Construction and characterization of a full-length HIV-1(92UG001) subtype D infectious molecular clone

Here we report the construction, sequencing, and biological characterization of a molecular clone of HIV-1(92UG001), a virus representative of subtype D strains circulating in Uganda. The virus produced by the clone has an aggressive syncytium-inducing phenotype, which matches that of the parental virus. This phenotype may be related to duplication of a binding site for a transcription factor, T cell factor 1alpha (TCF-1alpha), in the long terminal repeat of the virus.

Antiretroviral therapy for HIV-2 infected patients

OBJECTIVES

To evaluate clinical and RNA load response to antiretroviral therapy amongst patients infected with HIV-2 and to study the development of drug resistance.

METHODS

Seven HIV-2 seropositive patients were monitored with clinical examination, CD4 cell count and HIV-2 viral RNA load. Viruses from four subjects were genotyped and in vitro recovery of virus by co-cultivation with PBMCs and HVS T-cells was attempted. Viruses isolated from two subjects were assayed for phenotypic antiviral resistance. The main outcome measures were the relationship between disease stage, viral load, CD4 cell count, viral subtype and the clinical course of HIV-2 infection and the effect of combination antiretroviral therapy on disease progression, CD4 cell count, HIV-2 RNA viral load and drug resistance.

RESULTS

The median time of follow-up was 3 years (range 0-8 years). Three patients had AIDS, and one had symptomatic disease. Of the four patients genotyped, three were infected with HIV-2 subtype B and one with subtype A. Viraemia was detectable only at CD4 counts of less than 300 x 10(6)/ml. Two patients with high viral loads failed to respond to antiretroviral therapy although their treatment may not have been optimal. One developed in vitro phenotypic antiviral resistance. The genotype of this patient's viral reverse transcriptase is being analysed.

CONCLUSIONS

In contrast to HIV-1, HIV-2 RNA levels were often undetectable despite advanced disease and low CD4 cell counts. However, HIV-2 was clearly capable of causing CD4 cell depletion resulting in symptomatic disease. The principles of highly active antiretroviral therapy seem to apply to HIV-2 and suboptimal therapy may lead to drug resistance. The timing of therapy initiation, monitoring of response and the measurement of resistance remain unresolved issues and conclusions cannot be extrapolated from HIV-1.

Temporary myoclonus with treatment of congenital transcobalamin 2 deficiency

The treatment of acquired cobalamin deficiency in infants may result in the development of a syndrome defined by temporary involuntary myoclonic movements. A patient with an inborn error of metabolism resulting in transcobalamin 2 deficiency who was treated with cobalamin and then developed this syndrome is presented. Neurologic investigations were normal. The continuance of cobalamin and avoidance of antiepileptic drugs is recommended. To our knowledge this is the first such case.

Cardiac malformations associated with the congenital nephrotic syndrome

The association of cardiac malformation with the congenital nephrotic syndrome (CNS) has been previously reported in only one family. We report four patients with CNS: three with pulmonary valve stenosis (one requiring valvuloplasty) and one with discrete subaortic stenosis requiring surgical resection. We conclude that the cardiac status of all patients with CNS should be reviewed regularly by a paediatrician, with a low threshold for referral to a cardiologist, as flow murmurs due to chronic anaemia may obscure cardiac pathology. It is important to diagnose any associated cardiac lesions as these may require intervention, and may also predispose to the development of bacterial endocarditis if surgical or dental procedures are undertaken without appropriate antibiotic prophylaxis.

Absence of bone marrow amastigotes in a child with kala-azar and acute lymphoblastic leukaemia

Visceral leishmaniasis is suspected on the basis of clinical findings and a pancytopenic blood picture and is usually confirmed by the detection of amastigotes (Leishman-Donovan bodies) in a bone marrow aspirate. We describe a child on maintenance treatment for acute lymphoblastic leukaemia who developed visceral leishmaniasis and in whom amastigotes could not be detected in repeated bone marrow aspirates. Immunofluorescence antibody testing was positive. Immunocompromised patients in endemic areas who develop features of visceral leishmaniasis should have serological tests performed in addition to bone marrow aspiration in order to maximize the chances of making a diagnosis.

Construction and biological characterization of an infectious molecular clone of HIV type 1GB8

Here we report the construction, sequencing, and repair of a molecular clone of HIV-1GB8, a virus representative of HIV-1 subtype B strains circulating in the UK. The phenotype of virus produced by the clone matches that of the parental virus. The molecular clone will be used in the production of attenuated virus stocks for chemical inactivation to allow development of faccines based on killed whole virus preparations.

