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We determined the specificity and sequence of immunoglobulin molecules synthesized by monoclonal B cells from a patient with chronic lymphocytic leukaemia (CLL) who presented with a number of clinical and biological autoimmune symptoms. Heterohybrids obtained by fusion of CLL cells with the mouse X63-Ag 8.653 myeloma produced IgMλ MoAbs directed to the cardiolipin/β2 glycoprotein I (β2GPI) complex and ssDNA. They were devoid of polyreactivity. Nucleotide sequence analysis of the variable domain of the μ chain indicated the utilization of the VH4 71.2 gene or one allotypic variant, Dxp4 and JH3 segments. The λ light chain used the single gene from the Vλ8 subfamily. Jλ3 and Cλ3 genes. The VH gene displayed 11 nucleotide changes in comparison with its putative germline counterpart- However, these nucleotide changes correspond to variations observed in other published VH4 sequences, suggesting gene polymorphism rather than somatic mutation. DXP4 and JH3 were also in germline configuration. The VL gene exhibited a single replacement mutation in CDR1. These data suggest that the monoclonal CLL B cells in this patient retained VH and VL genes in germline configuration although they secreted a pathogenic anti-cardiolipin antibody associated with clinical symptoms, vasculitis and thrombosis, which may be provoked by antibodies to the phosphoIipid/β2GPI complex. [ABSTRACT FROM AUTHOR]

In order to explain complement components abnormalities observed during septic shock, circulating immune complexes (C.I.C.) were searched for in sera from 34 patients with gram negative sepsis by two different methods: polyethylene glycol precipitation test based on physical properties of C.I.C. and C1q deviation test based on the property of radiolabelled C1q to react with C.I.C. Serum immunoglobulins (IgG, IgA, IgM) and complement components (C1q, C3, C4) levels were simultaneously determined. Seventeen patients with minimal haemodynamic abnormalities had normal or increased levels (except C4 at 62% of normal) and in eleven cases both tests for C.I.C. were simultaneously positive. Seventeen patients with severe septic shock had a decrease in IgG, IgM C1q, C3 and C4 and none had both tests for C.I.C. simultaneously positive (P less than 10(-4)). The disappearence of C.I.C. in patients with severe septic shock associated with evidence of complement activation suggests their involvement in the pathogenesis of septic shock in man. [ABSTRACT FROM AUTHOR]

This report describes a patient without evident underlying disease, in whom an acquired von Willebrand's syndrome was discovered before surgery. Coagulation abnormalities included a borderline bleeding time, a low retention of platelets on glass beads, decreased levels of factor VIII procoagulant activity (VIIIAHF), factor VIII-related antigen (VIIIAg), and ristocetin-induced agglutination cofactor (VIIIVWF). After cryoprecipitate infusion the patient did not have the expected rise and there was no secondary increment in VIIIAHF. The patient was treated with prednisone for three weeks without significant improvement in the laboratory findings. Spontaneous resolution was observed long after this therapy. The haemostatic abnormalities were attributable to the presence of an inhibitor directed against VIIIVWF. The inhibitor was found in the IgM fraction. Its autoimmune nature is probable although we failed to demonstrate any inhibitory effect of Fab obtained from the patient's purified IgM. Despite the lack of inhibitory effect against VIIIAHF and VIIIAg, the low levels of all three activities of the factor VIII complex could be explained by the short half-life of immune complexes between factor VIII and the inhibitor. [ABSTRACT FROM PUBLISHER]

Serum containing a monoclonal IgM protein from a patient with Waldenstroms' macroglobulinaemia gave intense immunofluorescent staining of kidney nuclei. The Fab mu fragments of this immunoglobulin were obtained. The IgM and Fab fragments reacted in vitro with kidney nuclei using unfixed cryostat sections of rat or mouse kidney. After treatment of the patient with chemotherapy, the monoclonal IgM disappeared, and no more antinuclear activity could be detected in the serum. The results strongly suggest that this IgM protein had antinuclear activity. [ABSTRACT FROM PUBLISHER]

To determine the clinical significance of antiphospholipid antibodies (aPL) in patients with immune thrombocytopenic purpura (ITP), anticardiolipin (aCL) (IgG and IgM) and lupus anticoagulant (LA) were sought at diagnosis in 215 ITP adults with platelets <50 x 10(9)/l. aPL (aCL and/or LA) were detected in 55 patients (26%): aCL alone in 39 (18%), aCL and LA in 15 (7%) and LA alone in one (0.5%). LA was significantly associated with high IgG-aCL levels (P = 0.001). Among age, sex, initial platelet count, bleeding score, acute or chronic ITP outcome, only younger age was significantly associated with LA-positivity (mean age 29 +/- 14 years vs. 45 +/- 20 years, P = 0.002). After a median follow-up of 31 months, 14/215 (7%) patients developed thrombosis (four arterial, 10 venous and/or pulmonary embolism); four of them (29%) had high aCL levels and LA. Multivariate analysis significantly associated thrombosis events only with age [hazard ratio (HR) = 1.6; 95% confidence interval (CI): 1.2-2.4], LA (HR: 9.9; 95% CI: 2.3-43.4) or high IgG-aCL level (HR: 7.5; 95% CI; 1.8-31.5). Although the thrombosis rate was low, the significant associations between thrombosis and LA or high aCL level suggest that aPL should be tested at ITP diagnosis.

