HTLV-I：HTLV-I.ppt

* * * * * * * * * * * * * * * * * * * * * * * Immunosuppression Patients with ATLL are immunosuppressed and at risk of developing opportunistic infections including pneumocystis jirovecii pneumonia, cryptococcus meningitis, and disseminated herpes zoster Severe, and often fatal, infestation by and dissemination of strongyloides stercoralis is common as well PATHOLOGY The organs involved varies but can include the peripheral blood and bone marrow, lymph nodes, and skin. The most characteristic morphologic change seen in ATLL is in the peripheral blood of leukemic cases. In such cases, medium sized lymphocytes with condensed chromatin and bizarre hyperlobated nuclei (clover leaf or flower cells) can be found, often resembling the Sezary cells of mycosis fungoides Bone marrow involvement is seen in approximately 35 percent of cases. Bone marrow infiltrates are usually patchy, ranging from sparse to moderate. Immunophenotype The malignant cell of origin in ATLL is considered to be an HTLV-I infected mature helper (CD4+) T-lymphocyte in various stages of transformation. At a minimum, suspected cells should be tested for CD3, CD4, CD7, CD8, and CD25. Tumor cells express T-cell associated antigens (CD2, CD4, and CD5), but usually lack CD7 The most common immunophenotype is CD4+, CD25+, CD7-, and CD8- Rare cases are CD4-/CD8+ or CD4+/CD8+. Genetics? ?There is no distinct molecular or karyotypic abnormality in ATLL other than clonally-integrated HTLV-1, which is observed in all malignant cells . Karyotypic analysis is generally reserved for patients enrolled in clinical trials. The T-cell receptor genes are clonally rearranged . HTLV-1 infection Practically all patients with ATLL have serologic antibodies to HTLV-I. An enzyme-linked immunosorbent assay (ELISA) is the most frequently used screening test, using antigens prepared from whole virus lysate or by recombinant technology. Western blotting (WB) is normally used for confirmatory testing