Pseudohypocalcemia caused by perchlorate (Irenat (R))

Background: Blood gas analysis (BGA), including measurement of ionized calcium, is performed routinely in patients with end stage renal disease on renal replacement therapy, especially when using citrate for regional anticoagulation. After installation of a new blood gas analyzer (RAPIDpoint (R) 405; BGA), we observed lower ionized calcium concentrations in a few patients without signs of hypocalcemia, whereas calcium concentrations were normal using a standard laboratory method. Pseudohypocalcemia was of limited duration and correlated with the short-term intake of sodium perchlorate monohydrate (Irenat (R)). Methods: We prepared dilution series from whole blood samples and stock solutions of calcium and perchlorate with different concentrations of ionized calcium and perchlorate. Measurement of ionized calcium concentrations was performed using two different blood gas analyzers (RAPIDpoint (R) 405; BGA and Roche AVL 9180; standard laboratory method). Results: After addition of different amounts of perchlorate, significant lower ionized calcium concentrations were measured with BGA compared to the standard laboratory method using either preparations from whole blood samples or stock solutions. The addition of potassium or methylene blue known to complex perchlorate had no effect on the concentrations of ionized calcium measured with BGA. Using different mathematical methods, a calculation of the "real" ionized calcium concentration from the value measured with BGA was not possible. Conclusions: Based on our experiments, we confirm the hypothesis that perchlorate can influence the measurement of ionized calcium by BGA. As the effect depends on the ion selective electrode that is used, it is advisable to test the blood gas analyzer with calcium and perchlorate solutions

Outcome after Desensitization in HLA or ABO-Incompatible Kidney Transplant Recipients: A Single Center Experience

Background The shortage of deceased donors led to an increase of living donor kidney (LDK) transplantations performed in the presence of donor-specific antibodies (DSA) or ABO incompatibility (ABOi) using various desensitization protocols. Methods We herein analyzed 26 ABOi and 8 Luminex positive DSA patients who were successfully desensitized by anti-CD20, antigen-specific immunoadsorption and/or plasmapheresis to receive an LDK transplant. Twenty LDK recipients with non-donor-specific HLA-antibodies (low risk) and 32 without anti-HLA antibodies (no risk) served as control groups. Results 1-year graft survival rate and renal function was similar in all 4 groups (creatinine: 1.63 +/- 0.5 vs 1.78 +/- 0.6 vs 1.64 +/- 0.5 vs 1.6 +/- 0.3 mg/dl in ABOi, DSA, low risk and no risk group). The incidence of acute T-cell mediated rejections did not differ between the 4 groups (15% vs 12, 5% vs 15% vs 22% in ABOi, DSA, low risk and no risk), while antibody-mediated rejections were only found in the DSA (25%) and ABOi (7.5%) groups. Incidence of BK nephropathy (BKVN) was significantly more frequent after desensitization as compared to controls (5/34 vs 0/52, p = 0.03). Conclusion We demonstrate favorable short-term allograft outcome in LDK transplant recipients after desensitization. However, the desensitization was associated with an increased risk of BKVN

Solid Organ Transplantation in Patients with Inflammatory Bowel Diseases (IBD): Analysis of Transplantation Outcome and IBD Activity in a Large Single Center Cohort

