Search

Aims: The aims of this study were to: (i) determine the incidence of thymidine-associated mutations (TAMs) in an observational clinical cohort of naive HIV-1 patients who stopped first-line therapy including either zidovudine or stavudine; and (ii) assess the immunological and virological responses to subsequent second-line therapy in patients who switched from zidovudine to stavudine or conversely. Patients and methods: Plasma samples from 165 patients who stopped first-line antiretroviral therapy containing either zidovudine or stavudine were examined for the presence of drug-resistant genotypes. Subsequent second-line immunological and virological follow-up was performed in 136 patients who switched from zidovudine to stavudine and conversely. Results: Among the 93 patients who stopped first-line therapy including zidovudine and the 72 who stopped first-line therapy including stavudine, genotypic resistance testing was available for 67 (72&percnt;) and 54 (75&percnt;), respectively. The presence of TAMs was significantly more frequent in the zidovudine than the stavudine group (23.8&percnt; versus 5.5; P &equals; 0.006). The short- and long-term immunological and virological responses to second-line therapy were comparable in the zidovudine and stavudine groups, despite different baseline profiles of viral resistance (median increase in CD4 cells/mm3 at 1 year of therapy, 118 versus 119; viral load <400 copies/mL, 47&percnt; versus 47&percnt;). Conclusions: These results suggest that TAMs occur in more patients on antiretroviral regimens including zidovudine than on regimens including stavudine. Although the results from observational studies should be interpreted cautiously, these findings may be useful in determining the optimal sequencing of zidovudine and stavudine for the treatment of naive HIV-1-infected patients.

Progressive Multifocal Leukoencephalopathy (PML) is a severe and fatal demyelinating disease that occurs especially in HIV‐infected patients. It has been suggested that JC virus (JCV) migrates in peripheral blood leukocytes from the kidney to the central nervous system where it initiates demyelination. To investigate the physiopathological role of the peripheral blood virus in the development of PML, the prevalence of JCV infection and the levels of JCV DNA load were evaluated in peripheral blood leukocytes or mononuclear cells of 10 AIDS patients at the time of onset of PML symptoms, and in 150 non‐PML HIV‐1‐infected patients using a semiquantitative PCR and ELISA‐hybridization assay. In PML‐AIDS patients, 60% (6/10) were positive for JCV‐DNA detection in peripheral blood cells compared with 26% (13/50) and 18% (18/100) positive for non‐PML HIV‐infected control patients with CD4+ T lymphocyte counts below and above 200.106/l, respectively (60 vs. 26%, P= 0.06; 60 vs. 18%; P= 0.007). The prevalence of JCV infection in the peripheral blood cells taken from controls appeared to be independent of the CDC stage of infection and CD4+ T lymphocyte counts. The predictive positive value of a positive JCV DNA PCR in peripheral blood cells for the diagnosis of PML in an HIV‐infected patient was 16% whereas the predictive negative value was 96%. The levels of circulating JCV DNA load, ranging from 1.69 to 2.53 log of copies per 106cells, did not differ between patients at time of PML symptoms onset and controls, and appeared to be independent of the clinical and the biological status in control patients. The findings do not indicate any significant JCV genomic replication activity in peripheral blood cells at the onset of PML disease, and suggest that JCV replication markers in the systemic compartment would not be valuable for predicting the development of PML in AIDS patients. J. Med. Virol. 66:1–7, 2002. © 2002 Wiley‐Liss, Inc.

