Efficacy of Bamlanivimab/Etesevimab and Casirivimab/Imdevimab in Preventing Progression to Severe COVID-19 and Role of Variants of Concern

INTRODUCTION

The aim of this study was to evaluate the risk of hospitalization or death in patients infected by SARS-CoV2 variants of concern (VOCs) receiving combinations of monoclonal antibodies (mAbs), bamlanivimab/etesevimab or casirivimab/imdevimab.

METHODS

Observational prospective study conducted in two Italian hospitals (University Hospital of Pisa and San Donato Hospital, Arezzo) including consecutive outpatients with COVID-19 who received bamlanivimab/etesevimab or casirivimab/imdevimab from March 20th to May 10th 2021. All patients were at high risk of COVID-19 progression according to FDA/AIFA recommendations. Patients were divided into two study groups according to the infecting viral strain (VOCs): Alpha and Gamma group. The primary endpoint was a composite of hospitalization or death within 30 days from mAbs infusion. A Cox regression multivariate analysis was performed to identify factors associated with the primary outcome in the overall population.

RESULTS

The study included 165 patients: 105 were infected by the VOC Alpha and 43 by the VOC Gamma. In the Alpha group, no differences in the primary endpoint were observed between patients treated with bamlanivimab/etesevimab or casirivimab/imdevimab. Conversely, in the Gamma group, a higher proportion of patients treated with bamlanivimab/etesevimab met the primary endpoint compared to those receiving casirivimab/imdevimab (55% vs. 17.4%, p = 0.013). On multivariate Cox-regression analysis, the Gamma variant and days from symptoms onset to mAbs infusion were factors independently associated with higher risk of hospitalization or death, while casirivimab/imdevimab was protective (HR 0.33, 95% CI 0.13-0.83, p = 0.019).

CONCLUSIONS

In patients infected by the SARS-CoV-2 Gamma variant, bamlanivimab/etesevimab should be used with caution because of the high risk of disease progression.

A nosocomial measles outbreak in Italy, February-April 2017

We describe a nosocomial outbreak of measles that occurred in an Italian hospital during the first months of 2017, involving 35 persons and including healthcare workers, support personnel working in the hospital, visitors and community contacts. Late diagnosis of the first case, support personnel not being promptly recognised as hospital workers and diffusion of the infection in the emergency department had a major role in sustaining this outbreak.

Cyclovirus Vietnam DNA in immunodeficient patients

BACKGROUND

Cyclovirus Vietnam (CyCV-VN) is a CyCV detected in 2013 from cerebrospinal fluid (CSF) samples of patients with neurological disorders. Information on prevalence, pathogenesis and disease association of CyCV-VN is still very patchy.

OBJECTIVES AND STUDY DESIGN

In this study, we have used a PCR assay targeting the Rep gene to investigate the prevalence of CyCV-VN infection in blood and CSF samples of 346 Italian subjects.

RESULTS

Overall, 7% of blood samples were positive for CyCV-VN while the virus was not detected in any of the CSF samples. The prevalence of CyCV-VN was relatively high in HIV positive patients (21%), modest in patients with HBV or HCV infection (6%), and low in transplant recipient patients (2%). Positive patients showed low levels of CyCV-VN viremia. The virus was not detected in serum samples from healthy individuals. Longitudinal analysis of serum samples obtained from selected patients showed a stable or transient presence of circulating CyCV-VN.

CONCLUSIONS

The present study is the first to demonstrate CyCV-VN DNA circulation in Italy and to cast light on some biological aspects of this novel virus of men.

Genotypic testing on HIV-1 DNA as a tool to assess HIV-1 co-receptor usage in clinical practice: results from the DIVA study group

PURPOSE

We have developed a sequencing assay for determining the usage of the genotypic HIV-1 co-receptor using peripheral blood mononuclear cell (PBMC) DNA in virologically suppressed HIV-1 infected patients. Our specific aims were to (1) evaluate the efficiency of V3 sequences in B versus non-B subtypes, (2) compare the efficiency of V3 sequences and tropism prediction using whole blood and PBMCs for DNA extraction, (3) compare the efficiency of V3 sequences and tropism prediction using a single versus a triplicate round of amplification.

