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Biomedical subjects

E Mirapeix

Publications and source records attributed to E Mirapeix.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Systemic lupus erythematosus: a clinical and immunological study of 300 patients].

BACKGROUND: The aims of the present study were to analyze the clinical and immunologic characteristics of a wide group of patients with systemic lupus erythematosus (SLE) and define homogeneous subgroups with their own characteristics. METHODS: A prospective study of 300 patients diagnosed of SLE were studied. These patients were subdivided according to sex, age at the onset of the disease and immunologic profile. The statistical study was carried out by the chi (2), Fisher, Student's t and Mann-Whitney U tests. RESULTS: The series was made up of 266 (89%) females and 34 (11%) males. The mean age at onset of the disease was 31.8 +/- 14.6 years. In 48 (16%) patients the first manifestations appeared after the age of 50. Males were shown to present a lower prevalence of arthritis (59% vs 82% in woman, p < 0.005) and malar rash (29% vs 50%, p < 0.05), but had more cutaneous discoid lesions (18% vs 3% p < 0.001). In patients in whom the disease appeared after the age of 50 a lower prevalence of arthritis was presented (67% vs 82% in patients of less than 50 years of age, p < 0.005), malar rash (23% vs 53%, p < 0.001) and nephropathy (21% vs 41%, p < 0.05), but had greater myositis (17% vs 6%, p < 0.01). The absence of antinuclear antibodies (ANA) and the presence of anti-ds DNA and anti-ENA antibodies were associated with differences in the prevalence of different clinical manifestations. CONCLUSIONS: Sex, age and immunologic pattern in systemic lupus erythematosus permit the definition of homogeneous subgroups with their own characteristics: a) males present a lower prevalence of arthritis and malar rash, but a greater prevalence of cutaneous discoid lesions; b) patients over the age of 50 develop arthritis, malar rash and nephropathy with a lower prevalence but have a greater prevalence of myositis; c) patients without antinuclear antibodies and those with anti-ds DNA and anti-ENA antibodies present differences in the prevalences of different clinical manifestations.

Adolescent↗
PubMed1993

Anti-neutrophil cytoplasmic autoantibodies (ANCA): antigenic specificities and clinical associations.

We have conducted a prospective study of 372 patients with well-defined forms of systemic vasculitis and connective tissue diseases to determine the prevalence, the antigenic specificities and the clinical associations of ANCA in such cases. These antibodies were detected by indirect immunofluorescence on ethanol-fixed neutrophils and also by enzyme-linked immunosorbent assay using myeloperoxidase (MPO) as a substrate. In our study, ANCA with a cytoplasmic immunostaining pattern were mainly found in patients with biopsy-proven Wegener's granulomatosis with or without renal involvement and pulmonary hemorrhage. Furthermore, MPO-ANCA strongly correlated with necrotizing glomerular and alveolar capillaritis, mostly in patients having a well-established diagnosis of polyarteritis nodosa.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1993

Anti-granulocyte perinuclear antibodies but not anti-neutrophil cytoplasmic antibodies (ANCA) in rheumatoid arthritis.

We studied 45 patients with rheumatoid arthritis for the presence of ANCA. These antibodies were determined by indirect immunofluorescence (IIF) and by enzyme-linked immunosorbent assays (ELISAs) using as a substrate purified myeloperoxidase and purified extract of azurophilic granules. By IIF, we found a characteristic perinuclear immunostaining pattern in 21 cases (47%). However, no patient had a positive result by the two ELISAs performed. Patients with a positive IIF result had significantly higher levels of anti-nuclear and anti-ds DNA antibodies than those with a negative IIF result. Therefore, these antibodies must correspond to the previously reported as granulocyte specific antinuclear antibodies (GS-ANA).

Adult↗
PubMed1993

Synthesis of beta 2-microglobulin in lymphocyte culture: role of hemodialysis, dialysis membranes, dialysis-amyloidosis, and lymphokines.

