AB1169 IMMUNOMODULATORY EFFECTS OF SARS-CoV-2 VACCINATION: INCREASE OF REGULATORY T CELLS AFTER mRNA VACCINE

Background

Besides the ability to induce antigen-specific responses, vaccines can be endowed with immunomodulatory properties including the capacity to induce or downregulate regulatory T cells (Treg) that suppress adaptative and autoreactive immune responses (1).

Objectives

We asked if an anti-SARS-CoV-2 mRNA vaccine could also induce an accumulation of Treg cells in patients with mixed cryoglobulinemia vasculitis (MCV), who have a deficiency of Treg cells (2) and in healthy individuals. We also investigated immunologic variables possibly associated with a low immunogenicity of SARS-CoV-2 mRNA vaccine in patients with MCV (3).

Methods

We analyzed peripheral blood lymphocyte subpopulations and anti-SARS-CoV-2 serological response in 24 patients with MCV and 9 Healthy donors (HD) before and after 2 weeks after the second dose of the Pfizer/BioNTech vaccine.

Results

Among MCV patients we found 15 serological responders and 9 non-responders. All 5 seronegative patients treated recently with rituximab had <5 B cells/µL, whereas the absolute B cell count was increased in 2 of 4 untreated patients due to monoclonal B cell lymphocytosis, with monoclonal cells representing more than 90% of B cells, associated with non-Hodgkin lymphoma. The percentage of pathologic CD21low B cells was significantly increased in seronegative patients.

Before receiving the Pfizer/BioNTech vaccine, patients with MCV had a significantly reduced frequency of Treg cells among CD4+ T cells compared to HD. After the second dose of the vaccine, there was in MCV patients a significant increase in the percent and absolute count of Treg among CD4+ T cells

Concerning the pre-vaccination distribution of T cells subpopulations, including the percentages and absolute counts of total CD3+, CD4+, CD8+, HLA-DR+ activated, Treg or CD56+ natural killer T cells, we could not reveal any pattern significantly associated with lack of serological response to vaccine.

Conclusion

Our findings show that lack of immunoreactivity in patients with MCV may be associated with expansion of pathologic B cells and that anti-SARS-CoV2 mRNA vaccine may induce an increase of Treg cells.

References

[1]Krienke C. et al. A noninflammatory mRNA vaccine for treatment of experimental autoimmune encephalomyelitis. Science. 2021 Jan 8;371(6525):145-153.

[2]Boyer O. et al. CD4+CD25+ regulatory T-cell deficiency in patients with hepatitis C-mixed cryoglobulinemia vasculitis. Blood. 2004 May 1;103(9):3428-30.

[3]Visentini M. et al. Flares of mixed cryoglobulinaemia vasculitis after vaccination against SARS-CoV-2. Ann Rheum Dis. 2021 Nov 24:annrheumdis-2021-221248.

Disclosure of Interests

None declared

Inhibition of Leukocyte Migration by a Human Colon Cancer Extract

The direct leucocyte migration inhibition test in capillary tubes was used to test 10 patients with colonic adenocarcinoma against KCl soluble extracts of an allogenic colon cancer and an allogenic normal colon fragment. Inhibition was consistently found with the cancer extract but not with the normal tissue extract. None of the control group of patients affected by other tumors, intestinal and liver disorders showed a migration inhibition in response to the colonic tumor extract. Our findings strongly suggest the presence of a tumor-associated antigen in the cancer extract.

Correlation between terminal restriction fragments and flow-FISH measures in samples over wide range telomere lengths

OBJECTIVES

Terminal restriction fragment (TRF) analysis of human telomeres was used to calibrate flow-fluorescence in situ hybridization (FF) measures of telomere lengths to expand the range of measures and increase power of resolution of our previously published protocol. TRF data used as the gold standard should be obtained by electrophoresis with suitable resolution applied to appropriately isolated genomic DNA. When we considered TRF attained by correct methods, we found our method to be insufficiently accurate, thus we have reviewed our previously published FF protocol to obtain the best coefficient of determination (r(2)) between our experimental results and valid TRF lengths.

MATERIALS AND METHODS

Using human telomere-specific PNA probe, Cy5-OO-(CCCTAA)3 , we measured telomere lengths of continuous cell line and of peripheral blood lymphocytes by FF. We modified hybridization, stringency, negative control handling, stoichiometric DNA staining and telomere fluorescence assessment of the protocol.

RESULTS

We realized a procedure with increased power of resolution, improved TRF versus FF r(2) values that allowed simultaneous analysis of DNA and telomere duplication. Notwithstanding multiple steps in formamide sampling, recovery was satisfactory.

DISCUSSION

The reviewed FF protocol appeared at least as suitable as the TRF method. Measures obtained by TRF can be affected by chromosome end variability, DNA fragmentation, incomplete digestion and unsuitable electrophoresis. In contrast, the FF technique analyses telomeric sequences confined to preserved nuclei thus overcome most previous limitations. As yet, however, the FF telomere measure cannot be performed together with immunophenotyping and/or generation study by the dye dilution method.

Anti-infective prophylaxis for primary immunodeficiencies: what is done in Italian Primary Immunodeficiency Network centers (IPINet) and review of the literature

Primary immunodeficiencies (PIDs) are rare diseases characterized by an increased susceptibility to infections. Early diagnosis and appropriate treatment are critical for reducing morbidity and mortality. Based on available data, the efficacy of antibiotic administration for the prophylaxis of infections remains uncertain, and recommendations supporting this practice are poor. The use of antimicrobial prophylaxis is mainly based on single institution-specific experience without controlled measurements of patient safety and quality health outcomes. To address this issue an Italian Network on Primary Immunodeficiencies (IPINet) has been set up in 1999 within the Italian Association of Pediatric Hematology and Oncology (AIEOP) to increase the awareness of these disorders among physicians. Further, diagnostic and treatment guideline recommendations have been established to standardize the best clinical assistance to all patients, including antibiotic prophylaxis, and for a national epidemiologic monitoring of PIDs. The aim of this review is not only to give a scientific update on the use of antimicrobial prophylaxis in selected congenital immunological disorders but also to draw a picture of this practice in the context of the Italian Primary Immunodeficiency Network (IPINet). Controlled multicenter studies are necessary to establish if, when and how you should start an efficacious antimicrobial prophylaxis.

