[Immunocytochemical analysis of the inflammatory infiltrate in inclusion body myositis and other neuromuscular disorders with rimmed vacuoles]. / Análise imunocitoquímica do infiltrado inflamatório na miosite com corpos de inclusão citoplasmática e em outras doenças neuromusculares com vacúolos marginados.

Among 1400 muscle biopsies, we found 16 cases with rimmed vacuoles whose diagnosis were sporadic inclusion body myositis (IBM) (4 cases), juvenile spinal muscular atrophy (6 cases), distal myopathies (3 cases), limb-girdle muscular dystrophy (2 cases), and peripheral neuropathy (1 case). Monoclonal antibodies reactive for T lymphocytes and subsets, B lymphocytes, macrophages, natural killer cells, immunoglobulins, and complement were used to analyze the inflammatory infiltrate. The analysis was quantitative and according to the site of accumulation (interstitial, endomysial, and perivascular). The immunocytochemical analysis showed CD8+ lymphocytes in the interstitial in most cases, occasionally inside of muscle fibers, and rarely in the perivascular region. The IBM cases had an increased number of CD8+ lymphocytes comparing with the other diseases. CD8+/CD4+ ratio was increased in IBM compared with the other diseases. Macrophages were frequent in IBM, distal myopathy, and one case of limb-girdle muscular dystrophy. Natural killer cells were frequent at interstitial.

Inhibition of the classical and alternative pathways of the human complement system by glycosaminoglycan polysulfate.

Glycosaminoglycan polysulfate (GAGPS) concentration-dependently inhibited the activation of the classical and alternative pathways of the human complement system in vitro. Concentrations of > or = 0.2 mg/ml GAGPS prevented the cleavage of C4 by human aggregated gammaglobulin as evidence of inhibition of the classical pathway. At concentrations of > or = 0.15 mg/ml a concentration-dependent inhibition of the cleavage of factor B, the major step in the activation of the alternative pathway, was seen in the presence of inulin. Concentrations < 0.05 mg/ml did not have a measurable effect on either pathway. The lysis of sheep red blood cells, which is mediated largely by the classical pathway, was significantly inhibited at 3.84 mg/ml GAGPS, with a mean inhibition of 45.7%. On the other hand, the same concentration of GAGPS almost completely inhibited the lysis of rabbit red blood cells, which is mediated by the alternative pathway of complement. Our results suggest that the inhibition by GAGPS is an early event in the activation of complement, occurring before the assembly of the C3 convertases of either pathway. The possible use of this drug in acute life-threatening situations where complement is thought to have a pathogenic role is discussed.

Classical and alternative complement pathway activation in paracoccidioidomycosis.

The following study presents evidence of complement activation in paracoccidioidomycosis (PCM). Twenty-eight untreated patients were studied from endemic areas of Parana in southern Brazil. The activation of the classical pathway, evaluated by the C4d/C4 ratio, was significantly elevated in the patients compared to the control population (p < 0.005). Six patients were examined prospectively with the C4d/C4 assay during treatment and they showed a decrease in this ratio associated with clinical improvement. The activation of the alternative pathway was determined by rocket immunoelectrophoresis of fragment Ba. These levels were also significantly higher in the patient group in comparison to the controls (p < 0.0005). The prospective study also showed a significant variation in the Ba levels associated with clinical improvement (p < 0.01). Furthermore, the levels of C3, C4, CH50 and anti-Paracoccidioides brasiliensis IgG were determined in all patients. The anti-P. brasiliensis IgG levels showed a weak positive correlation with the C4d/C4 ratio (r[S] = 0.45; p < 0.03). The C3, C4 and CH50 levels did not show significant variations from the normal ranges. Our results suggest the involvement of both complement pathways, classical and alternative, in PCM and their association with disease activity.

Genetic variability of the MHC class III complement proteins C2, BF, C4A and C4B in southern Brazil.

We describe here the genetic variability of C2, C4 and BF in 225 healthy adult individuals from southern Brazil, including 172 Caucasoids, 47 Mulattos, 3 Blacks and 1 Amerindian. C2 gene frequencies were in accordance with those described for other populations, and two rare variants were observed. The BF allotype frequencies were slightly different between the Caucasoids and Mulattos, the latter having a higher BF*F frequency. A new BF*S variant, identified as S05 was observed in a Caucasoid individual. The frequencies of C4A and C4B in the Caucasoids were similar to other reported Caucasoid populations; a decrease of the silent allele B*Q0, and several rare variants were observed. A higher C4A*3 frequency and a remarkable decrease of C4A*Q0 were observed in the Mulattos. In addition, several C4 heteroduplications and aberrant allotypes were observed. Considering the high genetic variability found in a limited number of individuals, one may conclude that due to genetic admixture much heterogeneity might be expected for the MHC class III region in different Brazilian populations.

Evaluation of complement activation in premature newborn infants with hyaline membrane disease.

