Key Points This study is the first to assess the prognostic value of FVIII-specific antibody data in patients with AHA. Anti-FVIII IgA, but not immunoglobulin G, autoantibodies at baseline are potential predictors of recurrence and poor outcome of AHA.

Background: Recombinant porcine factor VIII (rpFVIII, OBI-1, susoctocog alfa) is used for the treatment of acute bleeds in patients with acquired hemophilia A (AHA).Inhibitors in AHA can sometimes cross-react with rpFVIII.Objectives: To assess the frequency, strength, and determinants of cross-reactivity.Patients/methods: Baseline samples from 70 patients of the prospective, observational cohort study GTH-AH 01/2010 were assessed for anti-human FVIII and anti-rpFVIII inhibitors using modified Nijmegen-Bethesda assays, as well as anti-human FVIII domain reactivity using enzyme-linked immunoassay (ELISA).Results: Anti-human FVIII inhibitors were present in all samples ranging between 0.7 and 3891 Bethesda Units (BU)/mL. Inhibitors from 31 of 70 patients (44%) partially inhibited rpFVIII with anti-rpFVIII titers ranging between 0.5 and 471 BU/mL. Anti-rpFVIII titers were ≤5 BU in most patients. Patients with cross-reacting inhibitors, as compared to patients without, had significantly higher anti-human FVIII titers (27.8 versus 5.4 BU/mL) and lower baseline FVIII activity (<1 versus 2.6 IU/dL). The ratio between anti-rpFVIII to anti-human titers was highest for inhibitors involving the C1 domain. Cross-reactivity was very rare, if inhibitors reacted only with the C2 domain of FVIII (6%). An anti-human FVIII titer of >100 BU/mL predicted cross-reactivity with 97% likelihood, whereas an anti-human FVIII titer of <3.8 BU/mL predicted absent cross-reactivity with 90% likelihood. Conclusion:Cross-reacting inhibitors should be considered when choosing a treatment for bleeding patients with AHA. Cross-reactivity is frequent in patients with anti-human FVIII titers of >100 BU/mL.

BackgroundSynovial sarcoma account for approximately 10 % of all soft-tissue tumors and occur most frequently in young adults. A specific translocation in this sarcoma induces fusion of the SYT gene on chromosome 18 to the SSX genes on chromosome X, leading to proliferation of the tumor cells. The need for non-invasive biomarkers indicating recurrence and activity of this disease has sparked research into short non-coding RNA known as microRNA (miRNA).MethodsBlood samples of patients with active synovial sarcoma and of synovial sarcoma patients in complete remission as well as of healthy donors and patients with active leiomyosarcoma, MPNST, Ewing sarcoma and liposarcoma were collected. Whole blood RNA was extracted and samples of patients with active synovial sarcoma and of healthy donors were analyzed using an Affymetrix GeneChip miRNA Array v. 4.0. qRT-PCR was carried out to confirm a panel of miRNAs which where differentially expressed in the miRNA array. This miRNA-panel was further evaluated in patients with synovial sarcoma in complete remission and patients with active leiomyosarcoma, MPNST, Ewing sarcoma and liposarcoma as well as in an independent cohort of synovial sarcoma patients.ResultsUnsupervised hierarchical clustering of the miRNA arrays separated patients with active synovial sarcoma from healthy controls. A panel of seven miRNAs (miR-99a-5p, miR-146b-5p, miR-148b-3p, miR-195-5p, miR-223-3p, miR-500b-3p and miR-505-3p) was further validated by qRT-PCR to be significantly upregulated in synovial sarcoma patients. Moreover, most of the analyzed miRNAs were shown to be significantly upregulated in synovial sarcoma patients compared to leiomyosarcoma, MPNST, Ewing sarcoma and liposarcoma patients. Validation of the miRNA panel in an independent cohort of synovial sarcoma patients confirmed higher expression levels compared to healthy controls and patients in complete remission.ConclusionOur results have identified a specific whole blood miRNA signature that may serve as an independent biomarker for the diagnosis of local recurrence or distant metastasis of synovial sarcoma. It even distinguishes synovial sarcoma from other sarcoma subtypes, thus potentially serving as a specific biomarker for synovial sarcoma.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-015-0424-z) contains supplementary material, which is available to authorized users.

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Soft tissue sarcomas (STS) are rare tumors of mesenchymal origin. About 50% of patients with STS experience relapse and more than 30% will die within 10 years after diagnosis. In this study we investigated circulating free DNA (cfDNA) and tumor‐specific genetic alterations therein (circulating tumor DNA, ctDNA) as diagnostic biomarkers. Plasma concentrations and fragmentation of cfDNA was analyzed with quantitative PCR. Patients with STS (n = 64) had significantly higher plasma concentrations and increased fragmentation of cfDNA when compared to patients in complete remission (n = 19) and healthy controls (n = 41) (p < 0.01 and p < 0.001). Due to overlapping values between patients with STS and controls, the sensitivity and specificity of these assays is limited. Sensitive assays to detect genomic alterations in cfDNA of synovial sarcomas (t(X;18)), myxoid liposarcomas (t(12;16) and TERT C228T promoter mutation) and well‐differentiated/de‐differentiated liposarcomas (MDM2 amplifications) were established. ctDNA was quantified in nine liposarcoma patients during the course of their treatment. Levels of breakpoint t(12;16) and TERT C228T ctDNA correlated with the clinical course and tumor burden in patients with myxoid liposarcomas (n = 4). ctDNA could detect minimal residual disease and tumor recurrence. In contrast, detection of MDM2 amplifications was not sensitive enough to detect tumors in patients with well‐differentiated/de‐differentiated liposarcomas (n = 5). Genotyping of cfDNA for tumor specific genetic alterations is a feasible and promising approach for monitoring tumor activity in patients with myxoid liposarcomas. Detection of ctDNA during follow‐up examinations despite negative standard imaging studies might warrant more sensitive imaging (e.g. PET‐CT) or closer follow‐up intervals to timely localize and treat recurrences.