Nodavirus provokes subclinical encephalitis and retinochoroiditis in adult farmed Atlantic cod, Gadus morhua L.

Viral nervous necrosis (VNN) caused by beta-nodavirus affects many species of farmed marine fish, in particular juveniles. Apparently healthy, normally feeding, adult farmed Atlantic cod, Gadus morhua, were sampled in a farm 14 months after an outbreak of VNN with clinical signs. Following necropsy, brain and eye tissues were examined by histology, immunohistochemistry and polymerase chain reaction (PCR). Nodavirus-provoked cell death and inflammation was detected in eye and brain, particularly in the retina and cerebellum and differed from that previously described in Atlantic cod during clinical stages of VNN. Virus was detected both by PCR and immunohistochemistry. This is, to the best of our knowledge, the first description of pathological changes associated with chronic subclinical nodavirus infection in Atlantic cod. Our observations suggest that severe infection and pathological changes may go undetected if investigations are restricted to clinical examination and macroscopic evaluation at necropsy.

T-cell/natural killer cell lymphoblastic lymphoma with an unusual coexpression of B-cell antigens.

Lymphoblastic lymphomas are usually B- or T-cell neoplasms. There exists a small group of T-cell lymphomas additionally coexpressing cytotoxic or natural killer (NK)-cell markers, supporting the hypothesis of a common T/NK-cell precursor and respective neoplasms. Clinically, lymphatic neoplasms of T/NK-cell phenotype are either extranodal lymphomas or acute leukemias. The clinical course of these T/NK neoplasms cannot be predicted by morphology and/or phenotype alone. However, the expression of a heterogeneous (T + NK or myeloid) marker profile or of "early" antigens (such as TdT, CD10, RAG1, RAG2) render them more likely to be in the acute leukemia group. We present a case of a 63-year-old woman with a bone marrow infiltrate, enlarged lymph nodes, and B-symptoms. A cervical lymph node biopsy showed a monomorphic blastic infiltrate with a T-cell phenotype, coexpressing NK markers (CD56, CD57, NK1) and B-cell antigens (CD20, CD79). To the best of our knowledge, this is a newly recognized phenotype that has not been reported before. T/NK-cell lymphomas, including blastic NK-cell leukemia/lymphoma and T-lymphoblastic lymphomas, have to be included in the differential diagnosis. Both groups have a different clinical behavior and prognosis. In particular, T/NK-cell lymphomas associated with an Epstein Barr virus infection are clinically very aggressive neoplasms.

[Comparative analysis of various standard immunohistochemical procedures]. / Vergleichende Analyse verschiedener immunhistochemischer Standardverfahren.

Immunohistochemical staining techniques, such as the APAAP, ABC, EnVision and Immuf1p4x methods, play a leading role in the search to solve the questions arising in clinical diagnosis. With the increase in number of techniques for diagnostic examination, the sarch for suitable method is becoming more and more important. The goal of this study was to compare these different treatments with regard to sensitivity and specificity. Furthermore, an analysis of time and cost was made. The primary antibodies used were CD20, CD30 and IgM, as well as receptor antibodies estrogen and progesterone. The variable costs of each technique were calculated based on selected examples. The APAAP method required the most time and was, at the same time, by far the most expensive treatment. The EnVision method required the least time and showed very good staining results, which were comparable to those of the ABC and ImmunoMax techniques. The staining costs could be reduced by about 95% and the staining intensity improved substantially by using expensive receptor antibodies in combination with the Immuno-Max method. This study illustrates the importance of knowing different examination techniques, as well as the costs arising by their usage.