RESULTS

The overall rate of successful V3 sequences ranged from 100 % in samples with >3,000 copies HIV-1 DNA/10(6) PBMCs to 60 % in samples with <100 copies total HIV-1 DNA /10(6) PBMCs. Analysis of 143 paired PBMCs and whole-blood samples showed successful V3 sequences rates of 77.6 % for PBMCs and 83.9 % for whole blood. These rates are in agreement with the tropism prediction obtained using the geno2pheno co-receptor algorithm, namely, 92.1 % with a false-positive rate (FPR) of 10 or 20 % and of 96.5 % with an FPR of 5.75 %. The agreement between tropism prediction values using single versus triplicate amplification was 98.2 % (56/57) of patients using an FPR of 20 % and 92.9 % (53/57) using an FPR of 10 or 5.75 %. For 63.0 % (36/57) of patients, the FPR obtained via the single amplification procedure was superimposable to all three FPRs obtained by triplicate amplification.

CONCLUSIONS

Our results show the feasibility and consistency of genotypic testing on HIV-1 DNA tropism, supporting its possible use for selecting patients with suppressed plasma HIV-1 RNA as candidates for CCR5-antagonist treatment. The high agreement between tropism prediction by single and triple amplification does not support the use of triplicate amplification in clinical practice.

Human gyrovirus DNA in human blood, Italy

HGyV in blood suggests the infection might be systemic.

Human gyrovirus (HGyV) is a recent addition to the list of agents found in humans. Prevalence, biologic properties, and clinical associations of this novel virus are still incompletely understood. We used qualitative PCRs to detect HGyV in blood samples of 301 persons from Italy. HGyV genome was detected in 3 of 100 solid organ transplant recipients and in 1 HIV-infected person. The virus was not detected in plasma samples from healthy persons. Furthermore, during observation, persons for whom longitudinal plasma samples were obtained had transient and scattered presence of circulating HGyV. Sequencing of a 138-bp fragment showed nucleotide identity among all the HGyV isolates. These results show that HGyV can be present in the blood of infected persons. Additional studies are needed to investigate possible clinical implications.

Absence of xenotropic murine leukemia virus-related virus in Italian patients affected by chronic fatigue syndrome, fibromyalgia, or rheumatoid arthritis

The xenotropic murine leukemia virus-related virus (XMRV) has been recently linked to chronic fatigue syndrome in a US cohort in whom the virus was demonstrated in 67&#x0025; patients vs 3.7&#x0025; healthy controls. Albeit this finding was not substantiated by subsequent reports and eventually considered a laboratory contamination, the matter is still the object of intense debate and scrutiny in various cohorts of patients. In this work we examined well-clinically characterized Italian patients affected by chronic fatigue syndrome, and also fibromyalgia and rheumatoid arthritis, two chronic illnesses of basically unknown etiology which show quite a few symptoms in common with chronic fatigue syndrome. Although we used recently updated procedures and controls, the XMRV was not found in 65 patients with chronic fatigue syndrome diagnosis, 55 with fibromyalgia, 25 with rheumatoid arthritis, nor in 25 healthy controls. These results add to the ever-growing number of surveys reporting the absence of XMRV in chronic fatigue syndrome patients and suggest that the virus is also absent in fibromyalgia and rheumatoid arthritis.

Performance of genotypic tropism testing on proviral DNA in clinical practice: results from the DIVA study group

OBJECTIVE

The DIVA study is aimed at setting up a standardized genotypic tropism-testing on proviral-DNA for the routine clinical diagnostic-laboratory.

