(18)F-Fluorodeoxyglucose positron emission tomography and serum cytokines and matrix metalloproteinases in the assessment of disease activity in Takayasu's arteritis.

OBJECTIVE: To evaluate (18)F-fluorodeoxyglucose ((18)F-FDG) uptake on positron emission tomography-computed tomography (PET-CT) and serum levels of different cytokines and matrix metalloproteinases (MMPs) in patients with Takayasu arteritis (TA) and associations with disease activity. METHODS: Serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-2, IL-6, IL-8, IL-12, IL-18, MMP-3 and MMP-9 were measured in 36 TA patients and 36 controls. Maximum standard uptake value (SUVmax) of (18)F-FDG in arterial walls was determined by PET-CT scans. TA patients were classified as active disease, inactive disease and possible active disease. RESULTS: Serum IL-6 and MMP-3 levels were higher in TA patients than in controls (p<0.001). Serum IL-6 was higher in patients with active disease and in patients with possible active disease than in inactive disease (p<0.0001). Patients with active disease had higher serum TNFα levels than patients with inactive disease (p=0.049) while patients with possible active disease presented higher IL-18 levels than patients with inactive disease (p=0.046). Patients with active disease had higher SUVmax values than those with inactive disease (p=0.042). By receiver operating characteristic (ROC) curve SUVmax was predictive of active disease in TA and values ≥1.3 were associated with disease activity (p=0.039). Serum TNF-α levels were higher in patients with SUVmax≥1.3 than <1.3 (p=0.045) and controls (p=0.012). Serum IL-6 levels were higher in patients with SUVmax≥1.3 than in controls (p<0.001). No differences regarding other biomarkers were found between TA patients and controls. CONCLUSIONS: Higher serum IL-6 and TNFα levels as well as higher (18)F-FDG uptake in arterial wall are associated with active TA.

18F-Fluorodeoxyglucose positron emission tomography and serum cytokines and matrix metalloproteinases in the assessment of disease activity in Takayasu's arteritis / Tomografia por emissão de pósitrons com 18F-fluordesoxiglicose e citocinas séricas e metaloproteinases da matriz na avaliação da atividade da doença na arterite de Takayasu

ABSTRACT Objective: To evaluate 18F-fluorodeoxyglucose (18F-FDG) uptake on positron emission tomography–computed tomography (PET–CT) and serum levels of different cytokines and matrix metalloproteinases (MMPs) in patients with Takayasu arteritis (TA) and associations with disease activity. Methods: Serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-2, IL-6, IL-8, IL-12, IL-18, MMP-3 and MMP-9 were measured in 36 TA patients and 36 controls. Maximum standard uptake value (SUVmax) of 18F-FDG in arterial walls was determined by PET–CT scans. TA patients were classified as active disease, inactive disease and possible active disease. Results: Serum IL-6 and MMP-3 levels were higher in TA patients than in controls (p < 0.001). Serum IL-6 was higher in patients with active disease and in patients with possible active disease than in inactive disease (p < 0.0001). Patients with active disease had higher serum TNFα levels than patients with inactive disease (p = 0.049) while patients with possible active disease presented higher IL-18 levels than patients with inactive disease (p = 0.046). Patients with active disease had higher SUVmax values than those with inactive disease (p = 0.042). By receiver operating characteristic (ROC) curve SUVmax was predictive of active disease in TA and values ≥1.3 were associated with disease activity (p = 0.039). Serum TNF-α levels were higher in patients with SUVmax ≥ 1.3 than <1.3 (p = 0.045) and controls (p = 0.012). Serum IL-6 levels were higher in patients with SUVmax ≥ 1.3 than in controls (p < 0.001). No differences regarding other biomarkers were found between TA patients and controls. Conclusions: Higher serum IL-6 and TNFα levels as well as higher 18F-FDG uptake in arterial wall are associated with active TA.

