Successful treatment of relapsing autoimmune thrombotic thrombocytopenic purpura with rituximab

Positive Response and Increase in ADAMTS13 with Scheduled Rituximab in a Patient with Relapsing Thrombotic Thrombocytopenic Purpura

Thrombotic thrombocytopenic purpura (TTP) is a coagulation disorder caused by a deficiency in ADAMTS13. Patients classically present with symptoms of end-organ damage as well as anemia and thrombocytopenia. Treatment is therapeutic plasma exchange (TPE) in the acute setting, with systemic immunosuppression for refractory cases.

A 48-year-old female diagnosed with TTP at age 42 presented initially with altered mental status (AMS), severe anemia, and thrombocytopenia requiring intensive care unit (ICU) admission. The patient was treated acutely and discharged from the hospital. During subsequent years, multiple relapses requiring hospitalization prompted scheduled maintenance with rituximab. Since maintenance therapy, the patient remained relapse-free while ADAMTS13 levels escalated.

Untreated, TTP is fatal. The treatment goal in the acute setting is the repletion of ADAMTS13 coupled with immunosuppression in refractory cases. Rituximab typically is reserved for patients who do not improve with initial TPE. Albeit unusual in TTP, rituximab maintenance in our patient induced remission.

Maintenance therapy with rituximab in patients with a history of relapsing TTP can blunt or obviate the frequency of relapses and hospital admissions. More research is required to establish the effectiveness of rituximab in the chronic treatment of TTP.

Child-onset and adolescent-onset acquired thrombotic thrombocytopenic purpura with severe ADAMTS13 deficiency: a cohort study of the French national registry for thrombotic microangiopathy

BACKGROUND

Thrombotic thrombocytopenic purpura is a rare thrombotic microangiopathy, related to a severe ADAMTS13 deficiency (a disintegrin and metalloprotease with thromboSpondin type 1 repeats, member 13; activity <10% of normal). Childhood-onset thrombotic thrombocytopenic purpura is very rare and initially often misdiagnosed, especially when ADAMTS13 deficiency is acquired (ie, not linked to inherited mutations of the ADAMTS13 gene). We aimed to investigate initial presentation, management, and outcome of acquired thrombotic thrombocytopenic purpura in children.

METHODS

Between Jan 1, 2000, and Dec 31, 2015, we studied a cohort of patients with child-onset and adolescent-onset acquired thrombotic thrombocytopenic purpura included in the French national registry for thrombotic microangiopathies at presentation and during follow up. The inclusion criteria were: first episode before age 18 years; ADAMTS13 activity less than 10% of normal at presentation; positive anti-ADAMTS13 autoantibodies during an episode, or a recovery of ADAMTS13 activity in remission, or both. ADAMTS13 activity and anti-ADAMTS13 autoantibodies were investigated by a central laboratory, and medical records were extensively reviewed to collect clinical and biological features with a standardised form. This study is registered with ClinicalTrials.gov, number NCT00426686.

FINDINGS

We enrolled 973 patients with childhood-onset thrombotic microangiopathy, of whom 74 had a severe ADAMTS13 deficiency (activity <10%) at presentation. 24 patients had an inherited thrombotic thrombocytopenic purpura also known as Upshaw-Schulman syndrome and five did not have follow-up data available, thus 45 children had acquired thrombotic thrombocytopenic purpura and were included in our database at presentation. 25 (56%) patients had idiopathic disease and 20 (44%) had miscellaneous associated clinical conditions. At diagnosis, median age was 13 years (IQR 7-16, range 4 months-17 years), with a sex ratio of 2·5 girls to 1 boy. Anti-ADAMTS13 autoantibodies were positive in 37 (82%) of 45 patients (24 [96%] of 25 idiopathic cases and 13 [65%] of 20 non-idiopathic cases). 39 (87%) of 45 patients were given plasma therapy and 21 (47%) received additional rituximab. Four (9%) children died after the first thrombotic thrombocytopenic purpura episode. Long-term follow up of the 41 survivors showed that ten (24%) patients relapsed and systemic lupus erythematosus occurred in two (5%) patients. Preemptive rituximab was used in seven (17%) of 41 patients with acquired thrombotic thrombocytopenic purpura.

INTERPRETATION

Our study shows that child-onset and adolescent-onset acquired thrombotic thrombocytopenic purpura have specific clinical, biological and therapeutic features. Long-term follow-up is crucial to prevent relapses of the disease, to identify the occurrence of autoimmune disorders, and to evaluate consequences on social life. Child-onset and adolescent-onset acquired thrombotic thrombocytopenic purpura is a crucial diagnosis in the field of paediatric haematologic cytopenias because it is a life-threatening disease requiring a specific management.

FUNDING

Assistance Publique-Hôpitaux de Paris, France.

From the nephrologist's point of view: diversity of causes and clinical features of acute kidney injury

Acute kidney injury (AKI) is a clinical syndrome with multiple entities. Although AKI implies renal damage, functional impairment or both, diagnosis is solely based on the functional parameters of serum creatinine and urine output. The latest definition was provided by the Kidney Disease Improving Global Outcomes (KDIGO) working group in 2012. Independent of the underlying disease, and even in the case of full recovery, AKI is associated with an increased morbidity and mortality. Awareness of the patient's individual risk profile and the diversity of causes and clinical features of AKI is pivotal for optimization of prophylaxes, diagnosis and therapy of each form of AKI. A differentiated and individualized approach is required to improve patient mortality, morbidity, long-term kidney function and eventually the quality of life. In this review, we provide an overview of the different clinical settings in which specific forms of AKI may occur and point out possible diagnostic as well as therapeutic approaches. Secifically AKI is discussed in the context of non-kidney organ failure, organ transplantation, sepsis, malignancy and autoimmune disease.