An analysis of serum samples positive for HTLV-III antibodies

Gastrointestinal tract and viral pathogens

Viral gastroenteritis is the most common viral illness that affects the gastrointestinal (GI) tract, causing inflammation and irritation of the lining of the stomach and intestines. Common signs and symptoms associated with this condition include abdominal pain, diarrhea, and dehydration. The infections commonly involved in viral gastroenteritis are rotavirus, norovirus, and adenovirus, which spread through the fecal-oral and contact routes and cause non-bloody diarrhea. These infections can affect both immunocompetent and immunocompromised individuals. Since the pandemic in 2019, coronavirus gastroenteritis has increased in incidence and prevalence. Morbidity and mortality rates from viral gastroenteritis have declined significantly over the years due to early recognition, treatment with oral rehydration salts, and prompt vaccination. Improved sanitation measures have also played a key role in reducing the transmission of infection. In addition to viral hepatitis causing liver disease, herpes virus, and cytomegalovirus are responsible for ulcerative GI disease. They are associated with bloody diarrhea and commonly occur in im-munocompromised individuals. Hepatitis viruses, Epstein-Barr virus, herpesvirus 8, and human papillomavirus have been involved in benign and malignant diseases. This mini review aims to list different viruses affecting the GI tract. It will cover common symptoms aiding in diagnosis and various important aspects of each viral infection that can aid diagnosis and management. This will help primary care physicians and hospitalists diagnose and treat patients more easily.

Acquired immunodeficiency syndrome mimicking Sjögren's syndrome and systemic lupus erythematosus

We describe a patient in whom the diagnosis of transfusion-associated acquired immunodeficiency syndrome (AIDS) was delayed because her clinical symptoms were similar to those of systemic lupus erythematosus and Sjögren's syndrome and because of a false-negative result on a Western blot test for human immunodeficiency virus. The importance of using different diagnostic tests for AIDS and the pitfalls in diagnosing AIDS in patients who appear to have connective tissue disease are discussed.

Acquired immunodeficiency syndrome (AIDS)

The Acquired Immunodeficiency Syndrome (AIDS), caused by the human immunodeficiency virus (HIV), also called the human T-lymphotropic virus type III/lymphadenopathy-associated virus [HTLV-III/LAV], has affected over 23,000 people; more than half of those with the disease have died. The actual case fatality rate approaches 100%. AIDS affects all groups and classes of people, although some are at special risk. Distribution of the disease is worldwide. The illness' effects on the body are widespread; of special interest are the ophthalmologic manifestations. The eye may be infected by various viruses (cytomegalovirus, varicella-zoster virus, herpes simplex virus or HIV itself), toxoplasma gondii, candida sp, cryptococcus neoformans, M. tuberculosis, or M. avium-intracellulare. Kaposi's sarcoma may affect the eye as well. Retinal vascular abnormalities (e.g., cotton-wool spots, vasculitis) are not uncommon in AIDS. The syndrome may present with neuro-ophthalmologic manifestations. No effective treatment for the illness is currently available, although several hold promise and there is hope for an AIDS vaccine. Prevention of infection through reduction of risks appears to be the only defense against AIDS at this time.

Evaluation of six enzyme immunoassays for antibody against human immunodeficiency virus

Six commercial enzyme immunoassays (EIA) were evaluated in 6488 serum samples, with immunoblot analysis as the confirmatory test for antibodies against human immunodeficiency virus (HIV). The Abbott and Wellcome tests identified all 163 immunoblot-positive samples correctly, whereas the other tests did not detect 1-3 samples. In AIDS patients (predominantly with antibodies to gp41env) Organon's EIA was less sensitive (p less than 0.05) and Wellcome's more sensitive (p less than 0.05) than the immunoblot assay. In symptom-free anti-HIV-positive subjects (antibodies to almost all viral antigens and high titres of anti-p24gag) all the EIA were significantly (p less than 0.05) less sensitive than the immunoblot assay. The frequencies of false-positive reactions in a "tricky" panel of samples from patients with autoimmune and acute viral diseases and in a blood-donor panel were Abbott 9.5%, 0.42%: Organon 1.7%, 0%; Litton 1.0%, 0.4%; Behring 2.7%, 0.06%; Wellcome 0%, 0%; and Pasteur 0%, 0.02%. The results of a seventh EIA (Dupont) were excluded from the study at the company's request. All six EIA evaluated are suitable tests for anti-HIV screening in samples from patients and blood donors.