RESUMO Objetivo: Avaliar a captação de 18F-fluordesoxiglicose (FDG) na tomografia por emissão de pósitrons – tomografia computadorizada (PET-CT) – e os níveis séricos de diferentes citocinas e da metaloproteinases da matriz (MMP) em pacientes com arterite de Takayasu (AT) e associações com a atividade da doença. Métodos: Foram mensurados os níveis séricos do fator de necrose tumoral-α (TNF-α), interleucina (IL)-2, IL-6, IL-8, IL-12, IL-18, MMP-3 e MMP-9 em 36 pacientes com AT e 36 controles. O valor padronizado de captação máximo (SUVmax) de 18F-FDG nas paredes arteriais foi determinado por exames de PET-CT. Os pacientes com AT foram classificados como doença ativa, doença inativa e possível doença ativa. Resultados: Os níveis séricos de IL-6 e MMP-3 foram mais altos em pacientes com AT do que nos controles (p < 0,001). Os níveis séricos de IL-6 foram mais elevados em pacientes com doença ativa e em pacientes com possível doença ativa do que naqueles com doença inativa (p < 0,0001). Os pacientes com doença ativa apresentaram níveis séricos mais elevados de TNF-α do que os pacientes com doença inativa (p = 0,049), enquanto os indivíduos com possível doença ativa apresentaram maiores níveis séricos de IL-18 do que os pacientes com doença inativa (p = 0,046). Aqueles com doença ativa apresentaram maiores valores de SUVmax do que aqueles com doença inativa (p = 0,042). De acordo com a curva ROC, o SUVmax foi capaz de predizer a doença ativa na AT e valores ≥ 1,3 estavam associados à atividade da doença (p = 0,039). Os níveis séricos de TNF-α foram maiores em pacientes com SUVmax ≥ 1,3 do que naqueles com valor < 1,3 (p = 0,045) e controles (p = 0,012). Os níveis séricos de IL-6 foram mais elevados em pacientes com SUVmax ≥ 1,3 do que nos controles (p < 0,001). Não foram encontradas diferenças em relação a outros biomarcadores entre pacientes com AT e controles. Conclusões: Níveis séricos elevados de IL-6 e TNF-α, bem como uma maior captação arterial de 18F-FDG, estão associados à AT ativa.

High frequency of immunodeficiency-like states in systemic lupus erythematosus: a cross-sectional study in 300 consecutive patients.

OBJECTIVE: To determine the frequency of immunodeficiency-like states in SLE and related clinical features. METHODS: Three hundred and fifteen SLE patients and 301 controls were evaluated for C4A and C4B gene copy number, immunoglobulin isotypes, IgG subclasses, total haemolytic complement (CH50), C2, C3 and neutrophil oxidative burst. C2 and C3 genes were sequenced in cases of low C2 or C3 levels. Those presenting abnormal CH50 with normal C2 and C3 underwent C1q-C9 determination. Patients with active SLE and abnormal results were re-tested after the flare or were excluded if no remission was attained. Fifteen patients were excluded on this basis. Persistent abnormal results characterized an immunodeficiency-like state. RESULTS: A significantly higher percentage of SLE patients presented an immunodeficiency-like state compared with controls (28.7% vs 3.3%; P < 0.001), especially low immunoglobulin serum levels. Rigorous testing confirmed only two cases of C2 deficiency carriers among the SLE patients. There were significantly more SLE patients with less than two C4A copies compared with controls. SLE patients had higher frequency of low IgG2, IgG3, IgG4 and IgM levels compared with controls. Patients with low IgG3 or IgG4 presented higher frequency of lupus nephropathy. Patients with low IgM had longer disease duration, older age at SLE onset and lower frequency of oral ulcers. CONCLUSION: An immunodeficiency-like state is present in a sizable fraction of SLE patients. Further studies are warranted to determine the impact of these immunodeficiency states and whether they are a primary condition or are secondary to confounding factors, including SLE itself.

Genetic analysis of enteropathogenic Escherichia coli (EPEC) adherence factor (EAF) plasmid reveals a new deletion within the EAF probe sequence among O119 typical EPEC strains.

