Adult ocular adnexal xanthogranulomatous disease associated with immunoglobulin G4-related disease: an unusual association.

Adult-onset xanthogranuloma (AOX) and immunoglobulin G4-related disease (IgG4-RD) are uncommon fibrosing conditions that may exhibit localized ocular manifestations and occasionally systemic symptoms. These conditions exhibit overlapping clinical and histological features, suggesting a potential correlation between them, although their exact relationship remains unclear. This paper presents the case of a black male patient exhibiting typical histological indications of both AOX and IgG4-RD. The patient responded positively to corticosteroid treatment.

Association of CXCL13 serum level and ultrasonographic findings of joints in patients with systemic lupus erythematosus and Jaccoud's arthropathy.

Objectives The objective of this paper is to perform an ultrasonography (US) analysis of hands and wrists in two groups of patients with systemic lupus erythematosus (SLE), with and without Jaccoud's arthropathy, matched by age and disease duration and to correlate them with levels of CXCL13 clinical features, laboratory tests and disease activity score. Methods Sixty-four patients with SLE were enrolled, 32 with and 32 without Jaccoud's arthropathy. Each patient underwent physical examination, laboratory tests (including CXCL13 by ELISA) and bilateral US. Synovial hypertrophy, tenosynovitis and erosions were evaluated according to a semiquantitative grading system with a 0-3 rating. US findings were correlated with serum levels of CXCL13, other serological parameters and disease activity index. Results Synovitis was found in 25/64 patients (39%) and tenosynovitis in 14/64 (22%). These findings were more frequent in SLE patients with Jaccoud's arthropathy, particularly tenosynovitis ( p = 0.002) and synovitis ( p = 0.01). Median serum level of CXCL13 was 20.16 pg/ml in the whole population (23.21 pg/ml in the Jaccoud's arthropathy group and 11.48 pg/ml in the group without). There was an association between the presence of disease activity and high level of CXCL13 ( p = 0.004). However, no association was found between high levels of CXCL13 and "arthritis" in SLEDAI, swollen joints on physical examination or synovitis on US. Conclusions US findings in joints of SLE patients with Jaccoud's arthropathy confirm that synovitis and tenosynovitis are common in these patients. In addition, serum level of CXCL13 is associated with disease activity in SLE but does not seem to be a biomarker for arthritis in these patients.

Anti-PR3 and anti-MPO antibodies are not present in sera of patients with pulmonary tuberculosis.

Anti-neutrophil cytoplasmic antibodies (ANCA) are autoantibodies directed to intracellular components of neutrophils and are present in several vasculitic syndromes. Recently, these autoantibodies have been described in other autoimmune disorders as well as in infectious diseases such as tuberculosis (TB). As there are some clinical similarities between TB and granulomatosis with polyangiitis, we searched for ANCA in a group of patients with proven TB. Patients with TB confirmed by chest X-ray and sputum bacilloscopy either before or within 30 days after beginning treatment were included in this study. Anti-MPO and anti-PR3 antibodies were studied using well-standardized ELISA kits (INOVA Diagnostics, Inc.). ANCA were also investigated by indirect immunofluorescence (IIF). Fifty TB patients (26 females, mean age 47.34 ± 17 years) were enrolled in the present study. No patient tested positive for ANCA by IIF, or anti-MPO or anti-PR3 antibodies by ELISA. Although previous studies have shown the presence of ANCA in some infectious diseases, the findings of the present study demonstrated the absence of such antibodies in TB. The discrepancy in the prevalence of ANCA in TB among different studies may be attributed to methodological factors and/or the genetic background of the studied populations.

Antibacterial, antibiofilm, and antivirulence potential of the main diterpenes from Copaifera spp. oleoresins against multidrug-resistant bacteria.

To evaluate the antibacterial, antibiofilm and antivirulence potential of the main diterpenes from Copaifera spp. oleoresins against multidrug-resistant (MDR) bacteria. Antimicrobial assays included determination of the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Minimum Inhibitory Concentration of Biofilm (MICB50), as well as synergistic and antivirulence assays for eight diterpenes against MDR. The tests revealed that two diterpenes (named 1 and 5) showed the best results, with MIC and MBC between 12.5 and 50 µg/mL against most MDR bacteria. These diterpenes exhibited promising MICB50 in concentration between 3.12-25 µg/mL but showed no synergistic antimicrobial activity. In the assessment of antivirulence activity, diterpenes 1 and 5 inhibited only one of the virulence factors evaluated (Dnase) produced by some strains of S. aureus at subinhibitory concentration (6.25 µg/mL). Results obtained indicated that diterpenes isolated from Copaifera oleoresin plays an important part in the search of new antibacterial and antibiofilm agents that can act against MDR bacteria.

