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Women with HIV infection are more likely to have bacterial vaginosis but it is not clear whether HIV infection causes the vaginosis or vice versa. Bacterial vaginosis is a bacterial infection of the vagina. Researchers took vaginal swabs to test 724 pregnant women for bacterial vaginosis. Ten of the women were HIV-positive. Three percent of the women with bacterial vaginosis were HIV-positive, compared to less than 1% of the women who did not have bacterial vaginosis. Bacterial vaginosis may increase a woman's risk of contracting HIV infection during sexual intercourse.

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.)

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We examined the effects of short interpregnancy intervals on small-for-gestational age and preterm births in a biracial population using North Carolina birth certificate data from 1988 to 1994. We defined small-for-gestational age birth as being below the 10th percentile on a race-, sex-, and parity-specific growth curve after a gestation of 37–42 weeks. We defined preterm birth as a gestation of less than 37 weeks. We analyzed birth records from all eligible singleton births to black or white women ages 15–45 years after an interpregnancy interval of 0–3 months (N = 11,451) and a random sample of singleton births after an interval of 4–24 months (N = 23,118). We defined interpregnancy interval exposure categories as 0–3, 4–12, and 13–24 months. The multivariate adjusted odds ratio for small-for-gestational age births after interpregnancy intervals of 0–3 months compared with 13–24-month intervals was 1.6 (95 confidence interval = 1.4–1.8). The odds ratio for preterm birth after interpregnancy intervals of 0–3 months was 1.2 (95 confidence interval = 1.1–1.3). Odds ratios did not vary substantially by race for either outcome. (Epidemiology 1999;10:250–254)

• Serum β2-microglobulin (β2M) levels were measured by radioimmunoassay in 962 unmarried men recruited by probability sampling from areas in San Francisco, Calif, most severely affected by the epidemic of acquired immunodeficiency syndrome (AIDS). From July 1984 to December 1987, 65 incident AIDS cases occurred in 388 homosexual/bisexual men infected by the human immunodeficiency virus (HIV) at the time of recruitment. The mean level of β2M in uninfected individuals at entry was 170 nmol/L. In HIV-seropositive patients who had not developed AIDS, the mean β2M level was 254 nmol/L, and in those who had developed AIDS, the β2M level was 347 nmol/L. After 36 months of follow-up, 34% of individuals with β2M levels greater than 322 nmol/L at entry developed AIDS, 21% of individuals with levels between 246 and 322 nmol/L developed AIDS, while only 7.3% of those with levels below 246 nmol/L developed AIDS. The β2M level predicted the development of AIDS independently of the CD4 lymphocyte count in HIV-seropositive individuals. Thus, 65.5% of HIV-seropositive individuals with β2M levels above 322 nmol/L and CD4 lymphocyte counts of below 500/μL developed AIDS in 3 years. This represents an 18.4-fold increased relative hazard at 3 years over individuals with β2M and CD4 cell counts within the reference range for uninfected individuals. A nomogram is provided that allows the easy calculation of the probability of an HIV-infected person developing AIDS in 36 months depending on prevalent levels of CD4 lymphocytes and serum β2M.(Arch Intern Med. 1990;150:73-77)