Transmission of human immunodeficiency virus (HIV) by blood transfusions screened as negative for HIV antibody

Photochemical decontamination of blood components containing hepatitis B and non-A, non-B virus

Diluted plasma samples containing 10(2), 10(3), 10(4), and 10(5) chimpanzee infectious doses (CID) of a human non-A, non-B hepatitis virus (NANBV) were treated with a combination of two psoralen compounds, 4'-aminomethyl-4,5',8-trimethylpsoralen and 4,5',8-trimethylpsoralen, and exposed to long wavelength ultraviolet. Each dilution was then transfused into one of four chimpanzees. In a second experiment, three samples containing 10(4.5) CID of hepatitis B virus (HBV) and two samples containing 10(4) CID of NANBV were treated with 8-methoxypsoralen (8-MOP) and ultraviolet irradiation. Two chimpanzees were each transfused with both a treated HBV and a treated NANBV sample. The third chimpanzee was inoculated with a treated HBV sample alone. In the six months after inoculation none of the animals showed biochemical or histological evidence of hepatitis. In experiments involving NANBV inocula, the susceptibility of the animals was confirmed by subsequent challenge with untreated NANBV. Factor VIII concentrate containing virus and photochemically treated as in the first experiment retained an average of 91% of its activity while that in the second experiment retained 94% of its activity.

Safety of blood and blood products in Scandinavia today

The safety of blood and blood products in Scandinavia today is high. An absolutely safe blood supply is, however, an unattainable goal. The dominating risk is transmission of non-A, non-B virus (NANBV). The calculated per blood unit risk is 1:200. The incidence of cirrhosis due to post-transfusion hepatitis NANB is calculated to at most 0.1% among recipients of blood components from about 5 donors. Other risk factors are transmission of hepatitis B virus (HBV), human immunodeficiency virus (HIV-1) and cytomegalovirus (CMV). The prevalence of HBsAg among first time donors is about 0.05% (Sweden). In Scandinavia, anti-HIV-1 has been found in 0.001% of donations from start of screening in 1985 to December 1987. The prevalence was higher in Denmark, lower in Finland (and perhaps Iceland). The prevalence has declined during the last years. As of June 1988, 117 patients in the Scandinavian countries have been infected by blood components, all but 2 before screening was introduced. Besides these, 226 haemophiliacs have been infected by, in almost all cases, imported clotting factor concentrates before heat treatment was introduced. Most of the infected patients are still asymptomatic. About 70% of blood donors have anti-CMV, a few percent of which will transmit CMV-infection, with severe symptoms, to immunosuppressed patients without anti-CMV.

Human retroviruses

After many unsuccessful years of searching, the first pathogenic human retrovirus, the human T-cell leukaemia lymphoma virus (HTLV-I), was reported as recently as 1980 and since that time has been causally linked to the adult T-cell leukaemia lymphoma syndrome. A second HTLV (HTLV-II) isolated shortly afterwards is less clearly linked to some leukaemic and chronic lymphoid malignancies. The second major family of human retroviruses are the human immunodeficiency viruses (HIV) the first group of isolates (HIV-I) of which cause the acquired deficiency syndrome (AIDS). A second group of these viruses (HIV-II), have recently been identified in West Africa. They appear to be less clearly associated with disease and more similar in molecular structure to the Simian immunodeficiency viruses. AIDS has now become a major global pandemic, and vaccine and therapeutic strategies are urgently being investigated in an effort to control the disease. Unfortunately, current results are not very encouraging. In the meantime, preventative and educational measures are of utmost priority in order to prevent further spread. It is not unlikely that new human retroviruses will be discovered over the next few years.

Transfusion transmitted human T-lymphotropic virus infections

Human immunodeficiency virus (HIV) type 1 has emerged during the 1980s as an important transfusion transmitted agent. The impact of HIV depends on the epidemiology and characteristics of the virus, serological response to infection and efficacy of serological tests to identify infected blood units. These factors will be described in the present article. The risk to acquire HIV today, by transfusion of anti-HIV screened blood, is extremely small in Scandinavia and the Western world. The risk can be further minimized by more sensitive screening tests and an improved donor information. The epidemiology in Scandinavia of other members of the human T-lymphotrophic viruses, HTLV-1 and HIV-2, has to be further investigated.

DNA diagnostics--molecular techniques and automation

Molecular biology has revolutionized the understanding of many aspects of human disease. Ongoing developments in DNA diagnostics--the analysis of disease at the nucleic acid level--will soon provide automated, rapid, and inexpensive analyses for DNA or RNA sequences associated with genetic, malignant, and infectious diseases. DNA diagnostics will also facilitate the identification of disease-associated genes at birth, thus creating new opportunities for preventive medicine.

Identification of HIV-infected seronegative individuals by a direct diagnostic test based on hybridisation to amplified viral DNA

There is a need for direct detection of the virus in people infected with human immunodeficiency virus (HIV), independently of a serological response. In this study, after enzymic amplification of a specific segment of the HIV genome, a simple slot-blot hybridisation procedure allowed unequivocal identification of HIV DNA in all seropositive subjects tested. More importantly, the hybridisation test allowed the detection of HIV DNA in several seronegative subjects from very high risk groups. This new direct approach towards the diagnosis of HIV infection, which can easily be carried out on a large scale, is therefore capable of identifying HIV-infected individuals before the development of antibodies.

Arthroscopic reconstruction of the anterior cruciate ligament using allograft tendon

Treatment of the anterior cruciate ligament (ACL)-deficient knee using an arthroscopic technique and freeze-dried allograft tendons in 23 patients was studied prospectively. Accurate placement of drill holes and anchoring positions for the allografts was effected through a standard arthroscopic approach combined with a 3 cm incision on the medial tibial flare. Candidates for reconstruction were those who were unable to tolerate brace therapy and who had no degenerative arthritis. The 23 patients were drawn from a group of 60 treated patients because their follow-up had been greater than or equal to 1 year. Their knees were assessed preoperatively and postoperatively with a Lysholm knee rating scale, Lachman test with KT-1000 arthrometric quantitation, pivot shift, Biodex test, and radiographs. Knee rating values improved in all knees, and only one patient had a significant deterioration in the KT-1000 reading. All patients with at least 20 months follow-up have resumed their preinjury activity levels.