New method to differentiate between lupus anticoagulants, progressive coagulation inhibitors and coagulation factor deficiencies in the mixing tests.

INTRODUCTION: Mixing tests in activated partial thromboplastin time (APTT) are used for the differentiation between lupus anticoagulants (LA), coagulation inhibitors, and factor deficient samples with APTT prolongation. However, the indexes for the differentiation have not been established. The present study aimed to develop new mixing test indexes for the differentiation. METHODS: Twenty-six LA-positive, 8 progressive coagulation factor VIII inhibitor, and 35 coagulation deficient samples were employed. APTT were measured for normal plasma, patient plasma, and mixing plasma prepared at a ratio of 1:1 proportion in both without incubation and 2 h-incubation. New two parameters named as ALD50 and mixture plasma-patient plasma after Warming change rate Subtraction (WaS) calculated from the clotting times of normal, 1:1 mixing and patient samples with/without 2 h-incubation were established. In the samples with WaS result of <10.2%, ALD50 of ≥87.8%, and < 87.8% were defined as LA and coagulation factor deficiency, respectively, and WaS of ≥10.2% defined progressive coagulation factor inhibitors. RESULTS: Sensitivity and specificity to LA were 80.8% and 93.0% for ALD50, and sensitivity and specificity to progressive coagulation factor inhibitor were 100.0% and 100.0% for WaS, respectively. The agreement between sample classification and WaS-ALD50 was 88.4% (61/69). CONCLUSIONS: ALD50 and WaS showed acceptable sensitivity and specificity to LA and progressive coagulation factor inhibitor, respectively. These indexes would be useful for the differentiation between LA, factor deficiency, and progressive coagulation factor inhibitor in the mixing tests.

[Autoimmune coagulation factor V/5 deficiency during chronic disseminated intravascular coagulation].

Aortic regurgitation, a thoracoabdominal aortic aneurysm, chronic myeloid leukemia, and chronic kidney disease were all being treated at two hospitals for an 83-year-old man. He was admitted to the Department of Orthopedics at our hospital with a lumbar compression fracture. Later, he experienced melena, for which the Department of Internal Medicine was consulted. Due to the aberrant results of PT-INR (7.1) and a PTT > 200 seconds on a coagulation test, we suspected the presence of an autoimmune coagulation factor deficiency, and prednisolone immunosuppressive therapy medication was started right away. Due to a sharp decline in FV/5 activity, the presence of FV/5 inhibitors, and the presence of anti-FV/5 autoantibodies, a final diagnosis of autoimmune coagulation factor V (FV/5) deficiency was made. After the start of immunosuppressive therapy, the FV/5 inhibitor and anti-FV/5 autoantibodies disappeared, and the FV/5 activity progressively returned to normal. Disseminated intravascular coagulation-which may have been caused by a known aortic aneurysm-worsened while tapering off prednisolone. Due to the patient's advanced age and other problems, the aneurysm was extensive and inappropriate for surgical repair. The coagulation test findings improved gradually upon initiation of warfarin therapy. Herein, the patient had autoimmune FV/5 deficiency, a rare disorder that made diagnosis and therapy difficult because of the patient's several coexisting conditions.

SHR2285, the first selectively oral FXIa inhibitor in China: Safety, tolerability, pharmacokinetics and pharmacodynamics combined with aspirin, clopidogrel or ticagrelor.

Purpose: To evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of SHR2285, the first oral coagulation factor XIa (FXIa) inhibitor developed in China in combination with aspirin, clopidogrel or ticagrelor in healthy subjects. Methods: This study was a single-center, randomized, double-blind, placebo-controlled (only SHR2285) design (NCT04945616). A total of 52 healthy subjects, 29 male and 23 female, were completed in this study. The subjects were divided into three groups: A, B and C, 16 subjects in group A [aspirin + clopidogrel + placebo or SHR2285 200 mg bid (1:3, 4 received placebo and 12 received SHR2285)] 16 subjects in group B [aspirin + clopidogrel + placebo or SHR2285 300 mg bid (1:3, 3 received placebo and 13 received SHR2285)] and 20 subjects in group C (aspirin + ticagrelor + placebo or SHR2285 300 mg bid (2:3, 8 received placebo and 12 received SHR2285)), respectively. All groups were administered orally for six consecutive days. Safety, tolerability, pharmacokinetics and pharmacodynamics parameters were assessed. Results: 1) SHR2285 was well tolerated, and all adverse events were mild. There was no evidence of an increased risk of bleeding. 2) After 6 days of twice-daily administration, SHR2285 could reach a steady state. The mean half-life of SHR2285 in group A, group B and group C was 13.9 h, 14.5 h and 13.8 h, respectively. 3) SHR2285 markedly inhibited FXI activity and prolonged activated partial thromboplastin time (APTT). In group A, group B and group C, the mean maximum inhibition rate of FXI activity was 84.8%, 89.3% and 92.2% and the mean maximum prolongation of APTT was 2.08-fold, 2.36-fold and 2.26-fold, respectively. Conclusion: These data suggest that SHR2285, a potential oral FXIa inhibitor, is expected to become a novel, safe and effective anticoagulant when combined with aspirin, clopidogrel or ticagrelor.

