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An expanded case definition for AIDS may more than double the number of HIV-positive individuals who are classified as having AIDS. The 1987 Centers for Disease Control (CDC) AIDS case definition may be expanded to include HIV-positive individuals with less that 200 CD4 T-cells per cubic millimeter of blood. The expanded case definition and two other expanded definitions of AIDS involving other T-cell subsets were used to classify 762 HIV-positive homosexual and bisexual men who were HIV-positive in 1984. Implementation of any one of the expanded definitions of AIDS in mid-1991 would have more than doubled the number of living HIV-positive individuals with AIDS. The proposed CDC definition would have increased the number of living HIV-positive individuals with AIDS in mid-1991 by 212%. The other two expanded case definitions would have increased this number by 266% and 272%.

Homosexual or bisexual men who have more sexual partners may have a higher risk of HIV infection than those with fewer sexual partners. Those who have receptive anal intercourse may also have a higher risk of HIV infection than those who do not. A study compared 83 homosexual or bisexual men who became HIV-positive between 1984 and 1989 to 246 who did not become HIV-positive during this time period. Fifty-seven percent of the HIV-positive men had five or more male sexual partners, compared to 34% of the HIV-negative men. Men who were HIV-positive were more likely to have had receptive anal intercourse or receptive oral intercourse than those who were HIV-negative. The risk of HIV infection was higher among men who used condoms with some partners than among those who did not use condoms with any partners. Men who used condoms with some partners may have had sex with a larger number of HIV-positive partners than those who did not use condoms with any partners.

Significantly more HIV-positive men surveyed in San Francisco used antiviral therapy and preventative anti-Pneumocystis carinii pneumonia (PCP) therapy in 1991 than in 1987-89. Of 42 men with AIDS, 93% had used antiretroviral drugs at some time, up from 58% in 1989, and 71% were currently using them. Also, 81% had used anti-PCP therapy before, up from 44% in 1989, and 67% were currently undergoing anti-PCP therapy. Of 313 HIV-positive men without AIDS, 57% had used antiretroviral drugs and 46% were currently taking them. Only 32% of them had ever undergone preventative anti-PCP therapy and 26% were currently undergoing anti-PCP therapy. The San Francisco HIV-positive population is more educated, has a higher socioeconomic status and greater awareness of and access to HIV treatment than does most of the HIV-infected population in the US. These finding suggest that in areas where both patients and doctors are well-informed of treatments available, high use of HIV therapy can be achieved.

Recent years have witnessed an increase in the rate of heterosexual transmission of human immunodeficiency virus (HIV), the causative agent of AIDS. Among heterosexual men, the proportion of AIDS cases increased from 0.1 percent of all US AIDS cases in 1983 to 1.4 percent in 1988; for heterosexual women, the percentage increased from 13 percent of all US AIDS cases in 1983 to 28 percent in 1988. The sexual behavior and changes in high-risk behavior of 179 heterosexual men from the San Francisco area were studied over a five-year period. When the study began, in 1984, none of the participants was infected with HIV. In more recent follow-up periods, the men reported fewer sexual partners and an increased use of condoms, compared with earlier follow-up periods. Men who were married during the five-year study (75) were analyzed separately from those who were not married. The number of unmarried men (104) who had two or more partners in the previous 6 months, decreased from 53.2 percent to 40.7 percent. One of the 209 men (less than 0.5 percent) became infected with HIV during the five-year study. (Consumer Summary produced by Reliance Medical Information, Inc.)

The polymerase chain reaction (PCR) is a new technique in which low levels of genetic material are amplified to large quantities so that they can be studied. PCR is used to detect low levels of HIV (human immunodeficiency virus) in individuals who do not have detectable levels of HIV antibodies (based on the commonly used antibody test). The significance of positive PCR results in HIV-negative (seronegative) men is controversial, and the relation between such findings and the epidemiology of HIV infection is uncertain. An analysis of the results of the PCR reaction was performed with 324 men from the San Francisco Men's Health Study; 105 men were exclusively heterosexual and 219 were homosexual or bisexual. None of the men had detectable antibodies to HIV on standard tests. The frequency of positive PCR reactions between the two groups was compared and the risk factors for infection among the homosexual men were evaluated. Approximately 8.6 percent of the samples were weakly positive by the PCR reaction, but none were definitely positive. This finding occurred to the same level in men who had homosexual contact and were at risk for developing infection and in heterosexual men who were not at risk. These findings demonstrate that PCR testing does not provide evidence for the existence of a group of homosexual men with very low levels of virus. In addition, the results do not provide any indication that HIV can exist in low levels, as might occur in cases of latent infection (one that did not fully develop) or viral exposure without infection. (Consumer Summary produced by Reliance Medical Information, Inc.)

