Vertical transmission of hepatitis A resulting in an outbreak in a neonatal intensive care unit.

Vertical transmission of hepatitis A virus (HAV) has not been reported. From 25 October to 15 November 1989, 10 cases of symptomatic HAV infection occurred among neonatal intensive care unit (NICU) staff. Testing of other NICU staff and patients identified 4 infected infants. Hepatitis A among staff was associated with caring for 1 of these infants, infant A (relative risk [RR], undefined; P = .05). Risk of illness was greater for staff who did not routinely wash their hands after treating infant A for apnea and bradycardia (RR = 4.9; P = .02). Staff, infants, visitors, and transfused blood products could not be implicated as a source of infant A's infection. Infant A's mother, however, was diagnosed with hepatitis A 10 days after premature labor and delivery. Evidence suggests that infant A was infected by his mother before or during birth. HAV then spread within the NICU because of breaks in infection control precautions. To prevent future outbreaks, NICU staff should adhere rigorously to body substance isolation measures.

HIV testing in prisoners: is mandatory testing mandatory?

We studied 977 newly incarcerated Oregon inmates to compare voluntary versus mandatory human immunodeficiency virus antibody (HIVAb) testing in the prison setting. All inmates were offered HIVAb counseling and testing. Blood drawn for routine syphilis serology from those who declined this offer was also tested for HIVAb after personal identifiers had been removed. Only 1.2 percent (12) prisoners were HIV positive. However, 62.5 percent (611) inmates were at risk for HIV infection by being an intravenous drug user, a male homosexual, or hepatitis B core antibody (HBcAb) positive. The ratio of at-risk, as yet uninfected inmates to those already HIV infected was 53 to 1. Two-thirds of all inmates including those at-risk chose to receive counseling and testing. In areas where most at-risk inmates are not yet infected, it may be more appropriate for HIV prevention activities in prison to focus on voluntary programs that emphasize education and counseling rather than mandatory programs that emphasize testing.

Macrophage-lymphocyte interactions mediated by soluble factors.

Adherent-cell-depleted primed rabbit splenocytes were capable of mounting an in vitro response to SRBC. The addition of alveolar macrophages (AM) to adherent-cell-depleted or unseparated lymphoid cell populations resulted in significant suppression of the PFC response. Suppressive activity was limited to AM and dependent on the presence of a ratio of 1 AM:20 lymphocytes. The cell-mediating suppression was found to be resistant to irradiation and antithymus globulin but sensitive to heat, freeze-thawing, and treatment with iodoacetamide. Suppression was mediated by a soluble factor (MW greater than 10,000 daltons) that required an AM-lymphocyte interaction for its production. Suppression appeared to be achieved through the inhibition of proliferation of antigen sensitive cells although the effect of AM could possibly be exerted on an early event in the immune response. AM were capable of enhancing the proliferative responses of rabbit lymphoid cells to PHA and Con A. Enhancing and suppressing activities of AM were abolished by inhibition of RNA synthesis but unaffected by inhibitors of DNA and protein synthesis.

Alveolar macrophage--induced suppression of the immune response.

Alveolar macrophages were shown to suppress the in vitro immune response of rabbit lymphoid cells stimulated with heterologous erythrocytes. Suppression was associated with an adherent, phagocytic cell that was resistant to the effects of irradiation and treatment with anti-thymus serum. Suppression was mediated by a soluble factor whose production was independent of antigen and required an interaction of viable alveolar macrophages and lymphocytes. Suppression was associated with an early event in the induction of the PFC response and appeared to affect lymphocyte proliferation. Suppression could not attributed to cytotoxicity, sequestration of antigen, depletion of nutrients or release of prostaglandins, arginase or thymidine. These results, taken together, provide additional information regarding immunological function of alveolar macrophages and suggest that they play a regulatory role in the immune response.