Interferon alpha (IFN‐α) is synthesized in response to viral infections. MxA protein, induced specifically by IFN‐α and β, expressed in peripheral blood cells, is detected more consistently than circulating IFN‐α in serum of patients with viral infections. Thus, activation of the IFN‐α/MxA system can be used as additional marker of the presence of a virus in patients. Therefore MxA protein and IFN‐α levels were measured in patients with multiple sclerosis (MS), a chronic neurological disease of unknown etiology, in order to investigate the possible role of viruses in the expression of this disease. The means of MxA values obtained by using an immunochemiluminescent assay were significantly higher in blood of patients with remitting (n = 197) or relapsing (n = 39) multiple sclerosis (MS) patients and in patients with viral infections than in blood from healthy controls (n = 25) and from patients with bacterial infections (n = 12). Intra‐individual variance in MxA levels in seven clinically stable remitting patients with MS was observed in the course of a follow‐up, and high MxA levels were detected in three of them in blood samples collected consecutively over several months. By using an ultra sensitive assay, a higher MxA‐inducer activity was obtained with sera from MS patients (n = 39) than with those from healthy controls (n = 12). Experiments with neutralizing antibodies proved that this activity in serum from patients was due to IFN‐α, whereas IFN‐α could not be detected by other methods. Altogether these results demonstrate that there is an activation of the IFN‐α/MxA system in MS patients, which is consistent with the hypothesis that a viral infection may be associated with MS. J. Med. Virol. 65:301–308, 2001. © 2001 Wiley‐Liss, Inc.

A rapid reverse transcription polymerase chain reaction (RT‐PCR) and microwell capture hybridisation assay with general specificity for enteroviruses was developed and compared with an improved nested RT‐PCR for the detection of enteroviral RNA sequences in endomyocardial tissue from patients with chronic dilated cardiomyopathy. This method could detect as few as 20 genomic RNA copies per 100 mg of heart tissue homogenate and results could be obtained within 8 hours. Of the 55 biopsy specimens aseptically collected from the explanted hearts of 55 patients, 21 (38.2%) were positive by RT‐PCR microplate assay, whereas only 19 (34.5%) were positive by nested RT‐PCR assay and none were positive by classical cell culture assays. No enterovirus was detectable by RT‐PCR or classical cell culture assays in any of the 55 heart biopsy specimens taken from organ donors without any known heart disease. Moreover, the nucleotide sequences of EV nested RT‐PCR products showed greatest similarity to group B Coxsackieviruses [CVB3 (n = 12) or CVB5 (n = 3)], but also to group A Coxsackieviruses (CVA21 (n = 1) or CVA9 ( n= 3)]. The described RT‐PCR and microwell capture hybridisation assay can be applied to the virological diagnosis of human enteroviral cardiac infections. Moreover our findings suggest that group B and group A Coxsackieviruses can persist in heart tissue from patients with end‐stage chronic cardiomyopathy, supporting the hypothesis that these viruses could be implicated in the etiology of idiopathic dilated cardiomyopathy. J. Med. Virol. 64:133–140, 2001. © 2001 Wiley‐Liss, Inc.

To define the role of enteroviruses and human rhinoviruses as etiological agents in childhood bronchiolitis, clinical aspirates from 84 infants admitted to hospital with symptoms of obstructive bronchiolitis were tested by picornavirus RT‐PCR assay, adenovirus PCR assay and classical immunofluorescence antigen detection of common respiratory viral agents. Respiratory syncytial viruses (A&B) were detectable in 45 of 84 (53.6%) nasopharyngeal aspirates from infants with bronchiolitis, whereas coronaviruses, influenza viruses, and parainfluenza viruses were not detectable in the same samples. Adenoviruses were detectable by PCR in 11 of 84 (13.1%) nasopharyngeal swabs. By using a picornavirus RT‐PCR assay followed by a differential molecular hybridisation, rhinovirus and enterovirus RNA sequences were detected in 16 of 84 (19%) and in 10 of 84 (11.9%) of the nasopharyngeal swabs tested. Positive human rhinovirus or enterovirus RT‐PCR assay, however, was the only evidence of respiratory infection in 8 of 84 (9.5%) and in 7 of 84 (8.33%) of the studied patients. Respiratory syncytial viruses, human rhinoviruses, adenoviruses, and enteroviruses occur in dual infections detected in 18 of 84 (21.4%) respiratory samples tested. The median duration of stay in hospital was not significantly different between the patients demonstrating a single viral infection and those with a dual viral infection (6.22 ± 2.07 vs. 5.04 ± 0.95 days; P> 0.05). In summary, combination of molecular and classical detection assays of common viruses can be used to demonstrate enterovirus and human rhinovirus respiratory infection in childhood bronchiolitis, and provides an improved approach to obtain new insights into concomitant viral respiratory tract infection in infants. J. Med. Virol. 61:341–346, 2000. © 2000 Wiley‐Liss, Inc.