Giant disseminated condylomatosis in SLE.

INTRODUCTION: Females with systemic lupus erythematosus (SLE) have higher prevalence of human papillomavirus (HPV) infection, which can lead to the development of warts. Herein we report the first case of giant disseminated condylomatosis (GDC) in a SLE female on mycophenolate mofetil (MMF). CASE REPORT: The patient, a 33-year-old, Black female, was diagnosed with SLE during her first pregnancy in 2003 based on the features of arthritis, skin rash, seizures, nephritis and presence of antinuclear antibodies. Her pregnancy resulted in preterm delivery of a stillborn fetus at 28 weeks. Since that time she has been treated with steroids and different regimens of immunosuppressive drugs such as cyclophosphamide, azathioprine and lately MMF. In the last few years she presented GDC involving the genital area in addition to skin on the lower abdomen. Topical therapy with trichloroacetic acid, imiquimod and podophyllin was only partially effective. Different types of HPV were identified in the lesions, being HPV-11 in abdomen, HPV 6, 11, 42 in vulva, HPV-6, 11 in vagina and HPV-6, 11 in endocervix. CONCLUSIONS: GDC may be a complication of SLE, secondary to the disease itself, its treatment or other factors not yet identified.

Effect of age at disease onset in the clinical profile of spondyloarthritis: a study of 1424 Brazilian patients.

OBJECTIVES: To analyse demographic and clinical variables in patients with disease onset before and after 40, 45 and 50 years in a large series of Brazilian SpA patients. METHODS: A common protocol of investigation was prospectively applied to 1424 SpA patients in 29 centres distributed through the main geographical regions in Brazil. The mean age at disease onset was 28.56 ± 12.34 years, with 259 patients (18.2%) referring disease onset after 40 years, 151 (10.6%) after 45 years and 81 (5.8%) after 50 years. Clinical and demographic variables and disease indices (BASDAI, BASFI, BASRI, MASES, ASQoL) were investigated. Ankylosing spondylitis was the most frequent disease (66.3%), followed by psoriatic arthritis (18%), undifferentiated SpA (6.7%), reactive arthritis (5.5%), and enteropathic arthritis (3.5%). RESULTS: Comparing the groups according to age of disease onset, those patients with later onset presented statistical association with female gender, peripheral arthritis, dactylitis, nail involvement and psoriasis, as well as negative statistical association with inflammatory low back pain, alternating buttock pain, radiographic sacroiliitis, hip involvement, positive familial history, HLA-B27 and uveitis. BASDAI, BASFI and quality of life, as well as physicians and patient's global assessment, were similar in all the groups. Radiographic indices showed worse results in the younger age groups. CONCLUSIONS: There are two different clinical patterns in SpA defined by age at disease onset: one with predominance of axial symptoms in the group with disease onset ≤ 40 years and another favouring the peripheral manifestations in those with later disease onset.

Chemical composition and biological activities of essential oil from flowers of Psidium guajava (Myrtaceae).

Xylella fastidiosa is a plant-pathogenic bacterium that lives inside host xylem vessels, where it forms biofilm which is believed to be responsible for disrupting the passage of water and nutrients. Pectobacterium carotovorum is a Gram-negative plant-specific bacterium that causes not only soft rot in various plant hosts, but also blackleg in potato by plant cell wall degradation. Chagas disease, which is caused by Trypanosoma cruzi, has been commonly treated with nifurtimox and benzonidazole, two drugs that cause several side effects. As a result, the use of natural products for treating bacterial and neglected diseases has increased in recent years and plants have become a promising alternative to developing new medicines. Therefore, this study aimed to determine, for the first time, the chemical composition of essential oil from Psidium guajava flowers (PG-EO) and to evaluate its in vitro anti-Xylella fastidiosa, anti-Pectobacterium carotovorum, anti-Trypanosoma cruzi and cytotoxic activities. PG-EO was obtained by hydrodistillation in a Clevenger apparatus while its chemical composition was determined by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Major compounds identified in PG-EO were α-cadinol (37.8%), ß-caryophyllene (12.2%), nerolidol (9.1%), α-selinene (8.8%), ß-selinene (7.4%) and caryophyllene oxide (7.2%). Results showed that the PG-EO had strong trypanocidal activity against the trypomastigote forms of Trypanosoma cruzi (IC50 = 14.6 µg/mL), promising antibacterial activity against X. fastidiosa (MIC = 12.5 µg/mL) and P. carotovorum (MIC = 62.5 µg/mL), and moderate cytotoxicity against LLCMK2 adherent epithelial cells in the concentration range (CC50 = 250.5 µg/mL). In short, the PG-EO can be considered a new source of bioactive compounds for the development of pesticides and trypanocide drugs.