BACKGROUND: Enteropathogenic Escherichia coli (EPEC) are classified into typical and atypical strains based on the presence of the E. coli adherence factor (EAF) plasmid. The EAF plasmid contains the bfp (bundle-forming pilus) operon and the perABC (plasmid encoded regulator) gene cluster. A 1-kb cryptic region of EAF plasmid has been widely used as a genetic probe for EPEC detection. However, some EPEC strains may harbor an EAF plasmid lacking the EAF probe sequence, which makes the differentiation between typical and atypical a complex task. In this study, we report the genetic analysis of the EAF plasmid-encoded genes in a collection of EPEC clinical isolates. METHODS: A total of 222 EPEC clinical isolates, which were previously classified as typical (n=70) or atypical (n=152) by EAF probe reactivity, were screened for the presence of different EAF sequences by PCR and DNA hybridization. RESULTS: All typical strains possessed intact bfpA and perA genes, and most of them were positive in the PCR for EAF probe sequence. However, a subset of 30 typical strains, 22 of which belonged to O119 serogroup, presented a 1652 pb deletion in the region between 1093-bp downstream perC and 616-bp of the EAF fragment. The bfpA, bfpG, and per genes were found in all typical strains. In addition, 32 (21%) atypical strains presented the perA gene, and 20 (13.2%) also presented the bfpA gene. Among the 32 strains, 16 belonged to the O119:H2, O119:HND, and ONT:HND serotypes. All 32 atypical strains contained perA mutation frameshifts and possessed an IS1294 element upstream of the per operon as detected by PCR followed by restriction fragment length polymorphism (RFLP) typing and multiplex PCR. Among the 20 bfpA probe-positive strains, eight O119 strains possessed deletion in the bfp operon at the 3'end of bfpA due to an IS66 element. CONCLUSION: Our data show that typical O119 strains may contain a deletion within the EAF probe sequence not previously reported. This new finding suggests that care should be taken when using the previously described EAF PCR assay in epidemiological studies for the detection of typical O119 strains. In addition, we were able to confirm that some atypical strains carry vestiges of the EAF plasmid.

[18F-Fluorodeoxyglucose positron emission tomography and serum cytokines and matrix metalloproteinases in the assessment of disease activity in Takayasu's arteritis]. / Tomografia por emissão de pósitrons com 18F-fluordesoxiglicose e citocinas séricas e metaloproteinases da matriz na avaliação da atividade da doença na arterite de Takayasu.

OBJECTIVE: To evaluate 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography-computed tomography (PET-CT)-and serum levels of different cytokines and matrix metalloproteinases (MMPs) in patients with Takayasu's arteritis (TA) and associations with disease activity. METHODS: Serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-2, IL-6, IL-8, IL-12, IL-18, MMP-3 and MMP-9 were measured in 36 TA patients and 36 controls. Maximum standard uptake value (SUVmax) of 18F-FDG in arterial walls was determined by PET-CT scans. TA patients were classified as active disease, inactive disease and possible active disease. RESULTS: Serum IL-6 and MMP-3 levels were higher in TA patients than in controls (p<0.001). Serum IL-6 was higher in patients with active disease and in patients with possible active disease than in inactive disease (p<0.0001). Patients with active disease had higher serum TNFα levels than patients with inactive disease (p=0.049) while patients with possible active disease presented higher IL-18 levels than patients with inactive disease (p=0.046). Patients with active disease had higher SUVmax values than those with inactive disease (p=0.042). By ROC curve SUVmax was predictive of active disease in TA and values ≥1.3 were associated with disease activity (p=0.039). Serum TNF-α levels were higher in patients with SUVmax ≥1.3 than<1.3 (p=0.045) and controls (p=0.012). Serum IL-6 levels were higher in patients with SUVmax ≥1.3 than in controls (p<0.001). No differences regarding other biomarkers were found between TA patients and controls. CONCLUSIONS: Higher serum IL-6 and TNFα levels as well as higher arterial 18F-FDG uptake are associated with active TA.

Phenotypic and genotypic characteristics associated with biofilm formation in clinical isolates of atypical enteropathogenic Escherichia coli (aEPEC) strains.

BACKGROUND: Biofilm formation by enteropathogenic Escherichia coli (EPEC) have been recently described in the prototype typical EPEC E2348/69 strain and in an atypical EPEC O55:H7 strain. In this study, we sought to evaluate biofilm formation in a collection of 126 atypical EPEC strains isolated from 92 diarrheic and 34 nondiarrheic children, belonging to different serotypes. The association of biofilm formation and adhesin-related genes were also investigated. RESULTS: Biofilm formation occurred in 37 (29%) strains of different serotypes, when the assays were performed at 26°C and 37°C for 24 h. Among these, four strains (A79, A87, A88, and A111) formed a stronger biofilm than did the others. The frequency of biofilm producers was higher among isolates from patients compared with isolates from controls (34.8% vs 14.7%; P = 0.029). An association was found between biofilm formation and expression of type 1 fimbriae and curli (P < 0.05). Unlike the previously described aEPEC O55:H7, one aEPEC O119:HND strain (A111) formed a strong biofilm and pellicle at the air-liquid interface, but did not express curli. Transposon mutagenesis was used to identify biofilm-deficient mutants. Transposon insertion sequences of six mutants revealed similarity with type 1 fimbriae (fimC, fimD, and fimH), diguanylate cyclase, ATP synthase F1, beta subunit (atpD), and the uncharacterized YjiC protein. All these mutants were deficient in biofilm formation ability. CONCLUSION: This study showed that the ability to adhere to abiotic surfaces and form biofilm is present in an array of aEPEC strains. Moreover, it seems that the ability to form biofilms is associated with the presence of type 1 fimbriae and diguanylate cyclase. Characterization of additional biofilm formation mutants may reveal other mechanisms involved in biofilm formation and bring new insights into aEPEC adhesion and pathogenesis.

