A Long-Term Follow-Up Study in Immune-Mediated Thrombotic Thrombocytopenic Purpura: What Are the Outcomes?

Endothelium damage triggers the multimeric protein von Willebrand factor (VWF) release and subsequent binding to platelets, which are recruited at sites of vascular injury. A complex and fragile equilibrium between circulating levels of von Willebrand factor and its metalloprotease, ADAMTS13, is responsible for the hemostatic balance. However, the presence of autoantibodies targeting ADAMTS13 results in an increase in von Willebrand factor, mainly in its ultra-large multimers. The latter lead to platelet aggregation, the formation of thrombi and microangiopathic hemolytic anemia. This pathologic condition, known as immune-mediated thrombotic thrombocytopenic purpura (iTTP), occurs with high morbidity and a high rate of relapses. In this work, the long-term follow-up of 40 patients with iTTP is reported. We assessed ADAMTS13 activity, plasmatic VWF levels and the ADAMTS13/VWF ratio, comparing iTTP relapsing patients with remitting ones. A decrease in the ADAMTS13/VWF ratio, along with a reduced ADAMTS13 activity, could serve as predictive and sensitive biomarkers of incoming relapses.

Anti-Phosphatidylserine, Anti-Prothrombin, and Anti-Annexin V Autoantibodies in Antiphospholipid Syndrome: A Real-Life Study.

The antiphospholipid antibodies (aPL) increase the risk of developing thrombotic events and may coexist with a variety of autoimmune diseases. They can be detected chronically or temporarily in patients with infectious diseases, during drug therapy, or in cases of cancer. A thrombotic event with aPL detection is known as antiphospholipid syndrome (APS) and the diagnostic criteria include the presence of lupus anticoagulant (LA), anticardiolipin (aCL) and ß2-glycoprotein-1(aß2GPI) antibodies. Other autoantigens recognized in APS are phosphatidylserine (aPS), prothrombin (aPT) and Annexin-5 (aA5). This real life study aimed to explore the connections between laboratory criteria and the prevalence of "non-criteria aPL" in APS. This study followed 300 patients with thrombosis and employed two phospholipid sensitivity assays for LA detection, chemiluminescence assays for aCL and aß2GPI and enzyme-linked immunoassays for aPS, aPT and aA5. A significant association was found between aPS and aCL (r = 0.76) as well as aß2GPI (r = 0.77), while the association with LA was less significant (r = 0.33). The results of the aPT and aA5 test did not correlate with criteria-antiphospholipid antibodies (r < 0.30). Since the risk of thrombotic complications increases with the intensity and the number of positive autoantibodies, measuring aPT and aA5 autoantibodies may be useful, particularly in aCL/aß2GPI-negative patients or in cases of isolated LA positivity.

Validation of PLASMIC score and follow-up data in a cohort of patients with suspected microangiopathies from Southern Italy.

Severe ADAMTS13 deficiency (activity < 10%) is pathognomonic of thrombotic thrombocytopenic purpura. ADAMTS13 testing is time-consuming and unavailable in many hospitals. Recently, a seven-variables score named PLASMIC score, has been developed to stratify acute patients, based on their risk of having a severe ADAMTS13 deficiency. We present the application of this score in a cohort of patients referred to our Center. From 2012 to 2017, 42 patients with suspected thrombotic microangiopathies from 6 Centers were referred to Hemostasis and Thrombosis Center of "Casa Sollievo della Sofferenza" Hospital/Research Institute for ADAMTS13 testing. For all patients, relevant medical and laboratory information were collected. To obtain the statistical measure of the discriminatory power of PLASMIC scoring system, the Area Under the Curve Receiver Operating Characteristic (AUC ROC) was calculated. We were able to calculate the PLASMIC score in 27 out of 42 patients; we found a good discrimination performance of the score with a resulting AUC value of 0.86 (95% CI 0.71-1.0; p = 0.015). All patients but one with a high risk PLASMIC score (6-7) showed a severe deficiency. Among patients belonging to the intermediate risk (PLASMIC score 5) group, 2 showed normal ADAMTS13 activity and 2 levels below 10%. In none of the patients in the low risk group (PLASMIC score 0-4), a severe ADAMTS13 deficiency was found. Present results confirm and extend previous data regarding the predictive value of the PLASMIC score. Indeed, it shows a good diagnostic performance and can be useful for decision makers to properly and promptly define the better therapeutic approach.

