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A Fornasieri

Publications and source records attributed to A Fornasieri.

At least 19 recordsLinked to original sources
PubMed1996

High binding of immunoglobulin M kappa rheumatoid factor from type II cryoglobulins to cellular fibronectin: a mechanism for induction of in situ immune complex glomerulonephritis?

In our previous experimental work we suggested that the frequent nephritogenicity of type II cryoglobulins could depend on a particular affinity of the immunoglobulin (Ig) M kappa rheumatoid factor (RF) component for mesangial matrix. Since cellular fibronectin (cFN) in the human kidney is mainly represented in glomerular mesangium, we studied the binding capacity to cFN of IgM kappa RFs from type II cryoglobulins compared with other different monoclonal and polyclonal IgM and IgM RFs. We purified 13 IGM kappa from human IgM kappa/IgG cryoglobulins, eight monoclonal IgM from patients with Waldenström's macroglobulinemia, nine polyclonal IgM from normal donors, and eight polyclonal IgM RFs from patients with rheumatoid arthritis. Purified IgM were used at the same concentration in enzyme-linked immunosorbent assay (ELISA) on cFN-coated plates. All the cryoglobulin IgM showed high specific binding to cFN while IgM from Waldenström's macroglobulinemia, normal IgM, and polyclonal IgM RFs had low or absent binding. These data were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cFN followed by Western blot analysis with purified IgM. The IgM kappa binding to cFN persisted using IgM kappa monomers, and was inhibited by cFN but not by plasma FN in a specific inhibition test. Further enzyme-linked immunosorbent assay studies showed that cryoglobulin IgM kappa RFs are still able to bind IgG in a dose-dependent manner once linked to solid-phase cFN. The data suggest that the affinity of cryoglobulin IgM kappa RFs for immobilized cFN could be involved in the particular high nephritogenicity of type II cryoglobulins and might lead to in situ immune complex formation.

Autoantibodies↗
PubMed1995

Cryoglobulinemic glomerulonephritis: a membranoproliferative glomerulonephritis induced by hepatitis C virus.

Mixed cryoglobulins (MCs) are proteins that precipitate from cooled serum, and are composed of a polyclonal immunoglobulin G (IgG) bound to another immunoglobulin that acts as an anti-IgG rheumatoid factor (RF). In type II mixed cryoglobulinemia, the antiglobulin component, usually of the IgM class, is monoclonal; it is polyclonal in type III mixed cryoglobulinemia. The majority of MCs are found in patients with connective tissue diseases, infectious or lymphoproliferative disorders, hepatobiliary diseases, or immunologically mediated glomerular diseases (secondary MCs). The etiology is not clear for 30% of all MCs, and this type of cryoglobulinemia is called "essential." There is a common clinical syndrome in types II and III essential mixed cryoglobulinemia (EMC) characterized by purpura, weakness, and arthralgia. In type II EMC only, in which an IgMk is the monoclonal RF, a membranoproliferative glomerulonephritis (MPGN) occurs with some peculiar morphologic and clinical features; this is termed "cryoglobulinemic GN." Glomerulonephritis can be differentiated from idiopathic MPGN, especially in the acute stage, which is characterized by an acute nephritic syndrome, by the following findings: (1) the presence of large deposits filling the capillary lumen that sometimes are shown to have a characteristic fibrillar or crystalloid structure by electron microscopy; (2) the extent of the exudative component consequent to the frequently massive infiltration of monocytes; (3) a more diffuse and evident thickening of the glomerular basement membrane, which has a double-contoured appearance that is mainly due to the peripheral interposition of monocytes, with less evident mesangial expansion; and (4) possibly some vasculitis in small and medium-sized renal arteries without concomitant features of segmental necrotizing GN or crescentic GN.(ABSTRACT TRUNCATED AT 250 WORDS)

Cryoglobulinemia↗
PubMed1995

Anti-mesangial and anti-endothelial cell antibodies in IgA mesangial nephropathy.

In the present study we verified by solid phase ELISA the presence of antibodies against mesangial and endothelial cell constituents in patients with IgA-GN and Schoenlein-Henoch syndrome (SH). An antigen extract was prepared by sonication of human mesangial cell (MC) monolayers between third and fifth subculture and coated at 20 micrograms/ml on microtiter plates where sera were tested by incubation for 2 h at 37 degrees C and addition of peroxidase-conjugated anti-human IgG or IgA. In comparison to 86 normal controls, increased levels of IgG anti-MC antibodies were found in 15/84 patients with IgA-GN and 4/11 with SH. IgA antibodies were always negative. Furthermore anti-endothelial cell antibodies (AECA) were sought in the same patients and controls by ELISA as previously described. Increased levels of IgG and IgA AECA were found in 25/62 and 24/46 patients respectively. A cross-inhibition test showed that preadsorbment of positive sera for both IgG anti-MC and IgG AECA on endothelial cells in culture resulted in an inhibited binding of IgG to MC. HPLC-ELISA and Western blot analysis of the MC extract showed a significant binding of IgG from ELISA-positive sera to a protein band of 25-50 kD. Similar results were obtained by Western blot analysis of an endothelial cell extract. These results suggest the identity of the antigens recognized by IgG antibodies on endothelial cells and MC in patients with IgA-GN.