Detection and genetic analysis of the enteroaggregative Escherichia coli heat-stable enterotoxin (EAST1) gene in clinical isolates of enteropathogenic Escherichia coli (EPEC) strains.

BACKGROUND: The enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1) encoded by astA gene has been found in enteropathogenic E. coli (EPEC) strains. However, it is not sufficient to simply probe strains with an astA gene probe due to the existence of astA mutants (type 1 and type 2 SHEAST) and EAST1 variants (EAST1 v1-4). In this study, 222 EPEC (70 typical and 152 atypical) isolates were tested for the presence of the astA gene sequence by PCR and sequencing. RESULTS: The astA gene was amplified from 54 strains, 11 typical and 43 atypical. Sequence analysis of the PCR products showed that 25 strains, 7 typical and 18 atypical, had an intact astA gene. A subgroup of 7 atypical strains had a variant type of the astA gene sequence, with four non-synonymous nucleotide substitutions. The remaining 22 strains had mutated astA gene with nucleotide deletions or substitutions in the first 8 codons. The RT-PCR results showed that the astA gene was transcribed only by the strains carrying either the intact or the variant type of the astA gene sequence. Southern blot analysis indicated that astA is located in EAF plasmid in typical strains, and in plasmids of similar size in atypical strains. Strains carrying intact astA genes were more frequently found in diarrheic children than in non-diarrheic children (p < 0.05). CONCLUSION: In conclusion, our data suggest that the presence of an intact astA gene may represent an additional virulence determinant in both EPEC groups.

Real-time multiplex PCR assay and melting curve analysis for identifying diarrheagenic Escherichia coli.

A real-time multiplex PCR assay was designed to amplify the virulence genes eae, pEAF, aatA, daaC, elt, est, ipaH, stx(1), and stx(2) for the detection of all diarrheagenic Escherichia coli pathotypes. This assay proved to be more sensitive and rapid than a conventional multiplex PCR for diarrheagenic E. coli isolates from children with diarrhea.

FCGR3B*03 allele inheritance pattern in Brazilian families and some new variants of gene FCGR3B.

BACKGROUND: The FCGR3B gene encoding the FcyRIIIb receptor for immunoglobulin G has three polymorphic forms known as HNA-1a, HNA-1b, and HNA-1c, encoded by the alleles FCGR3B*01, FCGR3B*02, and FCGR3B*03, respectively. It is not clear whether the inheritance of the FCGR3B*03 allele, which encodes the HNA-1c, is linked or not to the other two alleles. The objective of this study was to identify the inheritance pattern of the FCGR3B*03 allele in Brazilians. STUDY DESIGN AND METHODS: Blood samples from nine families with at least one FCGR3B*03(+) member, totalizing 47 individuals, were studied. The presence of the FCGR3B*01, FCGR3B*02, and FCGR3B*03 alleles was detected by the polymerase chain reaction with sequence-specific priming method, and all DNA samples were sequenced. RESULTS: In three of the nine studied families, the FCGR3B*03 was passed down with the FCGR3B*02, while in one family the FCGR3B*03 was inherited in linkage with FCGR3B*01. The other families were not informative regarding FCGR3B*03 inheritance. Sequencing showed for the first time one single-nucleotide polymorphism at Position 264 resulting from a simple substitution C→T; three other different substitutions at Position 230, T→A, T→G; and the presence of three nucleotides at Position 230 (T, G, and A). The previously reported variants FCGR3B*01A227G and FCGR3BG330T were also found. CONCLUSION: In this Brazilian FCGR3B*03(+) group we found that the inheritance of FCGR3B*03 took place by a linkage to FCGR3B*02 or to FCGR3B*01. Linkage of FCGR3B*03 to FCGR3B*02 was the most common. Additionally, we report SNPs that have not been described, suggesting that they might be more common than previously thought.

