Humoral immune response to ADAMTS13 in acquired thrombotic thrombocytopenic purpura

The apparently spontaneous development of autoantibodies to ADAMTS13 in previously healthy individuals is a major cause of thrombotic thrombocytopenic purpura (TTP). Epitope mapping studies have shown that in most patients antibodies directed towards the spacer domain of ADAMTS13 are present. A single antigenic surface comprising Arg(660) , Tyr(661) and Tyr(665) that contributes to the productive binding of ADAMTS13 to unfolded von Willebrand factor is targeted by anti-spacer domain antibodies. Antibodies directed to the carboxyl-terminal CUB1-2 and TSP2-8 domains have also been observed in the plasma of patients with acquired TTP. As yet it has not been established whether this class of antibodies modulates ADAMTS13 activity. Inspection of the primary sequence of human monoclonal anti-ADAMTS13 antibodies suggests that the variable heavy chain germline gene segment VH1-69 is frequently incorporated. We suggest a model in which 'shape complementarity' between the spacer domain and residues encoded by the VH1-69 gene segment explain the preferential use of this variable heavy chain gene segment. Finally, a model is presented for the development of anti-ADAMTS13 antibodies in previously healthy individuals that incorporates the recent identification of HLA DRB1*11 as a risk factor for acquired TTP.

Hairy pinnae after orchiectomy and chemotherapy for testicular cancer: acquired localized hypertrichosis of the ears

Acquired localized hypertrichosis has rarely been reported. Here, we describe a patient with localized hypertrichosis of the pinnae that occurred 4 months after orchiectomy and chemotherapy for a testicular carcinoma. To our knowledge, this is the first case of an acquired hypertrichosis of the pinnae after cancer therapy. We propose that in our patient either hypogonadism or the hormonal imbalance caused by the cancer therapy led to the development of the hairy pinnae, perhaps alongside a genetic predisposition for hairy ears.

Long-term follow-up of children with acute acquired concomitant esotropia

To study the clinical features and surgical outcome of type 2 (Burian-Franceschetti) acute acquired concomitant esotropia (AACE).

The word-length effect in acquired alexia, and real and virtual hemianopia

A word-length effect is often described in pure alexia, with reading time proportional to the number of letters in a word. Given the frequent association of right hemianopia with pure alexia, it is uncertain whether and how much of the word-length effect may be attributable to the hemifield loss. To isolate the contribution of the visual field defect, we simulated hemianopia in healthy subjects with a gaze-contingent paradigm during an eye-tracking experiment. We found a minimal word-length effect of 14 ms/letter for full-field viewing, which increased to 38 ms/letter in right hemianopia and to 31 ms/letter in left hemianopia. We found a correlation between mean reading time and the slope of the word-length effect in hemianopic conditions. The 95% upper prediction limits for the word-length effect were 51 ms/letter in subjects with full visual fields and 161 ms/letter with simulated right hemianopia. These limits, which can be considered diagnostic criteria for an alexic word-length effect, were consistent with the reading performance of six patients with diagnoses based independently on perimetric and imaging data: two patients with probable hemianopic dyslexia, and four with alexia and lesions of the left fusiform gyrus, two with and two without hemianopia. Two of these patients also showed reduction of the word-length effect over months, one with and one without a reading rehabilitation program. Our findings clarify the magnitude of the word-length effect that originates from hemianopia alone, and show that the criteria for a word-length effect indicative of alexia differ according to the degree of associated hemifield loss.

Acquired factor XIII deficiency: a therapeutic challenge

Less than 60 cases of acquired factor (F)XIII deficiencies have been reported, most having distinct clinical features. To illustrate the therapeutic challenges of acquired FXIII inhibitors, we report a case of a 65-year-old patient with no previous bleeding history who suddenly developed massive haemorrhages associated to a strong and isolated FXIII inhibitor. No underlying disorder has been detected till now after three years of follow-up. Despite aggressive treatment with prednisone, rituximab, cyclophosphamide, immunoglobulin, immunoadsorption and immune tolerance his inhibitor is still present, although at low titre and with a clinical benefit since the patient has no more bleed since more than one year. Moreover the patient had a venous thromboembolic complication. After a review of the management of acquired FXIII deficiency patients and based on the management of acquired haemophilia we discuss a possible strategy for such difficult cases.

Serum glucose levels for predicting death in patients admitted to hospital for community acquired pneumonia: prospective cohort study

To examine whether acute dysglycaemia predicts death in people admitted to hospital with community acquired pneumonia.