Using the water-soluble naphthalene carrier of singlet oxygen NDPO2, we have shown that pure singlet oxygen is able to inactivate enveloped viruses (human immunodeficiency virus type 1, herpes simplex virus type 1, cytomegalovirus, vesicular stomatitis virus), but has no effect on non-enveloped viruses (adenovirus and poliovirus 1). These results are related to the experiments on photoinactivation of viruses by hydrophobic photosensitizers (merocyanine 540, hypericin, phthalocyanines, hematoporphyrin and benzoporphyrin derivatives) and they strengthen the hypothesis that singlet oxygen plays a predominant role in this process.

The pathogenesis of CVB3‐induced chronic myocarditis remains unknown. Activated monocytes and macrophages may maintain ongoing inflammation during a persistent CVB3 infection and possibly represent the major mechanism leading to chronic myocarditis. We decided to study the activation status of cells by studying TNFα secretion in vitrousing whole blood culture in CVB3‐induced murine chronic myocarditis. Seven DBA/2 +/+ mice and 18 NMRI nu/nu mice were inoculated intraperitoneally with 5 × 105pfu of CVB3, and mice were mock‐infected. Thirty‐one days post‐infection, all mice were sacrificed, blood samples were obtained from the heart, and the heart was removed. Enteroviral genomic detection by RT‐PCR, virus isolation and histological analysis of heart samples were performed. Heparinized whole blood (25 μl) was cultured for 4 hr and 24 hr in sterile 96 well‐plate containing 225 μl RPMI in the presence or the absence of activators (LPS + PHA). The TNFα levels in the whole blood from mock‐infected DBA/2 (n= 4) and NMRI nu/nu mice (n= 5) were not different. A moderate increase of TNFα was observed in three out of five DBA/2 mice with negative CVB3 that had no histological abnormalities in myocardium. An increased level of TNFα was found in the sole DBA/2 mouse with positive CVB3 detection and chronic myocarditis. An increased level of TNFα was found in one out of nine NMRI nu/nu mice with positive CVB3 detection and chronic myocarditis and in one out of seven mice with positive CVB3 detection exempt of lesions in myocardium. In other infected mice, the level of TNFα was normal. Enteroviral genome was not detected in the blood from infected mice at 31 days post‐infection. The increased TNFα level in some mice may be designed for a beneficial inflammatory and immune response, however, an exaggerated release may be associated with an adverse effect. The normal TNFα level in whole blood cultures from mice with chronic myocarditis does not exclude enhanced cytokine production at infected loci such as myocardial tissue. This is the first report to use whole blood cultures to study the production of cytokines in virus‐induced disease in a small animal model.

Soluble forms of the two molecular species of the cell surface TNF receptors (sTNFR p55 and sTNFR p75) can reduce the activity of TNFα but they may also enhance its function by stabilizing the active TNFα oligomer. Considering the pathophysiological importance of sTNFR p75 for the regulation of the bioavailability of TNFα in the body, we determined the serum levels of sTNFR p75 and TNFα in 45 children and 28 adults with laboratory‐confirmed dengue infection by using immunoassays. The serum samples were obtained from day 1 to day 15 after the onset of the disease during the 1989–1990 outbreak of dengue‐3 in Tahiti, French Polynesia. The patients were clinically classified as having dengue hemorrhagic fever (DHF) and graded according to the criteria of the World Health Organization (WHO) into four grades from less severe (grade I) to severe (grade IV). The sera of both children and adult patients of all severity grades contained higher levels of sTNFR p75 than the sera of control subjects. Although high levels of TNFα were also detected in children and adults among grade I, II, III and IV patients, we found no correlation between sTNFR p75 and TNFα. We observed in adults a moderate elevation of sTNFR p75 and TNFα in sera compared with that observed in children. The raised levels of immunoreactive sTNFR p75 and TNFα in all clinical groups of dengue‐infected patients strongly indicate activation of the TNFα system during dengue infection. The balance between sTNFR p75 and TNFα may be altered in dengue infection. Further investigations are needed to understand the role of sTNFR p75 and TNFα in the pathogenesis of DHF and to improve the management of dengue infection.