Pigeon breeder's lung in childhood: varied clinical picture at presentation

Extrinsic allergic alveolitis occurs rarely in childhood. We present 5 cases and briefly review the literature regarding this condition in the pediatric population. This report includes all cases (n = 5) of extrinsic allergic alveolitis known to have occurred in childhood on Malta. All cases were males, and were initially misdiagnosed as having other respiratory illnesses or mental disturbances. The diagnosis was based on a history of exposure to birds, clinical findings, positive avian precipitins, a restrictive defect on pulmonary function tests, and a suggestive chest X-ray appearance. All were treated with high-dose oral steroids for 3-4 weeks, with excellent response. Although these patients appear to have suffered no long-term sequelae, delayed diagnosis can lead to irreversible pulmonary fibrosis. The diagnosis of extrinsic allergic alveolitis should be entertained early in the differential diagnosis of children presenting with unusual respiratory symptoms and signs.

Successful treatment of visceral leishmaniasis in Finnish-type congenital nephrotic syndrome

Visceral leishmaniasis is a parasitic disease endemic in the Mediterranean Basin, including Malta. Finnish-type congenital nephrotic syndrome is an autosomal recessive condition that presents in the first 3 months of life with heavy proteinuria, hypoalbuminemia with secondary edema, and hyperlipidemia. We present an infant with congenital nephrotic syndrome who had had unilateral nephrectomy and who also developed visceral leishmaniasis. He was successfully cleared of the infection by the administration of sodium stibogluconate, with no deterioration of renal function or other complications.

Visceral leishmaniasis in Malta--an 18 year paediatric, population based study

BACKGROUND

Visceral leishmaniasis (VL) is a chronic parasitic infection that infects approximately 400,000 individuals annually, with a predilection towards early childhood.

AIMS

To study the epidemiology of VL in childhood.

METHODS

VL is endemic in Malta, a small archipelago of islands in the centre of the Mediterranean with a total population approaching half a million. Notification of human cases of leishmaniasis is compulsory. Case records of all 81 paediatric patients with VL between 1980 and 1998 were analysed.

RESULTS

The annual incidence of VL declined for all cases of VL, and declined significantly for paediatric cases (p = 0.01). For 1994 to 1998, the overall incidence of VL was 0.9 per 100,000 total population and the paediatric incidence was 2.5 per 100,000 population. Median age at presentation was 34 months. Common features at presentation were splenomegaly, hepatomegaly, fever, and pancytopenia with high lymphocyte and monocyte counts. The diagnostic sensitivity of isolated immunofluorescent antibody testing was equivalent to bone marrow aspiration (95%). Blood transfusions for anaemia were required in 93% of patients. Eleven per cent had intercurrent infections. All patients were cured, and were initially treated with intravenous sodium stibogluconate. Defervescence occurred after a median of six days of treatment, and patients continued to be treated on a day case basis. Nine relapsers were retreated with sodium stibogluconate, achieving a cure rate of 94%, but five patients required additional drug therapy. There were no permanent sequelae associated with VL or its treatment.

CONCLUSIONS

The decreased incidence is attributed to the eradication of stray dogs which are the disease reservoir.

Twenty-four-hour heart rate variability to assess autonomic function in Parkinson's disease

OBJECTIVES

To evaluate the autonomic dysfunction in Parkinson's disease patients by means of a 24-h heart rate variability (HRV) method.

MATERIAL AND METHODS

Thirteen patients with a diagnosis of Parkinson's disease were compared with 13 age-matched healthy persons (control group). The 13 patients had a mean age of 70.5 years, and mean disease duration of 10.9 years. The autonomic function was evaluated by HRV analysis using a continuous 24-h ECG. The parameters of SDNN (standard deviation of the normal-to-normal intervals between adjacent QRS complexes), of LF (power in low frequency) and of HF (power in high frequency) were studied during the following 3 periods: 24 h, night and day.

RESULTS

The data show a statistically significant difference between groups for SDNN and LF in all the periods, while for HF parameters the difference is statistically significant only in the night period.

CONCLUSION

The use of the 24-h HRV method can provide more accurate and reproducible data than other conventional cardiovascular tests.