Fifteen premature newborns with hyaline membrane disease causing acute respiratory distress were evaluated for complement activation. A high intrapulmonary right-to-left shunt and marked arterial-alveolar oxygen difference indicated the severity of the respiratory failure. Twenty preterm healthy infants served as controls. Total haemolytic activity, plasma concentrations of complement components and regulatory proteins (C3, C4, C1-inhibitor, factors H and I) as well as activation products (C3a, C3dg, C1rsC1-inhibitor, C3b(Bb)P) gave no evidence of significant complement activation. Functional activity of the ubiquitous regulatory protein C1-inhibitor was significantly reduced without impact on classical pathway activation. These data suggest that, in contrast to the adult form of respiratory distress syndrome, the low-pressure pulmonary oedema characterising hyaline membrane disease is not mediated by activation of the complement system.

Complement activation in Brazilian pemphigus foliaceus.

Brazilian pemphigus foliaceus is an autoimmune blistering skin disease of man that has a very high incidence in a confined geographical distribution. Rocket immunoelectrophoresis of plasma showed increased levels of complement fragments, C4d and Ba, indicating activation of complement through both the classical and the alternative pathways. Less sensitive methods such as CH50, total C3 and C4 did not demonstrate this activation, and immune complex measurements were within normal range. While complement may not be absolutely necessary for the development of skin lesions, our longitudinal studies show that activation of complement is at its highest during the most active phase of the disease.

Complement and antibody deposition in Brazilian pemphigus foliaceus and correlation of disease activity with circulating antibodies.

Brazilian pemphigus foliaceus is a blistering skin disease endemic to central and southern areas of South America. In this study of skin biopsy specimens from 14 patients we present evidence that complement and immunoglobulins were present by direct immunofluorescence in the epidermal intercellular spaces in all patients. Eight of 14 patients had granular deposits of C3 in the basement membrane zone. By indirect immunofluorescence, serum samples from all 19 patients tested demonstrated the presence of circulating IgG autoantibody. Autoantibodies deposited in the intercellular spaces in titers ranging from 1:10 to more than 1:1280, and the titers drastically decreased during treatment. This is the first study to demonstrate complement deposition in the skin in Brazilian pemphigus foliaceus.

Clinical, immunological and epidemiological aspects of strongyloidiasis in an endemic area of Brazil.

Eighty-eight residents of Curitiba, Brazil, with parasitologically proven Strongyloides stercoralis infection were assessed clinically and evaluated for their specific and non-specific responses to the parasite. A control group of 73 patients with other intestinal parasites, but with negative stools for S. stercoralis were also evaluated. Abdominal symptoms and/or weight loss were present in 24% of the patients with strongyloidiasis and in 25% of the patients with other parasites only. Elevated peripheral eosinophilia (greater than 5%) was present in 68% of the patients with strongyloidiasis (mean = 10.6%) and in 73% of the individuals with other parasites only (mean = 8.8%). Total serum IgE were elevated (greater than IU/ml) in 84% of the patients with strongyloidiasis (mean = 2872 IU/ml), and in 79% of the patients with other parasites only. Over 90% of the patients with proven strongyloidiasis had detectable levels of parasite specific IgG and IgE antibodies, as detected by the ELISA and the RAST, respectively. These antibodies were present in 23% of the individuals in whom fecal examinations had failed to reveal S. stercoralis. We conclude that in an endemic area, gastrointestinal manifestations and non-specific indicators of parasitic infections, such as elevated peripheral eosinophilia and total IgE, are not useful indexes of the presence of strongyloidiasis. Immunoserologic tests, such as the ELISA and the RAST may represent sensitive and specific tools for the screening of candidates for immunosuppression and for gathering needed epidemiological information about this increasingly important opportunistic nematode.

Specific IgE responses in human strongyloidiasis.

IgE antibodies directed against Strongyloides stercoralis larval antigens were measured by a newly developed radioallergosorbant test (RAST). One hundred and fifty-two samples of sera from patients with parasitologically proven S. stercoralis infection were tested. One hundred and thirty-six of these (89.5%) were positive for parasite-specific IgE. Of 50 presumably non-infected North American adult control sera, 49 (98%) were negative. All sera from patients with other parasites were negative, except for two sera from subjects with Ascaris lumbricoides, who exhibited low positivity. Of eight sera from non-infected patients with allergies and high IgE levels, one was weakly positive, and the other seven were negative. Considerable individual variability was present in the levels of specific IgE as measured by the RAST in the infected patients. Significant differences were also found among the three major demographic groups which composed our study population, with Asians having higher values than Latin Americans and the latter having higher values than North American patients. We conclude that the majority of patients with strongyloidiasis develop IgE antibodies directed against antigens from filariform larvae, the invasive form of the parasite. While the functional significance of this response remains to be defined, the RAST for IgE may be a useful adjunct in the immunological evaluation of these patients.