Early detection of human immunodeficiency virus type 1 infection in Australian infants at risk of perinatal infection and factors affecting transmission

The earliest, most reliable methods for detecting human immunodeficiency virus type 1 (HIV-1) infection in infants at risk of perinatal HIV-1 and risks for transmission were investigated. Fifteen infants were followed prospectively from birth to age 21 to 48 months. Epidemiologic data on mothers during pregnancy were documented, and maternal proviral load (by quantitative polymerase chain reaction) and viral phenotype by HIV isolation were performed. Infants were assessed clinically and HIV isolation, HIV p24 antigen, polymerase chain reaction and total serum immunoglobulin determinations were performed. Four infants were infected. HIV isolation, HIV p24 antigen and polymerase chain reaction were positive within 3 months in all infected infants (100% sensitivity). False positive rates for a single test were 18, 9 and 9%, respectively. Median age of clearance of maternal antibodies was 13.4 +/- 2.1 months. Serum immunoglobulin G was significantly elevated after 6 months in all 4 infected infants. Advanced maternal age (> or = 30 years; Fisher's exact test, P > 0.014) was associated with transmission. A trend in higher maternal viral burden was observed among transmitters. Non-syncytium-inducing phenotype was present initially in all transmitting mothers.

Interleukin 4 and human immunodeficiency virus stimulate LFA-1-ICAM-1-mediated aggregation of monocytes and subsequent giant cell formation

The effects of recombinant interleukin 4 (IL-4) on cell cluster and multinucleated giant cell (MGC) formation from human immunodeficiency virus (HIV)-infected and uninfected monocytes were examined. Human blood monocytes were isolated by centrifugal elutriation and monoclonal antibody-complement-dependent lysis of residual T cells, and infected with low passage HIV strains. Monocytes were exposed to recombinant IL-4 (1 to 20 ng/ml), continuously after inoculation with HIV. Monocyte expression of ICAM-1 but not LFA-1 was significantly enhanced by IL-4 although substrate adherence was a more potent stimulus. Monocyte cluster and MGC formation was quantified after fixation and staining with Giemsa. Clusters of HIV-infected and uninfected monocytes were consistently and significantly increased at 4 to 7 days after IL-4 stimulation. The combination of HIV and IL-4 was more stimulatory than either treatment alone. In two out of five uninfected and three out of seven HIV-infected monocyte cultures, MGC formation was also markedly increased at 10 to 14 days after stimulation. Incubation with anti-LFA-1 (anti-CD11a, anti-CD18) and anti-ICAM-1 (anti-CD54) monoclonal antibodies reduced IL-4-stimulated aggregation in HIV-infected and uninfected monocytes and subsequently reduced MGC formation. Anti-ICAM-1 was not as effective as anti-CD11a or anti-CD18 in inhibiting aggregation of HIV-infected monocytes and in these cultures anti-ICAM-2 was also inhibitory. Extracellular HIV antigen concentrations were not consistently reduced by anti-CD11a or anti-ICAM-1. Hence IL-4 markedly enhanced monocyte aggregation in both HIV-infected and uninfected monocytes, probably through enhanced LFA-1-ICAM-1 interactions in all cultures and LFA-1-ICAM-2 interactions in infected monocytes, leading subsequently to MGC formation in some cultures.

Sulfated polyanions prevent HIV infection of lymphocytes by disruption of the CD4-gp120 interaction, but do not inhibit monocyte infection

