Congenital ADAMTS-13 deficiency presenting as life-threatening thrombosis during pregnancy

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease characterised by thrombocytopenia, microangiopathic haemolytic anaemia and microvascular thrombosis. Congenital TTP accounting for less than 5% of all TTP cases can have a late presentation in adulthood mostly triggered by predisposing factors such as infection, pregnancy and inflammation. We present a case of a 23-year-old woman who presented to us in the postpartum period with mesenteric artery thrombosis with infarcts and later was diagnosed as a case of TTP based on congenital a disintegrin and metalloproteinase with thrombospondin type 1 repeats 13 (ADAMTS-13) deficiency detected on ADAMTS-13 levels and gene sequencing. She was successfully managed initially with therapeutic plasma exchanges and is now on prophylactic fortnightly fresh frozen plasma infusions at 15 mL/kg body weight and continues to be in remission.

Annual Incidence and Severity of Acute Episodes in Hereditary Thrombotic Thrombocytopenic Purpura

Hereditary thrombotic thrombocytopenic purpura (hTTP) is a rare thrombotic microangiopathy characterized by severe congenital ADAMTS13 deficiency and recurring acute episodes causing morbidity and premature death. Information on the annual incidence and severity of acute episodes in hTTP patients is largely lacking. This study reports prospective data of 87 patients from the Hereditary TTP Registry (ClinicalTrials.gov NCT01257269) for survival, frequency and severity of acute episodes from enrollment until December 2019. The 87 patients, followed for median 4.2 years (range 0.01-15), had a median age at overt disease onset and at clinical diagnosis of 4.6 years and of 18 years (range 0.0-70 for both), respectively. Forty-three patients received regular plasma prophylaxis, while 22 did not, and treatment changed over time or was unknown in the remaining 22. Forty-three patients experienced 131 acute episodes of which 91 (69%) occurred in patients on regular prophylaxis. This resulted in an annual incidence of acute episodes of 0.36 (95%CI 0.29-0.44) with and of 0.41 (95%CI 0.30-0.56) without regular plasma treatment. More than one third of acute episodes (n=51) were documented in children <10 years of age at enrollment and were often triggered by infections. Their annual incidence of acute episodes was significantly higher than in patients >40 years of age (1.18 [95% CI 0.88-1.55] vs. 0.14 [95% CI 0.08-0.23]). Prophylactic plasma infusion regimens used were insufficient to prevent acute episodes in many patients. Such regimens are burdensome, caregivers, patients and their guardians are reluctant to start regular plasma infusions, from which particularly children would benefit.

Insights from the Hereditary Thrombotic Thrombocytopenic Purpura Registry: Discussion of Key Findings Based on Individual Cases from Switzerland

The Hereditary TTP Registry is an international cohort study for patients with a confirmed or suspected diagnosis of hereditary thrombotic thrombocytopenic purpura (hTTP) and their family members. Hereditary TTP is an ultra-rare blood disorder (prevalence of ∼1–2 cases per million), the result of autosomal-recessively inherited congenital ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) deficiency (ADAMTS13 activity <10% of the normal), and associated with yet many unanswered questions. Until December 2017, the Hereditary TTP Registry had enrolled 123 confirmed hTTP patients. Their median age at disease onset was 4.5 years (range: 0–70) and at clinical diagnosis 16.7 years (range: 0–69), a difference that highlights the existing awareness gap in recognizing hTTP. The systematic collection of clinical data of individual patients revealed their substantial baseline comorbidities, as a consequence of recurring TTP episodes in the past. Most notable was the high proportion of patients having suffered from premature arterial thrombotic events, mainly transient ischemic attacks, ischemic strokes, and to a lesser extent myocardial infarctions. At 40 to 50 years of age and above, more than 50% of patients had suffered from at least one such event, and many had experienced arterial thrombotic events despite regular plasma infusions every 2 to 3 weeks that supplements the missing plasma ADAMTS13. The article by van Dorland et al. (Haematologica 2019;104(10):2107–2115) and the ongoing Hereditary TTP Registry cohort study were recognized with the Günter Landbeck Excellence Award at the 50th Hemophilia Symposium in Hamburg in November 2019, the reason to present the Hereditary TTP Registry in more detail here.

Convalescent plasma as potential therapy for severe COVID-19 pneumonia.

At the beginning of the COVID-19 pandemic, there was high mortality and a lack of effective treatment for critically ill patients. Build on the experience in argentine hemorrhagic fever with convalescent plasma, we incorporated 90 patients into a multicenter study, and 87 were evaluable. We collected 397 donations from 278 convalescent donors. Patients received plasma with an IgG concentration of 0.7-0.8 (measured by Abbott chemiluminescence) for every 10 kg of body weight. Survival during the first 28 days was the primary objective. 77% were male, age 54 (+/-15.6 y/o (range 27-85); body mass index 29.7 +/-; 4,4; hypertension 39% and diabetes 20%; 19.5% had an immunosuppression condition; 23% were healthcare workers. Plasma was administered to 55 patients (63%) on spontaneous breathing with oxygen supplementation (mainly oxygen mask with reservoir bag in 80%), and 32 patients (37%) were infused on mechanical ventilation. The 28-day survival rate was 80%, with 91% in patients infused on spontaneous breathing and 63% in those infused on mechanical ventilation (p = 0.0002). There was a significant improvement in the WHO pneumonia clinical scale at 7 and 14 days, and in PaO2 / FiO2, ferritin and LDH, in the week post-infusion. We observed an episode of circulatory volume overload and a febrile reaction, both mild. Convalescent plasma infusions are feasible, safe, and potentially effective, especially before requiring mechanical ventilation, and are an attractive clinical option for treating severe forms of COVID-19 until other effective therapies become available.

Diacylglycerol kinase epsilon nephropathy: late diagnosis and therapeutic implications

A 17-year-old male presented thrombotic microangiopathy (TMA) at 6 months of age with arterial hypertension, anemia, thrombocytopenia and kidney injury improving with plasma infusions. Fourteen years later, he was diagnosed with severe arterial hypertension, increase in serum creatinine and chronic TMA on kidney biopsy. Eculizumab was started and after 18 months of treatment, he persisted with hypertension, decline in renal function and proteinuria. Genetic analysis demonstrated mutation in diacylglycerol kinase epsilon (DGKe). Complement blockade was stopped. This case of late diagnosis of DGKe nephropathy highlights the importance of genetic testing in patients presenting TMA during the first year of life.