Enhanced replication of M-tropic HIV-1 strains in Herpesvirus saimiri immortalised T-cells which express CCR5

A better characterisation of mononuclear cell-tropic (M-tropic) HIV-1 is central to disease control as these viruses predominate in disease transmission. M-tropic viruses do not replicate in conventional T-cell lines, and virus titres obtained in peripheral blood mononuclear cells (PBMC) are low. Human T-lymphocytes which have been immortalised by Herpesvirus saimiri strain C488 (HVS T-cells) are highly permissive to the replication of T-cell tropic strains of HIV. This study aimed to determine if HVS T-cells support replication of M-tropic HIV isolates that have not been adapted to conventional T-cell lines. A panel of PBMC low passage/primary field isolates and their molecular clones was used. Results show that infection in HVS T-cells was longer lived than in PBMC. In terms of peak virus titre and duration of productive infection, the two HVS T-cell lines studied were superior to PBMC, and one supported enhanced replication of all M-tropic isolates. This is important for generating M-tropic virus pools of sufficient titre for further biological studies such as virus neutralisation, co receptor usage and testing of antivirals. Phenotypic analysis showed that HVS T-cells are CD4+-activated memory cells expressing both CXCR-4 and CCR5 co receptors. Thus, HVS immortalisation appears to select for the T-cell subset targeted by HIV-1 in vivo.

Atrioventricular septal defect with separate right and left atrioventricular valvar orifices in a patient with foetal hydantoin syndrome

The teratogenic properties of phenytoin, including cardiac malformations, have been previously documented. We report one patient with foetal hydantoin syndrome and atrioventricular septal defect with common atrioventricular junction but separate right and left atrioventricular valves, an association that has not been described, to the best of our knowledge.

[Heart and autonomic nervous system in connective tissue disorders]

Heart rate variability (HRV) is a suitable diagnostic tool in identifying patients with autonomic nervous system (ANS) disorders even in pre-clinical stage. We have enrolled in this study all patients with large variety of connective tissue disorders, given the possibility of an involvement of ANS in these diseases. The study population consisted in eighty-five patients (68 females and 17 males), 35 of whom affected by systemic lupus erythematosus, 16 by rheumatoid arthritis, 14 by Sjögren syndrome, 12 by progressive systemic sclerosis, 3 by Behçet syndrome and 5 by antiphospholipid antibodies syndrome. The mean age ranged between 33.7 of patients with lupus erythematosus and 51.8 of those with Sjögren syndrome. As control, we enrolled healthy subjects of different age, divided into two groups, to rule out the aging as potential source of considered parameters alteration. The autonomic function has been evaluated by 24 hours ambulatory monitoring, using a Zymed 1210 Scanner with Zymed 3.74-PC 1990 software. We have considered: in the time domain, the standard deviation of the RR intervals average (SDNN) and the percentage of RR adjacent intervals differing each other more than 50 msec (pNN50); in the frequency domain, the low (LF) and high (HF) frequencies, the LF/HF ratio, and the total power (RT). The HRV parameters resulted abnormal in every type of the connective tissue diseases considered: particularly SDNN, pNN50, LF, HF and RT (p < or = 0.01).

IN CONCLUSION

the results of our study suggest that autonomic neuropathy may be present in any kind of connective tissue disorders even in preclinical stage.

Herpesvirus saimiri-immortalized human T-cells support long-term, high titred replication of human immunodeficiency virus types 1 and 2

Herpesvirus saimiri strain C488 transforms human CD4+ T-lymphocytes to continuous interleukin-2-dependent growth. Unlike human T-cell lines derived from tumours or those transformed by human T-lymphotropic virus 1, herpesvirus saimiri-immortalized T-cells (HVS T-cells) retain many functions of primary activated T-lymphocytes. We have characterized the course of human immunodeficiency virus types 1 and 2 (HIV-1/-2) infection in three HVS T-cell lines. Our results confirm that HVS T-cells are highly permissive to both HIV-1/-2 prototype viruses and to poorly replicating HIV-2 strains of restricted cell tropism. However, the infection was persistently productive for up to 5 months. The down-regulation of surface CD4 molecules was delayed and virus yields significantly exceeded those obtained in T-cell lines.

Heart rate variability and cardiac autonomic function in systemic lupus erythematosus

The cardiac autonomic function was evaluated in 23 patients with Systemic Lupus Erythematosus (SLE) without clinical expression of dysautonomia and in 14 healthy volunteer subjects as a control group, by analysis of Heart Rate Variability (HRV) from 24h ambulatory electrocardiography. All the patients were taking corticosteroids and 10 of them also Ciclosporin A (CsA). The following parameters of HRV were performed: Time domain: standard deviation of the RR intervals average (SDNN) and percentage of RR adjacent intervals differing from each other more than 50 msec (pNN50). Frequency domain: low frequencies (LF) and high frequencies (HF). Significant lower values were detected in SLE patients vs controls: SDNN = 69.40 vs 127.72; pNN50 = 16.44 vs 25.95; LF = 8.34 vs 34.97; HF = 3.21 vs 12.18. The incidence of autonomic dysfunction in our SLE population evaluated by considering intervals of normality is approximately 78% for SDNN; 17% for pNN50; 91% for LF and, finally, 56% for HF. The analysis of HRV may be a valuable technique in the study of the incidence of dysautonomia for these patients.