Correlations between the in vitrobiological properties of HIV strains isolated from patients and the prognosis of their disease have been reported. We developed a technique to study the phenotype of HIV strains isolated from patients. We used the P4 cell line, derived from HeLa cells, which has been transfected with receptor CD4 gene. HIV laboratory strain (HIVLAI) and peripheral blood leukocytes (PBLs) from donors infected with HIVLAIinduce syncytium in P4 cell cultures in vitro. The presence of reporter gene (LacZgene) under the control of the HIV‐1 long terminal repeat (LTR) in these cells allows colorimetric visualization of syncytia in the cytoplasm using a β‐galactosidase (βgal) assay in the presence of X‐gal. We cocultivated 1 × 106patient PBLs with 2 × 106normal PHA‐activated normal PBLs for 4 days in the presence of IL‐2 in 24‐well plates. Half of the medium was replaced twice a week and PHA‐activated normal PBLs were added every 7 days. HIV‐1 was isolated from cocultured PBLs of 18 patients with advanced‐stage HIV infection as assessed by the production of HIV p24 detected with a commercially available HIV‐1 p24 ELISA. Supernatant and 105cells were collected twice a week from cocultured PBLs and were added to P4 cells in 96‐well microtiter plates. The cultures were observed every day for 3 days and then the βgal assay was performed. We did not observe any effect with cells and supernatant from 8 patients, harvested from cultures incubated for as long as 28 days. The phenotype of these isolates was called NC (noncytopathic). In cells from 2 patients, we obtained blue multinucleated giant cells; the phenotype of these strains was called SI (syncytium inducing). In cultures from 8 other patients, we obtained the death of P4 cells without syncytium formation, and the phenotype of these strains was called CI (cell‐killing inducing). In every case, the cytopathic effect of HIV‐1 isolates could be detected with cocultured PBLs collected as early as day 4 of culture. Cocultured PBLs from 13 healthy controls did not alter the P4 cells. We displayed the replication of CI strains of HIV‐1, but not the one of NC strains in P4 cell line. Our micromethod allowed the detection of cytopathic effects of HIV isolates. Further investigations should define the clinical applications of this method.

Culture techniques for isolation of HIV‐1 from small amounts of whole blood (WB) treated with anticoagulant have been reported and gave results identical to those of culture of separated peripheral blood mononuclear cells. Some authors obtained much higher isolation rates when EDTA was used instead of heparin. We compared two previously described techniques for cultivation of HIV‐1 from WB of adult HIV+ patients staged according to the CDC classification. In addition, we assessed the influence of the type of anticoagulant used for the collection of blood in viral replication in cell cultures from whole blood. Small volumes of WB treated with either heparin or EDTA were cocultivated with phytohemagglutinin (PHA)‐stimulated peripheral blood mononuclear cells (PHA‐PBMC) from healthy donors. We used two procedures for WB culture: procedure I, based on the culture of 250 μl of WB with 1 × 106PHA‐PBMC from donors; and procedure II based on the culture of 500 μl of WB with 4× 106PHA‐PBMC from donors. The cocultures were placed in 24‐well plates and incubated for as long as 28 days in medium containing interleukin 2 (IL‐2). Twice weekly half of the medium was replaced with fresh medium. In procedure II, one million fresh PHA‐PBMC from donors was added on the 7th day of culture. The culture supernatant was assayed for the presence of HIV‐1 p24 antigen in an enzyme immunoassay. The kinetics of HIV‐1 replication in cultures of WB from 7 AIDS patients were similar using procedures I and II. In 8 HIV + patients the isolation rate was higher with heparin‐ than with EDTA‐treated samples. The isolation rate was higher in AIDS patients (n= 8) than in others with both methods. In stage IV patients without AIDS (n= 8) we failed to isolate HIV‐1 in 1 patient with procedure I, whereas we succeeded with procedure II. In stage II, HIV‐I was isolated in 1 of 4 patients with both methods. HIV was isolated in cultures of WB from patients receiving zidovudine or related nucleoside analogues and in cultures of WB from untreated patients. HIV‐1 could not be isolated from WB of patients with more than 400 CD4+ T lymphocytes in their peripheral blood (n=4); however, it was isolated from 14 of 16 patients with less than 400 CD4+ T lymphocytes. Our results suggest that procedure II is more sensitive than procedure I and that heparin is better than EDTA for collecting WB. We showed that the rate of HIV‐1 isolation from WB increased in advanced‐stage patients. Further studies are needed to define the clinical applications of WB culture.