Background Currently, limited data of the outcome of inflammatory bowel disease (IBD) in patients after solid organ transplantation (SOT) are available. We aimed to analyze effects of SOT on the IBD course in a large IBD patient cohort. Methods Clinical data from 1537 IBD patients were analyzed for patients who underwent SOT (n = 31) between July 2002 and May 2014. Sub-analyses included SOT outcome parameters, IBD activity before and after SOT, and efficacy of IBD treatment. Results 4.74% of patients with ulcerative colitis (UC) and 0.84% of patients with Crohn's disease (CD) underwent SOT (p = 2.69 x 10(-6),UC vs. CD). 77.4% of patients with SOT underwent liver transplantation (LTx) with tacrolimus-based immunosuppressive therapy after SOT. All LTx were due to primary sclerosing cholangitis (PSC) or PSC overlap syndromes. Six patients (19.4%) required renal transplantation and one patient (3.2%) heart transplantation. A survival rate of 83.9% after a median follow-up period of 103 months was observed. Before SOT, 65.0% of patients were in clinical remission and 5 patients received immunosuppressive therapy (16.1%). After SOT, 61.0% of patients were in remission (p = 1.00 vs. before SOT) and 29.0% required IBD-specific immunosuppressive or anti-TNF therapy (p = 0.54 vs. before SOT). 42.9% of patients with worsening of IBD after SOT were at higher risk of needing steroid therapy for increased IBD activity (p = 0.03;relative risk (RR): 10.29;95% CI 1.26-84.06). Four patients (13.0%) needed anti-TNF therapy after SOT (response rate 75%). Conclusions SOT was more common in UC patients due to the higher prevalence of PSC-related liver cirrhosis in UC. Despite mainly tacrolimus-based immunosuppressive regimens, outcome of SOT and IBD was excellent in this cohort. In this SOT cohort, concomitant immunosuppressive therapy due to IBD was well tolerated

Relative incidence of thrombotic thrombocytopenic purpura and haemolytic uraemic syndrome in clinically suspected cases of thrombotic microangiopathy

Background. Data are lacking on the relative incidence of thrombotic thrombocytopenic purpura (TTP), haemolytic uraemic syndrome (HUS) caused by Shiga toxin-producing Escherichia coli (STEC) and atypical HUS (aHUS) in patients presenting with thrombotic microangiopathies (TMAs). Methods. This was a prospective, cross-sectional, multicentre and non-interventional epidemiological study. Patients fulfilling criteria for TMAs (platelet consumption, microangiopathic haemolytic anaemia and organ dysfunction) were included in the study. The primary objective was to assess the relative incidence of TTP, STEC-HUS, aHUS and 'other' physician-defined diagnoses. The secondary objective was to develop an algorithm to predict a severe deficiency in ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity (<= 10%) using routine laboratory parameters. A post hoc classification using the recent Kidney Disease: Improving Global Outcomes diagnostic criteria was then undertaken to further classify patient groups. Results. aHUS was diagnosed with a relative incidence of 61%, whereas TTP, STEC-HUS and 'other' were diagnosed in 13, 6 and 20% of patients, respectively. In the post hoc analysis, 27% of patients with a TMA were classified as 'primary aHUS' and 53% as 'secondary aHUS'. Multivariate analysis revealed that severe deficiency in ADAMTS13 activity (<= 10%) was unlikely to underlie TMA if platelet and serum creatinine were above threshold values of 30 x 10(9)/L and 1.8 mg/dL, respectively (negative predictive value of 92.3 and 98.1, respectively, if one or both values were above the threshold). Conclusions. In this study, aHUS was the most common single diagnosis among patients presenting with a TMA. In the absence of an ADAMTS13 activity result, platelet count and serum creatinine may aid in the differential diagnosis

Incidence of rejection.

<p>The number of patient experiencing 1 or more biopsy proven rejections (including borderline cases with impaired renal graft function) according to the Banff 97 classification: 2 = antibody mediated rejection (AMR), 3 = borderline lesion, 4 I and 4 II = acute cellular rejection.</p

Loss of renal function within the first year.

<p>The GFR slope within the first year was assessed according to the following formula: GFR _{at 1 month}−GFR _{at 12 month}.</p

Alternate-day dosing of caplacizumab for immune-mediated thrombotic thrombocytopenic purpura

