MYOD-SKP2 axis boosts tumorigenesis in fusion negative rhabdomyosarcoma by preventing differentiation through p57Kip2 targeting

Rhabdomyosarcomas (RMS) are pediatric mesenchymal-derived malignancies encompassing PAX3/7-FOXO1 Fusion Positive (FP)-RMS, and Fusion Negative (FN)-RMS with frequent RAS pathway mutations. RMS express the master myogenic transcription factor MYOD that, whilst essential for survival, cannot support differentiation. Here we discover SKP2, an oncogenic E3-ubiquitin ligase, as a critical pro-tumorigenic driver in FN-RMS. We show that SKP2 is overexpressed in RMS through the binding of MYOD to an intronic enhancer. SKP2 in FN-RMS promotes cell cycle progression and prevents differentiation by directly targeting p27Kip1 and p57Kip2, respectively. SKP2 depletion unlocks a partly MYOD-dependent myogenic transcriptional program and strongly affects stemness and tumorigenic features and prevents in vivo tumor growth. These effects are mirrored by the investigational NEDDylation inhibitor MLN4924. Results demonstrate a crucial crosstalk between transcriptional and post-translational mechanisms through the MYOD-SKP2 axis that contributes to tumorigenesis in FN-RMS. Finally, NEDDylation inhibition is identified as a potential therapeutic vulnerability in FN-RMS.

Neutralizing IFNγ improves safety without compromising efficacy of CAR-T cell therapy in B-cell malignancies

Chimeric antigen receptor T (CAR-T) cell therapy may achieve long-lasting remission in patients with B-cell malignancies not responding to conventional therapies. However, potentially severe and hard-to-manage side effects, including cytokine release syndrome (CRS), neurotoxicity and macrophage activation syndrome, and the lack of pathophysiological experimental models limit the applicability and development of this form of therapy. Here we present a comprehensive humanized mouse model, by which we show that IFNγ neutralization by the clinically approved monoclonal antibody, emapalumab, mitigates severe toxicity related to CAR-T cell therapy. We demonstrate that emapalumab reduces the pro-inflammatory environment in the model, thus allowing control of severe CRS and preventing brain damage, characterized by multifocal hemorrhages. Importantly, our in vitro and in vivo experiments show that IFNγ inhibition does not affect the ability of CD19-targeting CAR-T (CAR.CD19-T) cells to eradicate CD19+ lymphoma cells. Thus, our study provides evidence that anti-IFNγ treatment might reduce immune related adverse effect without compromising therapeutic success and provides rationale for an emapalumab-CAR.CD19-T cell combination therapy in humans.

Spermine oxidase induces DNA damage and sensitizes fusion negative rhabdomyosarcoma cells to irradiation

Rhabdomyosarcoma (RMS) is a pediatric myogenic soft tissue sarcoma that includes fusion-positive (FP) and fusion-negative (FN) molecular subtypes. FP-RMS expresses PAX3-FOXO1 fusion protein and often shows dismal prognosis. FN-RMS shows cytogenetic abnormalities and frequently harbors RAS pathway mutations. Despite the multimodal heavy chemo and radiation therapeutic regimens, high risk metastatic/recurrent FN-RMS shows a 5-year survival less than 30% due to poor sensitivity to chemo-radiotherapy. Therefore, the identification of novel targets is needed. Polyamines (PAs) such as putrescine (PUT), spermidine (SPD) and spermine (SPM) are low-molecular-mass highly charged molecules whose intracellular levels are strictly modulated by specific enzymes. Among the latter, spermine oxidase (SMOX) regulates polyamine catabolism oxidizing SPM to SPD, which impacts cellular processes such as apoptosis and DNA damage response. Here we report that low SMOX levels are associated with a worse outcome in FN-RMS, but not in FP-RMS, patients. Consistently, SMOX expression is downregulated in FN-RMS cell lines as compared to normal myoblasts. Moreover, SMOX transcript levels are reduced FN-RMS cells differentiation, being indirectly downregulated by the muscle transcription factor MYOD. Noteworthy, forced expression of SMOX in two cell lines derived from high-risk FN-RMS: 1) reduces SPM and upregulates SPD levels; 2) induces G0/G1 cell cycle arrest followed by apoptosis; 3) impairs anchorage-independent and tumor spheroids growth; 4) inhibits cell migration; 5) increases γH2AX levels and foci formation indicative of DNA damage. In addition, forced expression of SMOX and irradiation synergize at activating ATM and DNA-PKCs, and at inducing γH2AX expression and foci formation, which suggests an enhancement in DNA damage response. Irradiated SMOX-overexpressing FN-RMS cells also show significant decrease in both colony formation capacity and spheroids growth with respect to single approaches. Thus, our results unveil a role for SMOX as inhibitor of tumorigenicity of FN-RMS cells in vitro. In conclusion, our in vitro results suggest that SMOX induction could be a potential combinatorial approach to sensitize FN-RMS to ionizing radiation and deserve further in-depth studies.

