Imatinib mesylate inhibits in vitro and ex vivo biological responses related to vascular occlusion in giant cell arteritis

Increased IL-17A expression in temporal artery lesions is a predictor of sustained response to glucocorticoid treatment in patients with giant-cell arteritis

BACKGROUND

Interleukin 17A (IL-17A) exerts pivotal proinflammatory functions in chronic inflammatory and autoimmune diseases.

OBJECTIVE

To investigate IL-17A expression in temporal artery lesions from patients with giant-cell arteritis (GCA), and its relationship with disease outcome.

METHODS

Fifty-seven patients with biopsy-proven GCA were prospectively evaluated, treated and followed for 4.5 years (52-464 weeks). Relapses, time (weeks) required to achieve a maintenance prednisone dose <10 mg/day, and time (weeks) to complete prednisone withdrawal were prospectively recorded. IL-17A mRNA was measured by real-time quantitative RT-PCR in temporal arteries from all patients and 19 controls. IL-17 protein expression was assessed by immunohistochemistry/immunofluorescence.

RESULTS

IL-17A expression was significantly increased in temporal artery samples from GCA patients compared with controls (6.22±8.61 vs 2.50±3.9 relative units, p=0.016). Surprisingly, patients with strong IL-17A expression tended to experience less relapses, and required significantly shorter treatment periods (median 25 vs 44 weeks to achieve <10 mg prednisone/day, p=0.0079). There was no correlation between IL-17A and RORc or RORα expression suggesting that these transcription factors may not exclusively reflect Th17 differentiation, and that cells other than Th17 cells might contribute to IL-17 expression in active patients. Accordingly, FoxP3(+)IL-17A(+) cells were identified in lesions by confocal microscopy and were dramatically reduced in specimens from treated patients.

CONCLUSIONS

IL-17A expression is increased in GCA lesions, and is a predictor of response to glucocorticoid treatment. The contribution of FoxP3+ cells to IL-17A production in untreated patients suggests that induced-Tregs may facilitate disease remission when proinflammatory cytokine production is downregulated by glucocorticosteroids.

Clinical features of polymyalgia rheumatica and giant cell arteritis

Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are inflammatory diseases that typically affect white individuals >50 years. Women are affected ∼2-3 times more often than men. PMR and GCA occur together more frequently than expected by chance. The main symptoms of PMR are pain and stiffness in the shoulders, and often in the neck and pelvic girdle. Imaging studies reveal inflammation of joints and bursae of the affected areas. GCA is a large-vessel and medium-vessel arteritis predominantly involving the branches of the aortic arch. The typical clinical manifestations of GCA are new headache, jaw claudication and visual loss. PMR and GCA usually remit within 6 months to 2 years from disease onset. Some patients, however, have a relapsing course and might require long-standing treatment. Diagnosis of PMR and GCA is based on clinical features and elevated levels of inflammatory markers. Temporal artery biopsy remains the gold standard to support the diagnosis of GCA; imaging studies are useful to delineate large-vessel involvement in GCA. Glucocorticoids remain the cornerstone of treatment of both PMR and GCA, but patients with GCA require higher doses. Synthetic immunosuppressive drugs also have a role in disease management, whereas the role of biologic agents is currently unclear.

Association of NOS2 and potential effect of VEGF, IL6, CCL2 and IL1RN polymorphisms and haplotypes on susceptibility to GCA--a simultaneous study of 130 potentially functional SNPs in 14 candidate genes

OBJECTIVE

Frequent genetic variants may be associated with GCA. Existing studies have analysed a limited number of candidate genes and genetic variants. To expand this information, we performed a case-control study genotyping 130 single nucleotide polymorphisms (SNPs) in 82 biopsy-proven GCA patients and 166 healthy controls from the Spanish population.

METHODS

SNPs in coding and regulatory gene regions of 14 candidate genes (CCL2, CCR7, IL10, IL12A, IL1A, IL1B, IL1RN, IL6, IL8, INFG, LTA, NOS2, TNF and VEGF) were explored using the Illumina Bead Array System. Multivariate methods based on logistic regression were used for statistical analysis.

