Diagnostic strategies for the histological examination of muscle biopsy specimens for the assessment of vasculitis in rheumatoid arthritis

Rheumatoid vasculitis in 2023: Changes and challenges since the biologics era

BACKGROUND

Significant changes in the epidemiology and natural history of rheumatoid vasculitis (RV) have occurred with the introduction of biological therapies such as TNF inhibitors (TNFi) and rituximab.

PURPOSE

This scoping review aims to address the key current challenges and propose updated criteria for RV. This will aid future descriptive observational studies and prospective therapeutic trials.

METHODOLOGY

The MEDLINE database was searched for eligible articles from inception through December 2022. Articles were selected based on language and publication date after 1998, corresponding to the approval of the first TNFi in rheumatic diseases.

RESULTS

Sixty articles were included in the review. The mean incidence of RV has decreased since the approval of biologic therapies in RA, from 9.1 (95% CI: 6.8-12.0) per million between 1988 and 2000 to 3.9 (95% CI: 2.3-6.2) between 2001 and 2010, probably due to significant improvement in RA severity and a decrease in smoking habits. Factors associated with an increased risk of RV include smoking at RA diagnosis, longer disease duration, severe RA, immunopositivity, and male gender (regardless of age). Homozygosity for the HLA-DRB104 shared epitope is linked to RV, while the presence of HLA-C3 is a significant predictor of vasculitis in patients without HLA-DRB104. Cutaneous (65-88%), neurologic (35-63%), and cardiac (33%) manifestations are common in RV, often associated with constitutional symptoms (70%). Histologic findings range from small vessel vasculitis to medium-sized necrotizing arteritis, but definite evidence of vasculitis is not required in the 1984 Scott and Bacon diagnostic criteria. Existing data on RV treatment are retrospective, and no formal published guidelines are currently available.

CONCLUSION

The understanding of RV pathogenesis has improved since its initial diagnostic criteria, with a wider range of clinical manifestations identified. However, a validated and updated criteria that incorporates these advances is currently lacking, impeding the development of descriptive observational studies and prospective therapeutic trials.

PRIMARY FUNDING SOURCE

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Vasculitic neuropathy

Vasculitis is a primary phenomenon in autoimmune diseases such as polyarteritis nodosa, Wegener's granulomatosis, Churg-Strauss syndrome, microscopic polyangiitis, and essential mixed cryoglobulinemia. As a secondary feature vasculitis may complicate, for example, connective tissue diseases, infections, malignancies, and diabetes. Vasculitic neuropathy is a consequence of destruction of the vessel wall and occlusion of the vessel lumen of small epineurial arteries. Sometimes patients present with nonsystemic vasculitic neuropathy, i.e., vasculitis limited to peripheral nerves and muscles with no evidence of further systemic involvement. Treatment with corticosteroids, sometimes in combination with other immunosuppressants, is required to control the inflammatory process and prevent further ischemic nerve damage.

Organotypic glioma spheroids for screening of experimental therapies: how many spheroids and sections are required?

Cancer spheroids are a valuable model for screening anticancer strategies. However, studies are published using various numbers of spheroids and sections per spheroid. Here, we establish the sample size requirements for valid screening strategies to treat glioma: how many spheroids per experimental group and how many sections per spheroid are required to detect one-third reduction in an endpoint measurement after treatment? From two glioblastoma patients, 32 untreated organotypic spheroids were cultured and sectioned entirely (14-100 sections per spheroid). The viable fraction was determined as endpoint by automated image analysis in sections and used to establish the minimally-detectable difference between a treatment and reference group. Variance was considerable with a coefficient of variance of 21%. The biological variation in viability in sections of spheroids produced 97% of variance when sample size was large. Variance increased when numbers of spheroids but not numbers of sections per spheroid were reduced. A minimum of 12 spheroids per group and one section per spheroid was required for a valid comparison of a treatment group and a control group. When 10 treatment groups and one control group were compared, 16 spheroids per group were required. Thus, the statistical power depended almost entirely on the number of organotypic glioma spheroids and hardly on the number of sections per spheroid. The organotypic glioma spheroid model does not appear to be suitable for high-throughput screening of anticancer strategies, because of the relatively large number of spheroids required. It is the model of choice for low-throughput screening, because this model is far more representative for the parental tumor than any other more efficient glioma model.

Systemic rheumatoid vasculitis: a review

OBJECTIVES

To review the most recent information on the incidence, clinical course, pathology, pathogenesis, diagnosis, and treatment of rheumatoid vasculitis (RV), including the still scanty data on the use of biologics.

METHODS

PubMed and MEDLINE databases (1950-2006) were searched for the key words "vasculitis" and "rheumatoid arthritis"; and "rheumatoid arthritis" and "extra-articular manifestations." All relevant articles in English and French were reviewed. Additional words used in follow-up research include "anti-TNF," "rituximab," "IL-1 receptor antagonists," and "CTLA-4 Ig," all in conjunction with "vasculitis." Pertinent secondary references were also retrieved.

RESULTS

RV is an inflammatory condition of the small- and medium-sized vessels that affects a subset of patients with established rheumatoid arthritis (RA) (approximately 1 to approximately 5%). It has a vast array of clinical manifestations with a predilection for the skin (peripheral gangrene, deep cutaneous ulcers) and the peripheral nervous system (mononeuritis multiplex). Because of the lack of specific signs and symptoms, the diagnosis relies on the exclusion of other causes of similar lesions (diabetes, atherosclerosis, drug reactions, infection, neoplasias) and, ideally, on the histopathological demonstration of necrotizing vasculitis. Despite the availability of a host of promising new drugs for the treatment of RA, no clinical trials have tested their efficacy in RV; therefore, its management remains largely empirical.

CONCLUSIONS

Although RV has apparently been decreasing over the last 2 decades, possibly as a consequence of the more energetic approach to the management of RA currently used, it remains an important complication of RA that needs to be promptly recognized and treated.