METHODS

Twelve local centres and 5 reference centres (previously cross-validated) were identified. For inter-center validation-procedure, 60 peripheral-blood mononuclear cells (PBMCs) aliquots from 45 HAART-treated patients were randomly chosen for population V3 sequencing on proviral-DNA at local HIV centre and at reference-laboratory. Viral tropism was predicted by Geno2Pheno algorithm (False Positive Rate [FPR] = 20%) as proposed by the European-Guidelines. Quantification of total HIV-1 DNA was based on a method described by Viard (2004).

RESULTS

Quantification of HIV-1 DNA was available for 35/45 (77.8%) samples, and gave a median value of 598 (IQR:252- 1,203) copies/10 PBMCs. A total of 56/60 (93.3%) samples were successfully amplified by both the reference and the local virological centers. The overall concordance of tropism prediction between local and reference centers was 54/56 (96.4%). Results of tropism prediction by local centers were: 33/54 (61.1%) R5 and 21/54 (38.9%) X4/DM.

CONCLUSION

There was high concordance in the genotypic tropism prediction based on proviral DNA among different virological centers throughout Italy. Our results are in line with other European studies, and support the use of genotypic tropism testing on proviral DNA in patients with suppressed plasma HIV-1 RNA candidate to CCR5-antagonist treatment.

Rapid increase in total torquetenovirus (TTV) plasma viremia load reveals an apparently transient superinfection by a TTV of a novel group 2 genotype

An apparently transient infection by a superimposed torquetenovirus (TTV) in a subject who already carried three different genotypes of the virus is described. The superinfection induced a rapid increase in the plasma TTV load and a decline in immunocomplexed virus. The superinfecting TTV was a novel group 2 genotype.

HIV-1 NAT minipool during the pre-seroconversion window period: detection of a repeat blood donor

BACKGROUND

The introduction of nucleic acid amplification technology (NAT) for screening pooled or individual donations remarkably improved the safety of blood products. The size of mini-pooled NAT is considered critical for identification of HIV-1 infected donors during preseroconversion phase of infection. We describe a case of HIV-1 infection in a serologically negative repeat blood donor identified by 16 minipool (MP) NAT.

MATERIALS AND METHODS

The donation was tested by Roche Cobas AmpliScreen HIV-1 Test with manual extraction (MultiPrep Specimen Processing Procedure). The sensitivity of different MP sizes was observed. Serial samples of infected donor were examined with different third and fourth generation HIV-1 serological assays.

RESULTS

In the index donation viral load was 515 copies/ml corresponding to about 50 IU when diluted in 16 MP. Abbott third and fourth generation EIA tests detected the seroconversion four days later the index donation.

CONCLUSION

The report emphasizes the relevance of a very small size of MP to really reduce the window serologic phase of current EIA test by HIV-1 NAT test.

Associations between nasal torquetenovirus load and spirometric indices in children with asthma

Fifty-nine children with well-controlled, mild to moderate persistent asthma were studied for the presence and load of torquetenovirus (TTV) in nasal fluid. Rates of TTV positivity and mean nasal TTV loads were not dissimilar to those observed in the general population and in a group of 30 age- and residence-matched healthy control children without a history of asthmatic disease. However, in the children with asthma, 3 important indices of lung function--forced expiratory flow (FEF) in which 25% and 75% of forced vital capacity (FVC) is expired (FEF(25%-75%)), forced expiratory volume in 1 s/FVC, and FEF(25%-75%)/FVC--showed an inverse correlation with nasal TTV load. Furthermore, signs of reduced airflow were more frequent in the children with asthma who had high nasal TTV loads (> or =6 log(10) DNA copies/mL of nasal fluid) than they were in those who had low nasal TTV loads (<6 log(10) DNA copies/mL of nasal fluid), despite similar therapy regimens. In contrast, the control children showed no associations between nasal TTV load and the spirometric indices. Levels of eosinophil cationic protein in sputum were also greater in the children with asthma who had higher nasal viral burdens than they were in those who had lower nasal viral burdens. These findings are the first report of TTV infection status in children with asthma and suggest that TTV might be a contributing factor in the lung impairment caused by this condition.