Toll-like receptor 9 polymorphisms in brazilian patients with systemic lupus erythematosus: a pilot study.

Toll-like receptor 9 (TLR9) is an important component of the innate immune system and have been associated with several autoimmune diseases, such as Systemic Lupus Erythematosus (SLE). The aim of this study was to investigate polymorphisms in TLR9 gene in a Brazilian SLE patients group and their association with clinical manifestation, particularly Jaccoud's arthropathy (JA). We analyzed DNA samples from 204 SLE patients, having a subgroup of them presenting JA (n=24). A control group (n=133) from the same city was also included. TLR9 single nucleotide polymorphisms (SNPs) (-1237 C>T and +2848 G>A) were identified by sequencing analysis. The TLR9 gene genotype frequency was similar both in SLE patients and the control group. In the whole SLE population, an association between the homozygosis of allele C at position -1237 with psychosis and anemia (p < 0.01) was found. Likewise, the homozygosis of allele G at position +2848 was associated with a discoid rash (p < 0.05). There was no association between JA and TLR9 polymorphisms. These data show that TLR9 polymorphisms do not seem to be a predisposing factor for SLE in the Brazilian population, and that SNPs are not associated with JA.

Spontaneous tendon rupture in systemic lupus erythematosus: association with Jaccoud's arthropathy.

Tendon rupture has rarely been described in patients with systemic lupus erythematosus. From observation of three cases of Jaccoud's arthropathy with tendon rupture, and considering that this arthropathy is more related to an inflammatory process of the tendon sheath than to synovitis per se, the intention of this study was to review the cases of tendon rupture in patients with systemic lupus erythematosus, in the hope of determining the frequency of Jaccoud's arthropathy associated with this complication. Systematic review using MEDLINE, Scielo and LILACS databases (1966 to 2009) and the following keywords: systemic lupus erythematosus, tendon rupture, Jaccoud's arthropathy. Secondary references were additionally obtained. Additionally, three Brazilian systemic lupus erythematosus patients who developed tendon rupture are described. Only 40 articles obtained fulfilled the previously established criteria. They were all case reports; the number of cases reported was 52 which, together with the three cases presented herein add up to 55 cases. Forty-six patients were women aged between 19 and 71 years, with a mean age of 40.1 +/- 12.4 years, and the average duration of the disease was 10 years. The most frequently observed rupture sites were the patellar and Achilles' tendons. While almost all patients described were on various doses of corticosteroids, 16 patients concomitantly had Jaccoud's arthropathy (29%). In conclusion, the association between Jaccoud's arthropathy and tendon rupture in systemic lupus erythematosus has been underestimated. As almost one-third of the systemic lupus erythematosus patients with tendon rupture also have Jaccoud's arthropathy, this arthropathy may be recognized as risk marker for tendon rupture.

Chemical composition and biological activities of essential oil from flowers of Psidium guajava (Myrtaceae) / Composição química e atividades biológicas do óleo essencial das flores de Psidium guajava (Myrtaceae)

