis (GCA) is a granulomatous systemic vasculitis of large- and medium-sized arteries that affects the elderly. In recent years, advances in diagnostic imaging have revealed a greater degree of large vessel involvement than previously recognized, distinguishing classical cranial- from large vessel (LV)- GCA. GCA often co-occurs with the poorly understood inflammatory arthritis/bursitis condition polymyalgia rheumatica (PMR) and has overlapping features with other non-infectious granulomatous vasculitides that affect the aorta, namely Takayasu Arteritis (TAK) and the more recently described clinically isolated aortitis (CIA). Here, we review the literature focused on the immunopathology of GCA on the background of the three settings in which comparisons are informative: LV and cranial variants of GCA; PMR and GCA; the three granulomatous vasculitides (GCA, TAK, and CIA). We discuss overlapping and unique features between these conditions across clinical presentation, epidemiology, imaging, and conventional histology. We propose a model of GCA where abnormally activated circulating cells, especially monocytes and CD4+ T cells, enter arteries after an unknown stimulus and cooperate to destroy it and review the evidence for how this mechanistically occurs in active disease and improves with treatment.

Peripheral retinal arteriolar leakage in giant cell arteritis: a case report

A 76-year old African American female with a history of arteritic ischemic optic neuropathy (AION) secondary to biopsy-proven giant cell arteritis (GCA) presented with unilateral vision loss in her contralateral eye despite high-dose oral steroid treatment. Dilated fundus examination revealed three cotton wool spots. Fluorescein angiography showed slowed arteriolar filling with late staining of small peripheral arteries, consistent with small vessel arteritis. Laboratory tests for alternative vasculitides were negative. Review of her temporal artery biopsy specimen confirmed lymphoplasmacytic inflammation around small adventitial vessels with no destructive granulomatous or leukocytoclastic small vessel vasculitis, consistent with GCA. Our unique case demonstrates peripheral small vessel retinal arteriolar leakage in GCA, which is a rare finding. This association is of interest because GCA is commonly associated with medium to large vessel pathology without small vessel involvement.

Diagnosis and management of giant cell arteritis: Major review

Giant cell arteritis is a medical emergency because of the high risk of irreversible blindness and cerebrovascular accidents. While elevated inflammatory markers, temporal artery biopsy and modern imaging modalities are useful diagnostic aids, thorough history taking and clinical acumen still remain key elements in establishing a timely diagnosis. Glucocorticoids are the cornerstone of treatment but are associated with high relapse rates and side effects. Targeted biologic agents may open up new treatment approaches in the future.

Significance of inflammation restricted to adventitial/periadventitial tissue on temporal artery biopsy

OBJECTIVE

To evaluate the characteristics and significance of inflammation restricted (RI) to the adventitial and/or periadventitial tissue on temporal artery biopsy (TAB).

METHODS

We studied a retrospective cohort of 80 patients with RI, extending our earlier series of 39 patients. For comparison purposes, we collected the same data from 254 patients with transmural inflammation (TMI) and 81 TAB-negative patients. A review of the literature was also performed.

RESULTS

A final diagnosis of giant cells arteritis (GCA) and/or polymyalgia rheumatica (PMR) was observed in 86% of patients with RI. Compared to TMI, GCA diagnosis was significantly less frequently observed in patients with RI and in those TAB-negative (p < 0.0001), while cranial manifestations were significantly less frequent (p = 0.001) and ESR and CRP values at diagnosis significantly reduced (p < 0.0001). PMR, permanent visual loss, and large vessel involvement at diagnosis were equally present in the 3 subgroups. The median duration of prednisone therapy, the cumulative prednisone dosages, and the relapse and long-term remission rates were similar between patients with GCA-RI and those with TMI. The positive likelihood ratios (LRs) of pathological evidence of RI at TAB for GCA or GCA/PMR diagnoses were 0.88 (CI, 0.61-1.27) and 1.15 (CI, 0.67-1.99), while that of inflammation limited to adventitia was 1.37 (CI, 0.59-3.19) and 3.77 (CI, 0.53-26.72). In the literature review, the positive LR of RI for GCA diagnosis was 0.92 (CI, 0.68-1.25).