Application of real-time PCR stool assay for Helicobacter pylori detection and clarithromycin susceptibility testing in Brazilian children.

BACKGROUND: Helicobacter pylori ClariRes assay is a novel commercially available real-time PCR assay allowing H. pylori detection and clarithromycin susceptibility testing in either gastric biopsy or stool specimens. OBJECTIVE: The aim of this study was to validate the novel biprobe real-time assay in stool specimens from 217 dyspeptic children. METHODS: DNA from gastric biopsies and stool specimens were obtained and submitted to the biprobe real time assay for H. pylori detection and clarithromycin susceptibility testing. RESULTS: The sensitivity, specificity, and test accuracy were 69, 100 and 93.9% for the detection of H. pylori infection and 83.3, 100 and 95.6%, for detection of clarithromycin resistance. CONCLUSION: This assay proved to be appropriate for H. pylori clarithromycin susceptibility testing, particularly in children populations where a high prevalence of clarithromycin-resistant strains is suspected.

High prevalence of clarithromycin resistance and cagA, vacA, iceA2, and babA2 genotypes of Helicobacter pylori in Brazilian children.

We isolated 45 Helicobacter pylori strains from 217 child patients. Resistance to clarithromycin, metronidazole, amoxicillin, and tetracycline was detected in 27%, 13%, 4%, and 0% of strains, respectively. The A2143G mutation was the most prevalent (67%) among clarithromycin-resistant strains. In addition, strain genotyping revealed a significant association between gastritis severity and the simultaneous presence of cagA, vacA s1m1, iceA2, and babA2 genes.

Adherence factors in atypical enteropathogenic Escherichia coli strains expressing the localized adherence-like pattern in HEp-2 cells.

Although atypical enteropathogenic Escherichia coli (aEPEC) strains are frequently implicated in childhood diarrhea in developing countries, not much is known about their adherence properties. The phenotypic and genotypic characterization of 29 aEPEC strains expressing the localized adherence-like pattern points toward the involvement of E. coli common pilus (ECP), intimins, and other known E. coli adhesins in this pattern.

Evidence of pathogenic subgroups among atypical enteropathogenic Escherichia coli strains.

We describe the characterization of 126 atypical enteropathogenic Escherichia coli (aEPEC) isolates from 1,749 Brazilian children. Classic aEPEC strains were more frequently found in children with diarrhea than in controls (P < 0.001), showing their importance as acute diarrhea agents in our country. Only aEPEC strains carrying either the ehxA or paa gene were significantly associated with diarrhea.

Identification and complete sequencing of novel human transcripts through the use of mouse orthologs and testis cDNA sequences.

The correct identification of all human genes, and their derived transcripts, has not yet been achieved, and it remains one of the major aims of the worldwide genomics community. Computational programs suggest the existence of 30,000 to 40,000 human genes. However, definitive gene identification can only be achieved by experimental approaches. We used two distinct methodologies, one based on the alignment of mouse orthologous sequences to the human genome, and another based on the construction of a high-quality human testis cDNA library, in an attempt to identify new human transcripts within the human genome sequence. We generated 47 complete human transcript sequences, comprising 27 unannotated and 20 annotated sequences. Eight of these transcripts are variants of previously known genes. These transcripts were characterized according to size, number of exons, and chromosomal localization, and a search for protein domains was undertaken based on their putative open reading frames. In silico expression analysis suggests that some of these transcripts are expressed at low levels and in a restricted set of tissues.

Identification and complete sequencing of novel human transcripts through the use of mouse orthologs and testis cDNA sequences

The correct identification of all human genes, and their derived transcripts, has not yet been achieved, and it remains one of the major aims of the worldwide genomics community. Computational programs suggest the existence of 30,000 to 40,000 human genes. However, definitive gene identification can only be achieved by experimental approaches. We used two distinct methodologies, one based on the alignment of mouse orthologous sequences to the human genome, and another based on the construction of a high-quality human testis cDNA library, in an attempt to identify new human transcripts within the human genome sequence. We generated 47 complete human transcript sequences, comprising 27 unannotated and 20 annotated sequences. Eight of these transcripts are variants of previously known genes. These transcripts were characterized according to size, number of exons, and chromosomal localization, and a search for protein domains was undertaken based on their putative open reading frames. In silico expression analysis suggests that some of these transcripts are expressed at low levels and in a restricted set of tissues.

