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A sensitive and specific avidin-biotin enzyme immunoassay that uses immunoreagents from naturally infected individuals was formulated for the detection of human immunodeficiency virus (HIV) antigens. A total of 500 cell culture samples from 111 cultures were tested in this assay and in a reverse transcriptase (RT) assay. Of 353 samples that were positive in the immunoassay, 174 were positive and 179 were negative in the RT assay. The specificity of the immunoassay results was supported by the failure of samples to react with nonimmune serum, by the ability of an anti-HIV type 1 monoclonal antibody to block the reactivity of selected samples, and by the appearance of RT activity in samples drawn from some cultures after a longer period of cultivation. HIV antigens were detected in 174 of 176 RT-positive samples (sensitivity, 98.9%). A comparison of the kinetics of antigen production and RT activity revealed that detectable antigen levels frequently preceded the appearance of RT activity. Thus, 50% of virus-containing cultures were identified within 9 days by immunoassay compared with 14 days by RT assay. In addition, RT activity was often detected intermittently in cultures sampled on several days, whereas antigen levels did not decline after initial appearance. Enzyme immunoassays for HIV antigen detection that use easily obtained reagents and simple technologies could facilitate laboratory and clinical research which requires cultivation of viruses.

In order to define the risk factors for infection with hepatitis C virus, the authors determined the prevalence and incidence of antibodies to hepatitis C in three cohorts in Baltimore, Maryland, enrolled in prospective studies of human immunodeficiency virus (HIV-1) infection. Among 500 multi-transfused patients who underwent cardiac surgery in 1985 and 1986, 12 (2.4%) were hepatitis C seropositive before surgery while 19 (3.9%) developed antibodies in the 8-12 months after surgery. The seroprevalence of hepatitis C virus among 225 intravenous drug users followed since 1988 was 85%, which did not vary by HIV-1 status. Longer duration of intravenous drug use was significantly associated with hepatitis C seropositivity. Among 926 homosexual/bisexual men followed since 1984, 15 (1.6%) were hepatitis C seropositive; only intravenous drug use and a history of hepatitis A were marginally associated with hepatitis C in this population. No association was found between hepatitis C virus and HIV-1 or sexual behavior variables in this population. These data suggest that hepatitis C is readily transmitted by blood exposure, but is transmitted inefficiently by sexual means.

We determined intrathecal synthesis (ITS) of anti-HIV-1 immunoglobulin in 62 CSF samples from 51 HIV-1 seropositive homosexual men using an ELISA technique with paired serum and CSF samples diluted to a concentration of IgG of 10 μg/ml. All subjects were neurologically normal and none was taking zidovudine. We estimated duration of HIV-1 infection from semiannual serologic testing during the 3-year period before CSF analysis and detected ITS of anti-HIV-1 immunoglobulin in 2 of 12 (17) of those with <18 months of HIV-1 seropositivity, in 3 of 21 (14) with 19 to 36 months, and in 13 of 29 (45) with >36 months of HIV-1 seropositivity (p0.037). There was a trend toward an inverse relationship between level of ITS and the peripheral blood T-helper lymphocyte count. This study demonstrates that increasing ITS of anti-HIV-1 IgG is related to duration of HIV-1 infection and suggests an inverse correlation with systemic immune status. The detection of ITS of anti-HIV-1 immunoglobulin is not necessarily a marker of clinically overt neurologic involvement.

Two human retroviruses, HIV-1 and HTLV-I, have been associated with myelopathies in addition to other neurologic disorders. We report an American dually infected with HIV-1 and HTLV-I who developed steroid-responsive myeloneuropathy. This 28-year-old bisexual man developed interstitial pneumonitis and a transient midthoracic sensory level followed by the evolution of a slowly progressive spastic paraparesis and sensorimotor neuropathy. Serologic studies demonstrated coinfection with both HIV-1 and HTLV-I. Peripheral blood absolute CD4 count was persistently within the normal range. Cranial MRI was normal and spinal MRI showed T3-T10 atrophy. Serial CSF analyses demonstrated marked intrathecal synthesis of anti-HTLV-I IgG, lymphocytic pleocytosis, elevated protein and immunoglobulin G, and oligoclonal bands. HIV-1 was isolated from CSF but not from peripheral nerve. Lymphoproliferative studies confirmed spontaneous proliferation in both blood and CSF. Soluble interleukin 2 receptor and soluble CD8 were greatly elevated in blood and CSF when compared with patients with HIV-related vacuolar myelopathy and seronegative patients with other causes of myelopathy. Nerve biopsy showed epi- and endoneurial CD8 lymphocytic infiltration without vasculitis; muscle biopsy showed features of acute and chronic denervation. A 6-week course of prednisone produced sustained improvement in leg strength and walking times. We speculate that the myeloneuropathy was caused by HTLV-I in the setting of coinfection with HIV-1.