Safe and effective off-the-shelf immunotherapy based on CAR.CD123-NK cells for the treatment of acute myeloid leukaemia

Background

Paediatric acute myeloid leukaemia (AML) is characterized by poor outcomes in patients with relapsed/refractory disease, despite the improvements in intensive standard therapy. The leukaemic cells of paediatric AML patients show high expression of the CD123 antigen, and this finding provides the biological basis to target CD123 with the chimeric antigen receptor (CAR). However, CAR.CD123 therapy in AML is hampered by on-target off-tumour toxicity and a long “vein-to-vein” time.

Methods

We developed an off-the-shelf product based on allogeneic natural killer (NK) cells derived from the peripheral blood of healthy donors and engineered them to express a second-generation CAR targeting CD123 (CAR.CD123).

Results

CAR.CD123-NK cells showed significant anti-leukaemia activity not only in vitro against CD123⁺ AML cell lines and CD123⁺ primary blasts but also in two animal models of human AML-bearing immune-deficient mice. Data on anti-leukaemia activity were also corroborated by the quantification of inflammatory cytokines, namely granzyme B (Granz B), interferon gamma (IFN-γ) and tumour necrosis factor alpha (TNF-α), both in vitro and in the plasma of mice treated with CAR.CD123-NK cells.

To evaluate and compare the on-target off-tumour effects of CAR.CD123-T and NK cells, we engrafted human haematopoietic cells (hHCs) in an immune-deficient mouse model. All mice infused with CAR.CD123-T cells died by Day 5, developing toxicity against primary human bone marrow (BM) cells with a decreased number of total hCD45⁺ cells and, in particular, of hCD34⁺CD38⁻ stem cells. In contrast, treatment with CAR.CD123-NK cells was not associated with toxicity, and all mice were alive at the end of the experiments. Finally, in a mouse model engrafted with human endothelial tissues, we demonstrated that CAR.CD123-NK cells were characterized by negligible endothelial toxicity when compared to CAR.CD123-T cells.

Conclusions

Our data indicate the feasibility of an innovative off-the-shelf therapeutic strategy based on CAR.CD123-NK cells, characterized by remarkable efficacy and an improved safety profile compared to CAR.CD123-T cells. These findings open a novel intriguing scenario not only for the treatment of refractory/resistant AML patients but also to further investigate the use of CAR-NK cells in other cancers characterized by highly difficult targeting with the most conventional T effector cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-022-01376-3.

Abstract 668: A MYOD-SKP2 axis boosts oncogenic properties of fusion negative rhabdomyosarcoma and is counteracted by neddylation inhibition in vitro and in vivo

Rhabdomyosarcoma (RMS) is a pediatric soft tissue sarcoma characterized by an impaired myogenic differentiation despite the expression of myogenic master genes MYOD and MYOG. Therefore, the restoration of differentiation is considered an anti-cancer therapy. SKP2 is an oncogenic E3-ubiquitin ligase that promotes cell proliferation by targeting the CDKi p21Cip1 and p27Kip1. Previous works showed that SKP2 overexpression is induced by the fusion oncoprotein PAX3-FOXO1 expressed in fusion positive (FP)-RMS cells, and promotes tumor cell proliferation through p27kip1 degradation. However, the role of SKP2 in fusion negative (FN)-RMS cells, devoid of any fusion gene, remains unclear. We report here that SKP2 transcript and protein levels are up-regulated in RMS patients and cell lines compared to normal tissue. Accordingly, we observed increased acetylation of H3K27 histone mark in RMS patients and cell lines compared to myoblasts and muscle tissue. We then show that in RMS cell lines SKP2 expression is induced by MYOD, which binds two SKP2 regulatory regions, an intronic and a distal enhancers, identified by Hi-C and 3C experiments. SKP2 knockdown in FN-RMS cells leads to p21Cip1 and p27Kip1 protein levels up-regulation coupled with G1/S cell cycle arrest. Rescue experiments showed that SKP2 promotes cell proliferation directly targeting p27Kip1. Moreover, SKP2 binds and promotes degradation of p57Kip2 and its silencing restores myogenic differentiation associated to MYOG and de novo MyHC expression in FN-RMS cells. SKP2 depletion also induces cell senescence and prevents anchorage-independent growth and stemness in vitro, and tumor growth in vivo. In turn, SKP2 forced expression partially rescued the anti-cancer effects preventing the increase of p21Cip1, p27Kip1, p57Kip2 and MYOG, promoting re-entry into cell cycle, inhibiting human myoblasts cell differentiation and restoring the tumorigenic potential in FN-RMS. Since neddylation is an essential step for the activity of SKP2, we used MLN4924, an inhibitor of the Nedd8 Activating Enzyme (NAE), under clinical investigation, to resume SKP2 knockdown features. MLN4924 induces p21Cip1 and p27Kip2 expression, promotes senescence and apoptosis, and hampers cell growth in vitro and in vivo both in FP- and FN-RMS. These results unveil an unprecedented role for SKP2 in governing both proliferation and myogenic differentiation in RMS, suggesting that targeting SKP2 functions through MLN4924 treatment might have clinical relevance in FP- and FN-RMS. The study has been founded by AIRC and 5xmille 2021/Ministero della Salute to RR.