Neuron specific enolase concentration is increased in serum and decreased in platelets of patients with active systemic sclerosis.

OBJECTIVE: To determine frequency, origin, and clinical associations of elevated serum neuron specific enolase (NSE) in systemic sclerosis (SSc). METHODS: Serum was obtained from 75 patients with SSc, 20 systemic lupus erythematosus, 8 polymyositis, 10 idiopathic interstitial lung disease, and 10 healthy volunteers. NSE status was determined in serum (in all individuals) and in platelet lysate (in volunteers and 30 patients with SSc). RESULTS: Elevated serum NSE (mean 22.6 ng/ml, range 12.1-68.2 ng/ml) was observed in 26 patients with SSc (34.6%). Those with diffuse SSc had higher serum NSE than those with limited disease (16.5 +/- 13.4 vs 9.6 +/- 5.0 ng/ml, p = 0.006). No association was found between serum NSE and lung or esophagus involvement. Patients with long-standing disease had lower serum NSE than those with early disease (10.8 +/- 7.3 vs 16.1 +/- 13.6 ng/ml, p = 0.05). Serum NSE was 19.4 +/- 13.0 ng/ml in patients with total skin score (TSS) > 20, 8.3 +/- 2.1 ng/ml in patients with TSS < 5, and 6.0 +/- 3.1 ng/ml in volunteers (p = 0.01). NSE platelet lysate concentration was 3.6 +/- 2.9 ng/ml in patients with TSS > 20, 12.4 +/- 4.1 ng/ml in those with TSS < 5, and 14.1 +/- 6.5 ng/ml in healthy individuals (p < 0.001). Volunteers and SSc patients with low TSS had comparable S/PL-NSE index (serum/platelet lysate NSE concentration) (0.42 +/- 0.16 and 0.75 +/- 0.33, respectively), both lower than SSc patients with high TSS (7.45 +/- 5.57) (p < 0.001). CONCLUSION: Elevated serum NSE was observed in one-third of SSc patients but not in other autoimmune rheumatic diseases. The inverse relationship between serum and platelet lysate NSE concentration suggests platelet activation as the origin of high serum NSE in SSc. NSE S/PL was the best discriminatory variable between healthy volunteers and SSc patients as well as between patients with high and low TSS. High serum NSE and high NSE-S/PL index seemed to be associated with SSc disease activity. Further work is warranted to investigate a possible role for this marker in assessing disease activity and therapy response.

Influência do descongelamento seriado do soro na detecçäo de auto-anticorpos (AAC) em doenças reumáticas auto-imunes (DRAI) / Detection of autoantibodies on serum aliquots submitted to serial freeze-thaw cycles

Introduçäo: Os auto-anticorpos (AAC) säo de grande relevância clínica em doenças reumáticas auto-imunes (DRAI), tanto para diagnóstico quanto para monitoraçäo terapêutica. Sua presença pode variar de acordo com a atividade da doença, tratamento ou condicionamento do soro. Diversos estudos clínicos utilizam alíquotas de soro estocado rotineiramente, acreditando que este permaneça estável, apesar do tempo decorrido e da repetiçäo de ciclos de congelamento/descongelamento; porém, a manutençäo da reatividade de soros estocados frente a diversos antígenos näo foi avaliada de modo sistemático. Com relaçäo a alguns AAC específicos, como a anticardiolipina e o anticolágeno do tipo II desnaturado, é sabido que sua detecçäo é alterada pelo calor e pela estocagem do soro. Objetivo: Investigar a influência de ciclos de congelamento/descongelamento do soro na detecçäo de AAC em soros de pacientes com DRAI. Casuística e método: Foi coletado o soro de dez pacientes com DRAI acompanhados no ambulatório da Disciplina de Reumatologia da Unifesp. Os soros foram separados e divididos em duas alíquotas (A e B), que foram congeladas a -20 C. A amostra B foi submetida a 100 ciclos diários de descongelamento por uma hora, seguido de recongelamento a -20 C. A alíquota A näo foi submetida a nenhum ciclo, sendo mantida a -20 C até o momento do uso. Foram realizados os seguintes testes imunológicos: FAN (imunofluorescência indireta em células HEp-2), fator reumatóide (aglutinaçäo pelo látex), anti-ENA (imunodifusäo dupla, hemaglutinaçäo passiva e ELISA) e anticardiolipina (ELISA). Resultados: Näo se observou qualquer diferença entre as alíquotas A e B em relaçäo ao padräo ou título de AAC por imunofluorescência indireta (IFI), nenhuma variaçäo dos títulos do FR, anti-ENA (DO por ELISA), imunodifusäo e anticardiolipina por ELISA. Houve queda no título do anticorpo anti-SS-A/Ro quando detectado por hemaglutinaçäo passiva na alíquota B de três soros. Conclusäo: Os resultados mostram que a detecçäo de AAC näo se modifica após repetidos ciclos de congelamento/descongelamento. Entretanto, a sensibilidade da reaçäo de hemaglutinaçäo passiva pode estar diminuída em alíquotas antigas e utilizadas diversas vezes

