[Acquired hemophilia A as a cause of postoperative bleeding]. / Erworbene Hämophilie A als postoperative Blutungskomplikation.

Acquired spontaneous hemophilia is a rare but potentially life-threatening disease, which poses a major challenge to intensive care medicine. We report a case in which the disease occurred postoperatively in a patient following uncomplicated lumbal discectomy. The clinical sequelae involved hemorrhagic shock (cHb 4.1 g/dl; hct 17 %; systolic BP 60 mmHg; HR 130/min; saO2 73 %) due to retroperitoneal hematoma eight days after neurosurgical intervention. While lesions of the retroperitoneal vessels were not found during emergent angiography and laparotomy, the laboratory results showed a slightly prolonged activated prothrombin time (aPTT; 47 s). However, application of fresh frozen plasma (FFP) even prolonged the aPTT (53 s). Analysis of clotting factors proved a deficiency of factor VIII with a reduced activity of about 20 %, which was resistant against therapy with desmopressin (DDAVP) and substitution of factor VIII. Thus, the plasma-mix-test was performed, showing complete inactivation of the factor VIII-activity of the pooled plasma. This evidenced the presence of acquired inhibitors against factor VIII. Hemostasis was successfully and immediately restored with the application of recombinant factor VIIa (rFVIIa), including boluses of 60 - 80 microg/kg every 6th - 8th hour (supplemented with tranexamic acid, 3 x 1 g/d), leading to a continuous infusion of 12 microg/kg per hour. With prednisolone (1 mg/kgBW/d) over the ensuing 8 weeks, the antibodies were sufficiently suppressed and no additional substitution of factor VIII was necessary to maintain normal hemostasis.

Major membrane proteins and lipoproteins as highly variable immunogenic surface components and strain-specific antigenic markers of Mycoplasma arthritidis.

Surface antigenic variation was investigated in Mycoplasma arthritidis, an agent that produces chronic arthritis in rats which shares several features with many mycoplasma-induced diseases and thus defines a well-characterized model system. Hyperimmune rabbit antisera (anti-ISR1, anti-PG6, anti-H606 and anti-158p10) to whole M. arthritidis organisms were used as immunological probes in Western immunoblots of four M. arthritidis prototype strains (ISR1, PG6, H606 and D263) and five rat-passaged substrains (ISR1p1, ISR1p7, ISR1p8, 158p10 and D263p1). Several prominent antigens were identified that varied in expression. By Triton X-114 phase fractionation and treatment of whole cells with trypsin and carboxypeptidase Y, these strain-variant antigens were shown to be integral membrane proteins with C-termini and portions of the polypeptide chains oriented outside the membrane. Western blot immunoscreening of a large number of randomly selected clonal isolates and well-established clonal lineages from stock cultures of M. arthritidis ISR1p7, 158p10, PG6 and H606 revealed an expanded repertoire of variant membrane proteins whose expression was subject to independent, reversible phase variation. Colony immunoblots of these clonal populations with a hyperimmune rabbit antiserum to a gel-purified variant membrane protein (P36) showed that this phase switching occurred at a high frequency (10(-4) to 10(-2) per generation). Detailed immunological and biochemical characterization of the phase-variant membrane proteins demonstrated that they are: (i) antigenically related or distinct; (ii) apparently specific to particular strain populations; (iii) proteins or lipoproteins; (iv) major immunogens of M. arthritidis, recognized by serum antibodies from convalescent rat; and (v) able to undergo variation in expression during in vivo passage. Thus, M. arthritidis possesses a complex system capable of creating large repertoires of cell surface phenotypes which may affect the multiple interactions of this organism with its host and dictate its potential as a successful infectious agent and pathogen.