Skeletal muscle fibers produce B-cell stimulatory factors in chronic myositis

IntroductionWe aimed to identify B-cell-mediated immunomechanisms in inclusion body myositis (IBM) and polymyositis (PM) as part of the complex pathophysiology.Materials and methodsHuman primary myotube cultures were derived from orthopedic surgery. Diagnostic biopsy specimens from patients with IBM (n=9) and PM (n=9) were analyzed for markers of B cell activation (BAFF and APRIL) and for chemokines that control the recruitment of B cells (CXCL-12 and CXCL-13). Results were compared to biopsy specimens without myopathic changes (n=9) and hereditary muscular dystrophy (n=9).ResultsThe mRNA expression of BAFF, APRIL, and CXCL-13 was significantly higher in IBM and PM compared to controls. Patients with IBM displayed the highest number of double positive muscle fibers for BAFF and CXCL-12 (48%) compared to PM (25%), muscular dystrophy (3%), and non-myopathic controls (0%). In vitro, exposure of human myotubes to pro-inflammatory cytokines led to a significant upregulation of BAFF and CXCL-12, but APRIL and CXCL-13 remained unchanged.ConclusionThe results substantiate the hypothesis of an involvement of B cell-associated mechanisms in the pathophysiology of IBM and PM. Muscle fibers themselves seem to contribute to the recruitment of B cells and sustain inflammation

What are the clinical results of operated fractures of the talus?

Our study focuses to determine the medium-range results of function and radiological flndings of operatively treated fractures of the talus. Furthermore we had the intention to investigate risl-factors for posttraumatic arthrosis and necrosis of the talus. Material and Methods: We included all 41 patients (w/m: 13/28) operated between 19952000 with talus neck, corpus or dislocated fracture of the talus edge (open/closed: 11/30). Fractures were classified according to Hawkins: type 1: 6x, type II: 17x, type III: 7x, type IV: 3x, 8x dislocated peripheral fractures. 39x screw osteosynthesis, 2x K-wire fixation were done and 12 additive transfixation with fixateur externe. Score: AOFAS Ankle-Hindfoot-Scale, radiological assessment according to the Bargon score. 34 patients, mean age 35 years (12-60), were followed up clinically with an average of 4 years (24-72 months). Results: AOFAS Score: pain (40 points): circle divide 31 [10-40]; function (50 points): circle divide 39 [14-50]; alignement(10 points): circle divide 7 [0-10]; degree of arthritis due to the Bargon scale: 0 degrees: 5x, 1 degrees: 8x, 2 degrees: 7x, 3 degrees: 7x. Complications: 4x necrosis of margin of the wound, 1 deep infection, 5 necrosis of the talus bone. The severity of the fracture was I x type II according to Hawkins 3x type III and 1x type IV. 3 of the 5 patients who developed a talus necrosis had 2 degrees or 3 degrees soft tissue damage. One patient had an imminent compartment syndrome. One patient who suffered a polytrauma was operated six days post injury. Second operation: 1 Syme amputation due to necrosis of the talus subsequent to an infection. 4 x arthrodesis of the upper ankle joint and 5x arthrodesis of the subtalar joint due to posttraumatic arthritis. Conclusion: Primary screw osteosynthesis is the treatment of choice depending on the lesions of the soft-tissue and accompanied injuries in combination with a fixateur externe. Nevertheless the primary osteosynthesis is not able to prevent necrosis of the talus completely, that occurs in a frequency of 15%. Risk factors for a posttraumatic arthritis in addition to the type of fracture and the result of reconstruction are an accompanied soft tissue defect and local capsule-band complex with necessary temporary transfixation. Early plastic reconstruction of defects can reduce the time of immobilisation and allows motion therapy. The functional results are positive compared with the radiological results that showed arthritis in 70%

Skeletal muscle fibers produce B-cell stimulatory factors in chronic myositis

We aimed to identify B-cell-mediated immunomechanisms in inclusion body myositis (IBM) and polymyositis (PM) as part of the complex pathophysiology.Open-Access-Publikationsfonds 202