Especificidade antigênica e isótipos de auto-anticorpos em LES familiar / Antigenic specificity and isotype of autoantibodies in familial systemic lupus erythematosus

Ojetivo: Comparar a especificidade e isótipos dos auto-anticorpos (AA) em duplas de pacientes com LES familiar em relaçäo a duplas näo consangüíneas. Métodos: Foram selecionados, ao acaso, 19 duplas de pacientes lúpicos consangüíneos de primeiro grau e 19 duplas de pacientes lúpicos näo consangüíneos. Os auto-anticorpos foram estudados pelas técnicas de imunofluorescência indireta (IFI) em células Hep-2 e Crithidia lucilae, por imunodifusäo dupla contra extrato de timo de vitelo (anti-ENA) e por immunoblot com extrato total de células HeLa. A classe isotípica foi determinada por IFI com conjugados específicos. Os resultados obtidos em cada dupla foram analisados através de índices comparativos para esta finalidade: índice de concordância isotípica (ICI), índice de concordância de anticorpos anti-ENA (ICE) e índice de concordância de bandas ao immunoblot (ICB). Para análise estatística foram utilizados o teste de Wilcoxon e teste do qui-quadrado, estabelecendo-se em alfa menor ou igual a 0,05 o nível de rejeiçäo da hipótese de nulidade, Na análise dos resultados näo se observou diferença significante entre as duplas lúpicas consangüíneas e näo consangüíneas em relaçäo à prevalência de anticorpos antinucleares por IFI, à prevalência e concordância das diversas classes isotípicas, e quanto à concordância de anticorpos anti-ENA. Por outro lado, as duplas lúpicas consangüíneas apresentaram maior concordância de bandas ao immunoblot em relaçäo às duplas näo consangüíneas {ICB médio = 45 nas duplas consangüíneas e ICB médio = 17,6 nas duplas näo consangüíneas, com p < 0,05 (T calc.= 15,0 para T crítico= 35)]. Conclusäo: O encontro de maior concordância na especificidade de auto-anticorpos em pacientes lúpicos consangüíneos corrobora a noçäo de que o perfil de auto-anticorpos no LES é determinado, ao menos parcialmente, pela constituiçäo genética dos indivíduos

Activity of bristles from an Amazonian lepidoptera, "Premolis semirufa", on the human complement system

O lepidóptero Premolis semirufa habita os seringais da regiao Amazônica. Os seringueiros denominam pararama a forma larval do inseto e pararamose a doença ocupacional causada pelo contato acidental com cerdas da larva ou casulo durante a coleta do látex. Os sintomas imediatos que se seguem ao contato sao locais e consistem em prurido intenso, edema e dor, que sao geralmente transitórios e desaparecem em poucos dias. Entretanto, em algumas circunstâncias, o processo torna-se crônico, podendo evoluir para a deformidade e imobilizaçao da articulaçao afetada, lembrando, sob alguns aspectos, artrite reumatóide. O estudo da açao in vitro de cerdas e substâncias solúveis associadas sobre o sistema complemento humano mostrou que tanto cerdas quanto extrato salino inativam complemento total e o componente C2, geram C3d a partir de C3, sem afetar os níveis de Clq. Estes resultados sugerem que a via clássica de ativaçao do complemento nao está envolvida no processo. A inativaçao direta de C2 e a geraçao de C3d sao compatíveis com a presença de substâncias solúveis com açao lítica associadas às cerdas, embora nao tenha sido excluída ativaçao paralela da via alternativa como mecanismo de produçao de C3d