HTLV-III antibody testing in three Danish blood banks

The Organon Teknika Vironostika anti-HTLV-III/LAV test was evaluated in three Danish blood banks. The evaluation comprised in total 3,940 consecutive donors. In all three blood banks the tests were carried out exactly according to the manufacturer's instructions, using a low cut-off value defined as (4N + P)/5, where N and P are means of optical densities of known negative and positive samples. By this method the overall frequency of repeatably positive samples was 0.30%. When tested by Western blot, however, none of these samples were shown to contain specific antibodies against HTLV-III/LAV proteins. When testing different categories of patients, only sera containing HLA antibodies gave rise to false-positive reactions. Finally, important differences in the results were observed regarding sample preparation, single or dual wavelength optical density readings, and the experience of the technical staff.

Importance of western blot analysis in predicting infectivity of anti-HTLV-III/LAV positive blood

Stored donor and recipient sera from prospective studies of post-transfusion hepatitis were analysed for the presence of human T-cell lymphotropic virus type-III/lymphadenopathy associated virus (HTLV-III/LAV) antibodies as determined by enzyme-linked immunosorbent assays (ELISA). Of 3961 donor samples given to 461 patients, only 2 (0.05%) contained specific HTLV-III/LAV antibodies as determined by an avidin-biotin-enhanced western blot tech nique. Anti-HTLV-III/LAV was measured before and 3 and 6 months after transfusion in 295 recipients of anti-HTLV-III-negative blood, 7 recipients of ELISA-positive blood which was western blot negative, and 2 recipients of ELISA-positive blood confirmed as specific by western blot. Only the last 2 recipients became infected with HTLV-III/LAV, as assessed by antibody seroconversion (p less than 0.0001). Serocon version occurred early (6 and 8 weeks after transfusion) and was characterised first by antibody to p24 and later by antibody to p41. AIDS has not developed in either patient, but one has a T4/T8 ratio of 0.4 and impaired mitogen responses; the second patient has no evidence of immune dysfunction 4 years after exposure. This study confirms that HTLV-III/LAV infection can be transmitted by blood transfusion and supports the advisability of anti-HTLV-III/LAV testing of all blood donors. It also confirms the validity of western blot testing for HTLV-III/LAV specificity and suggests that ELISA-positive, western-blot-negative blood may not be infectious.

Which anti-HTLV III/LAV assays for screening and confirmatory testing?

In preparation for routine anti-HTLV-III/LAV testing in the UK five commercial assays (A-E) were evaluated using 360 sera selected on clinical and epidemiological grounds. These comprised 220 specimens from blood donors, 83 specimens from patients in high-risk groups, and 57 specimens with features likely to produce false-positive results. Probably erroneous positive results arose from assay A in all three categories and assay B in the second and third categories. These reactions were much more common after specimens had been heated to 56 degrees C for 30 min. Except that an anti-HLA DR4,B5-containing serum was repeatedly positive by C, assays C, D, and E apparently did not give rise to false-positive results. Results by these three assays were also highly reproducible. In tests on serum dilutions the highest titres were obtained by assays A and D, but assays C and E discriminated most clearly between anti-HTLV-III/LAV positive and negative sera. These two assays were rapid and convenient and seemed particularly suitable for testing blood donations. Assay D was almost comparable with them in performance but more difficult to use. The commercial assays C, D and E, an antibody capture assay, and a simple immunofluorescence test could be the basis for a methodologically diverse national system of primary and confirmatory testing for anti-HTLV-III/LAV.

Transmission of human T-cell lymphotropic virus type III (HTLV-III) by artificial insemination by donor

Four of eight recipients of artificial insemination (AI) with cryopreserved semen from a symptomless carrier of human T-cell lymphotropic virus type III (HTLV-III) were found to have antibody to the virus. One has generalised, persistent lymphadenopathy while the other three remain symptom free 3 years after insemination. Three subsequently became pregnant more than a year after contact with the infected semen; the children, who are now over 1 year of age, are in good health and do not have HTLV-III antibodies. These observations emphasise the need for a rigorous screening programme for potential AI donors; they also suggest that fresh semen should not be used in AI. The findings confirm the role of semen in heterosexual transmission of the virus and suggest that in women with HTLV-III antibodies pregnancy and subsequent breast-feeding does not necessarily lead to infection of the infant.