Citation Format: Silvia Pomella, Matteo Cassandri, Doris Phelps, Clara Perrone, Michele Pezzella, Marco Wachtel, Benjamin Sunkel, Antonella Cardinale, Zoe Walters, Cristina Cossetti, Sonia Rodriguez, Nadia Carlesso, Janet Shipley, Lucio Miele, Beat Schafer, Enrico Velardi, Peter Houghton, Berkley Gryder, Benjamin Stanton, Concetta Quintarelli, Biagio De Angelis, Franco Locatelli, Rossella Rota. A MYOD-SKP2 axis boosts oncogenic properties of fusion negative rhabdomyosarcoma and is counteracted by neddylation inhibition in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 668.

MET Inhibition Sensitizes Rhabdomyosarcoma Cells to NOTCH Signaling Suppression

Rhabdomyosarcoma (RMS) is a pediatric myogenic soft tissue sarcoma. The Fusion-Positive (FP) subtype expresses the chimeric protein PAX3-FOXO1 (P3F) while the Fusion-Negative (FN) is devoid of any gene translocation. FP-RMS and metastatic FN-RMS are often unresponsive to conventional therapy. Therefore, novel therapeutic approaches are needed to halt tumor progression. NOTCH signaling has oncogenic functions in RMS and its pharmacologic inhibition through γ-secretase inhibitors blocks tumor growth in vitro and in vivo. Here, we show that NOTCH signaling blockade resulted in the up-regulation and phosphorylation of the MET oncogene in both RH30 (FP-RMS) and RD (FN-RMS) cell lines. Pharmacologic inhibition of either NOTCH or MET signaling slowed proliferation and restrained cell survival compared to control cells partly by increasing Annexin V and CASP3/7 activation. Co-treatment with NOTCH and MET inhibitors significantly amplified these effects and enhanced PARP1 cleavage in both cell lines. Moreover, it severely hampered cell migration, colony formation, and anchorage-independent growth compared to single-agent treatments in both cell lines and significantly prevented the growth of FN-RMS cells grown as spheroids. Collectively, our results unveil the overexpression of the MET oncogene by NOTCH signaling targeting in RMS cells and show that MET pathway blockade sensitizes them to NOTCH inhibition.

Detecting a rare composite small bowel lymphoma by Magnetic Resonance Imaging coincidentally: A case report with radiological, surgical and histopathological features

INTRODUCTION

Diagnosing lymphoma continues to prove challenging in the clinical practice. Composite lymphoma (CL) is defined by the coexistence of different lymphoma subtypes in the same anatomical location. This condition has seldom been witnessed in the gastrointestinal (GI) tract. We weren't able to find previous cases in the literature about small bowel CL with follicular lymphoma (FL) and classical Hodgkin lymphoma (CHL). Surgery is the treatment of choice to obtain accurate histology, to manage and prevent acute complications. We state that this work has been reported in line with the SCARE criteria.

CASE PRESENTATION

We describe an extremely rare case of small bowel CL, presenting as an intestinal bulky mass with circumferential infiltration of bowel loops. The small bowel tumor was incidentally detected by abdominal Magnetic Resonance Imaging (MRI) in a 64-year-old man who suffered from rectal discomfort and non-specific clinical symptoms. After this radiological finding, the patient underwent multiphase contrast computed tomography (MDCT) for initial staging and to study vascular involvement. Surgery was recommended to obtain an accurate diagnosis both due to initial symptoms of the intestinal obstruction and to avoid small bowel complications. The histopathological examination revealed a small bowel CL composed mainly of B cells FL with also CHL components.

