Background: Neutrophil extracellular traps (NETs) can stimulate thrombosis, and their degradation is decreased in several autoimmune disorders. It was recently reported that some patients with haemolytic uraemic syndrome (HUS) also fail to degrade NETs and that neutrophils from Shiga toxin-associated HUS are primed to form NETs. Method: We used a well-characterized cohort of 74 thrombotic microangiopathy (TMA) patients, with a subset also providing follow-up samples, and 112 age-matched controls to investigate NET degradation and serum nuclease activity in TMA before, during and after treatment. Results: We identified that in the cohort of TMA patients, 50% of patients with Shiga toxin-associated HUS displayed a decreased ability to degrade NETs. NET degradation correlated with serum nuclease activity, but not with autoantibodies against double-stranded DNA, which has been previously observed in some autoimmune disorders. Further, NET degradation negatively correlated with serum creatinine levels, suggesting that kidney function was negatively impacted by the low NET degradation ability. Conclusions: We revealed that decreased NET degradation is a common feature of Shiga toxin-associated HUS and that it is associated with decreased kidney function in these patients. It remains to be clarified whether improving NET degradation would be beneficial for the patient.
Keywords:Polymorphonuclear leukocyte neutrophil granulocyte elastase thrombotic thrombocytopenic purpura disease activity complement activation Introduction: Genetic and autoimmune risk factors contribute to the development of thrombotic thrombocytopenic purpura (TTP) but triggers are needed to bring about acute disease. The aim of the study was to investigate the association of neutrophil activation with acute TTP, to assess whether neutrophil activation changes during plasma exchange therapy and to show if complement-and neutrophil activation are parallel, characteristic processes in acute TTP. Materials and Methods: Altogether 49 EDTA-plasma samples of 21 TTP patients with acute disease and 17 in remission were investigated along with 20 healthy controls. A stable complex of PMNE-proteinase-inhibitor was measured by ELISA (Calbiochem, Merck-Millipore, Darmstadt, Germany). Results: Acute disease was associated with significantly increased PMNE levels, the group medians were similarly low in TTP patients in remission and in healthy controls. Increased PMNE levels were characteristic for hematologically active and ADAMTS13 deficient form of TTP. PMNE concentration inversely correlated to disease activity markers platelet count (r = − 0.349, p = 0.032) and hemoglobin levels (p = − 0.382 p = 0.018). Achievement of remission was associated with significant reduction of plasma PMNE levels (p = 0.031, Wilcoxon test). There was positive correlation between PMNE levels and complement activation markers C3a and Bb. Conclusions: We report increased PMNE levels in acute TTP and showed its association to activity markers of acute TTP and complement activation. Effective treatment of an acute TTP episode resulted in marked decrease in PMNE levels. Our data support and extend previous observations that neutrophil extracellular traps may be released in acute TTP and potentially contribute to the pathophysiology of this disease.
Pentraxin-3 (PTX3) and C-reactive protein (CRP) have been shown to regulate complement activation
in vitro
, but their role has not been investigated in complement consumption
in vivo
. Thrombotic microangiopathies (TMA) are often accompanied by complement overactivation and consumption, therefore we analyzed the relation of the systemic pentraxin levels to the complement profile, laboratory parameters and clinical outcome of TMA patients. We determined the PTX3 and CRP levels, complement factor and activation product concentrations in blood samples of 171 subjects with the diagnosis of typical hemolytic uremic syndrome (STEC-HUS) (
N
= 34), atypical HUS (aHUS) (
N
= 44), secondary TMA (
N
= 63), thrombotic thrombocytopenic purpura (TTP) (
N
= 30) and 69 age-matched healthy individuals. Clinical data, blood count and chemistry were collected from medical records. To determine the
in vitro
effect of PTX3 on alternative pathway (AP) activation, sheep red blood cell-based hemolytic assay and AP activity ELISA were used. We found that PTX3 levels were elevated in the acute phase of STEC-HUS, aHUS and secondary TMA, whereas PTX3 elevation was exceptional is TTP. Conversely, a significantly higher median CRP was present in all patient groups compared to controls. PTX3, but not CRP was associated with signs of complement consumption
in vivo
, and PTX3 significantly decreased the AP hemolytic activity
in vitro
. Our results provide a detailed description of acute phase-TMA patients' complement profile linked to changes in the systemic pentraxin levels that may support further molecular studies on the function of PTX3 in disease pathogenesis and add to the laboratory assessment of complement consumption in TMA.
A primer hyperoxaluria ritka anyagcsere-betegség. A glioxilát anyagcserezavara miatt nagy mennyiségű oxalát keletkezik, amely – mivel rosszul oldódik – a szövetekben oxalátkicsapódáshoz, oxalosishoz vezet. Az oxalosis elsőként a veséket érinti, enyhébb formában urolithiasishoz, súlyos esetekben nephrocalcinosishoz és progresszív vesefunkció-romláshoz, végül végstádiumú veseelégtelenséghez vezet. A betegség típusát genetikai vizsgálattal lehet pontosan azonosítani. Klinikai megjelenése nagyon változatos. Enyhébb esetekben az oxaláttermelés csökkentése és kicsapódásának gátlása jelenthet terápiás lehetőséget, súlyosabb esetben vesepótló kezelésre lehet szükség. A betegség kóroki terápiáját egyelőre a májátültetés jelenti. Az oxalát kialakulásában kulcsszerepet játszó enzim RNS-interferencia útján történő gátlásán alapuló biológiai terápia új perspektívát jelenthet a betegség komplex kezelésében.
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