Recently, we showed that during the acute phase of immune-mediated thrombotic thrombocytopenic purpura (iTTP), ADAMTS13 circulates in an open conformation. Although the cause of this conformational change in acute iTTP remains elusive, ADAMTS13 is mainly closed in iTTP patients (i) in remission with an ADAMTS13 activity >50% and undetectable anti-ADAMTS13 autoantibodies, and (ii) after rituximab treatment, suggesting a role for anti-ADAMTS13 autoantibodies. Therefore, IgGs from 18 acute iTTP patients were purified and added to closed ADAMTS13 in healthy donor plasma. This resulted in open ADAMTS13 in 14/18 (78%) samples, proving that indeed anti-ADAMTS13 autoantibodies can induce an open ADAMTS13 conformation. To further elucidate the conformation of ADAMTS13 in iTTP patients, we studied a novel iTTP patient cohort (n=197) that also included plasma samples of iTTP patients in remission where ADAMTS13 activity was <50%. The open ADAMTS13 conformation was not only found during acute iTTP but also in patients in remission with an ADAMTS13 activity <50% and in half of the patients with an ADAMTS13 activity >50%, although free anti-ADAMTS13 autoantibodies were not always detected. Thus open ADAMTS13 is not only a hallmark of acute iTTP, but also a novel biomarker to detect subclinical iTTP in patients in remission. Finally, a long term follow-up study in one iTTP patient showed that the open conformation precedes a severe drop in ADAMTS13 activity. In conclusion, we have shown that anti-ADAMTS13 autoantibodies from iTTP patients induce an open ADAMTS13 conformation. Most importantly, an open ADAMTS13 conformation is a biomarker for subclinical iTTP and could become an important tool in TTP management.

In patients who exhibit signs of inflammation or infection with increased C-reactive protein values during psychopharmacological treatment, especially under clozapine and risperidone, therapeutic drug monitoring is recommendable in order to minimize the risk of intoxications due to elevated drug concentrations.

BACKGROUND Thrombotic thrombocytopenic purpura (TTP) is an acute life‐threatening microangiopathy with a tendency of relapse characterized by consumptive thrombocytopenia, microangiopathic hemolytic anemia, and spontaneous von Willebrand factor–induced platelet clumping leading to microthrombi. The brain is frequently affected by microthrombi leading to neurologic abnormalities of varying severity. STUDY DESIGN AND METHODS The aim of this observational cohort study was to investigate the prevalence of depression and cognitive deficits in 104 patients having survived acute TTP. TTP survivors were repeatedly assessed by means of different standardized questionnaires to evaluate depression (IDS‐SR) and mental performance (FLei). We received answers of 104 individual TTP patients and 55 of them participated in both surveys. RESULTS Seventy‐one of the 104 responding TTP patients (68%) suffered from depression and the severity of depression was similar in both surveys performed 1 year apart. Furthermore, TTP patients had considerably lower cognitive performance than controls. There was no correlation between prevalence of depression and cognitive deficits and the number and the severity of acute episodes. Impairment of mental performance correlated with the severity of depression (rs = 0.779). CONCLUSION The prevalence of depression and cognitive deficits was significantly higher in TTP patients. Cognitive impairment seemed to be a consequence of depression, almost independently of number and severity of TTP episodes.

The complement and coagulation cascades interact at multiple levels in thrombosis and inflammatory diseases. In venous thrombosis, complement factor 3 (C3) is crucial for platelet and tissue factor (TF) procoagulant activation dependent on protein disulfide isomerase (PDI). Furthermore, C5 selectively contributes to the exposure of leukocyte procoagulant phosphatidylserine (PS), which is a prerequisite for rapid activation of monocyte TF and fibrin formation in thrombosis. Here, we show that monoclonal cofactor-independent antiphospholipid antibodies (aPLs) rapidly activate TF on myelomonocytic cells. TF activation is blocked by PDI inhibitor and an anti-TF antibody interfering with PDI binding to TF, and requires C3 but unexpectedly not C5. Other prothrombotic, complement-fixing antibodies, for example, antithymocyte globulin, typically induce TF activation dependent on C5b-7-mediated PS exposure on the outer membrane of monocytes. We show that aPLs directly induce procoagulant PS exposure independent of C5. Accordingly, mice deficient in C3, but not mice deficient in C5, are protected from in vivo thrombus formation induced by cofactor-independent aPLs. Only immunoglobulin G (IgG) fractions with cofactor-independent anticardiolipin reactivity from patients with antiphospholipid syndrome (APS) induce complement-independent monocyte PS exposure and PDI-dependent TF activation. Neither a human monoclonal aPL directed against β2-glycoprotein I (β2GPI) nor patient IgG with selective reactivity to β2GPI rapidly activated monocyte TF. These results indicate that inhibitors of PDI and TF, but not necessarily clinically available drugs targeting C5, have therapeutic benefit in preventing thrombosis associated with APS caused by pathogenic aPLs primarily reactive with lipid, independent of β2GPI.

Major problems of current antidepressant pharmacotherapy are insufficient response rates and difficulties in response prediction. We recently provided preliminary evidence in a small study that patients with major depressive disorder (MDD) with a hypomethylation of the CpG-87 site of the promoter IV region of the brain-derived neurotrophic factor (BDNF) gene are less likely to benefit from antidepressants. Here, we aimed at replicating this finding in a secondary analysis of 561 MDD patients (mean age 40.0 ± 11.9 years, 56% female) included into the Early Medication Change study (EMC). We measured BDNF exon IV promoter and p11 gene methylation at Baseline (BL) as well as BDNF-plasma-levels (pBDNF) at BL and day 14 and related them to treatment outcome. Although we were not able to replicate the predictor function of hypomethylation of the BDNF exon IV promoter, a subgroup of patients with severe depression (Hamilton Depression Rating Scale [HAMD-17] ≥ 25) (n = 199) and hypermethylation at CpG-87 of the BDNF exon IV promoter had significantly higher remission rates than patients without a methylation (p = 0.032). We also found that 421 (75%) of 561 patients showed an early improvement (≥ 20% HAMD-17 reduction after 2 weeks), which was associated with a 4.24-fold increased likelihood to remit at study end compared to the 140 patients without early improvement. However, specificity of response prediction of early improvement was low (34%) and false positive rate high (66%). The combination of early improvement with a pBDNF increase between BL and day 14, however, increased the specificity of response prediction from 34 to 76%, and the combination with methylation of the CpG-87 site of the BDNF exon IV promoter from 34 to 62%. Thus, the combined markers reduced false positives rates from 66 to 24% and 38%, respectively. Methylation at other sites or p11 promoter methylation failed to increase specificity of early improvement prediction. In sum, the results add to previous findings that BDNF, BDNF promoter methylation and the combination of clinical and biological markers may be interesting candidates for therapy response prediction which has to be confirmed in further studies.Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT00974155, identifier: NCT00974155