CONCLUSION

It is important to note that involvement of the proximal ileal loops is very rare in small bowel lymphoma. MRI represents a precious diagnostic tool to evaluate the intra and extramural extent of the tumor.

[Anti-rabies measures by the Infectious Disease Prevention Service at the "La Sapienza" University of Rome in the years 2005-2007]

Antirabies service activities of the Infectious Diseases Prophylaxis Centre of the Sapienza University of Rome during the period 2005-2007. Authors analyzed data, of antirabies activity, from 3206 patients treated at the Infectious Diseases Prophylaxis Centre of the University of Rome "La Sapienza" during the period 2005-2007 Dogs were responsible for most bites (92.1%). All patients went first to the Emergency Room where tetanus prophylaxis was administrated only with specific immunoglobulins (51.5%): to such patients we suggested to implement prophylaxis with vaccination. For other patients (19.4%) we prescribed only vaccine tetanus prophylaxis. Antirabies vaccine (PCEC) has been injected in 604 patients (18.8%). Rabies immunoglobulins have been prescribed only to 11 (0.4%) patients that were bitten during travel to Asia or Africa (0.4%). The authors emphasize the opportunity to reduce the administration of anti-tetanus immunoglobulin in Emergency Room by a deeper evaluation of patient's immunity; moreover the authors confirm a clear quantitative reduction of prophylactic interventions against rabies in Italy.

Effects of Cimicifuga racemosa extract on liver morphology and hepatic function indices

Cimicifuga racemosa (black cohosh) is a herbaceous perennial plant, that has been traditionally used for a variety of ailments (dyspepsia, climacteric complaints, muscular rheumatisms, menstrual cramps). From laboratory and clinical studies, black cohosh seems to have a relatively good safety profile, even if a number of case reports of hepatotoxicity were a matter of recent concern.

AIM

A number of case reports indicated that C. racemosa could induce hepatotoxicity. We evaluated the effects of black cohosh extract on liver morphology, and on levels of various hepatic function indices in rats.

METHODS

Wistar rats received 300mg/kg/day of C. racemosa extract by gavage, for 30 days. Biochemical analysis of serum was conducted by an automated, random-access clinical chemistry analyzer. Liver samples were used for hystomorphological and immunohistochemical examination, for the detection of apoptosis (TUNEL assay), and for the determination of GSH level (spectrophotometrical analysis).

RESULTS

C. racemosa extract does not affect liver morphology and hepatic function indices, in rats.

CONCLUSIONS

On the basis of experimental data, the use of 300mg/kg/day of black cohosh appears quite safe in rats. Nevertheless, in humans the safety of C. racemosa should be further monitored, in terms of patient-related factors.

An open-label trial of levetiracetam in severe myoclonic epilepsy of infancy

OBJECTIVE

To conduct an open-label, add-on trial on safety and efficacy of levetiracetam in severe myoclonic epilepsy of infancy (SMEI).

PATIENTS AND METHODS

SMEI patients were recruited from different centers according to the following criteria: age > or =3 years; at least four tonic-clonic seizures/month during the last 8 weeks; previous use of at least two drugs. Levetiracetam was orally administrated at starting dose of approximately 10 mg/kg/day up to 50 to 60 mg/kg/day in two doses. Treatment period included a 5- to 6-week up-titration phase and a 12-week evaluation phase. Efficacy variables were responder rate by seizure type and reduction of the mean number per week of each seizure type. Analysis was performed using Fisher exact and Wilcoxon tests.

RESULTS

Twenty-eight patients (mean age: 9.4 +/- 5.6 years) entered the study. Sixteen (57.1%) showed SCN1A mutations. Mean number of concomitant drugs was 2.5. Mean levetiracetam dose achieved was 2,016 mg/day. Twenty-three (82.1%) completed the trial. Responders were 64.2% for tonic-clonic, 60% for myoclonic, 60% for focal, and 44.4% for absence seizures. Number per week of tonic-clonic (median: 3 vs 1; p = 0.0001), myoclonic (median: 21 vs 3; p = 0.002), and focal seizures (median: 7.5 vs 3; p = 0.031) was significantly decreased compared to baseline. Levetiracetam effect was not related to age at onset and duration of epilepsy, genetic status, and concomitant therapy. Levetiracetam was well tolerated by subjects who completed the study. To date, follow-up ranges 6 to 36 months (mean, 16.2 +/- 13.4).

CONCLUSION

Levetiracetam add-on is effective and well tolerated in severe myoclonic epilepsy of infancy. Placebo-controlled studies should confirm these findings.