Background The anti-von Willebrand factor (VWF) nanobody caplacizumab directly prevents the fatal microthrombi formation in immune-mediated thrombotic thrombocytopenic purpura (iTTP), thereby adding a new therapeutic principle to the treatment of this disorder. However, real-world treatment modalities beyond clinical trials remain heterogeneous. Methods Here, we describe the risks and benefits of an alternate-day dosing regimen for caplacizumab by thoroughly analyzing the timing and outcome of this approach in a retrospective cohort of 25 iTTP patients treated with caplacizumab at seven different medical centers in Austria and Germany between 2018 and 2021. Results Alternate-day dosing of caplacizumab appeared feasible and led to persisting normal platelet counts in most patients. Five patients experienced iTTP exacerbations or relapses that led to the resumption of daily caplacizumab application. VWF activity was repeatedly measured in 16 of 25 patients and documented sufficient suppression by caplacizumab after 24 and 48 h in line with published pharmacodynamics. Conclusion Extension of caplacizumab application intervals from daily to alternate-day dosing may be safely considered in selected patients after 3 to 4 weeks of daily treatment. Earlier modifications may be discussed in low-risk patients but require close monitoring for clinical and laboratory features of thrombotic microangiopathy

Diminished Short- and Long-Term Antibody Response after SARS-CoV-2 Vaccination in Hemodialysis Patients

Short-term studies have shown an attenuated immune response in hemodialysis patients after COVID-19-vaccination. The present study examines how antibody response is maintained after vaccination against SARS-CoV-2 in a large population of hemodialysis patients from six outpatient dialysis centers. We retrospectively assessed serum antibody levels against SARS-CoV-2 spike protein and nucleocapsid protein (electrochemiluminescence immunoassays, Roche Diagnostics) after COVID-19-vaccination in 298 hemodialysis and 103 non-dialysis patients (controls), comparing early and late antibody response. Compared to a non-dialysis cohort hemodialysis patients showed a favorable but profoundly lower early antibody response, which decreased substantially during follow-up measurement (median 6 months after vaccination). Significantly more hemodialysis patients had anti-SARS-CoV-2-S antibody titers below 100 U/mL (p < 0.001), which increased during follow-up from 23% to 45% but remained low in the control group (3% vs. 7%). In multivariate analysis, previous COVID-19 infections (p < 0.001) and female gender (p < 0.05) were significantly associated with higher early as well as late antibody vaccine response in hemodialysis patients, while there was a significant inverse correlation between patient age and systemic immunosuppression (p < 0.001). The early and late antibody responses were significantly higher in patients receiving vaccination after a SARS-CoV-2 infection compared to uninfected patients in both groups (p < 0.05). We also note that a higher titer after complete immunization positively affected late antibody response. The observation, that hemodialysis patients showed a significantly stronger decline of SARS-CoV-2 vaccination antibody titers within 6 months, compared to controls, supports the need for booster vaccinations to foster a stronger and more persistent antibody response

ADAMTS13 and VWF activities guide individualized caplacizumab treatment in patients with aTTP

Introduction of the nanobody caplacizumab was shown to be effective in the treatment of acquired thrombotic thrombocytopenic purpura (aTTP) in the acute setting. The official recommendations include plasma exchange (PEX), immunosuppression, and the use of caplacizumab for a minimum of 30 days after stopping daily PEX. This study was a retrospective, observational analysis of the use of caplacizumab in 60 patients from 29 medical centers in Germany. Immunosuppressive treatment led to a rapid normalization of ADAMTS13 activities (calculated median, 21 days). In 35 of 60 patients, ADAMTS13 activities started to normalize before day 30 after PEX; in 11 of 60 patients, the treatment was extended beyond day 30; and in 5 patients, it was extended even beyond day 58 due to persistent autoimmune activity. In 34 of 60 instances, caplacizumab was stopped before day 30 with a favorable outcome whenever ADAMTS13 activities were >10%. In contrast, 11 of 34 patients with ADAMTS13 activities <10% at the time of stopping caplacizumab treatment developed a nonfavorable outcome (disease exacerbation or relapse). In some cases, prolongation of the treatment interval to every other day was feasible and resulted in a sustained reduction of von Willebrand factor activity. ADAMTS13 activity measurements are central for a rapid diagnosis in the acute setting but also to tailor disease management. An ADAMTS13 activity-guided approach seems safe for identifying the individual time point when to stop caplacizumab to prevent overtreatment and undertreatment; this approach will result in significant cost savings without jeopardizing the well-being of patients. In addition, von Willebrand factor activity may serve as a biomarker for drug monitoring