Diluted whole blood (WB) culturing may be the most appropriate milieu in which to study cytokine production in vitro.We tested TNFα and IL‐6 production using small volumes of WB (25 μl) from HIV‐1 positive patients with a one‐step procedure that combines WB stimulation with LPS, PHA and cytokine measurement. We studied 49 patients without secondary infection or at distance of secondary infection staged according to the 1993 classification of the CDC and 12 healthy seronegative subjects. Heparinized blood from 5 control subjects had been collected sequentially during a period of 5 months. The individual variations of TNFα and IL‐6 production were limited for all these individuals. In 1 out of 20 CDC group A patients, 6 out of 17 CDC group B patients and 3 out of 12 CDC group C patients, we obtained higher values of TNFα than the mean + 2 S.D. of the control group. In 3 out of 20 CDC group A patients, 1 out of 17 CDC group B patients without AIDS and 5 out of 12 CDC group C patients, the TNFα values were lower than the mean −2 S.D. of the control group. Low IL‐6 values were obtained in 1 out of 20 CDC group A patients and 1 out of 17 CDC group B patients and 3 out of 12 CDC group C patients. There was no correlation between TNFα production in vitroand plasma level of TNFα. We found no correlation between the levels of cytokines and monocyte count or between the levels of cytokines and CD4 T‐cell count in peripheral blood. Our data point out a disarray in TNFα and IL‐6 production by WB from HIV‐1 infected patients. The relationship between the disarray of cytokine production and cytopathogenicity of HIV‐1 isolates in the P4 cell line was investigated in this study. We found a correlation between the high level of TNFα produced by WB and the phenotype of HIV‐1 isolates isolated from patients. The one‐stage procedure used in this work is of potential value to investigate the activation status of cells for monitoring HIV‐1 positive individuals and predicting HIV‐1 phenotype.

The pathogenesis of dengue hemorrhagic fever (DHF) is not well known, but the role of host factors has been suggested. The level of immunoreactive circulating and cell‐generated tumor necrosis factor alpha (TNFα) was studied in 35 patients with DHF; its relationship with virus isolation and/or genome detection by reverse transcription polymerase chain reaction (RT‐PCR) and specific antibodies were detected by hemagglutination inhibition (HI). Large variation of TNFα plasma levels was obtained in dengue‐infected patients at the same stage of the disease and at the same day after infection. Most of the patients (14 out of 17 patients) who displayed augmented spontaneous in vitro production of TNFα by heparinized whole‐blood culture compared with controls also had elevated levels of TNFα in the plasma. The TNFα values in lipopolysaccharide and phytohemagglutinin heparinized whole‐blood cultures were not higher in patients than in controls, but low TNFα levels were obtained in three out of 30 patients. An inverse correlation was observed between spontaneous in vitro TNFα production and viral replication, which raises the issue of the antiviral effect of TNFα in dengue infection. The results do not support the hypothesis of the role of antibody‐dependent enhancement giving rise to increased viremic titers and production of TNFα in patients. The present study demonstrates the activation of the TNFα‐producing cells in dengue‐infected patients and suggests further investigation to define the mechanism and the role of TNFα in the pathogenesis of dengue virus infection. J. Med. Virol. 54:210–218, 1998.© 1998 Wiley‐Liss, Inc.