Improved procedure for the measurement of telomere length in whole cells by PNA probe and flow cytometry

OBJECTIVES

Peptide nucleic acid (PNA) probes hybridize to denatured telomeric sequences in cells permeabilized in hot formamide. In reported protocols, the hybridization was conducted in solutions with high formamide concentrations to avoid the DNA renaturation that can hamper binding of the oligo-PNA probe to specific sequences. We postulated that telomeric DNA, confined in the nuclear microvolume, is not able to properly renature after hot formamide denaturation. Therefore, to improve hybridization conditions between the probe and the target sequences, it might be possible to add probe to sample after the complete removal of formamide.

MATERIALS AND METHODS

After telomeric DNA denaturation in hot formamide solution and several washes to remove the ionic solvent, cells were hybridized overnight at room temperature with human telomere-specific PNA probe conjugated with Cy5 fluorochrome, Cy5-OO-(CCCTAA)(3) . After stringency washes and staining with ethidium bromide, the cells were analysed by flow cytometry and by using a confocal microscope.

RESULTS

Using three continuous cell lines, different in DNA content and telomere length, and resting human peripheral blood T and B lymphocytes, we demonstrated that the oligo-PNA probe hybridized to telomeric sequences after complete removal of formamide and that in the preserved nucleus, telomeric sequence denaturation is irreversible.

CONCLUSION

According to our experience, oligo-PNA binding results is efficient, specific and proportional to telomere length. These, our original findings, can form the technological basis of actual in situ hybridization on preserved whole cells.

A simultaneous occurrence of Tolosa-Hunt syndrome and fibrillary glomerulonephritis: a case report

Fibrillary glomerulonephritis (FibGN) is a rare cause of progressive renal dysfunction, often leading to dialysis within a few years. A 60-year-old woman presented with a 2 month history of right-sided retro-orbital pain and recent diplopia. Laboratory testing revealed an altered renal function with increased serum creatinine and mild proteinuria. MRI of the brain revealed the presence of a soft tissue mass on the right cavernous sinus compatible with the diagnosis of Tolosa-Hunt syndrome (THS). Renal biopsy showed a pattern compatible with fibrillary glomerulonephritis. For this reason steroid therapy was initiated at a dose of 1 mg/kg/day and adjusted according to the clinical course. Neurological symptoms regressed shortly after the beginning of therapy and renal function and proteinuria remained stable for the 3 years following the withdrawal of steroid therapy. Percutaneous renal biopsy was again performed and confirmed the previous diagnosis of FibGN in association with other glomerular-lesion-like mesangial widening, thickening of capillary walls and severe arterio-arteriolosclerosis. This case report describes what is believed to first report of the association of FibGN and THS, which both responded to steroid therapy.

Quality in emergency departments: a study on 3,285,440 admissions

INTRODUCTION

A multi-centre study has been conducted, during 2005, by means of a questionnaire posted on the Italian Society of Emergency Medicine (SIMEU) web page. Our intention was to carry out an organisational and functional analysis of Italian Emergency Departments (ED) in order to pick out some macro-indicators of the activities performed. Participation was good, in that 69 ED (3,285,440 admissions to emergency services) responded to the questionnaire.

METHODS

The study was based on 18 questions: 3 regarding the personnel of the ED, 2 regarding organisational and functional aspects, 5 on the activity of the ED, 7 on triage and 1 on the assessment of the quality perceived by the users of the ED.

RESULTS AND CONCLUSION

The replies revealed that 91.30% of the ED were equipped with data-processing software, which, in 96.83% of cases, tracked the entire itinerary of the patient. About 48,000 patients/year used the ED: 76.72% were discharged and 18.31% were hospitalised. Observation Units were active in 81.16% of the ED examined. Triage programmes were in place in 92.75% of ED: in 75.81% of these, triage was performed throughout the entire itinerary of the patient; in 16.13% it was performed only symptom-based, and in 8.06% only on-call. Of the patients arriving at the ED, 24.19% were assigned a non-urgent triage code, 60.01% a urgent code, 14.30% a emergent code and 1.49% a life-threatening code. Waiting times were: 52.39 min for non-urgent patients, 40.26 min for urgent, 12.08 for emergent, and 1.19 for life-threatening patients.

Occult hepatitis C virus infection in type II mixed cryoglobulinaemia

Mixed cryoglobulinaemia, when not secondary to other well-defined immunological disorders, is commonly associated with hepatitis C virus (HCV) infection. However, a minority of cases lack evidence of HCV infection and are, therefore, defined as 'true essential' mixed cryoglobulinaemias. We thoroughly investigated three such patients to determine the aetiology of this disorder. Antibodies to HCV (anti-HCV) and HCV RNA, detected by sensitive enzyme-linked immunosorbent and polymerase chain reaction assays in serum and in concentrated cryoglobulins, were repeatedly negative in the three patients. Despite the lack of evidence for HCV infection, two of them were still treated with interferon alpha-2a assuming unrecognized viral infection. Both patients demonstrated excellent clinical and laboratory responses, but cryoglobulinaemia relapsed after the withdrawal of therapy. At the time of relapse, HCV RNA genomic sequences were detected for the first time in the cryoprecipitates of both patients. In the third case, HCV RNA was demonstrated for the first time during a flare of cryoglobulinaemia coincident with varicella infection. In all three patients anti-HCV antibodies remained negative throughout follow-up. We conclude that some apparently 'essential' forms of mixed cryoglobulinaemia can be caused by occult HCV infection. Interferon therapy can be taken into consideration in such HCV-negative cases.