Abstract Xylella fastidiosa is a plant-pathogenic bacterium that lives inside host xylem vessels, where it forms biofilm which is believed to be responsible for disrupting the passage of water and nutrients. Pectobacterium carotovorum is a Gram-negative plant-specific bacterium that causes not only soft rot in various plant hosts, but also blackleg in potato by plant cell wall degradation. Chagas disease, which is caused by Trypanosoma cruzi, has been commonly treated with nifurtimox and benzonidazole, two drugs that cause several side effects. As a result, the use of natural products for treating bacterial and neglected diseases has increased in recent years and plants have become a promising alternative to developing new medicines. Therefore, this study aimed to determine, for the first time, the chemical composition of essential oil from Psidium guajava flowers (PG-EO) and to evaluate its in vitro anti-Xylella fastidiosa, anti-Pectobacterium carotovorum, anti-Trypanosoma cruzi and cytotoxic activities. PG-EO was obtained by hydrodistillation in a Clevenger apparatus while its chemical composition was determined by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Major compounds identified in PG-EO were α-cadinol (37.8%), β-caryophyllene (12.2%), nerolidol (9.1%), α-selinene (8.8%), β-selinene (7.4%) and caryophyllene oxide (7.2%). Results showed that the PG-EO had strong trypanocidal activity against the trypomastigote forms of Trypanosoma cruzi (IC50 = 14.6 μg/mL), promising antibacterial activity against X. fastidiosa (MIC = 12.5 μg/mL) and P. carotovorum (MIC = 62.5 μg/mL), and moderate cytotoxicity against LLCMK2 adherent epithelial cells in the concentration range (CC50 = 250.5 μg/mL). In short, the PG-EO can be considered a new source of bioactive compounds for the development of pesticides and trypanocide drugs.

Resumo Xylella fastidiosa é uma bactéria patogênica que vive dentro dos vasos do xilema hospedeiro, onde forma um biofilme responsável por interromper a passagem de água e nutrientes. Pectobacterium carotovorum é uma bactéria Gram-negativa que causa não só podridão macia em várias plantas hospedeiras, mas também canela-preta na batata por degradação da parede celular da planta. A doença de Chagas, causada pelo Trypanosoma cruzi, é comumente tratada com nifurtimox e benzonidazol, duas drogas que causam vários efeitos colaterais. Como resultado, o uso de produtos naturais para o tratamento de doenças bacterianas e negligenciadas aumentou nos últimos anos e as plantas continuam sendo uma alternativa promissora para o desenvolvimento de novos medicamentos. Portanto, este estudo teve como objetivo determinar, pela primeira vez, a composição química do óleo essencial de flores de Psidium guajava (PG-EO) e avaliar suas propriedades anti-Xylella fastidiosa, anti-Pectobacterium carotovorum, anti-Trypanosoma cruzi e citotóxica in vitro. PG-EO foi obtido por hidrodestilação em um aparelho Clevenger, enquanto sua composição química foi determinada por cromatografia em fase gasosa com detecção por ionização por chama (CG-DIC) e por cromatografia em fase gasosa acoplada à espectrometria de massa (CG-EM). Os principais compostos identificados no PG-EO foram α-cadinol (37,8%), β-cariofileno (12,2%), nerolidol (9,1%), α-selineno (8,8%), β-selineno (7,4%) e óxido de cariofileno (7,2%). Os resultados mostraram que o PG-EO apresentou forte atividade tripanocida contra as formas tripomastigotas de T. cruzi (CI50 = 14,6 μg/mL), promissora atividade antibacteriana contra X. fastidiosa (MIC = 12,5 μg/mL) e P. carotovorum (MIC = 62,5 μg/mL) e citotoxicidade moderada contra células epiteliais aderentes (LLCMK2) na faixa de concentração (CC50 = 250,5 μg/mL). Em suma, o PG-EO pode ser considerado uma nova fonte de compostos bioativos para o desenvolvimento de pesticidas e drogas tripanocidas.

Spinal cord compression by ectopic calcinosis in scleroderma.

Systemic sclerosis (SS) is a chronic, multisystemic disease, characterized by inflammation associated with fibrosis. Calcinosis is one of the manifestations of this disorder, observed in 10 to 20% of cases. It is usually located on the extensor surface of the phalanges, peri-articular tissue and near the bone prominences. There are only a few cases reported of SS with vertebral column involvement and spinal cord compression by calcinosis causing serious neurological complications. We describe a fatal case of SS who showed tetraplegia secondary to ectopic calcinosis in the cervical medulla and present a review of the literature on the subject.

An improved anti-C3/IgG ELISA for quantification of soluble immune complexes.