Coagulation factor inhibitors in COVID-19: From SARS-CoV-2 vaccination to infection.

Background: Recent reports have highlighted patients with COVID-19 and vaccine recipients diagnosed with coagulation factor inhibitors. This is challenging. as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been identified as a prothrombotic risk factor, with heparin treatment decreasing mortality. However, both infection and vaccination have been associated with immune-mediated hematologic abnormalities, including thrombocytopenia, further rendering these groups at risk for both hemorrhagic and thrombotic events. Objectives: We sought to characterize the incidence and clinical findings of coagulation factor inhibitors in patients with COVID-19 and vaccine recipients. Methods: We queried the US Centers for Disease Control and Prevention's Vaccine Adverse Event Reporting System (VAERS), a publicly accessible database, for reports of potential bleeding episodes or coagulation disturbances associated with SARS-CoV-2 vaccination. We performed an additional comprehensive literature review to identify reports of SARS-CoV-2 infection or vaccination-associated coagulation factor inhibitors. Results: VAERS data showed 58 cases of coagulation factor inhibitors, suggesting a rate of 1.2 cases per 10 million doses. A total of 775 articles were screened and 15 were suitable for inclusion, with six reports of inhibitors after vaccination and nine reports of inhibitors after infection. Inhibitor specificity for factor VIII was most common. Among reported cases, two patients expired due to hemorrhage, one following infection and one following vaccination. Conclusion: The incidence of coagulation factor inhibitors in patients with SARS-CoV-2 vaccination and infection appears similar to the general population. Nonetheless, given the importance of heparin therapy in treating hospital patients, recognition of inhibitors is important.

Retrospective examination of coagulation parameters in 33 patients with autoimmune coagulation factor deficiencies in Japan: A single-center analysis.

BACKGROUND: The early diagnosis and prompt treatment of autoimmune coagulation factor deficiencies (AiCFDs) are challenging for physicians when patients present with pseudo-deficiencies or pseudo-inhibitors of multiple coagulation factors. A reason for this is the diagnostic confusion caused by the apparent reduction in coagulation factor activity when using common one-stage coagulation factor measurement assays. METHODS: After confirming the presence of autoantibodies against each coagulation factor, we retrospectively examined the activity of factors X, VIII, and IX (FX, FVIII, and FIX, respectively) and each coagulation factor inhibitor using their chromogenic substrates among 33 patients with AiCFD. RESULTS: Because the apparent coagulation factor deficiency was completely or partially restored in the chromogenic assay, 4, 9, and 22 patients with AiCFD were suspected of having pseudo-FX, pseudo-FVIII, and pseudo-FIX deficiencies, respectively. Moreover, in the chromogenic assay, the specific activities of FX, FVIII, and FIX (determined by their antigen levels) were higher than those in the one-stage assay. The titers for FV inhibitors showed negative correlations with the ratios of FX, FVIII, and FIX activities measured via the one-stage assay and the chromogenic assay. An especially high titer of one coagulation factor inhibitor tends to either cause pseudo-deficiencies or get mistaken for being a pseudo-inhibitor of other coagulation factors. CONCLUSION: Chromogenic assays appear to be superior to conventional one-stage assays when measuring coagulation factor activity in AiCFD cases. Detection of anti-coagulation factor autoantibodies is recommended to avoid overlooking the presence of non-neutralizing autoantibodies.

Pathological coagulation parameters in as many as 54 patients with autoimmune acquired factor XIII deficiency due to anti-factor XIII autoantibodies.

INTRODUCTION: Autoimmune factor XIII (FXIII) deficiency (AiF13D) due to anti-FXIII autoantibodies is an extremely rare, life-threatening bleeding disorder that mostly occurs in the elderly. The number of patients diagnosed with AiF13D has been increasing in Japan, probably because of the nationwide survey on AiF13D supported by the Japanese Ministry of Health, Labour and Welfare. AIM: To explore the pathologic characteristics of coagulation parameters in AiF13D. METHODS: AiF13D-suspected cases were consulted, and underwent unified/integrated coagulation screening and were definitively diagnosed as AiF13D separately. RESULTS: AiF13D patients had lower FXIII antigen levels than non-AiF13D patients, but their values overlapped. Among a series of 22-item screening tests and their resulting parameters, the 'FXIII inhibitory potential' yielded by a 1:1 mixing test of the patient's and healthy control's plasma and its 'residual FXIII activity' in 54 AiF13D cases were most distinguishable from 139 non-AiF13D cases, followed by FXIII activity per se and FXIII-specific activity. While the cross-linked α2 -plasmin inhibitor level reduced, the levels of D-dimer, fibrin/fibrinogen degradation products and plasmin-plasmin inhibitor complex increased, probably because the patients' haematoma nonspecifically induced secondary fibrinolysis in both AiF13D and non-AiF13D patients. CONCLUSION: AiF13D appears to induce a hypocoagulopathy combined with a hyper-fibrinolytic state secondary to severe FXIII deficiency caused by anti-FXIII autoantibodies, and the consequent bleeding further modifies its pathological conditions. In addition, the 1:1 mixing test of FXIII activity was confirmed to be a reliable screening method for AiF13D, especially when its derivative parameter, such as the 'FXIII inhibitory potential' or 'FXIII inhibitory potential ratio', is employed.

