PB0306 - Clinical characteristics and management of acquired thrombotic thrombocytopenic purpura: data from a single-centre experience.

Sunday, June 23, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Co-Author(s)

Sara Pezzato

specialist in internal medicine
Department of Medicine, University of Verona, Italy
Verona, Veneto, Italy
EM

Elena Malloggi

resident in internal medicine
Department of Medicine, University of Verona, Italy
Verona, Veneto, Italy
SM

Sara Moruzzi

Doctor
Department of Medicine, University of Verona, Italy
Verona, Veneto, Italy
Fp

Francesca pizzolo

Professor
Department of Medicine, University of Verona, Italy
Verona, Veneto, Italy
GP

Giovanni Poli

Doctor
Section of Clinical Biochemistry, University of Verona, Italy
Verona, Veneto, Italy
GB

Giulio Bonisoli

resident in internal medicine
Department of Medicine, University of Verona, Italy
Verona, Veneto, Italy
Nicola Osti

attending physician
University of Verona
Mezzocorona, Trentino-Alto Adige, Italy
SS

Silvia Suardi

Doctor
Department of Medicine, University of Verona, Italy
verona, Veneto, Italy
LD

Lorenzo Delfino

Doctor
Department of Medicine, University of Verona, Italy
Verona, Veneto, Italy
GL

Giuseppe Lippi

Professor
Section of Clinical Biochemistry, University of Verona, Italy
Verona, Veneto, Italy
SF

Simonetta Friso

Director
University of Verona
Verona, Veneto, Italy

Presenting Author(s)

Nicola Martinelli, MD, PhD

Associate Professor of Internal Medicine
University of Verona
Verona, Veneto, Italy

Background: Acquired thrombotic thrombocytopenic purpura (aTTP) is a rare disease mediated by autoantibodies blocking ADAMTS13, the von Willebrand Factor (vWF)-cleaving protease.

Aims: To evaluate the clinical-laboratory characteristics of aTTP patients at time of first diagnosis, relapse, and remission.

Methods: In this retrospective study, we analyzed medical records of patients with aTTP diagnosis, defined by low ADAMTS13 activity ( <10%) and detection of anti-ADAMTS13 autoantibodies, who were hospitalized in our Institute from January 2010 to December 2022.

Results: Eleven subjects with aTTP were identified (6/5-females/males, median age at onset 54 years). Three subjects had clinical relapses for a total of 17 aTTP acute events (9 first events and 8 relapses). Organ damage was characterized by neurological, cardiac, and mucocutaneous involvement, which was more common at first diagnosis than at relapse (7/9vs4/8, 5/9vs2/8, 5/9vs2/8, respectively). No first event but 3 relapses had only laboratory findings of thrombocytopenia and microangiopathic haemolytic anaemia. In all the 17 events PLASMIC score was ≥5. Beyond plasma exchange and immunosuppression, 6 events were treated with caplacizumab, the anti-vWF nanobody, which was associated with a reduced number of plasma-exchanges to achieve clinical response (median 7vs16) and a shorter hospital stay (median 23vs29 days). No death was observed. Three subjects had biochemical relapses, i.e. reduction of ADAMTS13 activity without thrombotic microangiopathy, and were treated successfully with rituximab (n=2) or corticosteroids (n=1). During the intercritical periods of remission, subjects with relapses had lower levels
and higher variance of ADAMTS13 activity than those without relapses (49±30%vs78±18%, P<0.001).

Conclusion(s): The data of this small study support the use of PLASMIC score as diagnostic tool and caplacizumab as therapeutic agent in aTTP, as well as the role of ADAMTS13 activity monitoring during remission and the use of rituximab in biochemical relapses. The development of large multicentric registers with adequate statistical power is eagerly needed.