Correlation between Torque tenovirus infection and serum levels of eosinophil cationic protein in children hospitalized for acute respiratory diseases

Children with bronchopneumonia have considerably higher Torque tenovirus (TTV) loads than do children with milder acute respiratory diseases (ARDs). Moreover, in children with ARDs, high TTV loads correlate with low percentages of circulating CD3+ and CD4+ T cells and with elevated percentages of B cells, suggesting that TTV might be immunomodulatory. Here, we show that, in children with ARDs, the presence of TTV and TTV load correlate with concentrations of serum eosinophil cationic protein. The possible mechanisms whereby TTV infection might lead to augmented activity of eosinophils and the implications for pathogenesis are discussed.

Relationship of TT virus and Helicobacter pylori infections in gastric tissues of patients with gastritis

Blood and gastric tissue biopsies of 34 patients with gastritis were tested for the presence of TT virus (TTV), a ubiquitous virus found in the blood of most humans. Thirty-one of these patients were TTV positive, and 27 patients had virus in both tissues. In addition, 13 of the patients who had TTV in gastric tissue were Helicobacter pylori positive. There was an association of higher TTV titers in gastric tissues of patients who were H. pylori positive than in those in whom the bacterium could not be detected. Furthermore, this association was stronger in H. pylori-positive patients with the presence of the cagA protein. Of 10 specimens in which genogroup determination was carried out in the gastric corpus, 5/5 that were H. pylori positive showed the presence of TTV genogroup 3, while for those that were H. pylori negative, 5/5 showed the presence of genogroup 1t. By contrast, genogroup 1 was found in the corpus of only one H. pylori-positive patient, and genogroup 3 in only one H. pylori-negative patient. The histological severity of gastritis did correlate significantly with loads in the gastric tissues. There was no significant difference in TTV titer in blood of patients regardless of H. pylori infection status. These findings pique interest in clarifying the role of TTV, alone or in association with H. pylori infection, in the pathogenesis of gastritis.

Relationships between TT virus infection and hepatitis C virus response to interferon therapy in doubly infected patients

A group of 24 well-characterized patients doubly infected with hepatitis C virus (HCV) and TT virus (TTV) were studied to evaluate whether the loads and number or identity of the genogroups of TTV they carried could affect the response of HCV infection to interferon-alpha (IFN) treatment. The features of HCV infection in the study patients provided a fair representation of the variables that are usually found in considering patients for IFN treatment. The same was true for the features of TTV infection. In particular, plasma loads of TTV varied over a wide range in individual patients, and infection with multiple TTV genogroups was extremely frequent. TTV genogroups 1 and 3 were the most prevalent, followed by genogroups 4 and 5. The HCV response to IFN was evaluated by measuring plasma viraemia at 24 hours and 30 days after initiation of treatment. The results showed that the TTV parameters investigated had little or no impact on the response of HCV to therapy. Due to study design, these results do not exclude that the presence of a concomitant TTV infection can affect how HCV infection responds to treatment. However, they indicate that, should such effects exist, they would be independent on load and genetic features of the infecting TTV.

Low prevalence of TT virus in the cerebrospinal fluid of viremic patients with central nervous system disorders

TT virus (TTV) is a widespread infectious agent of humans identified in 1998. In infected individuals, TTV induces persistent viremia but its life cycle and pathogenic potential are still poorly understood. In the present study, the presence of TTV DNA in 32 consecutive paired serum and cerebrospinal fluid (CSF) samples from patients with neurological (mainly multiple sclerosis) disorders was investigated by means of a sensitive quantitative real-time PCR assay. Of the 24 patients who were found to carry TTV DNA in serum, 3 also had detectable TTV DNA in their CSF. Two TTV positive CSF samples had markers indicative of blood contamination or a disrupted blood-brain barrier and contained considerably lower TTV loads as compared with the corresponding serum samples, thus suggesting that the virus they contained was of plasma origin. These findings indicated that in general TTV does not permeate effectively an intact blood-brain barrier. Furthermore, the CNS does not represent a common site of TTV replication and persistence. However, at least one exception was observed: the third TTV positive CSF sample (obtained from a patient with subacute dementia of unknown origin) showed no markers suggestive of disrupted blood-brain barrier or blood contamination and had a TTV DNA concentration similar to that found in the patient's serum. In addition, the TTV isolates detected in the two body fluids were distinct genetically. The detection of TTV DNA in CSF is of considerable interest but the clinical significance remains unknown.