[Acquired blood coagulation factor â ¤ deficiency in a patient with severe burn].

In March 2017, a severely burned male patient aged 36 years with hypovolemic shock was admitted to our hospital. The patient received large quantities of antibiotics and blood products and repeated skin graft after admission, and then he suffered wound errhysis and throat congestion. The patient was healthy before without family history of bleeding or thrombosis disease. Laboratory tests showed that prothrombin time and activated partial coagulation time were remarkably prolonged, blood coagulation factor Ⅴ activity was extremely low, and the result of qualitative test of coagulation factor inhibitor was positive. Acquired blood coagulation factor Ⅴ deficiency was diagnosed. After application of dexamethasone (5 mg, twice per day) and infusion of fresh frozen plasma, blood coagulation indicators of patients recovered in 4 days, the result of qualitative test of coagulation factor inhibitor was negative, and bleeding symptoms were improved.

Acquired blood coagulation factor Ⅴ deficiency in a patient with severe burn / 中华烧伤杂志

In March 2017, a severely burned male patient aged 36 years with hypovolemic shock was admitted to our hospital. The patient received large quantities of antibiotics and blood products and repeated skin graft after admission, and then he suffered wound errhysis and throat congestion. The patient was healthy before without family history of bleeding or thrombosis disease. Laboratory tests showed that prothrombin time and activated partial coagulation time were remarkably prolonged, blood coagulation factor Ⅴ activity was extremely low, and the result of qualitative test of coagulation factor inhibitor was positive. Acquired blood coagulation factor Ⅴ deficiency was diagnosed. After application of dexamethasone (5 mg, twice per day) and infusion of fresh frozen plasma, blood coagulation indicators of patients recovered in 4 days, the result of qualitative test of coagulation factor inhibitor was negative, and bleeding symptoms were improved.

Routine measurements of factor VIII activity and inhibitor titer in the presence of emicizumab utilizing anti-idiotype monoclonal antibodies.

Essentials Emicizumab (Emi) affects the APTT-based assays of factor (F)VIII activity and inhibitor titer. A mixture of two anti-Emi monoclonal antibodies (mAb) effectively neutralized the Emi activity. Anti-Emi mAbs completely eliminated the influence of Emi on FVIII activity and inhibitor titer. The inclusion of anti-Emi mAbs in routine FVIII assays would be useful for Emi-treated patients. SUMMARY: Background Emicizumab is an anti-factor (F)IXa/X bispecific monoclonal antibody (mAb), mimicking the factor (F)VIIIa cofactor activity. Emicizumab does not require activation by thrombin and its shortening effect on the activated partial prothrombin time (APTT) is more pronounced than that of factor (F)VIII. APTT-based FVIII activity (FVIII:C) and FVIII inhibiter titer measurements are influenced by the presence of emicizumab. Aim To establish a reliable APTT-based assay to measure FVIII in the presence of emicizumab. Methods Plasmas from hemophilia A (HA) patients without or with inhibitors were studied using one-stage FVIII:C and Bethesda inhibitor assays. Two recombinant anti-idiotype mAbs to emicizumab (anti-emicizumab mAbs) were prepared, rcAQ8 to anti-FIXa-Fab and rcAJ540 to anti-FX-Fab. Results The combined anti-idiotype mAbs (2000 nm each) eliminated the effects of emicizumab on APTTs of HA plasmas without or with inhibitor by competitive inhibition of antibody binding to FIX(a)/FX(a). Measurements of FVIII coagulation activity in HA plasmas without inhibitor were overestimated in the presence of emicizumab (1 µm = ~150 µg mL-1 ) at all reference levels of FVIII. The addition of anti-emicizumab mAbs to the assay mixtures completely neutralized the emicizumab and facilitated accurate determination of FVIII:C. Anti-FVIII inhibitor titers were undetectable in the presence of emicizumab in HA plasmas with inhibitor or normal plasmas mixed with anti-FVIII neutralizing antibodies. These effects of emicizumab were completely counteracted by the addition of the anti-idiotype mAbs, allowing accurate assessment of inhibitor titers. Conclusion The in vitro inclusion of anti-emicizumab mAbs in the standard one-stage coagulation assays prevented interference by emicizumab and enabled accurate measurements of FVIII:C and inhibitor titers.