Association of pelvic endometriosis with alopecia universalis, autoimmune thyroiditis and multiple sclerosis

An adult Caucasian female developed a previously unreported association of pelvic endometriosis (PE) with the triad of alopecia universalis (AU), autoimmune thyroiditis (AT) and multiple sclerosis (MS). Molecular human leukocyte antigen (HLA)-tissue typing of this subject showed the presence of the DR(2) 15 and DR(3) 17 alleles, which are associated to an increased risk of MS and AT, respectively. Clinical onset of AT followed withdrawal of corticosteroid treatment for AU, whereas MS become clinically evident after withdrawal from long-term estroprogestin therapy for PE. This clinical case is presented to discuss the autoimmune origin of PE, its possible association with multiple autoimmune disorders as well as the effect of other factors, such as administration and/ or discontinuation of specific hormonal regimens, on genetic autoimmunity-prone background.

Leptospirosis survey in wild rodents living in urban areas of Rome

The aim of the study was to survey the current extension of the infected brown rats (Rattus norvegicus) living on the site Ripa Grande-San Michele port located in the center of the sity along the accessible right bank of the Tiber river by using a specific molecular technology. The detection of Leptospira, in 11 trapped brown rats, by tube-based Polymerase Chain Reaction (PCR) was performed. The amplified samples were analysed by capillary zone electrophoresis (CZE). Sequence analysis of the amplified DNAs confirmed the specificity of the detection of leptospires. Five out of 11 brown rats exhibited positivity for Leptospira. The survey points out the high rate of leptospiral infection in the brown rats living in the most ancient urban area of Rome.

Persistent hepatitis G virus (HGV) infection in chronic hemodialysis patients and non-B, non-C chronic hepatitis

Three groups of patients have been studied longitudinally for 24 months to analyze the role of hepatitis G virus (HGV) in hepatic disease. Group 1 consisted of 50 patients with non-B, non-C chronic hepatitis, group 2 consisted of 44 hemodialyzed patients, and group 3 consisted of 50 healthy blood donors. The presence of HGV RNA was detected by both reverse transcription-polymerase chain reaction (RT-PCR) and capillary zone electrophoresis (CZE). At the baseline visit the HGV RNA was detected in seven out of 50 patients with non-B, non-C chronic hepatitis, in two out of 44 hemodialyzed patients, and in three out of 50 healthy blood donors. HGV-infected hemodialyzed patients and HGV viremic blood donors had serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels within normal limits. During the follow-up period the two HGV-positive hemodialyzed patients and the three infected healthy blood donors did not show any sign of hepatic disease. There were no significant differences between HGV-positive patients in the three groups at the beginning and at the end of the follow-up. No considerable deterioration of general health conditions was observed on the basis of clinical and laboratory data in HGV-positive chronic hepatitis patients. Finally, HGV does not seem to be responsible for hepatic disease.

Detection and clinical evaluation of GBV-C/HGV in plasma from patients with chronic hepatitis of unknown etiology

PURPOSE

The role of GBV-C/HGV virus infection in patients with chronic hepatitis of unknown etiology has been studied. Two groups of patients have been included: a) 50 consecutive patients with chronic hepatitis (mean age 47 yrs; M/F = 35/15), negative for markers of hepatitis viruses (HBV-HCV). These patients did not show evidence of metabolic, autoimmune, alcoholic or toxic liver disease; b) 50 healthy blood donors (mean age 35 yrs; M/F = 35/15). All the subjects were HIV-seronegative.

PATIENTS AND METHODS

The detection of GBV-C/HGV RNA was performed by reverse transcription-polymerase chain reaction techniques and capillary zone electrophoresis analysis (CZE).

RESULTS

There was no difference between the two groups of patients (14% vs 6%; p = 0.18 NS).

CONCLUSIONS

The etiopathogenetic role of GBV-C/HGV in chronic hepatitis of unknown etiology is yet to be shown.

Use of sulphonated probes for detecting human immunodeficiency virus-1 transcripts by in situ hybridization

A detailed procedure is described that allows detection of the presence of human immunodeficiency virus-1 (HIV-1) transcripts within both acetone-fixed tissues and peripheral blood mononuclear cells. This assay uses cDNA probes labelled by a non-isotopic procedure that results in the modification of cytosine residues through covalent linkage to a sulphone group. In situ hybridized probe is then detected by an alkaline phosphatase-conjugated antibody specifically directed against the sulphone hapten. This procedure is specific, rapid and safe and can be applied in the research as well as in the clinical pathology settings.

