6th ESACP Congress, Heidelberg, April 7-11, 1999

A108
"BITTEN FIBRES" IN SCELETAL MUSCLE BIOPSIES - A DISTINCT MORPHOLOGICAL FEATURE AS AN INDICATOR FOR IMMUNOLOGICAL DISORDERS
Nafe R 1, Schlote W 1, Schneider 2

1) Edinger Institute of Neuropathology, Clinics of Johann-Wolfgang-Goethe University, Frankfurt/Main, 2) Institute of Biometrics, Medical School, Hannover, Germany

"Bitten Fibres" (BF) have been shown to occur in muscle biopsies from patients with immunological disorders, especially with collagen diseases. Nevertheless, they have not reached a wide interest in analytical cellular research up to now. They are characterized by small concave irregularities of the sarcolemma and can be reliably diagnosed in good frozen sections, better in araldite embedded semithin-sections. In our studies, we proved other distinct morphological features: a thickened basal lamina surrounding the sarcolemma and the capillaries, as well as deposits of immunglobulin at the basement membrane. A numerical increase of capillaries between the muscle fibres was seen in some cases. Especially, it has been proven, that cases with BF (n=11) can be reliably distinguished from controls (n=8) and from cases with neurogenic atrophy (n=10) by means of morphometric shape analysis using Fourier-Analysis of the fibres outlines. Bitten Fibres thus seem to be an important cytological feature for the neuropat hologist indicating an immunological disorder, especially if there are no further signs of pathological alterations in the muscle biopsy.