Clonality and specificity of cryoglobulins associated with HCV: pathophysiological implications

Background/Aims: Hepatitis C virus (HCV) infection plays a central role in the pathogenesis of mixed cryoglobulinemia through molecular mechanisms which remain to be elucidated. The aim of this study was to investigate the role of antibody responses to HCV in the pathogenesis of cryoglobulinemia through characterization of the anti-HCV specificity and immunochemical characteristics of the immunoglobulins involved in cryoprecipitation.Methods: Sera from 50 consecutive patients with chronic HCV infection (RNA positive) were screened for the presence of cryoglobulins. The two major components of cryoprecipitates, IgM rheumatoid factors and IgG, were separated by high performance liquid chromatography and analyzed for immunochemical composition by immunoblotting and antibody specificity by ELISA and immunoblotting using recombinant HCV proteins and synthetic peptides as antigens.Results: Cryoprecipitates were observed in 27 patients and characterized by immunofixation: 13 (48%) were classified as type II and 14 (52%) as type III. Monoclonal immunoglobulins were detected by immunoblotting in 20 cryoprecipitates: IgM in 14 samples and IgG in 14, which a clear preponderance of IgG3 (). Specificity studies on sera and purified IgM and IgG fractions from cryoprecipitates revealed enrichment in cryoglobulins, predominantly polyclonal IgG1, reactive with the HCV structural proteins, whereas specificities for nonstructural viral proteins were relatively less represented compared to whole serum. No restricted pattern of fine specificity was observed. IgG3 subclass was apparently not involved in HCV nucleoprotein binding.Conclusions: Our findings do not support a direct link between monoclonal cryoglobulins and immune response to HCV. According to the proposed pathogenetic model, HCV infection can induce the formation of cryoprecipitable rheumatoid factors, sustain their production, and eventually lead to monoclonal B-cell expansion through several cooperative mechanisms.     

Impact of anti-rheumatic drugs and steroids on clinical course and prognosis of COVID-19

Clinical Rheumatology -     

The degrees of plasma cell clonality and marrow infiltration adversely influence the prognosis of AL amyloidosis patients

BACKGROUND AND OBJECTIVE: Primary amyloidosis is a lethal form of plasma cell (PC) dyscrasia characterized by deposits of monoclonal immunoglobulin light chains that cause organ dysfunction. In contrast to multiple myeloma, the amyloid clone is typically indolent and of small size, and marrow PC clonality is not always apparent. This is generally investigated by analyzing the light chain isotype ratio in bone marrow PC. We investigated whether the degree of PC infiltration (PC%) and clonality (PC isotype ratio) affected survival in 56 consecutive patients with primary amyloidosis. DESIGN AND METHODS: PC% was determined by morphologic examination. Immunofluorescence microscopy was used to determine the PC light chain isotype ratio. Statistical analysis was carried out using Cox regression models. RESULTS: The degrees of PC clonality and infiltration were inversely correlated with survival (PC isotype ratio, p = 0.001; PC%, p = 0.008). The two variables were weakly correlated (p = 0.02; r = 0.3). Bone marrow PC isotype ratio demonstrated a powerful independent prognostic value at multivariate analysis when analyzed together with congestive heart failure (the major known negative prognostic factor) and PC%. k/l ratio cut-off values of 0.2 (l patients, p = 0.022) and 16 (k patients, p = 0.03) discriminated two groups with a similar number of patients and significantly different survivals. INTERPRETATION AND CONCLUSIONS: PC clonality and marrow infiltration are important parameters that influence prognosis, presumably because they reflect the amount of pathogenic light chain synthesis.     

Three-dimensional Nuclear Telomere Architecture Is Associated with Differential Time to Progression and Overall Survival in Glioblastoma Patients

The absence of biological markers allowing for the assessment of the evolution and prognosis of glioblastoma (GBM) is a major impediment to the clinical management of GBM patients. The observed variability in patients'' treatment responses and in outcomes implies biological heterogeneity and the existence of unidentified patient categories. Here, we define for the first time three GBM patient categories with distinct and clinically predictive three-dimensional nuclear-telomeric architecture defined by telomere number, size, and frequency of telomeric aggregates. GBM patient samples were examined by three-dimensional fluorescent in situ hybridization of telomeres using two independent three-dimensional telomere-measurement tools (TeloView program [P₁] and SpotScan system [P₂]). These measurements identified three patients categories (categories 1–3), displaying significant differences in telomere numbers/nucleus (P₁ = .0275; P₂ ≤ .0001), telomere length (P₁ and P₂ = .0275), and number of telomeric aggregates (P₁ = .0464; P₂ ≤ .0001). These categories corresponded to patients with long-term, intermediate, and short-term survival, respectively (P = .0393). The time to progression analyses showed significant differences between the three categories (P = .0167). There was a correlation between time to progression, median survival, and nuclear telomere architecture. Our study suggests a link between patient outcome and three-dimensional nuclear-telomere organization and highlights the potential clinical power of telomere signatures as a new prognostic, predictive, and potentially pharmacodynamic biomarker in GBM. Furthermore, novel automated three-dimensional high-throughput scanning as developed here permits to obtain data from 300 nuclei in 20 minutes. This method is applicable to any cell type and scanning application.     