Sulfated polyanions (SPs) bind variably to lymphocyte-expressed CD4 and inhibit binding of monoclonal antibodies to the first two domains of CD4. To further define this interaction, soluble recombinant CD4 (sCD4; four extracellular domains), its truncated amino-terminal two-domain derivative, and three linear peptide analogues spanning residues 6-60 (6-24, 20-40, 41-60) in the first domain were investigated for SP binding. Dextran sulfate (DXS) (500 kDa), polyvinyl sulfate, fucoidan, and carrageenan-kappa, each immobilized on carboxymethyl cellulose fibers, bound strongly to both the two-domain and four-domain recombinant CD4 molecules (similar to that observed with native CD4), whereas dextran sulfate (5 kDa), chondroitin 6-sulfate, and pentosan sulfate bound relatively poorly. No peptide binding to SPs was observed. Recombinant gp120 bound poorly (< 10%) to all of the immobilized polyanions, except pentosan sulfate (17%), for which some binding was noted. Binding of radiolabeled V3 loop peptide to SPs was slightly greater, with 20-30% binding to polyvinyl sulfate, dextran sulfate (500 kDa), and pentosan sulfate. Competitive binding studies demonstrated the predominance of sCD4 rather than rgp120 binding to SPs and supported previous data demonstrating a binding site for DXS (500 kDa) on the first domain of CD4 adjacent to the gp120 binding site and recognized by OKT4C and E monoclonal antibodies. Hence disruption of the CD4-gp120 interaction is probably responsible for most of the observed antiviral activity of SPs toward HIV infection of lymphocytes. However, HIV infection and gp120 binding to monocytes was unaffected by SPs, probably because SPs were unable to block the CD4-gp 120 interaction in monocytes.

The magnitude of HIV replication in monocytes and macrophages is influenced by environmental conditions, viral strain, and host cells

It has been difficult to standardize the effects of various stimuli on HIV replication in monocytes and macrophages in different laboratories. In this study we have shown that it is possible to standardize HIV inocula, culture conditions, and HIV antigen assay to achieve reproducibility with the same viral isolate and donor monocyte and macrophage. However, changes in serum concentration, in the strain of blood-derived isolate (even at low passage), in the donor source of the monocyte/macrophage, and in the state of cellular maturation all influenced HIV production by these cells. The donor source of monocytes contributed as much to variability in HIV production as the HIV strain and results were reproducible when the same source was used repeatedly. These in vitro data suggest that genetic differences may contribute to differences in HIV replication in macrophages and consequently to tissue virus load in vivo.

Molecular mechanisms of IL-4 effect on HIV expression in promonocytic cell lines and primary human monocytes

HIV-1 can productively infect mononuclear phagocytes derived from blood, bone marrow, brain, and lung. Interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-alpha) have previously been shown to stimulate HIV replication in monocytes and macrophages. The mechanism of IL-4 stimulation was investigated and compared with the known effects of TNF-alpha. IL-4 up-regulated the expression of HIV mRNA within the first 2 days after infection of promonocytic U-937 cells and 3 to 4 days after infection of plastic-adherent blood macrophages with HIV-1. TNF-alpha also up-regulated production of HIV RNA but to a greater degree than IL-4, reaching a peak 3-4 days after addition. Northern blot analyses showed an increase in genomic and spliced RNAs at these times. However, there was reduced stimulation of HIV mRNA production when IL-4 and TNF-alpha were combined. These techniques are being used to further elucidate the mechanism of action of cytokines that inhibit HIV replication in purified human monocytes and macrophages.

HIV infection of placental macrophages: their potential role in vertical transmission

Placental macrophages were isolated and cultured in vitro to investigate their susceptibility to HIV infection and possible role in vertical transmission of HIV. After 10 days of in vitro culture the cells were positive for nonspecific esterase and acid phosphatase and negative for myeloperoxidase and placental alkaline phosphatase. They expressed cell surface HLA-ABC, HLA-DR, CD45, as well as CD68 intracellularly, as detected by flow cytometry, confirming their macrophage lineage. Approximately 80% of cells expressed surface CD14. CD4 antigen was expressed at very low levels and was confirmed by antibody blocking experiments. Infection of placental macrophage cultures with HIV resulted in a transient peak of viral replication 3 to 7 days after infection, but no later rise in HIV was detected with culture of up to 60 days. HIV replication was not up-regulated by coculture with phytohemagglutinin-stimulated lymphocytes or by treating infected cultures with tumor necrosis factor alpha or granulocyte-macrophage colony-stimulating factor.