T-Cell immune activation in children with vertically transmitted hepatitis C virus infection

Little is known concerning the clinical features, the histological outcome, and the effects on the maturation of immune system of children with vertically-transmitted hepatitis C virus (HCV) infection. Specifically, no data are available on the peripheral distribution of T-cell subsets. The frequency of naive and memory cells, activated T cells, and cytokine-producing T cells was analyzed in nine HCV-infected children born to HCV-positive mothers. In HCV-infected children, the distribution of naive and memory cells was not significantly altered in the CD4 subset whereas within the CD8 subset, an increase of memory and a decrease of naive cells was observed. The frequency of HLA-DR-positive and Fas-positive T cells was increased in HCV-infected children in both CD4 and CD8 subsets. The distribution of Fas-expressing T cells was directly related to that of HLA-DR cells and inversely related to the frequency of naive T cells. In regard with cytokine production we found increased levels of both CD4 and CD8 interferon-gamma (IFN-gamma)-producing cells whereas no difference in the percentage of interleukin-2 (IL-2)-producing T cells was observed. No meaningful correlation was observed between individual T cell subsets and ALT levels or HCV viral load. In conclusion, our results indicate an increased T-cell activation and a shift to a T(H)1 pattern of cytokine production in children with vertically transmitted HCV infection. The cause of this kind of immune response could reside in the persistent antigenic stimulation by chronic HCV infection.

A unified procedure for conservative (morphology) and integral (DNA and immunophenotype) cell staining for flow cytometry

BACKGROUND

Current methods for multiparameter DNA flow cytometry suffer from several limitations. These include significant modifications of cell morphological parameters, the impossibility to counterstain cells with certain fluorochromes, and laborious tuning of the instrument that, for some procedures, must be equipped with an ultraviolet (UV) laser. To overcome these problems, we developed a novel method for the simultaneous analysis of morphological parameters, four-color immunophenotyping, and stoichiometric DNA labeling using a bench-top flow cytometer.

METHODS

The method consists of a mild permeabilization/fixation treatment at room temperature, followed by labeling with fluorochrome-conjugated monoclonal antibodies (mAbs) and with the DNA dye 7-aminoactinomycin D (7-AAD) at 56 degrees C.

RESULTS

Using this method, we analyzed resting peripheral blood mononucleated cells (PBMC), proliferating T cells cultured in the presence of interleukin-2 (IL-2), and lymphoblastoid B cells. Lymphocytes, monocytes, and lymphoblasts treated by this procedure retained differential light scattering (DLS) characteristics virtually identical to those of untreated cells. This allowed regions to be drawn on forward scatter (FSC) and side scatter (SSC) cytograms resolving different cell populations. DLS were preserved well enough to distinguish large lymphoblasts in the S or G2/M phases from small G0/G1 cells. Also, stainability with fluorescein-isothiocyanate (FITC), R-phycoerythrin (PE), allophycocyanin (APC)-conjugated mAbs was generally preserved. DNA labeling with 7-AAD was of quality good enough to permit accurate cell cycle analysis.

CONCLUSIONS

The method described here, which we called integral hot staining (IHS), represents a very simple, reproducible, and conservative assay for multiparameter DNA analysis using a bench-top flow cytometer. Last but not least, the cytometer tuning for multiparameter acquisition is straightforward.

Latent class analysis of DSM-IV schizotypal personality disorder criteria in psychiatric patients

The aim of the study was to evaluate the latent structure of DSM-IV schizotypal personality disorder (SPD) diagnostic criteria. The sample consisted of 564 consecutively admitted inpatients and outpatients. Exploratory latent class analysis identified a four-class model as the best fitting model for DSM-IV SPD criteria. The first of the SPD latent classes was mainly characterized by odd thinking, inappropriate affect, and interpersonal features; the second class by cognitive/perceptual difficulties; the third class by paranoid features; and the fourth class by absence of SPD features. The conditional probability pattern of the fourclass solution could be safely replicated across confounder strata. Unlike previous findings, oddness, aloofness, and social withdrawal, rather than positive symptoms, best characterized SPD even in clinical samples.

Human T cells with a type-2 cytokine profile are resistant to apoptosis induced by primary activation: consequences for immunopathogenesis

The mechanisms leading to a relative dominance of T cells producing type 2 cytokines in certain human immune disorders are still unclear. We investigated the relative susceptibility to apoptosis induced by primary in vitro activation of human type 1 (producing interferon-gamma (IFN-gamma)) or type 2 (producing IL-4) T cells. Peripheral blood lymphocytes were isolated from patients with immune disorders characterized by expansion of type 2 cells (four with AIDS and hyper-IgE/hypereosinophilia, one with Churg-Strauss syndrome, and one with idiopathic hypereosinophilic syndrome) or from individuals with normal cytokine balances. Cells were stimulated for 16 h with ionomycin and phorbol ester, and apoptosis of cytokine-producing cells was assessed by flow cytometry. T cells with a type-2 cytokine profile, i.e. producing IL-4 alone, were significantly more resistant to activation-induced apoptosis than those producing IFN-gamma alone. This was observed in AIDS patients, whose type 2 cells were mostly CD8+, as well as in the patients with Churg-Strauss and with hypereosinophilic syndrome. CD4+ and CD8+ IL-4-producing cells were equally resistant to apoptosis. Lower susceptibility to apoptosis of type-2 T cells was also observed in subjects with normal cytokine balances. Bcl-2 expression was high in type-2 cells and in viable type-1 cells, whereas it was low in apoptotic type-1 cells. Resistance to activation-induced apoptosis may explain the expansion of cells producing type-2 cytokines in certain immune disorders.