RESULTS

Nine SNPs located in five genes had significant association with GCA risk (P < 0.05). These SNPs were located in the NOS2 (rs2779251), VEGF (rs1885657, rs2010963, rs699946 and rs699947), IL1RN (rs17207494), IL6 (rs7805828 and rs1546766) and CCL2 (rs1860190) genes. The strongest associations were seen for rs2779251, rs1885657 and rs2010963 (P = 2.3 × 10(-5), P = 0.0078 and P = 0.0097, respectively). The presence of the minor allele of NOS2 variant rs2779251 had a protective effect on the risk for GCA [odds ratio (OR) = 0.27, 95% CI 0.14, 0.52]. Risk alleles for three of the four SNPs in the VEGF gene (rs2010963, rs699946 and rs699947) were associated in homozygosis with increased risk (OR = 4.22, 95% CI 1.38, 12.87; OR = 9.04, 95% CI 1.58, 51.81; and OR = 2.38, 95% CI 1.05, 5.38, respectively), whereas a minor allele for the other SNP (rs1885657) had a protective effect (OR = 0.46, 95% CI 0.26, 0.84).

CONCLUSION

Common genetic variants in NOS2, VEGF, IL6, ILRN1 and CCL2 genes are associated with GCA, indicating a polygenic influence on disease susceptibility.

Clinical relevance of persistently elevated circulating cytokines (tumor necrosis factor alpha and interleukin-6) in the long-term followup of patients with giant cell arteritis

OBJECTIVE

To assess the clinical relevance of increased circulating cytokines in patients with giant cell arteritis (GCA) after long-term followup.

METHODS

We performed a cross-sectional evaluation of 54 patients with biopsy-proven GCA prospectively followed for a median of 5.4 years (range 4-10.5 years). GCA-related complications, vascular events, relapses, current prednisone dose, time required to achieve a maintenance prednisone dosage <10 mg/day, cumulated prednisone at that point, and adverse effects during followup were recorded. Serum interleukin-6 (IL-6) and tumor necrosis factor alpha (TNFalpha) were determined by immunoassay.

RESULTS

All patients were in clinical remission. Both cytokines were significantly higher in patients than in controls (mean +/- SD 21 +/- 35 versus 5 +/- 11 pg/ml; P < 0.001 for IL-6 and mean +/- SD 32 +/- 14 versus 16 +/- 9 pg/ml; P < 0.001 for TNFalpha). No differences were found in patients with or without GCA-related complications or vascular events during followup. Circulating cytokines were significantly higher in patients who had experienced relapses (mean +/- SD 25 +/- 39 versus 10 +/- 11 pg/ml; P = 0.04 for IL-6 and mean +/- SD 34 +/- 15 versus 25 +/- 11 pg/ml; P = 0.042 for TNFalpha). IL-6 was significantly higher in patients still requiring prednisone (mean +/- SD 29 +/- 45 versus 13 +/- 17 pg/ml; P = 0.008), and TNFalpha correlated with cumulated prednisone dose (r = 0.292, P = 0.04). No significant relationship was found between elevated cytokines and prednisone adverse effects or patients' quality of life.

CONCLUSION

Circulating TNFalpha and IL-6 may persist elevated in GCA patients after long-term followup and remain higher in patients who have experienced more relapsing disease. However, in this patient cohort, elevated circulating cytokines were not associated with increased frequency of GCA complications, vascular events, or treatment-related side effects.

An approach to the diagnosis and management of systemic vasculitis

The systemic vasculitides are a complex and often serious group of disorders which, while uncommon, require careful management in order to ensure optimal outcome. In most cases there is no known cause. Multi-system disease is likely to be fatal without judicious use of immunosuppression. A prompt diagnosis is necessary to preserve organ function. Comprehensive and repeated disease assessment is a necessary basis for planning therapy and modification of treatment protocols according to response. Therapies typically include glucocorticoids and, especially for small and medium vessel vasculitis, an effective immunosuppressive agent. Cyclophosphamide is currently the standard therapy for small vessel multi-system vasculitis, but other agents are now being evaluated in large randomized trials. Comorbidity is common in patients with vasculitis, including the cumulative effects of potentially toxic therapy. Long-term evaluation of patients is important in order to detect and manage relapses.

The spectrum of vascular involvement in giant-cell arteritis: clinical consequences of detrimental vascular remodelling at different sites

Although repeatedly reported in the literature, the extracranial involvement by giant-cell arteritis has been considered anecdotal until recent years. The emergence of new or improved imaging techniques along with a closer follow-up of these patients and their increase in life expectancy are beginning to underline that the clinical impact of extracranial involvement by GCA may be more relevant than previously thought. This review focuses on the extent of vascular involvement in GCA as reported by pathology and imaging studies as well as the clinical consequences of imperfect vascular remodelling in various vascular territories.