VASCULITIS SYNDROMES: Edited by Curry L. Loening
Substantial discussion has been generated regarding recent advances in the understanding of the pathogenesis of vasculitis. Although some discoveries have caused debate among the scientific community, all have had a role in advancing basic understanding of these diseases. Biologic therapies targeting specific cytokines or cell types have shown success in treating some types of vasculitis. Many of these agents have proven to be as effective as and safer than more established immune modulatory drugs. Despite promising results, the ‘cure’ for vasculitis remains elusive suggesting that our basic understanding of these diseases is inadequate. Fundamental questions remain unanswered. First and foremost, what causes vasculitis? The identity of various infectious agents (cryoglobulinemia and hepatitis C or polyarteritis nodosa and hepatitis B) and the association of certain medications with vasculitis have partially addressed this question. But for diseases such as giant cell arteritis, Takayasu arteritis, granulomatosis with polyangiitis (Wegener's) and others, no cause has been identified. Additional questions remain unanswered. For example, why do some vasculitides have tropism for specific arterial beds? Why does giant cell arteritis affect elderly patients and Takayasu arteritis affect young patients? What determinants must be inherited or acquired to develop vasculitis and why do some patients respond well to certain drugs while others do not? These and other questions highlight our knowledge gaps and significant advancements in the treatment of these diseases may not be possible until these are answered.
In the following reviews, experts address evolving concepts in the field of vasculitis. Stone and colleagues discuss new, potential therapeutic targets in patients with large vessel vasculitis. Biologic agents that inhibit interleukin-6 have shown encouraging results in patients with giant cell arteritis and Takayasu arteritis but despite their clinical efficacy, arterial inflammation may not be suppressed in all patients. Rituximab, a biologic agent that targets CD20 on the plasma membrane of B cells, has benefited some patients with Takayasu arteritis or IgG4-related aortitis. These studies lend further support to the role of B cells in the pathogenesis of these diseases.
Cacoub and colleagues review newly proposed classification criteria for cryoglobulinemic vasculitis and discuss clinical and laboratory features common in patients afflicted with this disorder. The authors also discuss the role of inflammatory cells in cryoglobulinemic vasculitis and for which patients rituximab has shown efficacy.
The review by Springer and colleagues discusses the prevalence of thrombosis in patients with vasculitis. Thrombosis is a widely recognized problem, particularly for patients with granulomatosis with polyangiitis or Behcet's disease. The authors discuss risk factors for the development of thrombosis and the role of anticoagulation and immunosuppressive therapy for the treatment of thromboembolism. Lastly, Kain and colleagues discuss the pathogenic role of autoantibodies to human lysosome-associated membrane protein 2 (hLAMP-2) in patients with vasculitis commonly associated with ANCA. The authors compare different laboratory assays used to detect these autoantibodies. They also review recently published studies that report contrasting results regarding the prevalence of autoantibodies to hLAMP-2 in vasculitis patients. These chapters should enhance the readers’ understanding in the pathogenesis, diagnosis and treatment of these vexing disorders.
Conflicts of interest
I declare no conflicts of interest.