A psychometric study of DSM-IV passive-aggressive (negativistic) personality disorder criteria

The passive-aggressive (negativistic) personality disorder (PAPD) is one of the most controversial personality disorders. In order to assess DSM-IV PAPD psychometric properties and comorbidity pattern in a mixed psychiatric sample, 379 consecutively admitted in- and outpatients were administered SCID-II, Version 2.0. Confirmatory factor analysis showed that DSM-IV PAPD is a unidimensional construct with adequate internal consistency (K-R 20 = .85). A strong, specific association (odds ratio = 10.38, 95% CI = 4.83-22.30) was observed between DSM-IV PAPD and narcissistic personality disorder (NPD). Confirmatory factor analysis showed that DSM-IV PAPD should be considered as a subtype of a broader narcissistic disorder.

Patterns of covariation of DSM-IV personality disorders in a mixed psychiatric sample

The covariation patterns of DSM-IV personality disorders (PDs) were studied in 431 consecutively admitted psychiatric patients. The co-occurrence rate was greater than 50% for all DSM-IV PDs. Both bivariate association tests and loglinear models showed distinct significant covariation patterns among PDs which were stable across confounder strata. DSM-IV PD clusters were not replicated, with the exception of cluster A. Principal-component analysis (PCA) showed the presence of 3 latent dimensions, thus explaining the DSM-IV PD covariation patterns. These results seem to stress the inadequacy of the DSM-IV categorical model of PD assessment. The need for a reduction of axis II categories and the inclusion of a dimensional model in the diagnostic assessment of DSM-IV PDs are discussed.

Mixed cryoglobulinemia secondary to visceral Leishmaniasis

We describe a case of type II mixed cryoglobulinemia, with monoclonal IgMkappa rheumatoid factor, associated with visceral leishmaniasis caused by Leishmania infantum. Involvement of Leishmania antigen(s) in the formation of cryoprecipitable immune complexes was suggested by the fact that cryoglobulinemic vasculitis subsided after antiparasite therapy and that anti-Leishmania antibodies, as well as rheumatoid factor, were enriched in the cryoprecipitate. We observed 2 additional patients with visceral leishmaniasis and cryoglobulinemic vasculitis. All 3 patients had seemingly contracted leishmaniasis in Italy, were hepatitis C virus negative, and were initially diagnosed as having autoimmune disorders. These findings indicate that Leishmania can be an etiologic agent of type II mixed cryoglobulinemia. This parasitosis should be taken into consideration in the differential diagnosis of vasculitides in endemic areas.

Brief communication: criterion validity of the Personality Diagnostic Questionnaire-4+ (PDQ-4+) in a mixed psychiatric sample

Three hundred consecutively admitted in- and outpatients were administered the Personality Diagnostic Questionnaire-4+ (PDQ-4+). The Structured Clinical Interview for DSM-IV Axis II Personality Disorders, Version 2.0 (SCID-II) was used as the external diagnostic standard for personality disorder (PD) assessment. SCID-II was administered blind to PDQ-4+ scores. Low agreement between PDQ-4+ and SCID-II was observed for both dimensional and categorical PD evaluations. Receiver operating characteristic (ROC) analysis showed a definitively satisfactory discriminatory capability only for two PDQ-4+ PD scales (dependent, and antisocial). In agreement with previous studies, these results showed that PDQ-4+ was not a substitute for a structured diagnostic interview.

Lymphocyte activation gene-3 (LAG-3) expression and IFN-gamma production are variably coregulated in different human T lymphocyte subpopulations

We evaluated the relationship between cytokine profile and the expression of the lymphocyte activation gene-3 (LAG-3) in both T cell clones and polyclonal T cell lines; LAG-3 is a CD4-like protein whose expression is reportedly restricted to Th1/0 cells and dependent upon IFN-gamma. We found that, while LAG-3 was expressed only by CD4+ T cell clones producing IFN-gamma, most CD8+ clones producing IL-4 but not IFN-gamma (i.e., with a T cytotoxic-2-like profile) were LAG-3+. The intensity of LAG-3 expression by CD8+ clones correlated with the amount of released IFN-gamma, suggesting that this cytokine is not required for expression but rather for the up-regulation of LAG-3. Flow cytometric analyses of polyclonal T cell lines confirmed that LAG-3 could be expressed by both CD4+ and CD8+ cells that did not contain cytoplasmic IFN-gamma. In these cell lines, large proportions of CD4+ and CD8+ cells coexpressed LAG-3 and CD30, a putative marker of Th2-like cells. Overall, our data do not support the earlier suggestion that LAG-3 and CD30 are selective markers of T cells with type-1 and type-2 cytokine profiles, respectively.

Death of bystander cells by a novel pathway involving early mitochondrial damage in human immunodeficiency virus-related lymphadenopathy

Destruction of immune cells in peripheral lymphoid tissues plays presumably a pivotal role in acquired immune deficiency syndrome pathogenesis. We found that cell suspensions obtained from lymph nodes of eight human immunodeficiency virus (HIV)-infected individuals contained variable proportions (2.1% to 18.3%, median 11.2%) of dead lymphocytes permeable to supravital dyes, represented by CD4+, CD8+, and B cells. The frequency of dead cells correlated directly (R = 0.847) with the amount of HIV provirus in the cell populations, and HIV provirus was enriched in the dead cell fractions. Similar proportions of dead cells were observed in cell suspensions from lymphadenopathic lymph nodes of HIV- donors, but not from small resting HIV- lymph nodes. Electron microscopic and flow cytometric analyses revealed that most dead cells from HIV+ lymph nodes lacked internucleosomal DNA fragmentation but displayed combined features of apoptosis and necrosis, eg, chromatin condensation and mitochondrial swelling. Cells with similar morphology were readily identified in lymph node tissue sections, and marked mitochondrial swelling could be occasionally observed in cells with otherwise normal morphology. Our findings have two major implications. One is that the in vivo cell death in HIV-infected lymph nodes occurs predominantly through a novel pathway, related to but distinct from classical apoptosis and characterised by early and severe mitochondrial damage. The second implication is that HIV-related lymphadenopathy is accompanied in vivo by massive destruction of uninfected lymph node cells. Comparable levels of cell death were observed in other inflammatory lymphadenopathies not related to HIV; however, the uniquely endless and generalized nature of HIV lymphadenopathy might render this "inflammatory" cell destruction a powerful pathogenetic mechanism, accounting for the progressive disruption and depletion of lymphoid tissues seen in HIV infection.