TT virus (TTV) loads associated with different peripheral blood cell types and evidence for TTV replication in activated mononuclear cells

TT virus (TTV) loads associated with the peripheral blood cells of seven patients known to carry the virus in plasma were investigated by real-time PCR. Whereas red cells/platelets were uniformly negative, six and four patients yielded positive peripheral blood mononuclear cells (PBMCs) and polymorphonuclear leukocytes, respectively, but viral titres were generally low. Fractionation of PBMCs into monocyte- and B, T4, and T8 lymphocyte-enriched subpopulations showed no pattern in the viral loads that might suggest the preferential association of TTV to one or more specific cell types. TTV-negative PBMCs absorbed measurable amounts of virus when incubated with infected plasma at 4 degrees C. Furthermore, cultures of TTV-negative phytohaemagglutinin-stimulated PBMCs exposed in vitro to virus-positive plasma and faecal extracts released considerable levels of infectious TTV into the supernatant fluid and the same was true for TTV-positive stimulated PBMCs. These results indicate that, whereas freshly harvested resting PBMCs seem to produce little, if any TTV, stimulated PBMCs actively replicate the virus.

Rapid changes in hepatitis C virus quasispecies produced by a single dose of IFN-alpha in chronically infected patients

The effects of a single dose of 3 international megaunits of interferon-alpha2b (IFN-alpha2b) on hepatitis C virus (HCV) load and quasispecies were examined 24 h after administration in 12 previously untreated, chronically infected patients. All patients had viremia loads appreciably reduced relative to baseline values, thus confirming that the viral load is rapidly affected by IFN-alpha2b. Five patients also exhibited changes in plasma HCV quasispecies composition that were clearly evident by single-strand conformation polymorphism, analysis, thus indicating that one dose of IFN-alpha2b may suffice to produce rapid perturbations in the genetic heterogeneity of circulating HCV. Prior to IFN-alpha2b administration, 3 patients exhibited viral quasispecies differences between plasma and peripheral blood mononuclear cells (PBMC). Interestingly, in 2 such patients, the viral quasispecies found in the 24-h plasma resembled that in the pre-IFN PBMC. The latter finding raises the possibility that in these patients, the differences in quasispecies composition between pre-IFN and post-IFN plasma resulted from increased representation of lymphoid tissue-originated variants in the latter sample, possibly because of poor sensitivity to IFN-alpha2b of HCV replication in the lymphoid compartment.

High prevalence of TT virus (TTV) and TTV-like minivirus in cervical swabs

Genomes of TT virus (TTV) and TTV-like minivirus DNA were detected in 80% and 61% of cervical swabs from healthy women, respectively, regardless of concurrent human papillomavirus infection. These results show that the potential exists for sexual transmission of TTV and related viruses.

TT virus levels in the plasma of infected individuals with different hepatic and extrahepatic pathology

TT virus (TTV) infection is extremely widespread in the general population. A sensitive real-time PCR assay was developed that quantitated accurately the most prevalent TTV genotypes in Italy. When used to test 217 individuals for TTV viraemia, the overall prevalence was 94%. Viraemia levels varied widely amongst individual subjects, with no major differences related to gender or age. The highest TTV titres were in haemophiliacs and in patients with non-A-E hepatitis, but they did not differ from the group with miscellaneous diseases. HIV- and HCV-infected subjects and patients with primary liver diseases had TTV loads similar to those of healthy individuals.