Dialysis-amyloidosis (A beta 2M) is a recently recognized chronic complication in long-term dialysis patients, apparently effecting 5% to 10% of all dialysis patients. In 1985, Gejyo et al (Biochem Biophys Res Commun 129:701-706, 1085) and Shirahama et al (Lab Invest 53:705-709, 1985) identified beta 2-microglobulin (beta 2-M) as the major constituent protein of this unique type of systemic amyloidosis. The specific pathogenesis of A beta 2M remains unknown, although beta 2-M has been clearly identified as playing a central role as the amyloidogenic protein. To investigate the factors responsible for in vitro beta 2-M synthesis, we studied beta 2-M production by lymphocyte cultures obtained from dialysis patients and grown under a variety of different conditions, and compared the results to a control group of subjects with normal renal function. We could not demonstrate any stimulatory influence on beta 2-M synthesis by the hemodialysis treatment, the type of dialysis membrane used, or the clinical presence of A beta 2M. Rather, dialysis membranes, sterilized with ethylene oxide or gamma rays, added to the lymphocyte cultures exerted a strong dose-dependent inhibitory effect on beta 2-M synthesis. From the results of this study, we conclude that peripheral blood lymphocytes in uremic patients synthesize beta 2-M normally and that the direct interaction between circulating lymphocytes and the dialysis membrane that occurs during hemodialysis does not seem to contribute directly to beta 2-M synthesis.

Adult↗
PubMed1992

Anti-myeloperoxidase autoantibodies in patients with necrotizing glomerular and alveolar capillaritis.

We conducted a prospective study of 651 Mediterranean patients from Catalonia (Spain) with well-defined forms of systemic vasculitis, connective tissue diseases, and renal and pulmonary disorders to determine the prevalence and clinical value of antineutrophil cytoplasmic autoantibodies (ANCA) with myeloperoxidase (MPO) specificity (MPO-ANCA). ANCA were first tested by indirect immunofluorescence on ethanol-fixed neutrophils. When a positive result was obtained, then MPO-ANCA were identified by performing the immunofluorescence assay again on neutrophils from a voluntary donor known to have a complete and selective deficiency of MPO. This disorder was detected by automated flow cytochemistry with the Technicon system and was further verified by cytochemical and biochemical studies. We detected MPO-ANCA in 61 of 70 (87%) patients with a perinuclear pattern (p-ANCA), but in none of 25 with a cytoplasmic pattern (c-ANCA). These results were corroborated by enzyme-linked immunosorbent assay (ELISA) using human purified MPO as a substrate. On immunofluorescence microscopy, all patients with MPO-ANCA were found to have a typical and restrictive immunostaining pattern. In our study, while c-ANCA were mainly found in patients with biopsy-proven Wegener's granulomatosis, MPO-ANCA identified those with idiopathic and polyarteritis nodosa-associated necrotizing and crescentic glomerulonephritis. In addition, pulmonary hemorrhage with necrotizing alveolar capillaritis as the main morphologic substrate occurred frequently among patients with MPO-ANCA, including three affected by polyarteritis nodosa and three who had pulmonary hemorrhage as the only clinical finding. On the other hand, these antibodies could be also detected in 30% of patients with a proven diagnosis of anti-glomerular basement membrane (GBM) disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1992

Antimyeloperoxidase autoantibody-associated necrotizing alveolar capillaritis.

In this report, we describe 3 patients who had pauci-immune necrotizing alveolar capillaritis-related pulmonary hemorrhage and who never developed other organic involvement, as revealed by clinical and laboratory data and also by autopsy examination in 1 case. Serum samples from these patients disclosed antimyeloperoxidase autoantibodies with initial immunofluorescence titers ranging from 1:1,600 to 1:3,200. Rapid institution of immunosuppressive therapy, as well as plasma exchange, led to prompt clinical improvement in 2 patients who were receiving mechanical ventilation support. We conclude that antimyeloperoxidase autoantibodies become new clues to support an underlying alveolar capillary vasculitis in patients with idiopathic isolated pulmonary hemorrhage, thus facilitating therapeutic decisions in this life-threatening condition.