CONCLUSION

A large part of the patients with RI have GCA/PMR, however, the diagnostic value of RI for GCA diagnosis is not relevant.

Review: What Is the Current Evidence for Disease Subsets in Giant Cell Arteritis?

Giant cell arteritis (GCA) is an autoimmune vasculitis affecting large and medium‐sized arteries. Ample evidence indicates that GCA is a heterogeneous disease in terms of symptoms, immune pathology, and response to treatment. In the current review, we discuss the evidence for disease subsets in GCA. We describe clinical and immunologic characteristics that may impact the risk of cranial ischemic symptoms, relapse rates, and long‐term glucocorticoid requirements in patients with GCA. In addition, we discuss both proven and putative immunologic targets for therapy in patients with GCA who have an unfavorable prognosis. Finally, we provide recommendations for further research on disease subsets in GCA.

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.

Poor Predictive Value of Isolated Adventitial and Periadventitial Infiltrates in Temporal Artery Biopsies for Diagnosis of Giant Cell Arteritis

OBJECTIVE

We investigated the diagnostic value of inflammation limited to the adventitia (ILA), and isolated vasa vasorum or small-vessel vasculitis (VVV, SVV) in temporal artery biopsies (TAB) for giant cell arteritis (GCA).

METHODS

Two pathologists reviewed consecutive first TAB. Using the clinical diagnoses as the gold standard, positive predictive values (PPV) were calculated.

RESULTS

Among the 75 patients without classic TAB features of GCA, 8 had GCA diagnoses. The PPV of ILA, VVV, and SVV seen by either or both pathologists were 17%, 0%, and 7%, and 17%, 0%, and 10%, respectively.

CONCLUSION

(Peri)adventitial infiltrates in TAB poorly predict GCA.

Advances in the diagnosis of large vessel vasculitis

The diagnosis of large-vessel vasculitis has experienced substantial improvement in recent years. While Takayasu arteritis diagnosis relies on imaging, the involvement of epicranial arteries by giant-cell arteritis facilitates histopathological confirmation. When appropriately performed temporal artery biopsy has high sensitivity and specificity. However, an optimal biopsy is not always achievable and, occasionally, the superficial temporal artery may not be involved. Imaging in its various modalities including colour-duplex ultrasonography, computed tomography angiography, magnetic resonance angiography and positron emission tomography, are emerging as important procedures for the diagnosis and assessment of disease extent in large-vessel vasculitis. Recent contributions to the better performance and interpretation of temporal artery biopsies as well as advances in imaging are the focus of the present review.

Inflamed temporal artery: histologic findings in 354 biopsies, with clinical correlations