Detection of HIV-1 genome in leukocytes of human colostrum from anti-HIV-1 seropositive mothers

In order to obtain more information about the presence of HIV-1 in mononuclear cells of colostrum, research was carried out on both the HIV-1 genome in the cellular fraction of colostrum and the viral antibody in cell-free colostrum of eight anti-HIV-1 seropositive asymptomatic mothers. In five cases cell fractions of the colostrum harbored HIV-1 genome by DNA-DNA and DNA-RNA in situ hybridization, whereas viral antibody were detected in all cell-free colostrum specimens. The data confirms the colostrum as a possible route of HIV-1 infection.

Persistence of HIV-1 silent infection in seronegative subjects at high risk

Twenty regular sexual partners of HIV-1 infected subjects, without detectable human immunodeficiency virus (HIV-1) antibody and positive for HIV-1 genome by in situ hybridization (ISH), were selected and studied longitudinally for 6-36 months to estimate the duration of silent infection. During the follow-up period, 10 showed atypical Western Blot (WB) patterns. Two seronegative partners seroconverted. Rapid progress to AIDS was observed in 7 seropositive subjects.

Effect of human T lymphotropic retrovirus-I exposure on cultured human glioma cell lines

Four different human tumor cell lines of glial origin have been exposed to a human T lymphotropic retrovirus (HTLV-I). All these cell lines were positive for the glial marker glial fibrillary acidic protein (GFAP). The presence of virus RNA was demonstrated by in situ hybridization using an HTLV-I, SStI-SStI viral insert as probe. Virus expression has been monitored through an indirect immunofluorescence assay using a monoclonal antibody against virus core protein p19. All the four glioma cell lines tested became positive for p19 after 2 weeks of co-cultivation and showed a clear alteration of GFAP expression.

Production of a nef-specific monoclonal antibody by the use of a synthetic peptide

Monoclonal antibodies have been generated against a synthetic peptide of the nef protein of human immunodeficiency virus type 1 (HIV-1) in order to further characterize the biochemical and functional nature of this protein and its role in the control of HIV-1 transcriptional regulation. Earlier studies indicated nef to be a negative regulatory factor for viral transcription, whereas more recent studies report evidence against this original hypothesis. Nef is a protein of 206 amino acids of approximately 27 kD in most HIV-1 isolates; however, in some other isolates a truncated form of 124 amino acids has been described. A peptide sequence of six amino acids, corresponding to a region of the nef protein exhibiting high-sequence homology to thymosin alpha 1 protein, has been synthesized by Merrifield solid-phase methodology. This peptide is coded by a sequence located upstream to the stop codon described in some HIV-1 isolates and then is maintained in both complete and truncated forms of the nef protein. F14.11 is a nef peptide-specific monoclonal antibody (IgG2a/k) exhibiting the ability to recognize natural nef protein in either radioimmunoassay, radioimmunoprecipitation assay, or immunocytochemical analysis. Since F14.11 is able to identify nef protein in the cytoplasm of lymphocytes from HIV-infected seronegative subjects it may prove useful in monitoring the expression of nef during the silent HIV-1 infection.

Detection of HIV genome in HIV antibody negative men

The presence of the human immunodeficiency virus (HIV) genome was investigated by applying in situ hybridisation techniques to peripheral blood mononuclear cells (PBMCs). Twenty asymptomatic anti-HIV seronegative homosexual men were the subjects of our study. The cells were hybridised with: (1) an SP 64 plasmid containing the nine-kilobase SstI-SstI viral insert from the lambda BH 10 recombinant clone; this can recognise both viral RNA and proviral DNA, and (2) with a pA01 plasmid containing HBV DNA genome. The DNA probes were modified by inserting an antigenic sulfone group in the cytosine moieties and the visualisation was performed by a double antibody immunohistochemical reaction. In two subjects both the HIV genome and HBV DNA were detected whereas another two subjects were positive for HBV DNA and for the HIV genome respectively. Thus people who are seronegative for anti-HIV specific antibodies may be infected with HIV.

HIV genome in peripheral blood mononuclear cells of seronegative regular sexual partners of HIV-infected subjects

We have investigated the presence of the human immunodeficiency virus (HIV) by using in situ hybridization on peripheral blood mononuclear cells (PBMCs) from seronegative regular sexual partners of HIV-infected subjects. The cells were hybridized with a 9 kilobase (kb) Sstl-Sstl lambda BH 10 probe, which was able to recognize both viral mRNA and proviral cDNA. Labeling was done by chemical insertion of an antigenic sulfone group in cytosine moieties and was visualized by a double-antibody immunohistochemical reaction. In all the subjects studied, the HIV genome was present. The HIV infected cells showed morphological aspects consistent with that of lymphocytes and monocytes. Our data suggest that the anti-HIV seronegative individuals who are regular sexual partners of HIV-infected subjects may be HIV-infected.

