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Latent structure analysis can be used to determine sensitivity and specificity rates of human immunodeficiency virus antibody assays in the absence of previous clinical or laboratory results. The technique was applied to the analysis of data obtained when a panel of serum samples, collected as part of a large-scale screening project, were subjected to four conventional bioassays (ag121, p24, gp120, and an enzyme-linked immunosorbent assay). To determine the accuracy of this statistical approach, the results of latent structure analysis were compared with the known clinical diagnoses of patients from whom the samples were taken, and nearly 100% agreement was obtained. Although a two-class latent structure model had some predictive value, a three-class model more adequately explained assay patterns. The use of the four standard assays in conjunction with the statistical methods described here would largely reduce the need for confirmatory Western blot assays in analyses of large panels of samples.

We used a link between cancer (859,398 reports) and AIDS (50,050 reports) registries in the United States to study whether nasopharyngeal carcinoma (NPC) was increased in the population with AIDS. There was no indication of a significantly increased risk up to or after the AIDS diagnosis, which argues against progressively failing immunity being important in the development of this malignancy.

In June 1982, the sexual practices of 245 homosexual male outpatients of private physicians were evaluated in relationship to decreased numbers of helper T lymphocytes, an abnormality that is characteristic of the acquired immunodeficiency syndrome (AIDS). Three risk groups were defined a priori--85 high-risk men from central Manhattan ("New York"), 96 intermediate-risk men from Washington, DC, with AIDS-area homosexual contacts ("Washington-exposed"), and 64 low-risk Washington, DC, men without such contacts ("Washington-unexposed"). An increasing number of homosexual partners was correlated with decreasing helper T-cell counts (R = -0.29, p = 0.009) and decreasing helper:suppressor T-cell ratios (R = -0.32, p = 0.005) in the entire study group combined and in New York subjects separately. Suppressor T-cell counts were unrelated to the number of partners in all three groups. Increasingly frequent receptive anal intercourse correlated with decreasing helper T-cell counts most clearly in the New York City group (R = -0.23, p = 0.04), somewhat less so in the Washington-exposed group (R = -0.18, p = 0.07), and not at all in the Washington-unexposed group (R = -0.09, p = 0.48). This association persisted in the New York and Washington-exposed groups after adjusting for seven other sexual practices, the number of homosexual partners, and five other potentially confounding variables. A transmissible agent associated with receptive anal intercourse best explains these data. The cause of these low helper T-cell counts may also be the cause of AIDS.

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