Adult↗
PubMed1992

In vitro spontaneous synthesis of beta 2-microglobulin amyloid fibrils in peripheral blood mononuclear cell culture.

beta 2-microglobulin-related amyloidosis (A beta 2M), in long-term dialysis patients, is a new and frequent complication for which the pathogenesis remains unknown. The authors documented, by light and high resolution electron microscopy, the spontaneous polymerization of beta 2-microglobulin to amyloid fibrils in mononuclear cell culture supernatants from dialysis patients. These data provide significant information about the pathogenesis of dialysis-amyloidosis, revealing an unusual and different fibrillogenic mechanism for beta 2-microglobulin and dialysis-amyloidosis than for other forms of amyloidosis. beta 2-microglobulin does not appear to require a proteolytic process before polymerization into amyloid fibrils and deposits. This study represents the first cell culture system in which beta 2-microglobulin amyloid fibrils have been spontaneously created.

Amyloid↗
PubMed1991

[Neutrophil anticytoplasmic antibodies in a patient with Wegener's granulomatosis: therapeutic implications of its detection and relation to clinical activity].

The case of a patient with a multisystemic process characterized by polyarthritis, hemoptysis, leucocytoclastic vasculitis, renal failure and ulcerated lesions in the palate and nasal bone is reported. The existence of antineutrophil anticytoplasmic antibodies (cytoplasmatic pattern) was proven by indirect immunofluorescence with an initial serum titration of 1:1.600. Detection of these antibodies permitted the establishment of immunosuppressive treatment when the clinical situation of the patient was considered serious (pulmonary hemorrhage with progressive diminution of the hematocrit). Four days after the initiation of treatment the histopathological results of the palate and nasal mucous biopsies were received and were compatible with Wegener's granulomatosis. Serial determination of the titers of these antibodies demonstrated a close correlation with the clinical biological activity of the process. Indeed, 3 days after initiation of the immunosuppressive treatment the concentration of the same had reduced to half, something which has not been previously reported. It is concluded that high specificity and sensitivity of antineutrophil anticytoplasmic antibodies with a cytoplasmatic pattern for Wegener's granulomatosis may contribute to the improvement, not only of the diagnosis but also to the prognosis, in permitting the immediate initiation of therapeutic measures when the clinical situation of the patient thus requires.

Adult↗
PubMed1991

Prognostic implication of anti-neutrophil cytoplasmic autoantibodies with myeloperoxidase specificity in anti-glomerular basement membrane disease.

Anti-neutrophil cytoplasmic autoantibodies (ANCA) were detected in 12 out of 37 (32%) serum samples from patients with anti-glomerular basement membrane (GMB) disease by an indirect immunofluorescence assay. In 11 cases, ANCA were directed against myeloperoxidase, as revealed employing neutrophils devoid of this enzyme as the test substrate. Patients having both ANCA and anti-GBM antibodies (AGBMA) were considerably older (mean age 59 years) than patients with AGBMA alone (mean age 33 years). In addition, patients with both antibodies had some clinical and pathologic data that suggested an associated systemic vasculitis. This was supported by the fact that among these patients, those with highest ANCA titres recovered renal function despite being initially on hemodialysis, as opposed to those with lowest ANCA titres or AGBMA alone. In patients with both antibodies, there was an inverse relationship between AGBMA and ANCA values (p = 0.02). Moreover, the mean AGBMA level tended to be higher for patients with AGBMA alone than for those with both ANCA and AGBMA. These results suggest that, at least in some cases, there may be a contribution of an ANCA-related mechanism in the pathogenesis of anti-GBM disease. Although the exact role of ANCA in this and other diseases remains to be clarified, there is important clinical evidence that in anti-GBM disease ANCA may represent a serologic marker of good prognosis identifying a subset of patients who may recover renal function.

Adolescent↗
PubMed1989

Cellular immunity analysis using monoclonal antibodies in human glomerulonephritis.

