Human T lymphotropic virus type I antibody patterns: evidence of difference by age and risk group.

Detection of human T lymphotropic virus type I (HTLV-I) antibody was assessed on 368 sera from subjects with different clinical features and from different parts of the world. Enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay for purified p24 antibodies (p24-RIA) used as screening tests agreed in 88.7% of the sera. The results from 247 selected sera were compared with western blot (WB). WB was reactive in sera five to 25 times more dilute than the last positive ELISA or p24-RIA, but different WB batches varied in sensitivity. ELISA was more sensitive than p24-RIA, and p24-RIA was more specific than ELISA. Indeterminate WB interpretations were common (25.5%). Most seropositive intravenous drug abusers had unusually strong p24 bands by WB. Among healthy individuals, positive WB reactivity increased with age, whereas indeterminate reactivity declined (P = .034). Thus, more-sensitive and -specific HTLV-I antibody tests are needed.

Epidemiology of human T-lymphotropic virus type III and the risk of the acquired immunodeficiency syndrome.

The discovery of human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) has opened a window to the understanding of the spectrum of the acquired immunodeficiency syndrome (AIDS) and related clinical syndromes. Analysis of risk factors for seropositivity has shown that HTLV-III is transmitted most efficiently via routes that involve close personal contact or parenteral exposure. Longitudinal studies have shown that HTLV-III infection has a long latent period. The prevalence of AIDS in different geographic areas and among different risk groups appears to depend in part on duration of exposure. Co-factors for AIDS outcome such as manner and route of exposure, underlying immune status, and host susceptibility are also likely to play a role in risk.

AIDS in Haitian-Americans: a reassessment.

PIP: The occurrence of acquired immunodeficiency syndrome (AIDS) in Haitians and Haitian-Americans has remained an enigmatic aspect of the AIDS mystery. Although Haitians are currently classified as a high risk group, this designation has been disputed. The incidence of AIDS in recent Haitian immigrants to the US has been estimated at 84/100,000, which is lower than the 200-240/100,000 figure put forward for other risk groups. To better understand the spread of AIDS within the Haitian population, a serologic study of human T-lymphotropic virus type III (HTLV-III) seropostivity was performed on 88 healthy Haitians and 21 Haitians with AIDS in New York City. 95.2% of Haitian AIDS patients compared with only 1.1% of controls had a positive ELISA for HTLV-III infection. The low rate of seropositivity in health Haitians contrasts sharply with the prevalence of seropositivity noted in other high risk groups. For example, HTLV-III antibodies have been detected in 53% of healthy New York homosexuals and over 60% of drug users in New York and New Jersey. A likely explanation is that only a small segment of Haitian-Americans are really at risk of HTLV-III infection, and that this risk is conferred not by practices widespread in the Haitian community but by homosexuality, drug abuse, blood transfusions, or other as yet unidentified modes of transmission. Support for this thesis is provided by data from Haiti, where AIDS cases have been associated with bisexuality, an extremely high prevalence of veneral diseases, and contact with prostitutes. It is concluded that the designation of the entire Haitian community as a high risk group for AIDS may be inappropriate.^ieng