Overshoot of FVIII activity in patients with acquired hemophilia A who achieve complete remission

High levels of factor VIII activity in patients with acquired hemophilia A in remission are associated with unusually low coagulation potentials

BACKGROUND

Elevated factor VIII activity (FVIII:C) is often observed in patients with acquired hemophilia A (PwAHA) in remission. However, comprehensive coagulation potentials in this patient group remain to be investigated.

AIM

To evaluate comprehensive coagulation potentials in PwAHA.

METHODS

We investigated coagulation function in eleven PwAHA with high FVIII:C (> 150 IU/dL) using thrombin generation assay (TGA) and/or rotational thromboelastometry (ROTEM), and compared findings with results obtained from contrived samples generated by spiking recombinant FVIII.

RESULTS

The median FVIII:C and FVIII inhibitor titers during remission in enrolled PwAHA were 206 IU/dL and 0.44 BU/mL, respectively. In all patients, lag time and time to peak were either prolonged or normal compared to contrived samples corresponding to their FVIII:C. However, higher values of peak thrombin and endogenous thrombin potentials compared to contrived samples were observed in two patients. ROTEM parameters were within normal ranges in all cases. One patient (FVIII:C 171 IU/dL) developed venous thrombosis and pulmonary embolism, but TGA parameters showed low or normal coagulation potential compared to contrived samples corresponding to his FVIII:C.

CONCLUSION

PwAHA with high FVIII:C could exhibit lower coagulation potentials than those corresponding to their FVIII:C.

ORIHIME study: real-world treatment patterns and clinical outcomes of 338 patients with acquired hemophilia A from a Japanese administrative database

BACKGROUND

Acquired hemophilia A (AHA) is a rare disorder, and clinical practices for treating AHA have not been fully clarified in Japan.

OBJECTIVES

This study aims to investigate the epidemiology of AHA and real-world treatment practices in Japan.

PATIENTS/METHODS

This observational study was based on a health administrative database of hospitalized patients diagnosed with AHA who were treated with immunosuppressants.

RESULTS

The study included 214 males and 124 females (mean age 75.7 years). The most frequently used bypassing agent was recombinant activated factor VII. The predominant choice of immunosuppressant for first-line treatment was steroid monotherapy. Median days from the index date to the start of rehabilitation was 65.0 for cardiovascular, 35.5 for respiratory and 23.0 for locomotor. The proportion of patients with an activities of daily living (ADL) score < 70 points was high at both first admission and final discharge (47.4% and 38.8%). The percentage of deaths during hospitalization was 18.6%.

CONCLUSIONS

This study clarified the treatment patterns and clinical outcomes of AHA in a large population in Japan. This was the first study showing ADL score distribution and time to rehabilitation. Further investigation is needed to develop better clinical practices for treatment of AHA.

Plasma proteomics associated with autoimmune coagulation factor deficiencies reveals the link between inflammation and autoantibody development

Autoimmune coagulation factor deficiency (AiCFD) is characterized by sudden excessive bleeding due to autoantibodies against coagulation factors. This occurs primarily in elderly patients with no family history or previous clotting issues. However, the detailed mechanisms underlying autoantibody development are not well understood. Here, we evaluated the plasma proteome in patients with AiCFD and compared it with that of 22 healthy controls and 17 patients with non-autoimmune acquired factor XIII deficiency (acF13D). We identified eighteen proteins whose plasma levels were higher in AiCFD than in either healthy controls or patients with acF13D. Most of these proteins were found to be acute-phase reactants or immunoglobulins. Patients with acF13D had lower levels of nine of these proteins and higher levels of the remaining nine compared to healthy controls. However, in all cases, these protein levels were much higher in patients with AiCFD than in those with acF13D. These results suggest that an inflammatory response independent of the acute inflammation caused by bleeding can occur, which may lead to the development of AiCFD. Therefore, we believe that severe and/or chronic inflammation, probably due to an underlying disease or aging, is the most important factor in autoantibody development.

Predictive significance of anti-FVIII immunoglobulin patterns on bleeding phenotype and outcomes in acquired hemophilia A: Results from the Quebec Reference Center for Inhibitors

BACKGROUND

Acquired hemophilia A (AHA) is a potentially life-threatening bleeding disorder caused by factor VIII (FVIII) autoantibodies, involving various immunoglobulin (Ig) isotypes and IgG subclasses.

OBJECTIVES

We analyzed the profile of Ig against FVIII in patients with AHA to identify Ig patterns predictive of bleeding phenotype and outcomes.

PATIENTS/METHODS

Ig detection and titration were determined by enzyme-linked immunosorbent assay (ELISA) at disease presentation in a cohort of 66 subjects from the Quebec Reference Centre for Inhibitors registry.

RESULTS

Most of plasma samples analyzed (97%) contained multiple anti-FVIII Ig isotypes and IgG subclasses, IgG(1,2,3,4) (24.2%), [IgG(1,2,3,4),IgA] (16.7%) and IgG(2.4) (13.6%) being the most prevalent combinations of Ig detected. AHA patients who presented with IgA antibodies were more likely to have an associated auto-immune disease (p = .049). The presence of IgG4-was associated with bleeding symptoms at presentation (p = .002). IgG1-positive patients were more likely to require transfusions with red packed cell (p = .014) whereas IgM detection was associated with a higher probability of death linked to AHA (p = .011).

CONCLUSION

The Ig pattern of AHA patients at diagnosis is widely heterogeneous and is at least partially associated with some underlying conditions. Our data supports the differential predictive significance for IgG1, IgG4 and IgM on bleeding severity and suggests that the early determination of Ig profile may help to identify AHA patients at higher risk of poorer outcomes.