Clinical impact of subgrouping ANCA-associated vasculitis according to antibody specificity beyond the clinicopathological classification.

OBJECTIVES: In ANCA-associated vasculitis (AAV), classifications have emerged to individualize homogeneous clinical and outcomes patterns, including the recently defined anti-MPO granulomatosis with polyangiitis (GPA) subgroup. This study aimed to retrospectively evaluate the impacts of re-classification based on clinicopathological criteria and/or ANCA specificity. METHODS: A retrospective monocentric study conducted at Caen University Hospital led to the identification of PR3 or MPO-ANCA AAV patients from January 2000 or September 2011, respectively, to June 2016. Eosinophilic GPA patients were excluded. AAVs were thereby also classified either as GPA or microscopic polyangiitis (MPA) according to the European Medicines Agency vasculitis algorithm. RESULTS: A total of 150 AAV patients were included (94 GPA, 56 MPA; 87 anti-PR3 and 63 anti-MPO patients). GPA patients exhibited a worse relapse-free survival but a better renal survival (P < 0.001 and P = 0.021, respectively) than MPA patients. Overall, relapse-free and renal survival rates were similar between anti-PR3 and anti-MPO patients (P = 0.35, 0.17 and 0.15, respectively). Similarly, the prognosis was identical between anti-MPO MPA patients and anti-PR3 MPA patients (P = 0.33, 0.19 and 0.65, respectively), and between anti-MPO GPA patients and anti-PR3 GPA patients (P = 0.06, 0.99 and 0.64, respectively). Moreover, anti-PR3 GPA and anti-MPO GPA patients exhibited no differences in clinical manifestations or BVAS score. CONCLUSION: Clinicopathological classification appeared to be the strongest criterion for distinguishing among homogeneous prognoses of AAV. Individualizing the anti-MPO GPA subgroup does not appear to bring additional value to clinical practice, but multicentre studies are required to confirm this trend.

Chronic intestinal pseudo-obstruction with dilated biliary tract as a spectrum of stiff person syndrome in a nondiabetic patient.

Stiff person syndrome (SPS) is a rare and challenging neuromuscular junction disorder with typical musculoskeletal manifestations associated with anti-GAD65 antibodies, extra rheumatological manifestations, including neuropsychiatric symptoms and severe dysautonomic troubles. Chronic intestinal pseudo-obstruction (CIPO) is also a rare condition corresponding to a sub-occlusive syndrome, resulting from the functional or structural impairment of smooth neuromuscular tissues of the intestinal tract. In the clinical spectrum of SPS, CIPO has rarely been described and dilated biliary tract has never been described. This present report is therefore the first in the context of anti-GAD65 antibodies with the additional involvement of the biliary tract. Here, we report the case of a 44-year-old woman hospitalized for a rapidly progressive CIPO associated with dilated biliary tract, revealing a typical SPS with slowly progressive rheumatologic complaints relegated to the background. The concomitant improvement of the neuromuscular function on skeletal, intestinal and biliary tree systems with the good outcomes of anti-GAD65 titer under immunosuppressant drugs, allowed us to link all three organic involvements to the antibody pathogenicity on the respective neuromuscular junctions. Therefore, we discussed their common pathogeny based on our patient's treatment outcome.