Clinical efficacy of pimobendan versus benazepril for the treatment of acquired atrioventricular valvular disease in dogs

Seventy-six dogs with clinical acquired atrioventricular valvular disease were evaluated to determine the efficacy of pimobendan (n=41) versus benazepril hydrochloride (n=35) in a randomized, positive-controlled, multicenter study. The study was divided into 56-day and long-term evaluation periods. In a subgroup of dogs with concurrent furosemide treatment (pimobendan [n=31], benazepril [n=25]), the Heart Insufficiency Score improved in favor of pimobendan (P=0.0011), equating to a superior overall efficacy rating (P<0.0001) at day 56. Long-term median survival (i.e., death or treatment failure) for dogs receiving pimobendan was 415 days versus 128 days for dogs not on pimobendan (P=0.0022).

Multiple B-cell clones producing antibodies directed to the spacer and disintegrin/thrombospondin type-1 repeat 1 (TSP1) of ADAMTS13 in a patient with acquired thrombotic thrombocytopenic purpura

BACKGROUND: The cysteine-rich/spacer domains of ADAMTS13 contain a major binding site for antibodies in patients with acquired thrombotic thrombocytopenic purpura (TTP). OBJECTIVE: To study the heterogeneity of the antibody response towards these domains an immunoglobulin V-gene phage-display library was constructed to isolate monoclonal anti-ADAMTS13 antibodies from the immunoglobulin repertoire of a patient with acquired TTP. METHODS: Combined variable heavy chain (VH) and variable light chain (VL) segments, expressed as single-chain Fv fragments (scFv), were selected for binding to an ADAMTS13 fragment consisting of the disintegrin/thrombospondin type-1 repeat 1 (TSP1)/cysteine-rich/spacer domains. RESULTS: Seven different scFv antibody clones were identified that were assigned to four groups based on their homology to VH germline gene segments. Epitope-mapping revealed that scFv I-9 (VH1-69), I-26 (VH1-02), and I-41 (VH3-09) bind to an overlapping binding site in the ADAMTS13 spacer domain, whereas scFv I-16 (VH3-07) binds to the disintegrin/TSP1 domains. The affinity of scFv for the disintegrin/TSP1/cysteine-rich/spacer domain was determined by surface plasmon resonance analysis and the dissociation constants ranged from 3 to 254 nM. The scFv partially inhibited ADAMTS13 activity. However, full-length IgG prepared from the variable domains of scFv I-9 inhibited ADAMTS13 activity more profoundly. Plasma of six patients with acquired TTP competed for binding of scFv I-9 to ADAMTS13. CONCLUSION: Our data indicate that multiple B-cell clones producing antibodies directed against the spacer domain are present in the patient analyzed in this study. Our findings also suggest that antibodies with a similar epitope specificity as scFv I-9 are present in plasma of other patients with acquired TTP.

[Community-acquired pneumonia--pathogens and assessment]

Pneumonia is one of the most important infectious diseases, both in terms of incidence as well as potential severity. Streptococcus pneumoniae remains the most prevalent etiologic agent, accounting for about two-thirds of bacteremic cases. Diagnostic procedures include chest radiography, blood culture, Gram staining and culture of expectorated sputum, urine antigen assays for Legionella pneumophila and pneumococci, and asservation of an initial serum sample for comparative serologic investigations. Molecular biology techniques continue to gain importance for the diagnosis of Chlamydia pneumoniae, Mycoplasma pneumoniae, Legionellae and viral respiratory infections, however, their availability at present is mainly restricted to research and reference laboratories.

"HIT on Trousseau" double trouble: acquired coagulopathy with femoral artery thrombosis

Trousseau Syndrome is a paraneoplastic procoagulant phenomenon. Heparin-induced thrombocytopenia (HIT) is a rare complication of anticoagulation with heparin. To our knowledge, the coincidence of the two has not been reported so far. We report a case of an acute thrombosis of the left femoral artery and distal leg arteries in a patient with an otherwise normal cardiovascular status. Endovascular revascularization attempts using mechanical rotational thrombectomy catheter, aspiration and local thrombolysis were unsuccessful. Progressive coagulation along the intra-arterial catheter was seen. Surgical thrombectomy of the femoral-pedal axis was successful, but the patient developed an immune-mediated HIT postoperatively. An adenocarcinoma of the colon was the likely cause for the initial arterial thrombosis, and probably adversely affected endovascular revascularization attempts. Subsequent HIT with microvascular thrombosis worsened ischemic damage leading to a below knee-amputation, despite patent large vessels. Compared to venous thrombosis, arterial thrombosis is a rare manifestation of Trousseau syndrome. The coincidence of it with HIT is even rarer. There may be a causal relationship between the two.