HBV and HIV expression in lymph nodes of HIV positive LAS patients: histology and in situ hybridization

The presence of hepatitis B virus (HBV) and human immunodeficiency virus (HIV) was investigated using hybridization in 15 lymph nodes and one Kaposi's sarcoma skin lesion obtained from HIV-positive patients. Cryostat tissue sections were hybridized with chemically modified DNA probes for HBV and HIV. HIV genome was mainly observed in the cytoplasm of cells present in 7/15 lymph nodes and in the Kaposi's sarcoma skin lesion, thus indicating the expression of HIV replication. Control samples hybridized with an HTLV I probe were negative. HBV genome was found in the cytoplasm of lymphoid mononuclear cells in 2/7 lymph nodes, obtained from HIV+ patients without serum markers of ongoing HBV infection. Lymph node positivity for HBV DNA also confirms that lymphoid cells may be a target for HBV. Since HBV infection seems to precede HIV infection in nearly all patients, it is possible that it may represent a factor facilitating the development of the HIV-related disease.

HIV viral sequences in seronegative people at risk detected by in situ hybridisation and polymerase chain reaction

A study was conducted to assess the occurrence of latent infection with the human immunodeficiency virus (HIV) among seronegative people at high risk of infection. The presence of HIV genomes was analysed by molecular techniques in two seronegative children born to mothers infected with HIV and in three regular sexual partners of seropositive drug addicts. The adults were selected from a seronegative cohort at high risk of infection because of their sexual contacts and the children selected because of impaired growth. HIV retroviral sequences were detected in four of the five subjects directly at the cellular level by in situ hybridisation in peripheral blood mononuclear cells. HIV genomic sequences were confirmed by in vitro amplification of viral DNA with the polymerase chain reaction technique. The existence of a latent viral infection state in these seronegative subjects indicates the unreliability of standard serological analysis in people who have been in regular contact with infected patients.

Expression of HIV in lymph node cells of LAS patients. Immunohistology, in situ hybridization, and identification of target cells

Monoclonal antibodies (MAb) anti-HIV core and envelope proteins and in situ hybridization, using cDNA HIV probe, were employed to determine which lymph node cells in LAS patients express viral antigens and viral nucleic acids. The results have been correlated with the histologic phases of LAS and with the germinal center lysis detected using DRC-1 MAb directed against follicular dendritic reticulum cells (FDRC). Viral antigens occasionally were detected on high endothelial cells of paracortical venules and frequently on germinal center FDR accessory cells; this last finding correlates well with the extent of FDRC lysis and of CD4+ and CD8+ lymphocyte infiltration in germinal centers. HIV replication, detected by in situ hybridization, was observed in mononucleated cells present in T and B areas and, in one case, in flat endothelium.

Reduced protection against hepatitis B virus following vaccination in patients with type 1 (insulin-dependent) diabetes

Twenty patients with well controlled Type 1 (insulin-dependent) diabetes of at least 10 years duration and 47 control subjects were vaccinated against the hepatitis B virus using the Hevac B vaccine. The vaccine was administered into the deltoid region on three occasions at intervals of 1 month. Thereafter a fourth dose was given to subjects still negative for antibody to hepatitis B surface antigen (HbsAb). The median rise of HbsAb titres was 230 mIU/ml in normal subjects and 50 mIU/ml in diabetic patients (p less than 0.001). Eight patients (40%) failed to reach HbsAb titres above 30 mIU/ml, the level considered to give optimal protection against the infection, whereas only one normal control subject failed to reach this level. Five patients (25%) showed no response despite a fourth dose of the vaccine. There was an increased frequency of HLA-DR7 in low responders and a decreased (less than 1.5) helper/suppressor lymphocyte ratio. Diabetic patients are thus less likely to mount a protective antibody response following vaccination against hepatitis. Since hepatitis B surface antigen is reported to be considerably more common in diabetic patients than control subjects, infection with hepatitis B virus may have a greater risk of chronicity in diabetes.