Zidovudine (also known as ZDV or AZT) is a drug that has been used widely since 1987, when it was first found to be effective in prolonging the life of patients with AIDS. Aerosol pentamidine (AP) is another drug that has been found to be effective against the complications of AIDS - it decreases the rate of recurrence of Pneumocystis carinii pneumonia (PCP), a disease which can be fatal. Despite the help these medications provide, little is known about the extent to which they are used. Data are presented here to shed light on this topic. The data were obtained from the San Francisco Men's Health Study and from the San Francisco General Hospital Cohort; approximately 500 subjects were interviewed regularly from 1987 to 1989. Between 1987 and 1989, the proportion of participants with AIDS using ZDV increased from 36 percent to 68 percent, and there was a similar increase in its use by asymptomatic and symptomatic HIV-infected patients. Use was higher for white subjects as a group than for Hispanic or black subjects, although the numbers of nonwhite subjects were small, so these findings are not necessarily representative. Age group and occupational status were not significant variables. Combined therapy (both ZDV and AP) was used by 43.9 percent of those with AIDS and only 4.8 percent of those with asymptomatic HIV infection. It is suggested that the data may be biased toward overestimating the use of ZDV and AP, because those participating in the study may have been better motivated and informed than the general population. The proportion of patients with AIDS not taking ZDV, about 42 percent, may be explained by side effects, or use of other experimental protocols rather than just failure to use the drug. The low rate of use of AP for prevention of PCP, on the other hand, is alarming and not likely to be due to the use of other drugs that are available, or side effects of AP. Perhaps inadequate health insurance, financial resources, or lack of HIV/AIDS-related education play a role in this trend. (Consumer Summary produced by Reliance Medical Information, Inc.)

Since mid-1987, the number of AIDS cases among homosexual and bisexual men, hemophiliacs and other recipients of transfusions has decreased. However, the number of AIDS cases among intravenous drug users and those who acquired the disease through heterosexual contacts has increased. Further analysis of these demographic groups showed that the incidence of AIDS has decreased among white gay men from urban areas such as New York City, Los Angeles and San Francisco, while there was no change in the incidence among nonwhite gay men from suburban or rural areas. The trends in the change in incidence were related to access to medical care and the use of the drug zidovudine by gays, hemophiliacs and recipients of transfusions. Zidovudine began to be nationally distributed during mid-1987. Data from the study support the theory that zidovudine use, and perhaps the use of other therapies, such as pentamidine prophylaxis against pneumonia caused by Pneumocystis carinii, and suppression of the herpes virus, contributes to the decreased incidence of AIDS in some groups and not others. It is important that zidovudine and other therapies become available to other groups, especially intravenous drugs users and those infected through heterosexual relationships, including minorities, women and those living outside of urban areas. It is felt that these groups do not have adequate access to treatment and that a decreased incidence of AIDS would also be seen in these groups if these treatments were available. (Consumer Summary produced by Reliance Medical Information, Inc.)

The polymerase chain reaction (PCR), a technique used to analyze genetic material, can be used to detect extremely small amounts of the human immunodeficiency virus type-1 (HIV-1). In fact, by analyzing DNA, PCR can detect the presence of the virus in individuals who do not seem to be infected, as indicated by the negative results of blood tests used to identify antibodies to HIV-1 (seronegative individuals). The sensitivity, specificity and accuracy of PCR testing were analyzed in five laboratories which were experienced in PCR techniques. All the laboratories used the same blood samples, which were obtained from 105 HIV-1 seronegative individuals who did not have any of the risk factors for HIV infection, such as homosexuality, hemophilia, intravenous drug use, and prostitution, and from 99 homosexual or bisexual men who were seropositive (that is, tested positive for antibody to HIV). The average sensitivity (being able to detect the presence of the virus) was 99 percent, with the range of sensitivity among the five laboratories ranging from 98 to 100 percent. The average specificity (the validity of detection) was 95 percent, with a range of 90 to 100 percent. The percentage of false-positive results (detected as positive, but really negative) was 2 percent, and the percentage false-negatives (detected as negative, but really positive) was 0.8 percent. Approximately 3 percent of the cases were misclassified due to laboratory error, such as specimen mix-up or carrying over results from one specimen to another. This study demonstrates that the PCR test had low specificity rates and high rates of false-negative results in some laboratories. Uniform results were not obtained in laboratories experienced in PCR techniques. The authors conclude that standardization of PCR testing must be achieved before this technique can be used as a routine test to determine the presence of HIV-1. Until then, PCR results should be interpreted with caution. (Consumer Summary produced by Reliance Medical Information, Inc.)

Beta 2-microglobulins (B2M), half of which are produced by lymphocytes (specialized white blood cells), are thought to be involved in the immune response. High numbers of beta 2-microglobulins have been reported in patients with kidney disease (because the microglobulins are cleared by the kidneys), autoimmune disorders (the immune system's failure to recognize the body's own cells) and infectious diseases, including the human immunodeficiency virus (HIV). It is not known if the microglobulin is high during infectious diseases because of increased production or increased release because of destruction of lymphocytes. Specialized white blood cells, CD4 lymphocytes, increase as HIV-infected patients become more ill with the disease AIDS (acquired immunodeficiency syndrome). To see if B2M and CD4 lymphocyte measurements can predict the development of AIDS, 962 unmarried men were studied in San Francisco. AIDS developed in 65 out of 388 men infected by the HIV. The average level of B2M in uninfected men was 170 (measured in nanomoles per liter), compared with 254 in HIV-infected men without AIDS and 347 in HIV-infected men with AIDS. Three year later, 34 percent of the men with B2M of 322 developed AIDS, 21 percent of the men with B2M between 246 and 322 developed AIDS and 7.3 percent of the men with B2M levels below 246 developed AIDS. When the two measurements were combined, 65 percent of men with a B2M of greater than 322 and CD4 lymphocytes of less than 550 developed AIDS within three years. The probability of HIV-infected individuals developing AIDS can be predicted by using B2M and CD4 measurements. (Consumer Summary produced by Reliance Medical Information, Inc.)

Study objectives: Results from several studies have described a relationship between pulmonary function and both all-cause and cause-specific mortality. The purpose of this study was to investigate the predictive value [...]