In order to analyse the relationships between enteroviral replication and the myocardial damage at the onset of chronic cardiac infection, 2 mouse strains with different degrees of immunological competence (NMRI nu/nu, DBA/2) were infected by a myocarditic Coxsackie virus B3 (CVB3‐M1) variant. At 31 days post‐inoculation, plaque‐forming assay, polymerase chain reaction (RT‐PCR), and immunohistochemistry were carried out for detecting viruses and viral components in the myocardium. The virological findings were related to histopathological changes in the myocardium as well to the dilatation of both cardiac ventricles. Chronic myocardial lesions characterized by large fibrosis areas and interstitial inflammatory infiltrates were detected together with cardiomegalia in 52.6% (10/19) of athymic mice and in 9% (2/22) of euthymic mice. Viral replication foci were located and were found only in myocarditic cells adjacent to myocardial inflammatory lesions by immunostaining myocardial tissue sections with anti‐serum to VP1 virus capsid protein. Using PCR followed by microwell capture hybridization assay, a large excess of viral positive strand RNA over negative strand was semiquantified in heart tissue from mice with chronic myocarditis, whereas approximately equal amounts of plus and minus strand RNA were detected in cases of persistent cardiac infection without chronic myocardial injuries. These findings provide evidence of the major role of viral replication in the pathogenesis of chronic murine CVB3‐induced cardiomyopathy. The results indicate that the cardiac persistence of enteroviral RNAs can be observed without chronic cardiomyopathy, which could be explained by a defective viral positive RNA replication. J. Med. Virol 52:206–214, 1997. © 1997 Wiley‐Liss, Inc.

Enteroviruses may be linked to insulin‐dependent diabetes mellitus (IDDM). The prevalence of enteroviral (EV) infection at onset of adult IDDM was investigated by detection of specific EV sequences in peripheral blood using a reverse transcription and a seminested polymerase chain reaction (seminested RT‐PCR). EDTA‐treated whole blood samples taken from 12 newly diagnosed IDDM patients with ketosis or ketoacidosis were examined. The comparison groups were 12 adult patients suffering from metabolic decompensation in the course of IDDM, 12 adult patients with decompensated non‐IDDM, and 15 healthy adults without any presumed EV infection or metabolic disease. EV genome was detected in five of 12 (42%) newly diagnosed IDDM patients and in one of 12 (8%) patients in the course of IDDM. By contrast, none of the 12 non‐IDDM patients and none of the 15 healthy adults had EV sequences in whole blood. Subsequent sequencing of the EV PCR products from the six positive patients showed a significant homology with Coxsackie B3 or B4 viruses, and some common patterns were observed among the sequences. The present study demonstrates that Coxsackie B virus RNA sequences can be detected in peripheral blood from patients at the onset or in the course of IDDM and provides evidence for a role for enteroviruses in adult type I diabetes. J. Med. Virol. 52:121–127, 1997. © 1997 Wiley‐Liss, Inc.