Adolescent↗
PubMed1995

Hepatitis C virus genotype in patients with essential mixed cryoglobulinaemia.

We studied 54 patients with essential mixed cryoglobulinaemia (EMC), (23 males, 31 females) mean age 61 years (range 28-77). Forty-one (76%) had type II cryoglobulinaemia and 13 (24%) type III. Antibodies to HCV were detectable by second-generation ELISA in 49 patients (91%) with confirmed or indeterminate RIBA results. HCV RNA was detected by RT PCR using 5' UTR nested primers; HCV genotypes 1a, 1b, 2 and 3a were identified by genotype-specific core-region nested primers. All patients (49) with antibodies to HCV in their serum were HCV-RNA positive; 27 (55.1%) had HCV subtype 1b and 21 (42.8%) type 2. In one patient the HCV genotype could not be determined. The genotype distribution was not different from that found in patients with chronic hepatitis C without cryoglobulinaemia. However, the presence of HCV subtype 1b correlated significantly with signs of chronic hepatitis and presence of peripheral neuropathy. Severity of disease tended to be worse in patients infected with HCV subtype 1b, but this was mainly due to liver disease. HCV genotypes may influence the clinical expression and, in particular, the severity of liver involvement in patients with EMC. Extent and severity of EMC disease in general may also be affected by the different HCV genotypes. These findings may have therapeutical implications, since the different HCV genotypes respond differently to interferon treatment.

Adult↗
PubMed1993

Glomerulonephritis induced by human IgMK-IgG cryoglobulins in mice.

BACKGROUND: Human cryoglobulinemia is sometimes associated with glomerulonephritis (GN) due to deposition of cryoglobulins (cryos). To see whether human cryos can induce GN in mice and to study time-related changes of glomerular lesions and possible factors of cryos' nephritogenicity, we developed an experimental passive model of cryoglobulinemic GN. EXPERIMENTAL DESIGN: Two cryos IgMk-IgG from 2 patients with active GN (OLD and SOR), 2 cryos IgMk-IgG (TAC and GRO) and 1 IgM lambda (CHI) from 3 patients without GN were purified, solubilized at 37 degrees C and injected intravenously into BALB/c mice, 4 mg, twice a day. To study the possible factors of cryo nephritogenicity, we analyzed: (a) the presence, amount, and size of complexed IgMk-IgG at 37 degrees C by fast flow liquid chromatography; (b) the Cc1 or Lc1 subclass of rheumatoid factors; (c) the isoelectric points of the IgMks; (d) The proportion of IgG subclasses in cryos. RESULTS: On day 1 from the beginning of intravenous injections, cryos OLD had induced mesangial deposits of human IgM, human IgG, mouse C3 and mesangial hypercellularity. On day 2, phagocytizing cells were found along with massive endoluminal and subendothelial deposits of IgM, IgG, and C3. On day 6, perivascular infiltrates of mononuclear cells were also seen. Cryos SOR induced a similar but milder form of GN. After administration of purified OLD IgMk, OLD IgG, GRO IgMk or GRO IgG, only OLD IgMk was deposited in the mesangium. Analysis of all the cryos revealed that: the amount of complexed IgMk-IgG at 37 degrees C was always less than 1% of cryos; Cc1 and Lc1 idiotypes were not related to the nephritogenicity of cryos, the isoelectric points of IgMks were 4.5 to 5.5 and IgG1 was the prevalent subclass. CONCLUSIONS: Data demonstrate that human cryos from patients with GN can induce GN in mice that resembles the corresponding human pathology. The affinity of IgMk for glomeruli and the unexpectedly small amounts of IgMk-IgG complexes at 37 degrees C suggest that there is a role of in situ binding in nephritogenicity which is independent of the isoelectric point, rheumatoid factor idiotype, or IgG subclass.

Aged↗
PubMed1988

Polymeric IgA and IgA rheumatoid factor decrease the capacity of serum to solubilize circulating immune complexes in patients with primary IgA nephropathy.