Monoclonal antibodies against class II antigens of the human major histocompatibility complex (MHC) (Edu 1), von Willebrand factor-related antigen marker of endothelial cell, T cells (Cris 1), helper/inducer T cells (T4) and cytotoxic/suppressor T cells (T8) by indirect immunofluorescence, and stain for nonspecific esterase characterizing monocytes-macrophages (Mo-Ma) were applied in 64 renal biopsies--54 glomerulonephritis (GN), 10 non-GN- and in 14 normal kidneys. Class II antigens were expressed on the endothelium of renal microvasculature in all specimens. Intraglomerular T cells and Mo-Ma were only present in GN. Mo-Ma appeared associated with endo- and extracapillary proliferation (Xc2 = 4.68; p less than 0.05), C3 (X2 = 4.21; p less than 0.05), and fibrinogen (X2 = 3.84; p less than 0.05) deposition; and those were most numerous in biopsies with intraglomerular T cells. Interstitial MHC-class II+ cells (Xc2 = 5.5; p less than 0.02), T cells (F = 3.37; p less than 0.005) and Mo-Ma (F = 2.45; p less than 0.05) were significantly higher in GN with endo- or extracapillary proliferation than in the remaining. In GN, correlations were seen between T cells and MHC-class II+ cells (r = 0.63; p less than 0.001), and Mo-Ma (r = 0.38; p less than 0.02), infiltrating the interstitium. Our results suggest that both humoral and cellular immunity contribute to macrophage glomerular infiltration in the human GN. Mononuclear cells, and no intrinsic renal cells, would be implicated in the cellular immune interactions in situ.

Adolescent↗
PubMed1986

Cellular infiltrate in renal graft rejection: T lymphocyte subsets detected by monoclonal antibodies.

We have examined the interstitial cellular infiltrate using monoclonal antibodies against T cells (Cris 1), helper/inducer T cells (OKT4) and suppressor/cytotoxic T cells (OKT8) by indirect immunofluorescence in renal biopsies taken from 14 transplanted patients during clinical episodes suggestive of acute (n = 9), chronic (n = 2) and no rejection (n = 3). Infiltrating T cells and T cell subsets were found to be significantly increased during all types of rejection (n = 11) as compared to no rejection (n = 3). Two types of biopsies could be distinguished according to the predominance of T cell subsets. In some biopsies (n = 6), OKT8+ cells were significantly more numerous that OKT4+ cells. In the remaining biopsies (n = 5), OKT4+ cells were more common that OKT8+ cells, the OKT4/OKT8 ratio being significantly higher. No association was observed between HLA mismatch and predominating T cell subset, neither for type nor outcome of graft rejection. Our results suggest that the OKT4+ cells may play a more important role than previously reported in renal graft rejection.

Adolescent↗
PubMed1985

Defective radioresistant suppressor cell activity in hemodialysis patients.

The immunologic alterations in patients on hemodialysis are only partially understood. We studied the Concanavalin A (Con A) induced suppressor cell activity of irradiated and nonirradiated cells in a mixed lymphocyte culture. Peripheral blood lymphocytes from 18 normal individuals and 14 patients on regular hemodialysis were incubated with two different concentrations of Con A (10 micrograms and 40 micrograms of Con A/million cells). Irradiated and nonirradiated cells were then tested for their capacity to suppress a standard MLC. The proliferative response to phytohemagglutinin, pokeweed mitogen and Con A was also determined. Suppressor cell activity of nonirradiated cells in hemodialysis patients was similar to that of controls, at both concentrations of Con A, while irradiated cells of hemodialysis patients showed a suppressor cell activity significantly lower than that of the controls, at a Con A concentration of 40 micrograms/10(6) cells (25.78 +/- 18.86% vs. 46.05 +/- 9.79%, p less than 0.001). The proliferative response of lymphocytes from hemodialysis patients to the three mitogens, did not show any difference when compared with normal controls. The normal proliferative response of lymphocytes from hemodialysis patients to mitogens and the normal suppressor cell activity of nonirradiated cells, suggest a normal T cell function. The abnormal suppressor cell activity in irradiated cells indicate that the radioresistant population has a functional defect. The cell responsible for this suppressor defect probably belongs to the monocyte/macrophage population because of its relative radioresistance.

Adult↗