Axonal transport of herpes simplex virions to epidermal cells: evidence for a specialized mode of virus transport and assembly

To examine the transmission of herpes simplex virus (HSV) from axon to epidermal cell, an in vitro model was constructed consisting of human fetal dorsal root ganglia cultured in the central chamber of a dual-chamber tissue culture system separated from autologous skin explants in an exterior chamber by concentric steel cylinders adhering to the substratum through silicon grease and agarose. Axons grew through the agarose viral diffusion barrier and terminated on epidermal cells in the exterior chamber. After inoculation of HSV onto dorsal root ganglia, anterograde axonal transport of glycoprotein and nucleocapsid antigen was observed by confocal microscopy to appear in exterior chamber axons within 12 h and in epidermal cells within 16 h, moving at 2-3 mm/h. Although both enveloped and unenveloped nucleocapsids were observed in the neuronal soma by transmission electron microscopy, only nucleocapsids were observed in the axons, closely associated with microtubules. Nodule formation at the surface of HSV-infected axons, becoming more dense at the axon terminus on epidermal cells, and patches of axolemmal HSV glycoprotein D expression were observed by scanning (immuno)electron microscopy, probably representing virus emerging from the axolemma. These findings strongly suggest a specialized mode of viral transport, assembly, and egress in sensory neurons: microtubule-associated intermediate-fast anterograde axonal transport of unenveloped nucleocapsids with separate transport of glycoproteins to the distal regions of the axon and assembly prior to virus emergence at the axon terminus.

Unlinked anonymous screening of antenatal patients for antibody to human immunodeficiency virus type 1 (HIV-1)

OBJECTIVES

To determine the prevalence of HIV-1 infection in the general community by using a target population (antenatal patients) as an indicator of infection, to monitor any change in the prevalence of HIV infection in this population and provide baseline information on heterosexual spread of HIV infection into this low prevalence population.

PATIENTS AND DESIGN

Between January 1989 and January 1992, 4537 unlinked anonymous antenatal sera were tested in two study groups at Westmead Hospital. Repeatedly reactive sera were confirmed by western blot and other supplementary assays as appropriate.

RESULTS

No significant change in the seroprevalence of HIV-1 infection was detected between the two study periods. Of the 2208 sera tested in 1989-1990, one (0.05%) was confirmed as positive and one (0.05%) gave a non-specific reaction by enzyme immunoassay (EIA). Of the 2329 sera tested in 1991-1992, there was one (0.04%) HIV-1 antibody positive serum, and two gave non-specific EIA reactions. These results were compared with three other sample populations tested at Westmead Hospital during the same period: linked antenatal patients, antenatal methadone clinic attendees and all women tested.

CONCLUSIONS

Periodic anonymous testing of a sample antenatal population (combined with screening of high risk patients) is useful for monitoring the prevalence of HIV infection in these populations and estimating any future need for generalised screening.

Herpes simplex virus type 2 infection of heterosexual men attending a sexual health centre

OBJECTIVE

To identify risk factors, particularly circumcision status, associated with serological evidence of herpes simplex virus type 2 (HSV-2) infection of heterosexual men.

DESIGN

A cross-sectional case-control study employing an anonymous delinked interviewer-administered questionnaire, clinical examination, and a type-specific serological test for HSV-2.

PARTICIPANTS AND SETTING

Three hundred consecutive heterosexual male patients at a public sexually transmissible diseases (STD) clinic in Sydney, Australia.

MAIN OUTCOME MEASURES

Associations between serological evidence of HSV-2 infection and history of genital herpes or contact with genital herpes, history of other common STDs, and demographic and behavioural factors such as age, education level, number of sexual partners and lack of circumcision.

RESULTS

One hundred and ninety-four patients (64.7%) had antibodies to HSV-2 but only 24% of these gave a history of genital herpes. A history of genital herpes or sexual contact with genital herpes, reported total lifetime number of sexual partners, failure to complete high school and a history of non-gonococcal urethritis or genital warts were associated with serological evidence of HSV-2 infection at the univariate level. Neither increasing age nor lack of circumcision was associated with HSV-2 infection. Following multivariate analysis only the lifetime number of partners and failure to finish high school were significantly strong predictors of HSV-2 infection.

CONCLUSION

This is the highest prevalence of HSV-2 infection ever detected in an Australian population and one of the highest recorded globally. As younger men were as commonly infected as older men, and an earlier (1985) study involving the same clinic yielded a lower prevalence, it appears that a high level of ongoing HSV-2 transmission is occurring among Sydney heterosexuals. Increased awareness of this fact could enhance safer sex campaigns.