Comparison of the Vbeta repertoire in peripheral blood and in lymph nodes of HIV-infected subjects reveals skewed usage predominantly in CD8+ T cells

Perturbations of the repertoire of variable-beta (Vbeta) regions of the T cell receptor have been observed in patients infected by HIV and have been attributed to stimulation by viral antigens or superantigens. We further sought for traces of HIV-induced perturbations by comparing Vbeta repertoire in peripheral blood and in lymphoid tissues of six infected patients. Vbeta expression was studied with a panel of 17 anti-Vbeta antibodies covering about 50% of the entire repertoire. We observed major divergences between lymph nodes and peripheral blood in the expression of several Vbeta segments, and these differences were significantly more frequent in CD8+ than in CD4+ T cells (P = 0.0097). Vbeta2 was perturbed in CD8 cells from all but one patient. One HIV-negative subject with localized reactive lymphadenopathy of unknown etiology had four perturbed Vbeta segments, including Vbeta2, in CD8+ cells, while another uninfected subject with an unreactive lymph node architecture had no perturbations. Our findings suggest that stimulation by HIV or by other antigens determines divergences in the Vbeta repertoire between lymphoid tissues and peripheral blood predominantly in CD8+ T cells.

Nonrheumatoid IgM in human hepatitis C virus-associated type II cryoglobulinemia recognize mimotopes of the CD4-like LAG-3 protein

Type II mixed cryoglobulinemia (CryoII) is an autoimmune disorder frequently associated to human hepatitis C virus (HCV) infection and characterized by the presence of cold-insoluble immunocomplexes containing IgM with rheumatoid activity. To identify disease-related epitopes, we screened a phage-displayed random peptide library using purified IgM from patients with HCV-associated CryoII(CryoII/HCV). A dominant population of phage isolates bearing the HPLAP pentapeptide consensus motif was identified and shown to be recognized by a nonrheumatoid IgM species strongly associated to CryoII/HCV. The phage-borne mimotopes (phagotopes) displayed a strong homology with an exposed extra-loop region of human lymphocyte activation 3 gene (LAG-3) product. Consistently, rabbit sera raised against a synthetic LAG-3 peptide efficiently recognized the selected phagotopes. Furthermore, one such phagotope was revealed to be a good immunogenic mimic of LAG-3 when injected into rabbits. IgM purified from CryoII/HCV patients' sera specifically reacted with the LAG-3 peptide in ELISA, and this binding was inhibited by the selected phagotopes. These results provide experimental support for a general strategy to identify novel autoantigens.

Nonrheumatoid IgM in human hepatitis C virus-associated type II cryoglobulinemia recognize mimotopes of the CD4-like LAG-3 protein

Type II mixed cryoglobulinemia (CryoII) is an autoimmune disorder frequently associated to human hepatitis C virus (HCV) infection and characterized by the presence of cold-insoluble immunocomplexes containing IgM with rheumatoid activity. To identify disease-related epitopes, we screened a phage-displayed random peptide library using purified IgM from patients with HCV-associated CryoII(CryoII/HCV). A dominant population of phage isolates bearing the HPLAP pentapeptide consensus motif was identified and shown to be recognized by a nonrheumatoid IgM species strongly associated to CryoII/HCV. The phage-borne mimotopes (phagotopes) displayed a strong homology with an exposed extra-loop region of human lymphocyte activation 3 gene (LAG-3) product. Consistently, rabbit sera raised against a synthetic LAG-3 peptide efficiently recognized the selected phagotopes. Furthermore, one such phagotope was revealed to be a good immunogenic mimic of LAG-3 when injected into rabbits. IgM purified from CryoII/HCV patients' sera specifically reacted with the LAG-3 peptide in ELISA, and this binding was inhibited by the selected phagotopes. These results provide experimental support for a general strategy to identify novel autoantigens.

Measurement of apoptotic cells in peripheral blood

The measurement of apoptosis in peripheral blood might represent a useful tool in acquired immunodeficiency syndrome (AIDS) and cancer research. Among the many assays that are currently used to identify apoptotic leukocytes, flow cytometric methods are the most valuable in terms of rapidity, simplicity, and level of analytical detail. Some flow cytometric assays may also offer the additional advantage of detecting the earliest phases of apoptosis, which is paramount importance for measuring apoptotic cells in vivo before they are destroyed by phagocytes.

TCL1 oncogene activation in preleukemic T cells from a case of ataxia-telangiectasia

The TCL1 oncogene on human chromosome 14q32.1 is involved in chromosome translocations [t(14;14)(q11;q32.1) and t(7;14)(q35;q32.1)] and inversions [inv14(q11;q32.1)] with TCR alpha/beta loci in T-cell leukemias, such as T-prolymphocytic (T-PLL). It is also involved in T-acute and -chronic leukemias arising in cases of ataxia-telangiectasia (AT), an immunodeficiency syndrome. Similar chromosomal rearrangements occur also in the clonally expanded T cells in AT patients before the appearance of the overt leukemia. We have analyzed the expression of TCL1 mRNA and protein in peripheral blood lymphocytes (PBLs) from four AT cases and from healthy controls. We found that the TCL1 gene was overexpressed in the PBLs of an AT patient with a large clonal T-cell population exhibiting the t(14;14) translocation but not in the lymphocytes of the other cases. Fluorescence in situ hybridization of the TCL1 genomic locus to lymphocyte metaphases from the AT patient with the T-cell clonal expansion showed that the breakpoint of the t(14;14) translocation lies within the TCL1 locus and is accompanied by an inverted duplication of the distal part of chromosome 14. These data indicate that TCL1 is activated in preleukemic clonal cells as a consequence of chromosome translocation involving sequences from the TCR locus at 14q11. Deregulation of TCL1 is the first event in the initiation of malignancy in these types of leukemias and represents a potential tool for clinical evaluation.

