Evolutionary Patterns of the Proviral gp90 V3 to V5 Regions of Equine Infectious Anemia Virus Associated with Immune Selection in Progressors and Nonprogressors

The aim of this study was to determine the genomic evolutionary pattern of virulent equine infectious anemia virus （EIAV） during persistent infection. The evolutionary dynamics of proviral genomes were examined by challenging an EIAV seronegative equine （pony 1） and three EIAV vaccinated equines （ponies 4, 7, and 8） with the Chinese virulent strain EIAV- L. Ponies 1 and 7 succumbed to disease and were called progressors, while ponies 4 and 8 lacked clinical symptoms and were considered nonprogressors. Sequences spanning the V3, V4, and V5 hyper-variable regions of the EIAV-L envelope gp90 gene were sequenced from each pony as evolutionary markers of the provirus. The proviral genome of the EIAV-L inoculum evolved during persistent infection and displayed different patterns between EIA progressors and nonprogressors. Inoculum-like variants were isolated from nonprogressors during persistent infection, but only from progressors during acute infection. Variant mutations from nonprogressors were dispersed throughout the sequenced region, while those from progressors were predominantly localized to V3. Humoral immunity and virus variant population selection analyses indicated that immune selection was positive in chronically infected progressors and weak in nonprogressors. In-frame stop codons were frequently localized to a defect ＂hot spot＂. The high number of defective variants in nonprogressors may promote disease survival.

Clinicopathologic,immunophenotypic and ultrastructrual analyses of ATLL patients with cutaneous involvement

Objective To study 4 cases of adult T cell leukemia/lymphoma (ATLL) as sociated with cutaneous lesions for clinicopathology, immunophenotype, human T cell leukemia/lymphoma virus type Ⅰ (HTLV Ⅰ) provirus DNA and their ultrastru cture. At the same time, HTLV Ⅰ provirus DNA of ATLL patients were also compar ed with 18 cases of cutaneous lymphoma (CL), two cases of actinic reticuloid as well as two cases of lymphocytic infiltration.Methods Immunohistochemistry studies were carried out on the infiltrati ng cells using monoclonal antibodies against CD45 RO, CD20, CD68 on paraffin e mbedded sections by ABC method and using monoclonal antibodies against CD3, CD4 and CD8 with indirect immunofluorescence (IIF) on frozen sections. Skin biopsies were examined by electron microscope. Serum and bone marrow cells were tested f or antibodies against HTLV Ⅰ associated antigen by IIF, and HTLV Ⅰ provirus DNA was examined by PCR method.Results The research showed four patients with ATLL manifesting cutaneo u s lesions, were subsequently found with additional systemic symptoms, as extensi vely enlarged superficial lymph node, abnormal increased IL 2 receptor, flower like cells in their peripheral blood and marrow. The HTLV Ⅰ provirus DNA was positi ve in the peripheral blood, bone marrow, cutaneous lesions and lymph node biopsy specimens by using PCR amplification of specific HTLV Ⅰ fragment while 18 cas es of the CL were negative for HTLV Ⅰ. The special ultrastructure of skin lesi ons was also found in ATLL patients.Conclusions The cutaneous involvement in ATLL is a type of cutaneous T cell lymphoma (CTCL) but shows some differential immunological markers for diffe rential diagnosis. The examination of HTLV Ⅰ antibodies or HTLV Ⅰ provirus D NA is necessary for diagnosis of ATLL. The ultrastrustural characteristics in skin lesions of ATLL were of atypic al lymphocytes and mononuclear cells invading the epidermis, and the mononuclear cells are possessing the phagocytic function and phagocytizing the degenerated epidermic cells or lymphocytes.