Comparison of Giemsa and fluorescent monoclonal antibody staining of inoculated cell cultures for diagnosis of Chlamydia trachomatis

Three methods of isolation and identification of Chlamydia trachomatis inclusions in cell monolayers were compared: Giemsa staining followed by darkfield microscopy of cycloheximide treated Buffalo green monkey kidney monolayers (BGM), fluorescent monoclonal antibody staining of cycloheximide treated BGM and of HeLa 229 monolayers. In an unselected group of 895 patients with suspected chlamydial infections including contacts of symptomatic patients, significantly more positive chlamydia isolates were detected with immunofluorescent monoclonal antibody staining of BGM and HeLa 229 than with Giemsa staining followed by darkfield microscopy on BGM. However, there was no disparity between the 2 staining methods with specimens from 156 patients with untreated non-gonococcal urethritis. In all chlamydia positive specimens, significantly more inclusions were seen after BGM-immunofluorescence than after HeLa-immunofluorescence or BGM-Giemsa. The extra cost associated with immunofluorescence staining was justified by the time saved in scanning.

Detection of immunoglobulin M antibodies to glycoprotein G-2 by western blot (immunoblot) for diagnosis of initial herpes simplex virus type 2 genital infections

Western blots (immunoblots) for the detection of immunoglobulin M (IgM) antibodies specific for herpes simplex virus type 1 (HSV-1) and HSV-2 in patients' sera were developed. The locations of the type-specific glycoprotein G (gpG-2) of HSV-2 (92- and 140-kDa forms) and glycoprotein C of HSV-1 (gpC-1), which carries mostly type-specific antigenic epitopes, were checked with specific monoclonal antibodies. Western blot assays for IgM antibody to gpC-1 or gpG-2 were performed after depletion of IgG by precipitation with anti-human IgG. In patients with primary HSV-2 genital infections, seroconversion of IgM and IgG antibodies to both the 92- and 140-kDa forms of gpG-2 was observed, although both antibodies appeared in convalescent-phase serum after the first week. IgM and IgG antibodies to low-molecular-size polypeptides (40 to 65 kDa) were the first antibodies observed in patients with primary infection, but these antibodies were cross-reactive with HSV-1 and HSV-2. However, in patients with recurrent HSV-2 infections, IgG antibodies to both forms of gpG-2 and the low-molecular-size polypeptides were found no matter how early after onset the patient was bled, and IgM to gpG-2 did not appear. In patients with nonprimary initial genital HSV-2 infections, IgG antibody to HSV-1 was demonstrated in the first serum specimen, and HSV-2-specific IgM was found in 39% of the serum specimens. Hence, the Western blot assay can be used to test for IgM antibody to gpG-2, allowing for the retrospective diagnosis of inital HSV-2 infections and its use as a supplementary test to the gpG-2 IgG enzyme-linked immunosorbent assays developed elsewhere. In contrast, IgM antibody to gpG-2 is not usually detected in patients with recurrent HSV-2 infections.

Human immunodeficiency virus type 1 infection of human placental macrophages in vitro

Placental macrophages (Hofbauer cells) were isolated and cultured in vitro to investigate their susceptibility to human immunodeficiency virus type 1 (HIV-1) infection. Of adherent cells, 80% expressed CD14, and > 99% were nonspecific esterase-positive. CD4 antigen was expressed at very low levels. CD4 mRNA could be detected in the cells by reverse transcription followed by polymerase chain reaction. The macrophages were infected productively after inoculation with low-passage blood isolates of cell-free HIV-1. Peak virus titers were detected 3-7 days after infection by HIV-1 antigen ELISA and reverse transcriptase assay. Replication of HIV-1 in placental macrophages was less than in blood monocytes. HIV-1 RNA was detected in placental macrophages by in situ hybridization 16 days after infection. Multinucleated giant cells were identified in some cultures, indicative of an HIV-induced cytopathic effect. Thus, placental macrophages can be infected productively with clinical isolates of HIV-1, and such cells may act as a reservoir of virus for transmission to the fetus in utero.

Herpes simplex virus type 2 antibody in patients attending antenatal or STD clinics

OBJECTIVE

To determine the prevalence of antibody to herpes simplex virus type 2 (HSV-2) in patients attending a general public antenatal clinic and three public sexually transmitted disease (STD) clinics in Sydney.