In situ hybridization of human immunodeficiency virus (HTLV-III) in cryostat sections of lymph nodes of lymphadenopathy syndrome patients

The presence of human immunodeficiency virus (HIV, or HTLV-III) genome sequence was investigated by means of in situ hybridization in cryostat sections of lymph nodes from lymphadenopathy syndrome (LAS) patients. The technique employed involved the modification of the DNA probe by chemical insertion of an antigenic sulfone group in cytosine moieties and the visualization of DNA by a double-antibody immunohistochemical reaction. The hybrid formation was revealed in five out of ten cases: in all positive samples, HIV was mainly observed in the cytoplasm of lymph node cells. The method of in situ hybridization described in the present paper is specific and has some advantages if compared with other techniques based on the use of DNA probes labelled with radioisotopes or biotin by nick translation.

Costs and benefits of the passive prophylaxis of hepatitis B in an Italian hospital

The authors report the clinical results and the cost/benefit analysis of a protocol of passive prophylaxis of hepatitis B based on the administration of two doses of three ml each of HBIG and on the control of anti-HBs levels by RIA for six months after accidental exposure in health-care personnel. Only two out of 351 susceptible subjects developed viral hepatitis instead of the expected 70 if passive prophylaxis had not been performed. The cost/benefit analysis showed a saving of 356 509 US$ in the past 36 months. Furthermore, the cost of each case of hepatitis prevented was 2194 US$, whereas the cost of one case of acute, benign hepatitis was 6180 US$. Since a saving of 3.39 US$ for each dollar spent is achieved, this protocol of passive prophylaxis appears more than adequate both clinically and economically. It is believed that the adoption of some general prophylactic measures will further stress the advantages of this procedure.

Fractionation and characterization of hydatid fluid antigens with identification of an antigen similar to human serum albumin

Human and sheep hydatid fluids were separated by ultrafiltration, gel chromatography and immunoabsorption into several immunogenic fractions in which both parasite antigens and host substances were present. The immunological characterization of proteic antigens was carried out by immunodiffusion and immunoelectrophoresis with rabbit and ram antisera. A line of identity was observed between a human fraction (labelled as III) and a sheep fraction (labelled as 2B). Further evidence of the presence of a parasitic antigen in fraction III was given by its reaction against an antiserum from ram directed against sheep fraction 2B. The immunological characterization of fraction III indicated a close similarity between human serum albumin and parasitic antigens.

Detection and partial characterization of circulating immune complexes in hydatid disease

Thirty sera from eight patients with disseminated or localized hydatid disease have been examined for the presence of circulating immune complexes (CICs) by the conglutinin-binding assay and for immunoglobulin levels. The highest levels of CICs were of the immunoglobulin A (IgA) class, with lower values of IgG-CIC and IgM-CIC; these results did not correlate, except for IgG, with the free immunoglobulin levels. Efforts to identify parasitic antigen(s) involved in the CIC formation with different methods have been unsuccessful. In the follow-up of each patient, CIC appeared to be better correlated to clinical conditions than to hemagglutination titers. We have concluded that the presence of CIC in hydatid disease is probably an expression of B-cell polyclonal activation and that these complexes are valuable in the clinical monitoring of the disease.

Non-A, non-B hepatitis: positive and negative considerations on 138 cases

In 138 patients with NANB H no correlations were observed regarding types of exposure (PTH: 19.5%, DA: 18.1%, Sporadic cases: 62.4%), age groups and periods of incubation. Precipitin lines were detected assaying by ID and/or CEP onset and recovery sera with heterologous reference sera positive for Ab or Ag, respectively, or with autologous sera; "Ag"' was present during acute phase of illness, "Ab" appeared with decrease of aminotransferases, and in most cases seroconversion was observed in accord with clinical course. In few patients double precipitin lines were evidenced (heterogeneity of Ag?), while one patient reacted with all reference sera and many others with two/three sera (two NANB viruses or two Ag/Ab systems?). Tendency towards chronicity emerged in four cases, and in these Ag/Ab systems had a different behaviour.

Post-transfusion hepatitis: antigen/antibody systems correlated with non-A, non-B hepatitis

In seven patients post-transfusion hepatitis (PTH) was due to non-A, non-B virus(es) (38.9% of all PTH, while 61.1% were due to hepatitis B virus (HBV). No clinical or biochemical differences were observed in non-A, non-B PTH when compared with PTH due to HBV, while incubation period was very ample, from 15 days to nine months (generally 45 days to two months). An antigen/antibody system was shared by five of our patients (their sera showed precipitin lines when assayed by immunodiffusion with known sources of antigen or antibody), while in one patient an antigen/antibody system was detected when onset serum was assayed with self-recovery serum but not when assayed with known sources of antigen and antibodies, nor with sera of the other five patients. Antigen was detected during the first weeks of illness, antibody at recovery, for both systems. The results suggest that there may be at least two antigen/antibody systems correlated to non-A, non-B hepatitis not necessarily linked to incubation period.