Evidence for a cytotoxic T-lymphocyte alveolitis in human immunodeficiency virus-infected patients.

A T8 lymphocyte alveolitis occurs in HIV-positive patients, even in the absence of any lung infections or tumors. Using the monoclonal antibody (MAb) D44, the CD8+ T cells can be further subdivided into two functional subsets of cytotoxic T lymphocytes (CTL; CD8+, D44+) and suppressor T cells (CD8+, D44-). A dual fluorescence analysis of alveolar and peripheral lymphocytes has been used in HIV-positive patients without lung infections or tumors to reveal a dramatic increase in alveolar T8 lymphocytes (83%), compared to peripheral values (52%), which was mainly composed (89%) of CD8+ D44+ CTLs. Functional studies confirmed the cytolytic activity of these phenotypically defined alveolar CTLs on autologous alveolar macrophages used as target cells, excluding a natural killer-like activity. An immuno-enzyme analysis concomitantly revealed the co-expression of the p18 HIV antigen and the CD4 molecule on the autologous alveolar macrophages. These data suggest that CTL alveolitis occurs during HIV infection and is directed against HIV-infected alveolar macrophages which are presumably the targets of the locally recruited lung CTLs.

Rapid, nonradioactive detection of clonal T-cell receptor gene rearrangements in lymphoid neoplasms.

Southern blot hybridization analysis of clonal antigen receptor gene rearrangements has proved to be a valuable adjunct to conventional methods for diagnosing lymphoid neoplasia. However, Southern blot analysis suffers from a number of technical disadvantages, including the time necessary to obtain results, the use of radioactivity, and the susceptibility of the method to various artifacts. We have investigated an alternative approach for assessing the clonality of antigen receptor gene rearrangements in lymphoid tissue biopsy specimens. This approach involves the amplification of rearranged gamma T-cell receptor genes by the polymerase chain reaction and analysis of the polymerase chain reaction products by denaturing gradient gel electrophoresis. By use of this approach, clonal rearrangements from neoplastic lymphocytes constituting as little as 0.1-1% of the total cells in the tissue are detected as discrete bands in the denaturing gel after the gel is stained with ethidium bromide and viewed under ultraviolet light. In contrast, polyclonal rearrangements from reactive lymphocytes appear as a diffuse smear along the length of the gel. Our findings suggest that polymerase chain reaction combined with denaturing gradient gel electrophoresis may offer a rapid, nonradioactive, and sensitive alternative to Southern blot analysis for the diagnostic evaluation of lymphoid tissue biopsy specimens.

Quantitation of T-cell DNA in cutaneous lymphoid infiltrates.

A method is described that allows the quantitation of T-cell DNA within a tissue biopsy specimen. This method is based on the densitometric evaluation of the multiband pattern of TCR-gamma gene rearrangements detectable in Southern blot analyses of polyclonal T-cell DNA digested with HindIII. These rearrangements can be detected down to a limit of approximately 5% T-cell DNA. The information derived from this type of analysis can be used to roughly assess the total T-cell content of lesional tissue specimens expressed as a percentage of total tissue DNA, and can be correlated with the pattern of T-cell infiltration visualized by immunohistology. This assessment can be used also to determine the threshold, expressed as a percentage of total lesional T-cell DNA instead of total tissue DNA, required for the detection of a monoclonal T-cell population by Southern blot analysis. These quantitative relationships may prove useful for studying cutaneous T-cell lymphoma and associated precursor conditions.