BACKGROUND

Highly specific tests for herpes simplex type 2 antibody, using the glycoprotein G2, have been recently introduced, allowing determination of past asymptomatic infection. Overseas studies have confirmed the long held suspicion that asymptomatic infection is more common than clinical genital herpes. The seroprevalence of HSV-2 in antenatal and STD clinic patients varies markedly in different countries. These are the first data available for Australia by means of this highly specific test.

DESIGN

Cross-sectional study of seroprevalence in these two patient groups. Sera used in the antenatal study were those submitted for routine antenatal screening for viral markers.

PARTICIPANTS

Two hundred and twenty-nine consecutive patients attending the Westmead Hospital antenatal clinics, and 107 consecutive patients attending three public STD clinics.

HYPOTHESES

That Australian populations show a relatively high prevalence of past asymptomatic infection with HSV-2; and that higher rates of infection will be found in patients attending STD clinics and with past or current histories of STDs.

MAIN OUTCOME MEASURES

Comparison of HSV-2 seroprevalence between antenatal clinic patients and STD clinic patients; and associations of HSV-2 antibody with age, sex, occupation, country of birth, a history of current or past STDs and antibody to HSV-1.

RESULTS

Antibody to HSV-2 was found in 14.5% of antenatal clinic patients and 40% of STD clinic patients. None of the antenatal patients and less than half of the seropositive STD clinic patients reported clinical genital herpes. Associations with age, socioeconomic status and previous HSV-1 infection were less marked than in studies from the United States. Female STD clinic patients had a significantly higher seroprevalence than males and three times the seroprevalence of age-matched antenatal clinic patients. The correlation between HSV-2 antibody and current gonorrhoea was more marked than that between HSV-2 and other STDs.

CONCLUSION

Asymptomatic infection with HSV-2 is quite common in Australian antenatal patients and more common in patients with STDs, who have higher rates of sexual exposure.

The reliability of serological tests for the diagnosis of genital herpes: a critique

The reliability and limitations of the currently used routine tests for herpes simplex virus type 2 (HSV-2) antibody in Australia are reviewed. Six case reports illustrate the clinical dangers of overinterpretation of the currently available kits and the need for a readily available specific HSV-2 antibody test. In Sydney, HSV-2 causes approximately 85% of primary genital herpes and > 95% of recurrent genital herpes. Due to the extensive serological cross-reactivity between HSV-1 and HSV-2, currently available "type specific" commercial assays cannot reliably distinguish between the 2. Isolation of herpes simplex virus (HSV) or detection of HSV antigen in vesicle fluid is the preferred diagnostic test but may be overlooked or patients may have no visible lesions. The only accurate techniques for detecting HSV-2 specific antibody are the Western blot assay and an enzymatic immunoassay using glycoprotein G (gG-2), a component of the HSV-2 envelope. These tests, which still are restricted to research laboratories can be used to accurately identify people with previous exposure to HSV-2 (IgG) or to diagnose primary infection where virus isolation has not been performed or is impossible. Current commercially available antibody tests may have extensive cross-reactivity.

Herpes simplex virus infection in pregnancy

Genital infections in pregnancy caused by herpes simplex virus types 1 and 2 are a difficult management problem. Both primary and recurrent genital herpes can range from severe, extensive ulceration to asymptomatic virus shedding. Although neonatal herpes is a well recognized complication of symptomatic maternal primary genital infection at the time of delivery, most cases are associated with asymptomatic virus shedding and absence of a history of genital herpes. Neonatal herpes may also be acquired in utero and in the postnatal period. The diagnosis of herpes simplex infection is made most reliably by virus isolation or antigen detection from samples obtained from clinically apparent lesions. Serology is useful for diagnosing primary herpes, and newer serological techniques allow the detection of HSV-2 specific antibodies. Strategies to prevent neonatal herpes are limited by the failure of currently available diagnostic tests to rapidly detect women in labour who are at risk of transmitting herpes, by the absence of proven antenatal screening tests for HSV, and by transmission of herpes to neonates from asymptomatic mothers. The most useful current strategy is careful examination of the vulva and cervix for herpes lesions in women coming to labour. Caesarean section is indicated in women with clinically apparent genital herpes at delivery. Effective and safe antiviral agents are available for treatment of maternal and neonatal herpes.