Frequency of provirus-bearing CD4+ cells in HIV type 1 infection correlates with extent of in vitro apoptosis of CD8+ but not of CD4+ cells

Lymphocytes from HIV-1-infected subjects undergo massive apoptosis when cultured in vitro, and this phenomenon might reflect pathogenetic mechanisms leading to immune dysfunction in vivo. However, (1) lymphocyte death is not restricted to CD4+ cells but seems to involve predominantly CD8+ cells, and (2) the same phenomenon occurs in other viral infections. Furthermore, it is not known whether a relationship exists between the HIV-1 burden and this type of cell death. In this work we sought to determine whether the HIV-1 provirus load correlates with the propensity to apoptosis of CD4+ and CD8+ cells. We studied 10 HIV-1-infected patients with CD4+ cell counts above 500/mm3 and free of concomitant infections. We correlated the frequency of HIV-1-infected CD4+ cells with the extent of culture-induced apoptosis as well as with the phenotype of the apoptotic lymphocytes. We found that the magnitude of apoptosis correlated with the frequency of HIV-1-infected CD4+ cells (p = 0.0007), and that increasing viral load and apoptosis were associated with a shift to the selective death of CD8+ cells. Our data support the view that, in addition to CD4+ cell killing, another immunopathogenic effect of HIV might be that of priming CD8+ cells to apoptosis. In vivo, this could eventually lead to the exhaustion of the cytotoxic T cell compartment.

CD8+ T lymphocytes provide helper activity for IgE synthesis in human immunodeficiency virus-infected patients with hyper-IgE

Increased levels of serum IgE and eosinophilia have been described in human immunodeficiency virus (HIV) infection, almost exclusively in patients with CD4+ cell count < 200 cells/microliters. IgE production is regulated by CD4+ T helper type 2 (Th-2) lymphocytes, producing interleukin 4 (IL-4) and expressing a ligand for the B cell-specific CD40 molecule (CD40 ligand [L]). A shift to a Th-2-like pattern of cytokine secretion has been postulated to be associated with progression toward acquired immunodeficiency syndrome (AIDS). We studied three AIDS patients with very high levels of IgE and almost complete depletion of CD4+ lymphocytes, suggesting that IgE synthesis could not be driven by CD4+ cells. IgE in vitro synthesis by cells from such patients was, however, inhibited by anti-IL-4. We show that both CD8+ T cell lines and the majority of CD8+ T cells clones derived from these patients produce IL-4, IL-5, and IL-6 in half of the cases together with interferon gamma (IFN-gamma). 44% of CD8+ T cell clones expressed a CD40L, and the supernatants of the clones were capable of inducing IgE synthesis by normal B cells costimulated with anti-CD40. CD8+ T cells in these patients therefore functionally mimic Th-2 type cells and may account for hyper-IgE and eosinophilia in the absence of CD4+ cells. The presence of such CD8+ cells may also provide a source of IL-4 directing the development of predominant Th-2 responses in HIV infection.

Activated and "memory" phenotype of circulating T lymphocytes in intrauterine life

We examined the expression of T cell markers in the peripheral blood of five immunologically normal human fetuses at 18-20 weeks of gestational age. The distribution of T cells expressing CD1, CD3, CD4, CD8, CD56, and the alpha/beta and gamma/delta receptors for antigen was comparable to that of newborns and normal adults, except for the absence of gamma/delta cells expressing the delta TCS-1 epitope. The V beta repertoire, as evaluated by two-color flow cytometry using mAbs to specific V beta families, was also comparable to that of adult samples. A significant fraction (8.9 to 16.4%) of fetal CD3+ T cells expressed the alpha chain of IL-2R (CD25) in the absence of HLA-DR; this suggests that antigenic stimuli trigger, during intrauterine life, an unusual pathway of T cell activation. Consistent with this, 7 to 27% of fetal T cells were found to express the CD45R0 marker of "memory" cells.

Detection and characterization of apoptotic peripheral blood lymphocytes in human immunodeficiency virus infection and cancer chemotherapy by a novel flow immunocytometric method

We have developed a quantitative and sensitive flow cytometric method for the detection of human apoptotic lymphocytes that, unlike previously described assays, allows their identification in mixed populations of peripheral blood leukocytes as well as their immunophenotyping. Apoptotic lymphocytes are identified on the basis of peculiar light scatter changes, reflecting their smaller size and their modified nucleus/cytoplasm organization, and of the decreased expression of surface CD45 molecules. Based on these criteria, apoptotic lymphocytes generated by exposure to ionizing radiation can be easily distinguished from viable cells and from necrotic lymphocytes generated by treatment with antibody and complement. Using this assay, we reappraised the phenomenon of the in vitro apoptosis of lymphocytes from patients with human immunodeficiency virus (HIV) infection. Lymphocytes from HIV patients, unlike those from normal HIV-negative subjects, undergo apoptosis upon simple in vitro culture. We found that the percentages of lymphocytes undergoing apoptosis were significantly higher in patients with low CD4 cell counts (< 400/microL) than in patients at earlier stages (> 400 CD4 cells/microL). However, phenotypic analysis disclosed that apoptotic lymphocytes generated in these cultures were mostly CD8+ T cells and CD19+ B cells. Thus, in contrast to what has been previously suggested, the phenomenon of in vitro lymphocyte apoptosis might not be pathogenetically related to the depletion of CD4+ T cells in acquired immunodeficiency syndrome. Nevertheless, it might represent an useful marker of disease progression. Our assay allows the analysis of unfractionated peripheral blood leukocytes and thus the identification of apoptotic lymphocytes circulating in vivo. Apoptotic lymphocytes could indeed be detected in the circulation of a patient with cancer shortly after high-dose cytotoxic chemotherapy. By contrast, no apoptotic lymphocytes could be detected in vivo in patients with early or advanced HIV infection.