Primary IgA nephropathy (IgAN) is characterized by the presence of immune complexes (IC), high levels of polymeric IgA (pIgA), and IgA rheumatoid factor (RF) in the blood. The impaired capacity of serum to solubilize IC in the presence of normal values of C hemolytic activity as well as high serum levels of C3, C4, and properdin factor B have led us to analyze whether pIgA and IgA RF from patients with IgAN where capable of inhibiting the capacity of normal human serum to solubilize immune precipitates (BSA-anti-BSA) preformed at equivalence. The results showed a significant reduced mean capacity of serum from patients with IgAN to solubilize "in vitro" immune precipitates (p less than 0.001) and significant high mean levels of pIgA (p less than 0.001) and IgA RF (p less than 0.005) in the blood. Increasing amounts of pIgA inhibited solubilization of IC in the fluid phase, and inhibitory activity was also shown by the IgA RF. There were inverse correlations between pIgA and the capacity of serum to solubilize IC (r = -0.36; p less than 0.05), and between IgA RF and the complement-mediated solubilization (r = -0.57; p less than 0.001). It is suggested that pIgA and IgA RF may be responsible for the impaired complement-mediated solubilization of serum and the persistence of insoluble nephritogenic IC in the blood of patients with primary IgAN.

Adolescent↗
PubMed1988

Identification of glomerular immune deposits in cryoglobulinemia glomerulonephritis.

To provide further evidence of the nature of intraglomerular immune deposits in essential mixed cryoglobulinemia (EMC), we used two mouse monoclonal antibodies against cross-reactive idiotypes present on monoclonal rheumatoid factors (MoRFs) from patients with type II-EMC. MoAb Cc1 reacted with 9 of 16 circulating IgMk MoRFs tested, and MOAb Lc1 with four of the remaining. Using indirect immunofluorescence and immunoperoxidase techniques, we could identify the same cross-reactive idiotype of the serum MoRF in the renal biopsy specimens from 11 of 13 patients with EMC glomerulonephritis. Kidney specimens from the three patients, whose MoRF was not recognized by MoAbs Cc1 and Lc1, were negative. Two out of 30 control renal biopsies from patients with other forms of glomerulonephritis were shown to contain idiotype (Cc1 and Lc1) positive material. Both patients had serum polyclonal RF which could account for this finding. In conclusion, our results provide direct evidence that serum cryo-MoRF participate in the formation of glomerular immune deposits and, presumably, in the pathogenesis of renal damage in EMC glomerulonephritis.

Animals↗
PubMed1988

Food antigens, IgA-immune complexes and IgA mesangial nephropathy.

To investigate whether patients with IgA nephropathy have an exaggerated serum IgA response to ubiquitous food antigens we measured serum IgA antibodies to gliadin, ovalbumin, bovine serum albumin (BSA), beta-lactoglobulin and casein in 120 patients and 53 normal controls, using ELISA. No significant differences were observed between patients and controls in serum IgA antibodies against each of the antigens tested. Moreover, no correlation was found between serum IgA antibodies and IgA-immune complexes (IgA CIC). However, nine patients but no controls had an association of two or more IgA antibodies to dietary antigens. Sixty-six per cent of these patients (vs 24% in the remaining population) had IgA CIC, suggesting a possible involvement of these antibodies in the constitution of IgA CIC. Analysis of sera by HPLC revealed that both monomeric and higher molecular forms of IgA antibodies were present, the latter being coincident with the peak of IgA CIC. Preincubation of sera with serial concentrations of the specific antigen decreased significantly IgA CIC, suggesting that in this subgroup of patients IgA antibodies to food antigens (mainly BSA) are involved in the formation of IgA CIC. BSA-containing IgA CIC were in fact demonstrated by ELISA using rabbit IgG anti-BSA coated plates and peroxidase-conjugated anti-human IgA. The role of these CIC in the pathogenesis of IgA nephropathy needs to be further elucidated.

Adolescent↗
PubMed1988

The clinical significance of IgA rheumatoid factor in idiopathic IgA mesangial nephropathy (Berger's disease).

IgA rheumatoid factor, IgA and IgG immune complexes were measured in 119 patients with IgA nephropathy. IgA rheumatoid factor was detected in 62/119 (52%) patients and in 92/265 (35%) serum samples. There was a good correlation (p less than 0.001) between the presence of IgA rheumatoid factor and the presence as well as levels of IgG immune complexes, but not between levels of IgA rheumatoid factor and other clinical or immunological parameters. However, higher levels of serum IgA were found in the subgroup of patients with constantly positive IgA rheumatoid factor. Using aggregated human IgG, we could not demonstrate antiglobulin activity in renal biopsy specimens from 36 patients. These results suggest that IgA rheumatoid factor does not play a primary role in renal damage in IgA nephropathy, but could simply reflect a response to IgG immune complexes in a disorder characterized by abnormalities of IgA production. Nevertheless, the presence of circulating IgA rheumatoid factor in a substantial proportion of patients, especially in those with features of polyclonal IgA activation, provides additional evidence for a general perturbation of IgA metabolism in this disease and could represent an antigen-specific system with which to study regulation of IgA synthesis.

