Assessment of aerosol containment on the ELITE flow cytometer.

Biohazardous aerosols generated during cell sorting have been of increased concern recently because of interest in sorting specimens containing human immunodeficiency virus type 1 (HIV-1). Current flow cytometers have features designed to contain such aerosols within the sorting chamber, but the efficacy of these features has not been established. Therefore, we tested aerosol containment by two ELITE flow cytometers (Coulter Cytometry, Inc., Hialeah, FL) during sorting of specimens containing high titers of bacteriophage. Agar plates confluent with susceptible Escherichia coli were used to detect infectious units released from the sorting chamber. Under recommended operating conditions very few infectious units were released from the sorting chambers. Release increased when the center stream was not optimally collected in a vacuum-exhausted tube or the chamber door was not completely closed. Failure of the negative pressure and high efficiency particle air (HEPA) filtration features had less of an effect. The data indicate that these standard safety features provide a rational expectation of safety for the flow cytometry operator.

Blood and plasma donations among a cohort of intravenous drug users.

We evaluated the blood and plasma donation histories of a cohort of 2921 intravenous drug users in Baltimore, Md, and correlated these histories with their human immunodeficiency virus (HIV) serologic status, numbers of CD4 lymphocytes in the peripheral blood, and stigmata of intravenous drug use (scarred veins). Of the 793 intravenous drug users (27.1%) who had donated blood or plasma, 652 (82.2%) donated after they had started using intravenous drugs. Most subjects donated at commercial plasma centers, where they were paid $10 to $15 per donation. Although the HIV-1 seroprevalence of the entire cohort was 24.1%, the HIV-1 seroprevalence among those reporting plasma or blood donations declined progressively with time, from 17.1% in those who last donated in 1985 to 3.6% in those who last donated in 1988-1989. Many of the 437 intravenous drug users who had donated plasma or blood since 1985, when screening for HIV-1 was initiated, had not been notified and counseled about their HIV test results. Current programs to exclude individuals with a history of intravenous drug use from the plasma donor pool should be reevaluated and improved.

KIE: The authors studied the blood and plasma donation histories of a cohort of intravenous drug users who had been recruited for a natural history study of HIV-1 infection. Most subjects who had donated blood after beginning to use intravenous drugs had done so at a commercial plasma center where they had been paid for their donation. According to self-reports, many of the subjects donating since 1985 (when mandatory screening of all donors for HIV antibodies began) had not been notified or counseled about their HIV status by personnel at the centers where they had donated. Nelson, et al. believe that greater efforts are needed to identify and exclude intravenous drug users as blood donors, and to notify and counsel potential donors whose blood tests positive for HIV antibodies.