Molecular properties, biology, and clinical implications of TT virus, a recently identified widespread infectious agent of humans

TT virus (TTV) was first described in 1997 by representational difference analysis of sera from non-A to non-G posttransfusion hepatitis patients and hence intensively investigated as a possible addition to the list of hepatitis-inducing viruses. The TTV genome is a covalently closed single-stranded DNA of approximately 3.8 kb with a number of characteristics typical of animal circoviruses, especially the chicken anemia virus. TTV is genetically highly heterogeneous, which has led investigators to group isolates into numerous genotypes and subtypes and has limited the sensitivity of many PCR assays used for virus detection. The most remarkable feature of TTV is the extraordinarily high prevalence of chronic viremia in apparently healthy people, up to nearly 100% in some countries. The original hypothesis that it might be an important cause of cryptogenic hepatitis has not been borne out, although the possibility that it may produce liver damage under specific circumstances has not been excluded. The virus has not yet been etiologically linked to any other human disease. Thus, TTV should be considered an orphan virus.

Lymphocyte subsets in hemodialyzed HCV+ and HCV- patients

The aim of our study was to get information on the immune status of patients who undergo haemodialysis in the presence of an HCV infection. This virus infects not only hepatocytes, but also blood mononuclear cells, in particular B cells [1], but we do not know the role of this lymphocyte involvement in the maintenance and progression of hepatitis. The impairment of the cell-mediated immune response in uraemic patients is well known, for example only 50–60% of uraemic patients undergo a seroconversion after HBV vaccine, compared to 95% of the normal population. Paradoxically the immunodeficiency is concomitant with an activation of related cells which is increased rather than ameliorated by the dialysis treatment [2]. In these patients lymphocytopenia is also present with a reduction of the absolute number of T lymphocytes which remain normal in percentage. The study was performed on the following groups of subjects.

High prevalence of TT virus viremia in italian patients, regardless of age, clinical diagnosis, and previous interferon treatment

The pathogenic potential of the newly discovered TT virus (TTV) is currently a matter of conjecture. Its presence was investigated in the serum of 660 patients, by polymerase chain reaction. TTV was detected in 50% of 221 patients with unselected pathologies, and no significant differences related to age, sex, or organ disease were noted. TTV was present at a significantly higher rate in hemophiliacs (73%) and at lower rates in patients with cirrhosis (30%) and rheumatoid arthritis (28%). Patients with other liver diseases, systemic lupus erythematosus, or psoriasis or receiving hemodialysis had rates of infection similar to those in unselected patients. TTV-positive patients treated with interferon-alpha for underlying type C hepatitis showed no appreciable changes of TTV viremia levels. Type 1b was by far the most frequent viral genotype (92%), followed by types 2c (5%) and 1a (3%).

Detection and quasispecies analysis of hepatitis C virus in the cerebrospinal fluid of infected patients

Hepatitis C virus (HCV) is a leading cause of liver damage and has also been implicated in extrahepatic pathologies. We examined for HCV RNA paired CSF and plasma samples from 12 viremia positive patients using PCR. The CSF from 5/5 HIV-infected patients and 5/7 HIV-negative patients were HCV RNA positive. Branched DNA analysis showed that HCV loads in CSF were much lower than in plasma. Several HCV-positive CSF showed no evidence of blood contamination, impaired blood-brain barrier, or intrathecal IgG production. Comparison of HCV quasispecies in three sets of samples suggested that the virus in CSF was of plasma origin.

Divergent evolution of hepatitis C virus in liver and peripheral blood mononuclear cells of infected patients

In infected individuals, hepatitis C virus (HCV) exists as a variably complex population of related genetic variants known as quasispecies. The quasispecies of HCV were studied previously in 10 chronically infected patients by single-strand conformation polymorphism analysis of a segment of the envelope gene E2/NS1 containing the hypervariable region 1 and it was found that certain variants (LC variants) were present both in the liver and in peripheral blood mononuclear cells (PBMC), others (L variants) were present in the liver but not in the PBMC, and still others (C variants) showed the opposite distribution. The sequence data obtained from nine such patients are reported, indicating that, within individual subjects, L and C variants are distinct phylogenetically. Results are described on the growth of HCV in stimulated healthy donor PBMC cultures supporting the concept that genetic divergence might stem, at least in part, from virus adaptation to growth in different cell types. This information may help to understand how HCV persists and produces disease in infected patients, especially with regard to extrahepatic pathology.