A molecular and serologic study of the envelope gene of the British isolate: HIV-1 GB8

The entire envelope gene of a British HIV-1 isolate, GB8, was cloned, sequenced and aligned with those of the reference strains MN, SF2 and IIIB/LAI. Three of the viruses (MN, IIIB/LAI, GB8) and their recombinant gp120s, were then characterised using an extensive panel of human HIV-1 positive sera and mapped neutralising monoclonal antibodies (MAbs). Overall, the GB8 env-gene translation product shares 84% homology with those of the reference strains. Across the V3 region homology was greater between GB8 and SF2/MN (74.3-88.6%) than IIIB/LAI (63.9-66.7%). Accordingly, GB8 was sensitive to V3-specific MAbs which neutralise MN/SF2 and resistant to those that neutralize IIIB/LAI. In the CD4 binding region the central MWQEVGKAMYAPPI was conserved in all viruses but homology in the N-terminus was greater between GB8 and SF2 and IIIB/LAI than MN. GB8 and IIIB/LAI were sensitive to all MAbs raised against the CD4 binding site whereas MN was resistant to 3 of 4 tested. Human sera obtained from a London-based cohort did not differentiate between GB8 and MN in neutralisation assays, whereas IIIB/LAI titres were significantly lower at all stages of disease. These results show that GB8 carries a consensus-like V3 loop and is as representative as MN of HIV-1 viruses circulating in the UK. To our knowledge, GB8 is the only British HIV-1 isolate which has been characterised to date.

Characterization and primary structure of a human immunodeficiency virus type 1 (HIV-1) neutralization domain as presented by a poliovirus type 1/HIV-1 chimera

The poliovirus/human immunodeficiency virus (HIV) chimera S1/env/3 presents the sequence DRPEGIEEEGGERDRDRS, a known glycoprotein gp41 neutralizing domain (residues 735 to 752) of HIV IIIB in an antigenic site of the Sabin type 1 strain of poliovirus. Of 10 monoclonal antibodies raised against the sequence as presented in S1/env/3, eight were shown to neutralize HIV IIIB in vitro whereas all 10 neutralized S1/env/3, suggesting that the presentation of the sequence is comparable between HIV and the poliovirus/HIV chimera. The monoclonal antibodies were characterized by the selection of escape mutants from S1/env/3 and by Pepscan analysis. The two methods gave similar results, identifying two epitopes involving amino acids corresponding to residues 740 to 743, and to residues 745 to 750 of gp41. Mutations selected in the chimera with S1/env/3-specific MAbs are identical or similar to changes occurring in vivo in natural isolates of HIV-1. This finding suggests that the epitope may be significant in the neutralization of HIV in vivo.

Coxsackievirus B4 infection of the mouse pancreas: the role of natural killer cells in the control of virus replication and resistance to infection

The role of natural killer (NK) cells in the early immune response to a pancreatropic isolate of coxsackievirus B4 (CVB4) was investigated in a murine model of pancreatitis. Endogenous (background) NK cell activity in fresh spleen effector cells from eight mouse strains was compared with virus-augmented NK cell activity 4 days post-infection (p.i.). A significant virus-induced increase (P less than or equal to 0.003) in NK cell activity was seen in seven of eight infected mouse strains, when virus titres in the pancreas were beginning to fall. Lesions in the exocrine pancreas were least extensive in the three strains with the highest endogenous NK cell activity. In C3H/HeJ mice that had been depleted of NK cells prior to infection with a low virus concentration, resistance to infection of the pancreas was completely abolished; myocarditis was also observed in one of these animals. Thus, NK cells may limit virus replication in the pancreas and play a role in resistance in C3H/HeJ mice. Virus-specific neutralizing antibody was not detected in the serum until 5 to 6 days p.i. in most strains and did not appear to influence pancreatic virus titres. It may be significant that CVB4 infection did not induce the expression of major histocompatibility complex (MHC) class I molecules on target acinar cells. With certain tumour cells, an inverse relationship between MHC class I expression and susceptibility to NK cell-mediated lysis is well documented.