The factors leading to spontaneous clearance of hepatitis C virus (HCV) or to viral persistence are elusive. Understanding virus-host interactions that enable acute HCV clearance is key to the development of more effective therapeutic and prophylactic strategies. Here, using a sensitive neutralization assay based on infectious HCV pseudoparticles (HCVpp), we have studied the kinetics of humoral responses in a cohort of acute-phase patients infected during a single nosocomial outbreak in a hemodialysis center. The 17 patients were monitored for the spontaneous outcome of HCV infection for 6 months before a treatment decision was made. Blood samples were taken frequently (15 +/- 4 per patient). Phylogenetic analysis of the predominant virus(es) revealed infection by only one of two genotype 1b strains. While all patients seroconverted, their sera induced two opposing effects in HCVpp infection assays: inhibition and facilitation. Furthermore, the ability of sera to facilitate or inhibit infection correlated with the presence of either infecting HCV strain and divided the patients into two groups. In group 1, the progressive emergence of a relatively strong neutralizing response correlated with a fluctuating decrease in high initial viremia, leading to control of viral replication. Patients in group 2 failed to reduce viremia within the acute phase, and no neutralizing responses were detected despite seroconversion. Strikingly, sera of group 2, as well as naive sera, facilitated infection by HCVpp displaying HCV glycoproteins from different genotypes and strains, including those retrieved from patients. These results provide new insights into the mechanisms of viral persistence and immune control of viremia.

The aim of this study was to analyze the clinical impact of hepatitis C virus (HCV)-related cryoglobulinemia in patients that had received liver transplants after HCV cirrhosis. Thirty patients who had received transplants between 1990 and 1996 for HCV cirrhosis and who had a follow-up longer than 1 year were studied. Serum HCV RNA levels, HCV genotype, cryoglobulinemia, rheumatoid factor, serum C3 and C4, IgA, IgG, IgM levels, liver tests, and liver histology were studied 30 +/- 16 months post-transplant. Cryoglobulinemia was found in 9 of 30 patients (30.0%) and was symptomatic in 4 of the 9 cases (glomerulonephritis, 1 case; palpable purpura, 3 cases). Age, sex distribution, alanine aminotransferase (ALAT) activity, and Knodell score did not differ, whether cryoglobulinemia was present or not. Rheumatoid factor (209.5 +/- 70.4 IU/l vs 12.0 +/- 4.4 IU/l, P = 0.004) and IgM levels (3.2 +/- 0.5 g/l vs 1.6 +/- 0.9 g/l, P = 0.0001) were significantly higher, and C4 levels (0.16 +/- 0.16 g/l vs 0.30 +/- 0.10 g/l, P = 0.009) were significantly lower in patients with cryoglobulinemia. One patient died from cryoglobulin-related renal failure. We concluded that, after liver transplantation (LT) for HCV cirrhosis, cryoglobulinemia was frequent and often symptomatic. Cryoglobulinemia did not seem to be associated with more severe graft damage. Cryoglobulinemia-associated morbidity must be taken into account in the management of post-transplant HCV infection.

Previous reports have highlighted the disparity in biocompatibility of two differently engineered heparin coatings during the cardiopulmonary bypass (CPB) procedure. The aim of this prospective study was to evaluate the impact of the difference in haemocompatibility provided by either the Duraflo II equipment or the Carmeda equipment in the terminal inflammatory response observed after coronary artery surgery. Thirty patients were randomly allocated to two groups to be operated on using either Duraflo II equipment (group I) or Carmeda equipment (group 2) for extracorporeal circulation (ECC). Initial inflammatory response was assessed by terminal complement complex activation (SC5b-9). The late inflammatory response observed in the postoperative period was assessed by measuring cytokine production (tumour factor necrosis (TNF alpha), interleukin IL-6, interleukin IL-8) and circulating concentrations of adhesion molecules (ELAM-1, ICAM-1). The release of SC5b-9 after CPB and after protamine administration was lower in group 2 than in group 1 (p = 0.0002 and p = 0.006, respectively). A significant production of cytokines was detected in both groups with peak values observed within the time range of 4-6 h after the start of CPB.

Thrombocytopenia is a frequent complication of primary antiphospholipid syndrome (PAPL) and has been attributed to antibodies directed against platelet glycoproteins (Gp) and also to antiphospholipid antibodies. We tested patients with PAPL with and without thrombocytopenia for specific antiplatelet autoantibodies. Platelet autoantibodies were detected by means of platelet immunoassays which included MAIPA with a panel of monoclonal antibodies directed against all the platelet Gps known to be possible targets for platelet autoantibodies. A high prevalence of serum platelet antibodies was found in patients with thrombocytopenia (73%, 11/15 patients) whereas antiplatelet antibody was detected in only one of the 10 control patients (P < 0.01). The antibodies mainly recognized GpIIbIIIa (n = 7), but also CD9 (n = 5), GpIaIIa (n = 4). GpIbIX (n = 3) and GpIV (n = 3). Platelet-Gp antibodies eluted from the platelet surface had the same reactivity as those found in the original sera from three of the four patients tested, whereas no anticardiolipin activity was found in the platelet eluates, suggesting the absence of cross-reactivity between anticardiolipin and antiplatelet antibodies. The MAIPA assay was also performed with F(ab')2 fragments obtained by pepsin digestion of serum IgG from four patients. The same results were obtained with F(ab')2 fragments and the original serum, demonstrating that platelet antibodies specifically bind in vivo to platelet Gps via their F(ab')2 fragments. Our results suggest a link between specific platelet antibodies and the thrombocytopenia of PAPL.