HLA-DRB4 as a genetic risk factor for Churg-Strauss syndrome

OBJECTIVE: To explore the association between HLA alleles and Churg-Strauss syndrome (CSS), and to investigate the potential influence of HLA alleles on the clinical spectrum of the disease. METHODS: Low-resolution genotyping of HLA-A, HLA-B, and HLA-DR loci and genotyping of TNFA -238A/G and TNFA -308A/G single-nucleotide polymorphisms were performed in 48 consecutive CSS patients and 350 healthy controls. RESULTS: The frequency of the HLA-DRB1*07 allele was higher in the CSS patients than in controls (27.1% versus 13.3%; chi(2) = 12.64, P = 0.0003, corrected P [P(corr)] = 0.0042, odds ratio [OR] 2.42, 95% confidence interval [95% CI] 1.47-3.99). The HLA-DRB4 gene, present in subjects carrying either HLA-DRB1*04, HLA-DRB1*07, or HLA-DRB1*09 alleles, was also far more frequent in patients than in controls (38.5% versus 20.1%; chi(2) = 16.46, P = 0.000058, P(corr) = 0.000232, OR 2.49, 95% CI 1.58-3.09). Conversely, the frequency of the HLA-DRB3 gene was lower in patients than in controls (35.4% versus 50.4%; chi(2) = 7.62, P = 0.0057, P(corr) = 0.0228, OR 0.54, 95% CI 0.35-0.84). CSS has 2 major clinical subsets, antineutrophil cytoplasmic antibody (ANCA)-positive, with features of small-vessel vasculitis, and ANCA-negative, in which organ damage is mainly mediated by tissue eosinophilic infiltration; analysis of HLA-DRB4 in patients categorized by different numbers of vasculitic manifestations (purpura, alveolar hemorrhage, mononeuritis multiplex, rapidly progressive glomerulonephritis, and constitutional symptoms) showed that its frequency strongly correlated with the number of vasculitis symptoms (P for trend = 0.001). CONCLUSION: These findings indicate that HLA-DRB4 is a genetic risk factor for the development of CSS and increases the likelihood of development of vasculitic manifestations of the disease.     

Telomeric aggregates and end-to-end chromosomal fusions require myc box II

Telomeres of tumor cells form telomeric aggregates (TAs) within the three-dimensional (3D) interphase nucleus. Some of these TAs represent end-to-end chromosomal fusions and may subsequently initiate breakage-bridge-fusion cycles. Wild-type (wt) and myc box II mutant (mt) Myc induce different types of genomic instability when conditionally expressed in mouse proB cells (Ba/F3). Only wt Myc overexpressing Ba/F3 cells are capable of tumor formation in severe combined immunodeficient mice. In this study, we investigated whether telomere dysfunction leading to TA formation is linked to the genetic changes that permit wt c-Myc-dependent transformation of Ba/F3 cells. To this end, we examined the 3D organization of telomeres after the deregulated expression of deletion myc boxII mutant (Delta106) or wt Myc. Delta106-Myc overexpression did not induce TAs, whereas wt-Myc deregulation did. Instead, Delta106-Myc remodelled the 3D telomeric organization such that telomeres aligned in the center of the 3D interphase nucleus forming a telomeric disk owing to a Delta106-induced G1/S cell cycle arrest. In contrast, wt-Myc overexpression led to distorted telomere distribution and TA formation. Analysis of chromosomal alterations using spectral karyotyping confirmed Delta106-Myc and wt-Myc-associated genomic instability. A significant number of chromosomal end-to-end fusions indicative of telomere dysfunction were noted in wt-Myc-expressing cells only. This study suggests that TAs may play a fundamental role in Myc-induced tumorigenesis and provides a novel way to dissect tumor initiation.     