We reviewed 888 temporal artery biopsies (TAB) performed in 871 patients in a single institution from January 1986 to December 2013. Forty-four biopsies (4.9%) were inadequate, 490 (55.2%) were devoid of inflammation and were considered negative, and 354 (39.9%) showed inflammation and were considered positive. On the basis of the localization of the inflammation, positive TABs were further classified into 4 categories: small vessel vasculitis (SVV), in which inflammation was limited to small periadventitial vessels devoid of muscular coat, with sparing of the temporal artery (32 cases, 9% of the positive biopsies); vasa vasorum vasculitis (VVV), in which inflammation was limited to the adventitial vasa vasorum (23 cases, 6.5% of the positive biopsies); inflammation limited to adventitia (ILA), in which inflammation extended from a strictly perivascular localization to the surrounding adventitia, without medial involvement (25 cases, 7% of the positive biopsies); and transmural inflammation (TMI), in which inflammation crossed the external elastic lamina and extended to the media (274 cases, 77.5% of the positive biopsies). In TMI, inflammation was generally more prominent between media and adventitia and mostly consisted of T lymphocytes and macrophages, with occasionally a significant number of plasma cells. Numerous eosinophils or neutrophils (with or without leucocytoclasia and suppurative necrosis), fibrinoid necrosis (limited to small branches of the temporal artery), and acute thrombosis were unusual, being present in 8%, 1.8%, 0.7%, and 9.5% of our biopsies with TMI, respectively. Giant cells, laminar necrosis, and calcifications prevailed along the internal elastic lamina and were present in 74.8%, 25.2%, and 20% of the biopsies with TMI, respectively. Among the 322 patients with positive TAB on whom we obtained clinical information, 317 had giant cell arteritis and 5 had a different disease: 3 (with SVV at histology) had ANCA-associated vasculitis, 1 (with SVV with amyloid deposits) had primary systemic amyloidosis, and 1 (with TMI limited to a small branch) had polyarteritis nodosa. In none of these cases the biopsy showed fibrinoid necrosis or significant numbers of eosinophils or neutrophils. Considering the 317 patients with giant cell arteritis, those with SVV and VVV compared with those with TMI had a significantly lower frequency of cranial manifestation (including headache, jaw claudication, and abnormalities of temporal arteries), lower serum levels of acute-phase reactants, and a reduced frequency of prednisone therapy at the time of TAB, of the "halo sign" at color duplex sonography of temporal arteries, and of systemic symptoms (for VVV). Polymyalgia rheumatica and blindness were equally represented in all patients groups, whereas there was a higher frequency of male sex and peripheral arthritis in patients with SVV. Patients with ILA were more similar to those with TMI, having a lower frequency of headache, of abnormalities of temporal arteries, and of a positive "halo sign" at color duplex sonography of temporal arteries. In conclusion, the histologic spectrum of inflammatory lesions that can be found in TAB is broad, and the differences have clinical implications.

Small-vessel vasculitis surrounding an uninflamed temporal artery and isolated vasa vasorum vasculitis of the temporal artery: two subsets of giant cell arteritis

OBJECTIVE

To evaluate the frequency and clinical characteristics of periadventitial small-vessel vasculitis (SVV) and isolated vasa vasorum vasculitis (VVV).

METHODS

We identified 455 temporal artery biopsies performed in residents of Reggio Emilia, Italy between 1986 and 2003. Slides of temporal artery biopsy specimens were reviewed by a pathologist who was blinded with regard to clinical data. SVV was defined as inflammation of the small vessels external to the temporal artery adventitia, and VVV was defined as isolated inflammation of temporal artery vasa vasorum. Medical records of patients with SVV and/or VVV were reviewed, and demographic, clinical, laboratory, and followup data were collected. For comparison purposes, we collected the same data from an equal number of randomly selected patients with evidence of classic giant cell arteritis (GCA).

RESULTS

Sixteen patients had SVV, 18 had isolated VVV, and 5 had both SVV and VVV. Compared with patients with classic GCA, the frequencies of headache, scalp tenderness, abnormalities of temporal arteries, jaw claudication, anorexia, and weight loss, the levels of acute-phase reactant at diagnosis, and the initial and cumulative doses prednisone were significantly lower and the frequency of peripheral synovitis was higher in the patients with SVV, and the frequency of cranial ischemic events was similar in the 2 groups. In contrast, the clinical characteristics and erythrocyte sedimentation rate at diagnosis of patients with isolated VVV were similar to those of patients with classic GCA.

CONCLUSION

Our findings indicate that isolated VVV and SVV should be considered part of the histopathologic spectrum of GCA.

A concomitant case of giant cell arteritis and microscopic polyangiitis with hemoperitoneum by rupture of the gastroepiploic artery

Giant cell arteritis (GCA) mainly involves large-sized arteries, while microscopic polyangiitis (mPA), characterized by pauci-immune necrotizing vasculitis, mainly affects small-sized vessels. We report a very rare concomitant case of GCA diagnosed by temporal artery biopsy and mPA with a high titer of myeloperoxidase antineutrophil cytoplasmic antibody, exacerbation of interstitial pneumonia, and suspected rapidly progressive glomerulonephritis. The patient died by sudden rupture of the gastroepiploic artery (medium-sized vessel), which may have been triggered by GCA and/or mPA.