HCMV-DNA is detected more frequently than infectious virus in blood leucocytes of immunocompromised patients: a direct comparison of culture-immunofluorescence and PCR for detection of HCMV in clinical specimens

In two studies comparing detection of human cytomegalovirus (HCMV) in 118 patients (93 of whom were immunocompromised) by the polymerase chain reaction (PCR) and virus isolation using either early antigen detection by culture-immunofluorescence or conventional cytopathic effect, DNA-PCR was found to be the most sensitive, followed by culture-immunofluorescence, then by cytopathic effect. Urine was inhibitory to the action of Taq polymerase; this was overcome by concentration of HCMV with PEG 6000 prior to gene amplification. Without PEG treatment, HCMV-DNA in 6 of the 11 specimens positive by culture-immunofluorescence was not detectable by PCR. In healthy seropositive individuals, HCMV-DNA was not detected in leucocytes. However, in immunocompromised patients with AIDS or transplants, and therefore at high risk of HCMV infection or reactivation, blood leucocytes were usually positive for HCMV-DNA (19/20), some for as long as 20 weeks after initial detection and persisting for long after culture-immunofluorescence became negative. Neither HCMV-RNA nor infectious HCMV were detected in the follow-up blood leucocyte specimens from immunocompromised patients who had detectable HCMV-DNA in these cells. These data suggest that persistence of HCMV-DNA in blood leucocytes of immunocompromised patients after reactivation or primary infection may be due to persistence of non-viable virus, residual HCMV genomic DNA, or latent HCMV-DNA.

The diagnosis of recent herpes simplex virus type 2 genital infections by the simplex-2 test

The prevalence of complement-fixing (CF) antibody against the AG-4 early antigen of herpes simplex virus (HSV) type 2 (HSV-2) was determined in patients with culture confirmed HSV-2 genital herpes and control groups using a commercial HSV-2 early antigen (Simplex-2; Gene Link Australia Ltd). Eighty seven per cent of 39 sera collected between 14 and 28 days after confirmed primary and recurrent HSV-2 infection were positive. In acute sera collected between 2-10 days after onset the Simplex-2 test was negative in all 90 patients with presumed primary infection but positive in 53% of 230 sera from recurrent infection. A specificity of 90-94.5% was obtained by testing 36 patients with recent proven HSV-1 infection and 331 control group patients. The Simplex-2 test may be useful in some cases of culture-negative, clinically suspected genital HSV-2 lesions only when sera are collected between 14-28 days after primary and recurrent infection. Its lack of specificity makes it unsuitable for the routine diagnosis of recent HSV-2 infection in the general population.

Identification of infection of an Australian resident with the human immunodeficiency virus type 2 (HIV-2)

OBJECTIVE

To present the first confirmed case of human immunodeficiency virus infection type 2 (HIV-2) in an Australian resident.

CLINICAL FEATURES

HIV-2 infection in a west African man resident in Sydney was diagnosed in 1992 at Westmead Hospital, Sydney, by serological testing. He was asymptomatic and the blood CD4 T-lymphocyte concentration was not significantly reduced. Infection was probably acquired before migration to Australia. The patient was initially tested for HIV-1 antibody as part of an application for permanent residency. He was in no obvious risk group or transmission category. His serum was repeatedly positive by Genetic Systems enzyme immunoassay (EIA) and borderline by Abbott EIA, was reactive to the HIV-2 peptide on a synthetic envelope peptide assay, and was strongly reactive to all HIV-2 specific viral protein bands on an HIV-2 western blot test. HIV-2 was isolated by co-cultivation of the patient's peripheral blood mononuclear cells and identified by hybridisation using HIV-2 specific oligonucleotide probes, with further confirmation by polymerase chain reaction.

INTERVENTION AND OUTCOME

The patient was counselled regarding the clinical course and prognosis of HIV-2 infection, the possible indications for zidovudine therapy, modes of transmission of the virus and safer sex precautions.

CONCLUSIONS

This is the first documented case of HIV-2 infection diagnosed in Australia and raises the possibility of other undetected cases. The cost effectiveness of general testing for HIV-2 needs to be assessed and formal epidemiological sentinel programs should be established to monitor specific Australian populations.