Clinical and laboratory characteristics of children positive for antiphospholipid antibodies.

BACKGROUND: It is difficult to estimate the actual prevalence of antiphospholipid syndrome (APS) in the paediatric population since there are no standardised criteria. We aimed to assess clinical and laboratory characteristics of a cohort of children positive for antiphospholipid antibodies (aPL) to contribute to the understanding of the heterogeneous aPL-related features in childhood. MATERIALS AND METHODS: Forty-four patients with prolonged activated partial thromboplastin time were enrolled and assigned to group I ("transiently positive") or group II ("persistently positive"), based on the detection of elevated aPL plasma levels [lupus anticoagulant (LA), anticardiolipin (aCL), and anti-ß2-glycoprotein I (anti-ß2GPI) antibodies] on, respectively, one or more occasions, at least 12 weeks apart, by standard procedures. The clinical history and symptoms of all patients were recorded. RESULTS: Thirty-three (75%) patients were assigned to group I, while the other 11 (25%) formed group II. Major associated diseases in group I were urticarial vasculitis (21%), acute infections (18%) and thalassaemia (12%). Five subjects (15%) were asymptomatic. Four out of the 11 subjects (36%) in group II had thrombotic events; they were all persistently aPL-positive and two of them had concomitant systemic lupus erythematosus. The rate of detection of LA-positivity was not significantly different between the two groups (76% vs 91%, p>0.05), whereas the percentage of patients positive for overall aCL was higher in group II than in group I (54% vs 42%, respectively; p<0.05). Specifically, aCL IgG and anti-ß2GPI IgM subtypes were significantly more represented in group II than in group I (100% vs 62% and 75% vs 33%, respectively; p<0.05). DISCUSSION: Our study shows that aPL-positive children have different features that should be taken into account in the classification of criteria for paediatric APS.

Cutaneous microcirculation is impaired in early autosomal dominant polycystic kidney disease.

BACKGROUND/AIMS: An endothelial dysfunction has been described in autosomal dominant polycystic kidney disease (ADPKD) before the development of hypertension and renal impairment. The aim of this work was to verify the existence of a microvascular reactivity in the early stages of ADPKD. METHODS: Fifteen ADPKD normotensive patients with normal renal function underwent laser Doppler examination of the cutaneous microcirculation in basal conditions and after the warm test, as well as evaluation of plasma concentrations of some endothelial activation parameters [total cholesterol and fractions, fibrinogen, von Willebrand factor, Lp(a)]. The results were compared with those in 15 healthy subjects, 15 essential hypertensive patients and 15 hypertensive ADPKD patients with normal renal function. RESULTS: Both basal and post-warm-test values were significantly lower in normotensive ADPKD subjects than controls (3.2 +/- 1 vs. 5.8 +/- 1.3 AU, p = 0.0001; 35.2 +/- 10.9 vs. 50.5 +/- 10.8 AU, p = 0.005, respectively). All evaluated parameters were within normal limits and comparable between normotensive ADPKD subjects and controls, except for LDL cholesterol (125 +/- 18 vs. 101 +/- 22 mg/dl, p = 0.01) and Lp(a), which was significantly higher in the ADPKD subjects (52.2 +/- 36 vs. 6.0 +/-4 mg/dl, p = 0.0006). CONCLUSION: Our study confirms the existence of a systemic microcirculation defect in ADPKD. The presence of high levels of Lp(a) could contribute to causing the high incidence of cardiovascular events in ADPKD.