Coxsackievirus B4 infection of the mouse pancreas: acute and persistent infection

The course of infection of a pancreas-adapted isolate of coxsackievirus B4 was followed over a 10 month period in a murine model. Following intraperitoneal inoculation a typical acute infection was seen in nine of 10 inbred mouse strains. Virus rapidly infected the exocrine pancreas, titres peaking 3 to 4 days post-infection (p.i.). Lesions were almost exclusively confined to pancreatic acinar cells and varied in severity among the inbred strains. Virus shed into the blood-stream was not cell-associated. Evidence of persistent infection was found in nine mouse strains and infective virus was recovered from the pancreas of seven strains for up to 10 months p.i. Approximately 28% of pancreases examined beyond the acute phase showed focal inflammation and 22% showed focal necrosis (cell death). Virus was occasionally recovered from other organs (heart, liver and spleen), but lesions were rarely seen. Virus-specific antigen was localized to small groups of pancreatic acinar cells using an indirect immunogold silver staining technique. These observations suggested that the virus persists in pancreatic tissues because it seems unlikely that virus disseminated from distant sites would cause such localized infection. In three of these strains, the course of infection may have been influenced by superinfection with mouse hepatitis virus.

Restriction of serum antibody reactivity to the V3 neutralizing domain of HIV gp120 with progression to AIDS

OBJECTIVE

To identify epitopes on HIV-1 gp120 that correlate with disease resistance and/or prognostic indication.

DESIGN

The identification of epitopes on HIV-1 gp120 was determined by testing the reactivity by immunoblotting of anti-HIV-positive human sera against partially cleaved Chinese hamster ovary (CHO) cell-derived recombinant gp120. Cleavage of recombinant gp120 occurs in the V3 loop region resulting in 70 and 50K cleavage bands if the protein is subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions. Antibodies reactive with the 120 Mr band alone on immunoblotting indicate that binding is restricted to this cleavage site. Reactivity to either of the cleavage products is independent of gp120 cleavage and indicates that binding occurs in sites other than the V3 cleavage region.

METHODS

A panel of anti-HIV-positive human sera was tested for virus neutralizing activity and reactivity by immunoblotting against CHO cell-derived gp120.

RESULTS

All sera reacted with the uncleaved from of gp120 but reacted either weakly or did not react with its cleavage products. There was a statistically significant correlation between serum reactivity to cleavage products and clinical stage of disease [Centers for Disease Control (CDC) criteria]. Sera of asymptomatic individuals (CDC stage II/III) were more likely to recognize either one or both of the cleavage products compared with sera from patients presenting with symptoms of disease (CDC stage IV). Furthermore, sera reacting with either one or both of the cleavage products were more likely to have higher neutralizing antibody titres than those that were unreactive.

CONCLUSIONS

There is a restriction of serum antibody reactivity (when tested by immunoblotting) to the V3 loop with progression to disease. Raised neutralizing antibody titres may be dependent on regions outside the V3 cleavage site.

Coxsackie virus B4 infection of the mouse pancreas: I. Detection of virus-specific RNA in the pancreas by in situ hybridisation

The pathology of Coxsackie virus B4 (CVB4) infection in a murine model was investigated by in situ hybridisation using a biotinylated cDNA probe derived from CVB4. During the acute phase of infection virus RNA sequences were detected in the exocrine pancreas of 60% of mice infected with a pancreotropic variant of CVB4. A positive hybridisation signal was observed in other organs in some animals including the heart and liver of 1 mouse 28 days after infection. The cellular distribution of virus RNA sequences corresponded well with the histological findings in most tissues. Possible causes for failure of hybridisation in some infected pancreases are discussed in conjunction with potential application of the technique in human pancreas biopsy samples.

Recognition of poliovirus/HIV chimaeras by antisera from individuals with HIV infection

The neutralization of five poliovirus/HIV chimaeras by serum from HIV-infected individuals was examined to evaluate the presentation of HIV envelope sequences, to assess the immune response of individuals to specific epitopes, and to relate it to the stage of disease. The sera were unable to differentiate between four of the chimaeras and the Sabin vaccine strain. With a fifth construct containing an immunodominant gp41 sequence, significant differential recognition was observed in approximately 67% of individuals with asymptomatic HIV infection [groups II and III of the Centers for Disease Control (CDC) classification of HIV infection] and 37% of patients with symptomatic disease (CDC group IV). Furthermore, among patients with CDC stage IV disease antibody levels against this construct and the titre achieved decreased with progression to further disease from approximately 40% in AIDS-related complex (ARC) patients (CDC group IVA and IVC-2 to 14% in those with AIDS (other group IV diseases). Loss of antibody to this construct did not result from a reduction in the anti-polio or anti-envelope response, but from a decline in antibody levels to the HIV sequence inserted in antigenic site 1.