Susceptibility of human and non-human cell lines to HCV infection as determined by the centrifugation-facilitated method

The centrifugation-facilitated inoculation method was used to test 51 human and non-human cell lines for ability to support HCV replication. As determined by nested RT-PCR, one fifth of the cell lines tested were virus positive 15 days post inoculation suggesting that the centrifugation-facilitated inoculation is an efficient method for cell infection with HCV. However, virus production by infected cultures remained of low grade, thus showing that the unknown factors which limit HCV replication in vitro are not overcome by the procedure.

Hepatitis C virus infection: prevalence in psoriasis and psoriatic arthritis

OBJECTIVE

To study the prevalence of hepatitis C virus (HCV) infection in 2 groups of patients, one group with psoriasis and the other with psoriatic arthritis (PsA).

METHODS

We detected anti-HCV antibodies by ELISA and by a recombinant immunoblot assay (RIBA) in the sera of 50 patients with psoriasis and 50 with PsA. As controls we used a group of 76 patients with rheumatoid arthritis (RA), and referred to data on the prevalence of HCV in the general Italian population.

RESULTS

By ELISA, anti-HCV antibodies were detected in 6/50 (12%) patients with PsA, in 5/50 (10%) patients with psoriasis, and in 4/76 (5.2%) patients with RA. All the reactive PsA and RA sera also tested positive on RIBA, while only 3 of the 5 positive results for sera of patients with psoriasis were confirmed by RIBA. The prevalence of HCV infection in patients with psoriasis was not significantly higher than in controls. In contrast, the rate of HCV infection observed in the 50 patients with PsA was higher than that in the other groups, the difference being statistically significant between patients with PsA and the general population.

CONCLUSION

Our data do not support the hypothesis that HCV infection may play a role in the pathogenesis of psoriasis. On the other hand they show a statistically significant difference between the prevalence of HCV infection in patients with PsA and the general population.

Differences in hepatitis C virus quasispecies composition between liver, peripheral blood mononuclear cells and plasma

Hepatitis C virus (HCV) exists in vivo as a highly variable mixture of closely related genomes (quasispecies), but the pathogenetic significance of such heterogeneity is still largely unknown. To investigate this issue, we compared the composition of HCV quasispecies found in the liver, peripheral blood mononuclear cells (PBMC) and plasma of ten patients by single-strand conformation polymorphism analysis of the E2/NS1 region and sequencing of the variants detected. We found considerable quasispecies differences between the liver and PBMC in all the patients, involving variant numbers, relative quantities and relative electrophoretic mobilities, but no apparent tissue-specific trend. Genome variants present in the liver and/or PBMC were not detected in the corresponding plasma samples, while certain HCV variants were present only in plasma. No dominant amino acids or amino acid pattern characteristic of variants present solely in the PBMC were detected in the E2/NS1 region sequenced.

Subtype 2c of hepatitis C virus is highly prevalent in Italy and is heterogeneous in the NS5A region

Hepatitis C virus (HCV) isolates, obtained from 50 Italian patients with community-acquired infection, that had previously been classified as subtype 2a or 2b by current rapid genotyping methods were further characterized by partial sequence analysis. All the isolates were reclassified: 45 within subtype 2c and the other 5 as subtype 1b, 3a, or 4d. Thus, subtype 2c is much more prevalent than previously recognized, with about 30% of all HCV strains detected in Italy being subtype 2c. In contrast, isolates of subtypes 2a and 2b appear to be infrequent, if not absent. Further studies showed that subtype 2c isolates are heterogeneous in the NS5A region, in that they may or may not contain a 57-nucleotide (nt) segment spanning from nt 7533 to nt 7589 of the viral genome. Partial nucleotide sequencing of the NS5B region of four 2c subtypes excluded the possibility that the isolates possessing or not possessing the 57-nt segment in the NS5A region may have resulted from recombination phenomena.

