T-cell neoplasms

NHLs are derived from monoclonal proliferation of B or, less commonly, T lymphocytes and their precursors. Two categories of B- and T-cell neoplasms are precursor neoplasms corresponding to the earliest stages of differentiation, and peripheral neoplasms corresponding to the more differentiated cell stages. 

These tumors include all T cell neoplasms that are derived from postthymic T cells and, because of immunophenotypic and apparent biologic similarities, include the natural killer (NK) cell lymphomas. 

Precursor B cell neoplasm Precursor T cell neoplasm Nodular... 

Marafioti T, Ascani S, Pulford K, et al. Expression of B-lymphocyte-associated transcription factors in human T-cell neoplasms. Am J Pathol. 2003 162 861-871. 

B- and T-cell neoplasms are divided into precursor disorders (lymphoblastic leukemias and lymphomas) with normal counterparts in the earliest bone marrow and thymus compartments, and mature, or peripheral, malignancies akin to normal extrathymic, nodal, splenic, or circulating lymphocytes. Discussion is focused on those malignancies commonly diagnosed using immunohistochemistry (i.e., solid tumors). 

Chott A, Vesely M, Simonitsch I, et al. Classification of intestinal T-cell neoplasms and their differential diagnosis. Am J Clin Pathol. 1999 111(1 Suppl 1) S68-S74. 

The immunoprofile of MNHL separates it from other malignant mixed-cell neoplasms of the mediastinum. It includes reactivity for CD45 in all lesional cells, as well as positivity for CD20 in B-cell tumors or CD3, CD43, or CD45R0 in T-cell neoplasms.Keratin is universally absent, but some p63 isoforms are variably expressed by non-Hodgkin lymphomas of various types. 

Immunohistochemically, the cells of RAH/ALCL are usually reactive for CD3, CD5, CD45, CD30, CD43, CD45RO, and CD99 in paraffin sections (Fig. 13.22). 9208,211-216 phenotype supports the interpretation of most of these lesions (=80%) as T-cell neoplasms. The remaining cases demonstrate null-cell differentiation. Primary ALCLs in the skin are typically negative for the ALK-1 protein, whereas systemic ALCLs that involve the skin are ALK-1 reactive. 

Lymphoid neoplasms are clone-expanded proliferations of cells representing distinct stages of B/T cell development. Immunoglobulin gene rearrangements can be detected to indicate monoclonality of B-cell lineage lymphoproliferative... 

Table 11 lists the reactivity of antibodies to various lymphoreticular neoplasms in formalin- or B5-fixed tissues. Many of the monoclonal antibodies available to B- or T-cell lymphomas are not strictly lineage specific (MBl, MB2, LNl, MTl). CD20 (L26) (45) for B-cells and CD45RO (UCHL-1) (46) for T-cells has been shown to be fairly specific. UCHL-1 is not present on all T-cells, therefore one may want to include another T-cell marker to detect T-cell lymphomas. (3-FI (47), which recognizes a framework epitope on the T-cell P chain antigen receptor, and anti-CD3 (48) may be particularly promising in specifically detecting T-cell lymphomas. 

T4. Tsuruda, K., Yamada, Y, Hirakata, Y, Sugahara, K., Maeda, T, Atogami, S., Tomonaga, M., and Kamihira, S., Qualitative and quantitative characterization of Fas (APO-I/CD95) on leukemic cells derived from patients with B-cell neoplasms. Leuk. Res. 23,159—166 (1999). 

According to the CDC, the diagnosis of AIDS constitutes certain opportunistic infections, neoplasms, encephalopathy or wasting syndrome in the presence of HIV infection. In 1993, the CDC expanded the criteria to also include CD4+ T-cell count below 200 cells/p,l in the presence of HIV infection. The most common opportunistic infections includepneumocystis carinii pneumonia, pneumonitis, toxoplasmosis, mycobacterial disease, recurrent herpes simplex virus infection and/or cytomegalovirus infection. Kaposi s sarcoma is the most common form of cancer. HIV-related nervous system diseases include acute septic meningitis, AIDS dementia complex, subacute encephalitis, HIV encephalopathy and CNS opportunistic infections and neoplasm. 

Lymphoid neoplasms are divided into three main categories B cell neoplasms, T/NK cell neoplasms, and Hodgkin lymphoma. The B and T/NK cell neoplasms are further divided into precursor B and mature B cell neoplasms and into precursor T and mature T/NK cell neoplasms, respectively. The mature B cell and T/NK neoplasms consist of a variety of different neoplastic lymphoid entities, which can be grouped based on primary clinical presentation or based on median survivals without treatment reflecting biologic behavior. However, due to the large number of separate entities, only the more common lesions will be discussed. For information concerning the entities not discussed here or for more in-depth information, the... 

R13. Royer, B., Cazals-Hatem, D., Sibilia, J., Agbalika, F., Cayuela, J. M., Soussi, T., Maloisel, F., Clauvel, J. P., Brouet, J. C., and Mariette, X., Lymphomas in patients with Sjogren s syndrome are marginal zone B-cell neoplasms, arise in diverse extranodal and nodal sites, and are not associated with viruses. Blood 90, 766-775 (1997). 

CDw52, a 21- to 28-kDa phosphatidylinositol-linked glycoprotein of unclear function, is widely expressed on the cell surface of both B and T lymphocytes (187). Anti-CDw52 mAbs include CAMPATH-1 and its humanized version CAMPATH-1H (187-188). CAMPATH-IH has been evaluated in multiple clinical trials, in which it has shown anticancer efficacy against a variety of lymphoid neoplasms (188-190). However, CAMPATH-IH also induced rapid depletion of both B cells and T cells, resulting in potentially profound immunosuppression (191). 

---