We measured serum and CSF β2-microglobulin (β2M) levels in HIV-1 seropositive individuals with and without dementia to determine the frequency and diagnostic utility of elevation of CSF β32M. We compared 34 samples from 27 patients with HIV-1 dementia with 110 samples from 54 HIV-1 seropositive participants in the Multicenter AIDS Cohort Study, none of whom had progressive dementia. Neurosyphilis and CNS opportunistic processes were excluded in all subjects. We stratified the nondemented subjects by duration of HIV seropositivity and peripheral blood CD4 count. Compared with the nondemented group, demented subjects had significantly higher CSF total protein, IgG, and CSF albumin/serum albumin ratios. A highly significant association was found between elevated CSF β2M and reduced CD4 count (p< 0.0001). No significant differences were noted between the demented and nondemented groups in CSF WBC count or in the frequency of CSF HIV-1 isolation. The mean CSF β2M was 1.9 mg/l in the nondemented subjects compared with 4.2 mg/l in those with dementia (p< 0.0001). We derived a cutoff of 3.8 mg/l from the distribution of CSF β2M in the nondemented group. The determination of CSF β2M had a sensitivity of 44, specificity of 90, and a positive predictive value of 88 for diagnosis of HIV dementia when compared with nondemented subjects with CD4 counts <200. In those without dementia, there was a strong correlation between serum and CSF β2M (r 0.50, p< 0.0001), but in demented subjects CSF β2M was elevated independently of serum levels, suggesting that CSF β2M is produced within the brain in HIV dementia. In the absence of CNS opportunistic processes, elevated CSF β2M >3.8 mg/l is a clinically useful marker for HIV dementia.

In this report we describe a novel, nonisotopic hybridization assay for the measurement of viral RNA in biological samples. The assay involved a solution-phase reaction between a biotinylated DNA probe and RNA target sequences. Labeled hybrids were detected in an immunoreaction by using a solid-phase anti-biotin antibody and an enzyme-labeled monoclonal antibody specific for DNA-RNA hybrids. This monoclonal antibody solution hybridization assay was compared with an antigen-capture immunoassay for the detection of human immunodeficiency virus in 436 cell culture samples from 60 seropositive patients. The sensitivity and specificity of the hybridization assay were 93.5 and 94.6%, respectively. Detection of human immunodeficiency virus solely by hybridization in the initial sample but not subsequent samples from seven cultures may reflect detection of virus that was present in the patients' lymphocytes but did not replicate in vitro. Since the assay method is adapatable to the detection of either RNA or DNA, it could provide a means for the detection of a wide range of viral nucleic acids.

A current concept of the serological response to human immunodeficiency virus (HIV) infection in humans is that antibodies to core antigens (p55, p24, and p15) are detectable earlier during initial stages of antibody production than antibodies against envelope antigens (gp160, gp120, and gp41). Comparative studies of Western blot (immunoblot), radioimmunoprecipitation assay (RIPA), and enzyme-linked immunosorbent assay (ELISA) during initial antibody production are limited to case reports and have not resolved the issue. Thirty of the 37 participants who are part of a prospective study had at least one specimen that was negative for anti-gp41 but had one or more other bands on Western blot. Twenty-seven of these 30 specimens were reactive for anti-gp120/160 in the RIPA. Of the same 30 specimens, kits from Bionetics identified 2 (7%), ElectroNucleonics 4 (13%), Abbott 13 (43%), Du Pont 25 (83%), and Genetic Systems 25 (83%). All participants had evidence of serological progression by Western blot, including a gp41 band, on subsequent visits; the ELISA kits of all manufacturers identified these later specimens with greater accuracy. These data show that the RIPA detects anti-envelope antibodies that may be not detectable by Western blot and that the production of anti-envelope antibodies approximately parallels the production of anti-core antibodies. The false-negative results by ELISA would permit transmission of HIV by blood transfusion from donors in early stages of infection. The sensitivity of licensed ELISA kits should be improved to identify antibody as soon as possible after infection.

Urethral exudates from male patients with gonorrhoea were studied by use of the critical point drying technique for scanning electron microscopy. The surfaces of phagocytes were extensively ruffled. This was interpreted to be the three-dimensional appearance of pseudopodia. Epithelial cells present in the urethral exudate showed a highly convoluted surface structure. Specimens of urethral exudate prepared by the freeze-etch technique showed that most N. gonorrhoeae were engulfed individually in phagocytes. Some phagosomes contained two or more gonococcal cells. Phagocytes containing gonococci were degranulated, but small granules were present in the phagosomes. Nuclear pores on the surface of the nuclear membrane were always associated with an indentation of the nuclear membrane. The outer layer of the nuclear membrane was smooth compared to the inner layer, [ABSTRACT FROM PUBLISHER]