Partial nucleotide sequencing of six subtype 2c hepatitis C viruses detected in Italy

The great majority of 121 hepatitis C virus (HCV) isolates obtained from 117 Italian patients with community-acquired infection could readily be typed by genotype-specific PCR. Subtype 1b was dominant (74 isolates); subtypes 2b, 2a, and 1a followed, with 19, 14, and 8 isolates, respectively. The six isolates that remained untyped by this method were classified as subtype 2c on the basis of sequence analysis of PCR amplicors obtained from the core and NS5 genes. These findings indicate that HCV subtype 2c has a relatively high prevalence in Italy. Sequencing the core region from positions 160 to 259 is sufficient to distinguish subtype 2c from other known HCV genotypes.

Serological reactivity and viral genotypes in hepatitis C virus infection

Patients infected with hepatitis C virus (HCV) were examined with four commercial HCV immunoblotting assays and for anti-GOR antibody to ascertain whether serological findings varied with the genotype of the infecting virus. The results indicate that patients infected with different HCV genotypes tend to show different immunoblotting profiles, mainly due to a low prevalence of antibodies to the viral region NS4 in patients infected with genotypes III and IV. Differences were more evident with second- than with third-generation assays. Patients infected with genotype IV exhibited a lower prevalence of anti-GOR antibody than patients infected with other genotypes.

Thymic lymphocytes. II. Phenotypic modifications of thymocytes after concanavalin A stimulation in the presence of interleukin 2: early modifications of Lyt 1+2+ subset and later proliferation of cells with more mature phenotypes

Cortical thymocytes are devoid of any immune function, as tested by presently available techniques. The ability of this subpopulation to respond to mitogens or antigens in the presence of interleukin 2 (IL-2) produced by activated mature T lymphocytes has been claimed but is still questioned. In an attempt to study the participation of the different thymocyte subsets and especially that of the cortical type, phenotypic modifications were examined during concanavalin A activation in the presence of IL-2. An immunofluorescent double labeling technique with anti-Lyt 1 and anti-Lyt 2 antibodies was used which led to the determination of four different phenotypes: Lyt 1+2+, Lyt 1+2-, Lyt 1-2+, and Lyt 1-2-. Careful analysis of cell viability in culture and expression of the results in absolute numbers of living cells per culture allowed us to follow modifications of small cellular subsets. Cultures of total thymocytes and PNA-agglutinated (enriched in Lyt 1+2+ cells) and non-PNA-agglutinated cells (enriched in Lyt 1+2-, Lyt 1-2+, and Lyt 1-2- cells) were studied. It was shown that thymocyte activation began by early phenotypic modifications which took place within the first 2 hr of culture but only when Con A plus IL-2 were used. These modifications imply the reduction of the Lyt 1+2+ pool and a compensatory enhancement of Lyt 1-2+ and Lyt 1-2- cells, without modification of the total cell number or [3H]thymidine incorporation. These early phenotypic changes are interpreted as the modulation of antigens on the surface of Lyt 1+2+ cells. The second phase of thymocyte activation implies cell death (essentially Lyt 1+2+ cells) and cell proliferation. The cells which specifically proliferate in the presence of Con A and IL-2 are Lyt 1+2- and Lyt 1-2+, the latter always being present in greater number. Cell survival and absolute number of Lyt 1+2- and Lyt 1-2+ cells in the activated PNA- -enriched population are always higher than in total thymocyte and PNA+ cells cultures. Thus, if Lyt 1+2+ cortical thymocytes do not proliferate by themselves, they seem to intervene by providing Lyt 1-2+ cells which proliferate secondarily.