Chronic colitis associated with human immunodeficiency virus infection

OBJECTIVE

A clinical and pathological description of chronic colitis associated with human immunodeficiency virus (HIV) infection.

DESIGN

A retrospective case review.

SETTING

Tertiary referral institution and specialist gastroenterology practice.

PATIENTS

A series of six patients with human immunodeficiency virus infection and chronic colitis observed for up to four years.

RESULTS

The six patients had chronic diarrhoea for longer than six months, rectal bleeding, abdominal pain and stool leukocytosis. The mucosal pattern on colonoscopy showed diffuse proctocolitis, consisting of contact bleeding, superficial ulcerations, exudates, and/or loss of vascular pattern. Colonic biopsies showed a persisting diffuse colitis characterised principally by a mixed inflammatory cell infiltrate (mononuclear cells and neutrophils) and essentially preserved crypt architecture after six to 39 months of histological follow-up. The histopathology over this time frame was not typical of ulcerative colitis or Crohn's disease, nor of the conventionally described forms of infective colitis. HIV nucleic acid was identified by insitu hybridisation in colonic biopsies from four patients. In two of three patients tested, the presence of HIV DNA was confirmed by Southern blot analysis. No other microbial agent could be demonstrated as the cause of diarrhoea. At presentation all patients had CD4+ lymphocyte counts greater than 265 x 10(6)/L and none had the acquired immunodeficiency syndrome. Four patients have gone into remission, the other two patients were not in remission at four and a half to five years after onset.

CONCLUSION

We suggest that chronic colitis may represent a new entity related to infection of the colon with human immunodeficiency virus.

Recombinant interleukin 4 stimulates human immunodeficiency virus production by infected monocytes and macrophages

Recombinant interleukin 4 (IL-4) stimulated extracellular (EC) and intracellular (IC) production of human immunodeficiency virus (HIV) from infected human blood-derived monocytes and macrophages when incubated with the cells after but not before virus inoculation. Significant stimulation was observed in 20 of 27 experiments with monocytes (inoculated with HIV immediately after adherence) and 10 of 13 experiments with macrophages (inoculated after 5 days adherence) using a total of 30 normal donors of monocytes and macrophages, and 11 recent isolates of monocytotropic HIV strains (after one passage in mononuclear cells). Marked increases in EC and IC HIV antigen were observed in some experiments, which were comparable with the maximal stimulatory effects of other cytokines such as IL-2. IL-4 also had similar effects on infectious HIV concentration as measured by reverse transcriptase and TCID50 assays. Antibody to IL-4 prevented the stimulatory effect of the cytokine. The proportion of monocytes and macrophages infected by HIV, as determined by in situ hybridization, also increased after incubation with IL-4 for 7 days. The most marked effects were observed with HIV-infected macrophages, for which the proportion of unstimulated infected cells was lower (35 to 45% increasing to 66 to 70% with IL-4 treatment). There was also an increased proportion of cells with high granule concentrations, suggesting that IL-4 increases the intracellular concentration of viral nucleic acids. This was supported by semi-quantitative hybridization experiments showing that total HIV RNA increased in IL-4-stimulated monocytes 48 to 96 h after HIV inoculation. A marked increase in aggregates was observed on day 7 in HIV-infected monocytes treated with IL-4, compared to that in HIV-infected cells alone or IL-4-treated uninfected monocytes. These findings suggest that IL-4 stimulates HIV replication in the early phases of infection and may also facilitate virus transmission by aggregate formation.

Concurrent zidovudine-induced myopathy and hepatoxicity in patients treated for human immunodeficiency virus (HIV) infection

Myopathy and hepatic toxicity are important complications of zidovudine (3'-azido-3'-deoxythymidine therapy) in patients infected with the human immunodeficiency virus (HIV) both may also occur in HIV infection in the absence of zidovudine therapy. We report 2 cases of myopathy caused by zidovudine, occurring within 16 wks of initiation of therapy, and a case of concurrent hepatic and muscle toxicity. In one case, electron microscopy demonstrated characteristic enlarged mitochondria with paracrystalline inclusions. This technique can distinguish the myopathies caused by either HIV or zidovudine. Both zidovudine-induced myopathy and hepatoxicity require discontinuation of the drug if severe.