The changes in type 1 (IL12, IFNγ, IL2) and type 2 (IL4, IL10) cytokine profiles may be associated with virological parameters of progression of the disease in HIV‐1‐infected patients. The production of cytokines was studied in LPS + PHA‐activated whole‐blood culture in HIV‐1‐infected individuals at different stages of the disease. The association was investigated between IL12p40 and IL12p70 profiles and other cytokines (IFNγ, IL4, IL10), as well as the isolation of cytopathogenic HIV‐1 strains. The phenotype of HIV strains was studied by a micromethod based on P4 cell line, allowing detection of cytopathic effects of HIV‐1 isolates (syncytium‐induction and cell‐killing without syncytium induction). The individual variations in IL12p40 and IL12p70 production were limited in the healthy controls. Low values were observed in HIV‐1‐infected patients. The production of IL12 (p40 and p70) and the IL12p70/IL4 ratio and the IFNγ/IL4 ratio were significantly lower in patients with cytopathic isolates compared with patients with noncytopathic isolates, and a correlation was obtained between the values of IL12 (IL12p40 and IL12p70) and those of IFNγ/IL4 ratio. There was no increase in the secretion of IL4 and IL10 in patients with cytopathic strains compared with other patients. The results indicate a decreased production of type 1 cytokines (IL12, IFNγ) in the presence of a relatively preserved production of type 2 cytokines (IL4, IL10) in HIV‐1‐infected patients. In conclusion, the defect of production of IL12 by whole blood is associated with virological correlates of progression of HIV‐1 disease. J. Med. Virol. 55:209–214, 1998. © 1998 Wiley‐Liss, Inc.

The level of sCD23 produced in the course of human immunodeficiency virus (HIV) infection was measured in patients grouped according to the Centers for Disease Control by using an immunoradiometric assay. Soluble CD23 was evaluated in supernatants of peripheral blood mononuclear cell (PBMC) (106cells/ml) stimulated by phytohemagglutinin (PHA). Compared with healthy controls (m±S.D. = 1.0 ±0.34 U/ml, n= 7), higher values were observed in some of the patients of group II (asymptomatic) (m±S.D. = 2±1.33, n= 9) and some of the patients of group IV (AIDS) (m±S.D. = 1.3 ±1.40, n= 8). Those results prompted us to compare the plasma levels of sCD23 in group II and group IV HIV‐infected patients and in healthy individuals. Soluble CD23 plasma levels in healthy patients (n= 42) ranged from 0 to 1.5 U/ml (m±S.D. = 0.9±0.33), in group II patients (n= 17) from 0 to 3 U/ml (m±S.D. = 0.92±0.83) and in group IV patients (n=73) from 0 to 2.9 U/ml (m±S.D. = 1.15±0.71). The differences between the patients and the healthy individuals were not statistically significant but individual sCD23 values higher than 2 U/ml were obtained in 6% of the group II patients and 16.7% of the group IV patients. Increased values of sCD23 were obtained in plasma from patients with secondary infectious diseases (groups IV‐C1 and IV‐C2) and from patients without secondary infectious diseases (group II, group IV‐A and group IV‐B). Elevated values of sCD23 were detected even in patients with low counts of CD4+T cells and CD8+T cells in their peripheral blood. sCD23 has numerous activities including control of IgE synthesis and cytokine‐like properties. Our results show a disarray of sCD23 in HIV‐infected patients which could be involved in drug reactions, allergic manifestations and the IgE‐level increase. Further investigations should attempt to define the role of sCD23 in clinical manifestations of HIV infection.

We investigated whether HIV‐1 can regulate tumor necrosis factor receptor (TNFR) expression in SupT‐1, a CD4 + T‐cell line. The cells were infected with HIV‐1 containing 1,000 cpm RT activity, as early as day 3 after infection and all along the culture the supernatant level of core protein p24 was >250 pg/ml, and on days 6 and 9 after infection, p24 was found in 10 % of the cells as determined by indirect immunofluorescence assay. The cells were growing without loss of viability. The study of TNFR expression was based on a microassay for measurement of binding of 125I‐TNFα to cells, in which free and cell‐bound ligand separation was performed by centrifugation through oil. Scatchard analysis of TNFα binding on days 6 and 9 after infection revealed a 90 % increase in the expression of high‐affinity membrane receptors in HIV + SupT‐1 culture compared with uninfected cells (mean +/‐S.D. = 501 +/‐148.5 vs. 263 +/‐77.8 receptors/cell, n= 9, P< 0.001) with no change in dissociation constants (mean +/− S.D. = 4.36 +/−1.06 vs. 4.00 +/−1.12 × 10−10m).