Clinical and laboratory diagnosis of autoimmune factor V inhibitors: A single institutional experience

Sridharan, Meera; Fylling, Kara A.; Ashrani, Aneel A.; Chen, Dong; Marshall, Ariela L.; Hook, C. Christopher; Cardel, Laynalee; Nichols, William L.; Pruthi, Rajiv K.

doi:10.1016/j.thromres.2018.09.044

Cited by 8 publications

(12 citation statements)

References 26 publications

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“…Accordingly, most patients suffered comorbidities including high blood pressure, diabetes mellitus and coronary artery disease, as previously reported 39 . In our study, almost half of the AFVI patients were asymptomatic which strikingly differs from previous reports 1,3,23,28,29 . This might be explained by a reporting bias since cases were selected through two national networks, including biologists.…”

Section: Discussioncontrasting

confidence: 82%

“…Treatment of AFVI is empiric and based on corticosteroids or intravenous immunoglobulins (IVIG), and transfusion support in patients with severe bleeding 3,26 . Data regarding the management of AFVI are scarce, however, and mostly based on few case reports 1,3,23,27–29 . To our best knowledge, no study has aimed to stratify the risk of bleeding in AFVI patients.…”

Section: Introductionmentioning

confidence: 99%

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Acquired factor V inhibitor: a nation‐wide study of 38 patients

et al. 2021

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Summary Acquired factor V inhibitor (AFVI) is an extremely rare disorder that may cause severe bleeding. To identify factors associated with bleeding risk in AFVI patients, a national, multicentre, retrospective study was made including all AFVI patients followed in 21 centres in France between 1988 and 2015. All patients had an isolated factor V (FV) deficiency <50% associated with inhibitor activity. Patients with constitutional FV deficiency and other causes of acquired coagulation FV deficiencies were excluded. The primary outcome was incident bleeding and factors associated with the primary outcome were identified. Thirty‐eight (74 [36–100] years, 42·1% females) patients with AFVI were analysed. Bleeding was reported in 18 (47·4%) patients at diagnosis and in three (7·9%) during follow‐up (7 [0·2–48.7] months). At diagnosis, FV was <10% in 31 (81·6%) patients. Bleeding at diagnosis was associated with a prolonged prothrombin time that strongly correlated with the AFVI level measured in plasma {r = 0·63, 95% confidence interval (CI) [0·36–0·80], P < 0·05}. Bleeding onset during follow‐up was associated with a slow AFVI clearance (P < 0·001). The corresponding receiver operating characteristics curve showed that AFVI clearance was predictive of bleeding onset with an AFVI clearance of seven months with a sensitivity of 100% (95% CI: 29–100) and a specificity of 86% (95% CI: 57–98, P = 0·02). Kaplan–Meier analysis showed that AFVI clearance >7 months increased the risk of bleeding by 8 (95% CI: [0·67–97], P = 0·075). Prothrombin time at diagnosis and time for clearance of FV inhibitor during follow‐up are both associated with bleeding in patients with AFVI.

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Section: Discussioncontrasting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Acquired factor V inhibitor: a nation‐wide study of 38 patients

et al. 2021

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“…As FV deteriorates quickly, the inhibitor measurements would not be reliable with the incubation step. 36…”

Section: Discussionmentioning

confidence: 99%

“…This would certainly be relevant to rare cases of factor V (FV) inhibitors. As FV deteriorates quickly, the inhibitor measurements would not be reliable with the incubation step 36 …”

Section: Discussionmentioning

confidence: 99%

The rapid Bethesda assay is equivalent to the standard Bethesda assay for detection of factor IX inhibitors in patients with severe haemophilia B

et al. 2020

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Introduction: The time-dependent nature of factor VIII (FVIII) inhibitors is well described, and the standard FVIII Bethesda assay used to measure inhibitors incorporates a 2-hour incubation. Despite case reports and reviews describing the immediate-acting nature of factor IX (FIX) inhibitors, many coagulation laboratories continue to use a traditional prolonged incubation for FIX Bethesda assays. To our knowledge, a comprehensive evaluation of the FIX Bethesda assay without incubation has not been reported. Aim: The goal of this study was to evaluate the performance of a rapid FIX Bethesda (ie no incubation) compared with the standard Bethesda assay (2-hour incubation). Methods: The analysis used a Bethesda assay configured for either immediate testing or a 2-hour incubation. Samples from 14 haemophilia B patients with inhibitors and 9 non-human controls were tested. Results: The two assays yielded similar performance overall. The average per cent difference in inhibitor titre between the rapid and standard FIX Bethesda assay was −3% (range −15% to +13%; P = .175) for patient samples and −2% (range −17% to +14%; P = .376) for controls. Conclusion: The rapid Bethesda assay showed good agreement with the standard Bethesda assay for determination of inhibitor levels in patients with severe haemophilia B. The rapid assay allows for faster assessment of inhibitors in patients with severe haemophilia B and has the potential to improve the ability of the coagulation laboratory to perform testing from a logistical viewpoint. Further studies involving larger numbers of patients would be important to confirm our findings.

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“…In the presence of FV inhibitors, mixing studies with normal plasma do not normalize these prolonged clotting times, owing to persistent isolated low plasma FV activity (FV:C) level. 3 Sometimes, FV inhibitors may lead to apparent inhibition of multiple coagulation factors mimicking a lupus anticoagulant (LA)-type interference. 2,[4][5][6][7] Herein, we report three patients with FV inhibitors, each exhibiting various laboratory profile, and in whom thrombin generation was measured in order to help discriminating between FV inhibitors and LA.…”

mentioning

confidence: 99%