Absence of antibodies to human herpesvirus-6 in patients with slowly-progressive human immunodeficiency virus type 1 infection

To evaluate a possible role for Human Herpesvirus-type 6 (HHV-6) coinfection as a co-factor in the progression of HIV-1 disease, we investigated the prevalence of seropositivity for HHV-6 in a cohort of HIV-1 infected patients. These patients were retrospectively divided into two groups according to the decline of CD4+ T cells during the follow up: 11 were classified as rapid decliners (less than 400 CD4+/cmm within 1 year), and 38 as slow decliners (greater than 400 CD4+/cmm after at least 4 years' follow up). HHV-6 antibodies were detected by a commercial immunofluorescence assay and by a Western blotting assay developed in our laboratory. Our results show that Western blot appears to provide results satisfactorily free of false positivities. We found that the frequency of HHV-6 seropositivity was significantly lower in the group of slow decliners, compared both to rapid decliners and to the general population. These data suggest a role for HHV-6 co-infection in the progression of HIV-1 disease.

Selective deficiency of CD4+/CD45RA+ lymphocytes in patients with ataxia-telangiectasia

Several immunological abnormalities have been observed in ataxia-telangiectasia (AT), the most consistent being defects of immunoglobulin isotypes, decreased T-cell numbers, and reduced proliferative responses to mitogens. We examined the distribution of T lymphocytes expressing distinctive surface Ag characteristic of "naive" (CD45RA+) and "memory" (CD29+, CD45RO+) T cells, in both CD4+ and CD8+ (bright and dim) lymphocytes from 13 AT patients, compared with healthy age-matched controls. We found that, irrespective of age, patients with AT had a severe deficiency of CD4+/CD45RA+ lymphocytes. This decrease accounted for the reduction of total CD4+ cells, since the absolute numbers of memory CD4+ cells were not significantly different in AT and in controls. Functional tests revealed poor proliferative responses to phytohemagglutinin and normal responses to soluble Ag (tetanus toxoid) in AT patients. These data fit with the distribution of naive and memory cells, which are known to respond predominantly to mitogens or to recall Ag, respectively. CD45RA molecules were normally expressed on CD8+ lymphocytes. This rules out a generalized defect of regulation or differential splicing as the cause of defective expression of CD45RA on CD4+ cells. The selective deficiency of CD4+CD45RA+ may provide a cellular basis for some functional T-cell abnormalities of AT patients. Furthermore, it might practically serve for an early, or even prenatal, diagnosis of this disease.

Heterogeneity in ataxia-telangiectasia: classical phenotype associated with intermediate cellular radiosensitivity

We identified a subgroup of ataxia-telangiectasia (AT) patients (2 sibs and 1 unrelated case) characterized by typical clinical manifestations of the disease and cellular radiosensitivity intermediate between classical AT and normal subjects. Our data and a literature review of the intermediate radiosensitivity AT cases show that radioresistant DNA synthesis, cellular radiosensitivity (measured in terms of survival and chromosome breakage), and the clinical hallmarks behave independently. This raises a number of interesting questions about the correlation between radiobiological and clinical features, and about the nature of the AT gene(s).

Plasma viraemia in seronegative HIV-1-infected individuals

It has been reported that the period of latency between HIV-1 infection and the production of antibodies against the virus is sometimes prolonged for greater than 6 months. However, the data supporting this are still controversial and it is not known whether these individuals are actually infectious, especially through body fluids. We have performed a prospective study of 65 high-risk HIV-1-antibody-negative individuals who were followed-up for a period of at least 1 year. Twelve of these individuals were shown by polymerase chain reaction (PCR) to be carriers of HIV-1 proviral sequences. The virus was isolated from lymphocytes in five out of 10 PCR-positive subjects and from cell-free plasma in two. Our data indicate that in some cases delayed seroconversions may be associated with productive infection, suggesting that mechanism(s) other than viral latency may be responsible for the absence of antibody responses to HIV-1 proteins.

Selective deficiency of interferon-gamma production in the hyper-IgE syndrome. Relationship to in vitro IgE synthesis

We measured the in vitro production of interferon-gamma (IFN-gamma) in five cases of hyper-IgE syndrome (HIgE), induced by mitogens, calcium ionophores and phorbol ester. The biosynthesis of IFN-gamma was severely reduced or undetectable in HIgE, while it was near normal in most atopic patients. The in vitro spontaneous production of IgE was increased overall in HIgE patients, although no correlation was found with serum IgE levels. Recombinant interleukin-4 (IL-4) induced a further increase in IgE synthesis, and its effect was totally antagonized by recombinant IFN-gamma; the same pattern of response was also observed in atopic subjects with high production of IgE. IFN-alpha synergized with IL-4 on IgE synthesis, whereas recombinant IL-6 gave opposite changes in individual cases tested. We propose that IFN-gamma deficiency may be responsible for some of the features of HIgE patients, including IgE levels and infections.

