A. Engelhardt

In order to compare the adverse effects with the benefits for the characterization of neuropathies after complete sural nerve biopsy, 56 out of 80 patients were examined postoperatively. Preoperatively, sensory deficits were reported by 30 patients (53%), paresthesia and dysesthesia by 18 (32%), and pain by 16 (28%). Twenty-one months after biopsy on the average, persistent loss of sensation was found in 52 patients (93%), persistent paresthesia and dysesthesia in 17 (30%) patients each, and persistent pain in 14 (25%) patients. Pain and paresthesia showed better postoperative improvement than the other sensory symptoms. 15 cases (27%) were diagnosed by histology alone. In 21 cases (37%), nonspecific histological findings contributed valuable diagnostic information. The remaining 20 cases (36%) continued to be unclear despite histology. Demyelinating or mixed-type neuropathies did not yield better results than purely axonal forms. We conclude that sural nerve biopsy is a valuable diagnostic tool, but its side-effects require careful selection of fully informed patients.

Wild birds are considered a potential reservoir or a carrier of viral diseases and may therefore play a role in the epidemiology of economically important or zoonotic diseases. In 2001 and 2002, a survey with special emphasis on virus isolation in migrating waders and some other birds were conducted. In one of the most important inland resting sites for migratory waterfowl, tracheal and cloacal swabs were collected from 465 waders representing 19 different species, and 165 other birds that were not captured on purpose. A total of 42 avian viruses were isolated, 34 of these were identified as paramyxoviruses (PMVs). The majority of isolates came from waders and wild ducks, and were characterized as PMV-1. In contrast, PMV-4 was found in wild ducks only, PMV-6 was mainly detected in wader species. Four avian influenza viruses (AIVs), belonging to H4 and H3 haemagglutinin subtype, were isolated from wild duck species. Furthermore, four reo-like viruses were isolated from one particular wader species for the first time. The majority of virus positive birds were <1 year old and did not show any clinical symptoms. There was no evidence for the presence of West Nile virus in these birds. These results confirm that the restricted resting sites in Western Europe must be considered as important locations for the intra- and interspecies transmission of avian viruses.

Fifteen sural nerve biopsies of vasculitic neuropathies have been compared with 11 cases of different non-vasculitic neuropathies and normal nerves from brain-dead organ donors. The APAAP (alkaline phosphatase monoclonal anti-alkaline phosphatase) immunostaining method was applied to cryostat sections from unfixed snap-frozen tissue samples. Immunoglobulins IgG, IgM, IgA, complement factors and light chains were reactive in biopsies of normal nerves as well as of vasculitic and nonvasculitic neuropathies. A strong reaction against IgE in the epineurial vessel walls was only seen in cases of Churg-Strauss-vasculitis. Antibodies against MHC class II (HLA DR) were positive in most of vasculitic infiltrates. Vascular endothelial cells were positive with anti MHC class I in all biopsies. A typical finding in all vasculitic neuropathies was the infiltration of epineurial vessels with CD4 positive and, to a lesser extent, CD8 positive lymphocytes. CD22 positive lymphocytes (B cells) have only been seen in about one third of vasculitic neuropathies. CD16 positive cells (NK-cells or neutrophils) could be demonstrated only in two biopsies. CD68 positive cells (macrophages) are frequently seen in most cases of neuropathy regardless of their etiology. The results support the concept of a primary T-cell mediated process against epineurial vessels as the most important mechanism in the pathogenesis of vasculitic neuropathies. In some cases with small epineurial infiltrates the vasculitic process can only be recognized with antibodies against CD4 or CD8. Therefore, the immunohistochemical evaluation of sural nerve biopsies may be helpful for identifying cases with microvasculitis.