Left main coronary artery disease. Clinical and angiographic features. A retrospective study regarding two groups of patients with left main coronary artery disease and three-vessel disease

BACKGROUND: The aim of this study was to assess the ability of clinical and instrumental features to identify patients with left main coronary artery disease (LMCD) compared with a three-vessel coronary artery disease group. METHODS: A cohort of 70 patients with LMCD was matched with another one of 66 patients with three-vessel disease. A history of angina before angiography was similar in both groups; the higher degrees of stable angina and the forms of unstable angina were moderately prevalent in the group with LMCD. RESULTS: In the last subgroup a significantly reduced incidence of previous acute myocardial infarction (AMI) was observed (p < 0.05). The resting electrocardiogram (ECG) showed higher incidence of atrial fibrillation (fa) and left bundle branch block (BBS) in the subjects with LMCD, with a statistic value (p < 0.05). The exercise test performed by a lot of patients appeared equally positive for inducible ischemia in the 2 groups. Significantly higher exercise peak load was achieved by the patients with three-vessel disease (p < 0.05). The coronary angiography showed a prevalence of right dominant circulation in the 2 groups; significantly the collateral circulation was more represented in the subjects with three-vessel disease (p < 0.05). Most patients with LMCD underwent a bypass coronary artery graft surgery (CABG surgery) more frequently than the ones with three-vessel disease (p < 0.01). In the former group the cardiovascular mortality within an average 2-year follow-up proved higher as to the latter group even if without statistic significance. CONCLUSIONS: Nevertheless this retrospective study showed some limitations. Particularly the incidence of clinical and instrumental variables and their capacity to differentiate LMCD patients from those with three-vessel disease were not demonstrated.     

Outcome and prognostic factors during the course of primary small-vessel vasculitides

OBJECTIVE: To identify the prognostic factors of relapse and/or death during the course of primary small-vessel vasculitides (PSVV), and to differentiate their prognostic relevance by the type of vasculitis. METHODS: Seventy-five patients were retrospectively followed up after diagnosis: 36 with Wegener's granulomatosis (WG), 23 with Churg-Strauss syndrome (CSS), and 16 with microscopic polyangiitis. Cox regression analysis was used to identify the significant predictors of relapse and death. RESULTS: Gastrointestinal (GI) involvement was associated with an increased risk of relapse, mainly in the patients with CSS, whereas renal disease and perinuclear antineutrophil cytoplasmic antibody positivity were correlated with a lower risk of relapse. Presence of nasal Staphylococcus aureus tended to increase the risk of relapse in CSS [hazard ratio (HR) 4.45, p = 0.087], but to decrease it in WG (HR 0.12, p = 0.066). Older age, renal and hepatic involvement, erythrocyte sedimentation rate >or= 100 mm/h, and serum creatinine level >or= 1.5 mg/dl were all related to higher risk of death in univariate analysis; however, only cerebral (HR 8.52, p = 0.021) and hepatic involvement (HR 4.40, p = 0.028) and serum creatinine level >or= 1.5 mg/dl (HR 5.72, p = 0.044) were independently correlated with an unfavorable prognosis for survival. The risk of death associated with each of these indicators did not depend on the form of PSVV. CONCLUSION: GI involvement increases the risk of relapse in CSS, whereas the prognostic significance of nasal S. aureus in terms of relapse seems to be opposite in patients with CSS and those with WG. Patients with cerebral, hepatic, and renal involvement have the poorest prognosis for survival. Our data do not show that the prognostic relevance of these factors depends on the form of PSVV.     

Apparent preferential loss of heterozygosity at TSC2 over TSC1 chromosomal region in tuberous sclerosis hamartomas

To investigate the molecular mechanisms of tuberous sclerosis (TSC) histopathologic lesions, we have tested for loss of heterozygosity the two TSC loci (TSC1 and TSC2) and seven tumor suppressor gene-containing regions (TP53, NF1, NF2, BRCA1, APC, VHL, and MLM) in 20 hamartomas from 18 TSC patients. Overall, eight angiomyolipomas, eight giant cell astrocytomas, one cortical tuber, and three rhabdomyomas were analyzed. Loss of heterozygosity at either TSC locus was found in a large fraction of the informative patients, both sporadic (7/14) and familial (1/4). Interestingly, a statistically significant preponderance of loss of heterozygosity at TSC2 was observed in the sporadic group (P < 0.01). Among the possible explanations considered, the bias in the selection for TSC patients with the most severe organ impairment seems particularly appealing. According to this view, a TSC2 defect might confer a greater risk for early kidney failure or, possibly, a more rapid growth of a giant cell astrocytoma. None of the seven antioncogenes tested showed loss of heterozygosity, indicating that the loss of either TSC gene product may be sufficient to promote hamartomatous cell growth. Finally, the observation of loss of heterozygosity at different markers in an astrocytoma and in an angiomyolipoma from the same patient might suggest the multifocal origin of the second-hit mutation. Genes Chromosom Cancer 15:18–25 (1996). © 1996 Wiley-Liss, Inc.