Relative increase of T cells expressing the gamma/delta rather than the alpha/beta receptor in ataxia-telangiectasia

In ataxia-telangiectasia, B-cell and T-cell deficiencies are thought to be due to a defect of rearrangements of immunoglobulin and T-cell receptor genes. T cells recognize antigens through two types of CD3-associated receptors: alpha/beta chains on mature cells and gamma/delta chains mostly on immature cells. We studied 10 patients with ataxia-telangiectasia and found that most had a relative increase of circulating T cells bearing gamma/delta receptors rather than alpha/beta receptors, as compared with normal subjects (P less than 0.001). Patients with other immune deficits, including eight with common variable immunodeficiency, one with Wiskott-Aldrich syndrome, two with hyperimmunoglobulinemia E syndrome, and one with severe combined immunodeficiency, had normal ratios of gamma/delta-bearing to alpha/beta-bearing cells. A marked predominance of gamma/delta-bearing T cells was found in a patient with a primary T-cell defect. The relative increase in gamma/delta-bearing T cells in the patients with ataxia-telangiectasia was largely accounted for by cells that reacted with the monoclonal antibody BB3, an apparently distinct subset of T cells that selectively express the C gamma 1 gene product of the T-cell receptor. Although they had normal ratios of gamma/delta-bearing to alpha/beta-bearing T cells, the patients with common variable immunodeficiency had a significant increase (P = 0.01) in the number of T cells expressing C gamma 2 that reacted with the monoclonal antibody delta-TCS-1. We conclude that the increased ratio of gamma/delta-bearing to alpha/beta-bearing T cells in ataxia-telangiectasia may reflect both a recombinational defect that interferes with T-cell and B-cell gene rearrangements and an inability to repair damage to the DNA.

Identification of 4 ataxia telangiectasia cell lines hypersensitive to gamma-irradiation but not to hydrogen peroxide

The effect of hydrogen peroxide on the rate of semi-conservative DNA synthesis in ataxia telangiectasia (AT) and normal human lymphoblastoid cells was investigated. The rate of DNA synthesis in AT cells was not depressed to a lesser extent than in normal cells, as might have been expected since H2O2 is a radiomimetic agent. On the contrary, 4 AT cell lines displayed a higher sensitivity to the inhibitory effect of H2O2 on DNA synthesis than 2 normal cell lines. Comparable levels of cytotoxicity were detected in cell viability studies. Furthermore, neither the level of DNA breakage produced by H2O2, nor the rate of repair of these lesions was significantly different in normal and AT cells. Together, these results indicate that the AT cell lines utilized in this study are not hypersensitive to the oxidant. It is suggested that H2O2 may not induce lethality via the direct action of the hydroxyl radical (OH.).

Agenesis of the corpus callosum, combined immunodeficiency, bilateral cataract, and hypopigmentation in two brothers

We describe 2 brothers with a malformation syndrome consisting of agenesis of the corpus callosum, cutaneous hypopigmentation, bilateral cataract, cleft lip and palate, and combined immunodeficiency. The clinical history of both patients was characterized by severe psychomotor retardation, seizures, recurrent severe respiratory infections, and chronic mucocutaneous candidiasis. The children died of bronchopneumonia at age 2 and 3 years, respectively. Immunological investigations showed, in one sib studied, skin anergy to recall antigens, profound depletion of T4+ lymphocytes, and serum IgG2 deficiency. Necropsy showed agenesis of the corpus callosum, hypoplasia of the cerebellar vermis, and profound hypoplasia of the thymus and of the peripheral lymphoid tissue. The distinctive features of these sibs appear to define a previously undescribed hereditary MCA/MR syndrome. The clinical and pathological findings seem to indicate, as a pathogenetic mechanism, a defect involving the embryonic organization of the central nervous system and of the immune system.

Establishment of a new Epstein-Barr virus-immortalized cell line from chronic lymphocytic leukemia with trisomy of chromosome 12 that produces monoclonal IgM against a sheep RBC antigen

Leukemia cells from a patient with chronic lymphocytic leukemia (CLL) were found to bind sheep RBC (SRBC) through their monoclonal surface IgM. A lymphoblastoid cell line was obtained by immortalization of leukemic cells with Epstein-Barr virus (EBV). Cultured leukemic cells were found to have a supernumerary chromosome 12, an abnormality typical of CLL of the B cell type. To our knowledge, this is the first EBV-immortalized cell line from B-CLL cells of known SRBC specificity and the third reported CLL cell line carrying trisomy of chromosome 12.

Case Report of a Burkitt-Like Lymphoma in a Bisexual Hiv-Positive Man

The clinical and pathologic features of a Burkitt-like lymphoma in a bisexual HIV-seropositive man are reported. Emphasis is placed on some histologic characteristics present in a hyperplastic lymph node removed 2 years before the development of the B-cell lymphoma.

Hypogammaglobulinemia with hyper-IgM, severe T-cell defect, and abnormal recirculation of OKT4 lymphocytes in a girl with chronic lymphadenopathy

We describe here one 8-year-old girl with an unusual form of immunodeficiency, characterized by hypogammaglobulinemia with hyper-IgM, severe T-cell defect, and chronic lymphadenopathy. Patient's B cells failed to produce IgG or IgA in vitro following stimulation with either pokeweed mitogen or Epstein-Barr virus, suggesting an intrinsic B-cell defect. Abnormal T-cell function was demonstrated by impaired in vivo delayed type hypersensitivity, reduction of mitogen-induced proliferation and interleukin 2 production, reduction of interferon-gamma production, and marked decrease of circulating OKT4+ cells. The latter cells were found in normal proportion in the patient's lymph node tissue. This finding suggests that the decrease of OKT4+ cells in peripheral blood was due to the abnormal recirculation of these cells. The identity of this syndrome with the infantile form of the acquired immunodeficiency syndrome was apparently ruled out by the failure to demonstrate HTLV-III-related sequences in patient's lymphocytes or virus-specific serum antibodies.