Adolescent↗
PubMed1987

IgA-antigliadin antibodies in IgA mesangial nephropathy (Berger's disease).

Circulating IgA-antigliadin antibodies were detected with enzyme linked immunosorbent assay (ELISA) in four of 121 patients (3%) who had IgA mesangial nephropathy and 14 of 17 children (82%) who had untreated coeliac disease. No positive cases were present in the 54 healthy subjects of the control group. Three patients who had IgA nephropathy and IgA-antigliadin antibodies underwent jejunal biopsy, and two showed mucosal atrophy. In these two patients urinary abnormalities, together with the IgA-antigliadin antibodies, disappeared completely after three months and five months, respectively, of following a gluten free diet. Circulating IgA immune complexes were found in most patients who had coeliac disease and Berger's disease associated with IgA-antigliadin antibodies, suggesting overactivity of the B cells producing IgA in both conditions. By contrast, a circulating IgA rheumatoid factor was detectable in three of the four patients who had IgA nephropathy and asymptomatic coeliac disease but was always absent in children who had coeliac disease but did not show signs of renal disease. These results suggest that a more complex abnormality in the IgA immune response is necessary for renal disease to become manifest in patients who have gluten enteropathy.

Adolescent↗
PubMed1986

Polymeric IgA rheumatoid factor in idiopathic IgA mesangial nephropathy (Berger's disease).

A specific and sensitive enzyme-linked immunosorbent assay (ELISA) was used to detect IgA rheumatoid factor (RF) in sera from 88 patients with IgA nephropathy (IgA GN), a disease characterized by abnormalities of IgA production. Significantly higher levels of IgA antiglobulins were demonstrated in IgA GN patients than in normal healthy controls and patients with other forms of chronic primary glomerulonephritis (mean +/- SEM 28.4 +/- 6.6 vs 6.0 +/- 0.4 and 8.3 +/- 1.2 micrograms/ml respectively; p less than 0.002). Interestingly, in contrast to rheumatoid arthritis, IgA RF activity was not associated with IgM antiglobulins. Analysis of sera fractionated by gel chromatography at acid pH revealed that anti-IgG activity resided predominantly in the polymeric fractions of IgA as confirmed by the ability to bind "free" secretory component. Several findings in patients with IgA GN suggest that the IgA deposited in the glomeruli is polymeric, and levels of circulating macromolecular IgA are increased. Our findings confirm a general perturbation of IgA metabolism in this disease. Although the polymeric nature of the IgA RF is suggestive of a mucosal origin, additional evidence is needed to confirm this hypothesis.

Adolescent↗
PubMed1986

Spontaneous and pokeweed mitogen induced production of rheumatoid factor and immunoglobulins in type II essential mixed cryoglobulinaemia.

In order to evaluate functional lymphocyte defects in type II essential mixed cryoglobulinaemia (EMC) in vitro production of immunoglobulins (Ig) and rheumatoid factor (RF) has been studied in basal conditions and under pokeweed mitogen (PWM) stimulation in 15 patients and in 17 control subjects. The major finding was a significantly high basal and inducible production of RF by EMC lymphocytes as compared with the RF production in controls, while synthesis of polyclonal Ig was unaffected. A good correlation existed between in vitro production and serum levels of RF. Peripheral blood SmIg+ and Ia+ cells were also significantly increased. The possibility that EMC shares some pathogenetic mechanism with rheumatoid arthritis on the one hand and with lymphoproliferative diseases on the other is considered.

Adult↗
PubMed1986

In vitro synthesis of IgM rheumatoid factor by lymphocytes from patients with essential mixed cryoglobulinemia.

Peripheral blood mononuclear cells (PBMC) from patients with Essential Mixed Cryoglobulinemia (EMC) were studied for their ability to synthesize polyclonal IgM and rheumatoid factor (RF) IgM in vitro. Our results indicate: that EMC-PBMC produce smaller amounts of polyclonal IgM but higher quantities of IgM-RF than normal PBMC after pokeweed mitogen (PWM) or Staphylococcus aureus activation, so that the IgM-RF to total IgM ratio is significantly greater in EMC than in normal cultures; that enriched EMC-B lymphocytes display a significantly higher spontaneous synthesis of IgM-RF than normal B lymphocytes and that the IgM-RF B cell clones are receptive to T cell regulation. Taken together these findings suggest an expansion of B cell clones committed to IgM RF production and the presence in peripheral blood of differentiated B lymphocytes capable of secreting IgM-RF in EMC.

Adult↗