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Wilms' tumor (WT) is associated with chromosomal deletions and loss of heterozygosity (LOH) of alleles at 11p13. The authors report the youngest known patient with diffusely anaplastic WT and, to their knowledge, the first case to demonstrate telomeric fusions as a chromosomal mechanism for the loss of bands 11p13 and 11p15 in WT. Recurrent clonal telomeric association (tas) initiated breakage/fusion cycles that resulted in deletions of chromosome bands 11p15, 11p13, and, subsequently, the entire short arm of chromosome 11. In addition, tas involving the long arms of chromosomes 7 and 9 resulted in the subsequent deletion of the long arm of chromosome 7. This report expands the spectrum of chromosomal mechanisms that can account for the loss of alleles on the short arm of chromosome 11 in WT by providing evidence that the progressive loss of critical chromosome regions associated with tumor suppression may occur as a result of chromosomal instability initiated by tas. Cancer 1994; 74: 767-73.

Cell-mediated cytotoxicity (CMC) specific for human immunodeficiency virus (HIV) is a type of antibody dependent cellular cytotoxicity (ADCC) activity, in which antibodies to HIV bind to immune cells, known as natural killer (NK) cells, enabling them to kill any cell containing HIV antigens. This type of cellular immunity occurs in early stages of the disease, but decreases with the progression of HIV. The factors that contribute to the decline of this activity were examined by studying the various conditions under which antibodies bind to the NK cells. Sera from patients with HIV infection were tested for the presence of antibodies that allow ADCC activity and for the binding of antibody to NK cells. HIV-infected patients without symptoms of AIDS had low levels of antibodies for ADCC, but did not have antibodies that could bind to NK cells. However, patients with AIDS had large amounts of antibodies for ADCC activity, but did not have antibodies that could bind to NK cells. There was also a group of patients who had low levels of CMC, but large amounts of antibodies which could bind to NK cells. This indicates that other factors besides the amount of antibody specific to HIV are involved in the decrease of CMC. Lymphocytes from AIDS patients had lower levels of ADCC and NK activity, compared with normal individuals, even if there was a lot of antibody present so that these cells could be armed. Therefore, in patients who are infected with HIV, there are defects in both the types and levels of antibodies and in the cells themselves. These defects result in the decline of CMC activity. To know what conditions would allow the arming of NK cells is important, since this information could be used to develop a type of immunotherapy for HIV infection or AIDS. (Consumer Summary produced by Reliance Medical Information, Inc.)