A semi-quantitative ELISA for complement-fixing, IgG-containing immune complexes (IC) is described. The assay is based on the insolubilization of IC by polyethyleneglycol, their capture by solid-phase anti-C3 antibodies, reaction with peroxidase-labeled anti-IgG antibodies and incubation with a chromogenic peroxidase substrate. It was markedly improved by the use of a single-step procedure which simultaneously washed and precipitated the insolubilized immune complexes. Intra-assay and inter-assay coefficients of variation were lower than 8.6 and 14.7%, respectively. As expected, higher levels of circulating immune complexes, in relation to healthy individuals, were found in patients with American visceral leishmaniasis (AVL), systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), with prevalences comparable to those described in the literature. The ELISA can be quickly assembled from reagents and plasticware widely available commercially, detects immune complexes fulfilling three different criteria and is more sensitive than a previously published method based on the same principles (detection limit for complement-sensitized aggregated IgG of 2 microg ml(-1) as compared with a detection limit above 16 microg ml(-1)).

Anticardiolipin antibodies in patients with infectious diseases.

IgG or IgM anticardiolipin antibodies were present in the sera of 67% of 33 patients with Hansen's disease, in 53% of 30 patients with tuberculosis and in 50% of 16 patients with endocarditis. Despite the high frequency of these antibodies, no patient had a history of thrombosis or abortion. Anti-denatured DNA antibodies were tested in patients with tuberculosis and patients with Hansen's disease. Only in the latter group did we observe a statistically significant association between anticardiolipin and anti-denatured DNA antibodies. Anticardiolipin binding activity, however, could not be inhibited by preincubation of sera with a variable concentration of denatured DNA. These data suggest that: a) Anticardiolipin antibodies in infectious diseases do not necessarily participate in the pathogenesis of thrombotic or obstetric complications; b) Anti-denatured DNA and anticardiolipin antibodies in the population studied do not have a cross-reaction.

Neuropsychiatric manifestations of systemic lupus erythematosus: the value of anticardiolipin, antigangliosides and antigalactocerebrosides antibodies.

In an attempt to find a serological marker for neuropsychiatric manifestations (NPM) of SLE, sera from 66 patients (classified in three groups, according to their NPM-defined, probable and without NPM) were analysed by ELISA for IgG and IgM anticardiolipin, antigangliosides and antigalactocerebrosides antibodies. A strong correlation was found between IgM antigangliosides and antigalactocerebrosides antibodies and NPM, but not with IgG class. IgM and IgG antibodies anticardiolipin were not correlated with NPM in this study. Both IgM antigangliosides and antigalactocerebrosides antibodies disappeared in seven patients with definite but clinically inactive NPM. The analysis of these autoantibodies showed an important role predictive for NPM in SLE; the negative test decreases the chance of the NPM.

Antiphospholipid antibodies in syphilis.

1. An enzyme-linked immunosorbent assay was used to determine the phospholipid specificity of antibodies present in sera from 35 syphilis patients. 2. Based on the cross-reaction obtained against a mixture of cardiolipin, phosphatidylcholine and cholesterol that is standard for flocculation tests according to the Venereal Disease Research Laboratory (CECON, São Paulo, Brazil), all 35 patients tested positive for antibodies of the IgG class whereas 13 (37%) also had IgM antibodies for the same mixture of lipids. IgG antibodies to cardiolipin were demonstrated in 2 patients (6%) and IgM antibodies in 5 (15%). Significant levels of IgG anti-phosphatidylcholine were detected in 3 patients (9%) and IgM antibodies in 4 (11%). IgG anti-phosphatidylethanolamine antibodies were found in 1 patient (3%) and IgM antibodies in 3 (9%). Antibody binding to cardiolipin plus cholesterol or cardiolipin plus phosphatidylcholine was as effective as when the standard mixture of all 3 lipids was used. 3. A comparison with serum from systemic lupus erythematosus patients and inhibition studies using liposomes of cardiolipin or the mixture of 3 lipids suggests that there are at least 3 groups of anticardiolipin antibodies.

[Weight for height of Chilean school children according to age and puberal development]. / Peso para la talla de escolares chilenos, segun la edad y el grado de desarrollo puberal.

In a sample of 6371 school age children, aged 9 to 15 years, representative of four Regions of Chile (II,V,IX, and XIII) weight for stature was evaluated, acocording to age and puberal stages of Tanner. The averages and medians of weight for stature between 130 at 170 cm for men and between 130 and 163cm for females are presented. Higher weight for height whith age and puberal stages was found in both sexes, but differences were not always significants. A very low correlation between weight, and chronologic age and low between weight and puberal status was observed. This was reflected for higher differences of weight in the successive puberal stages than in successive ages. We conclude that the puberal development rahter than chronologic age, must be use for a better nutritional evaluation of adolescents. Nevertheless, other parameters with better distribution in puberal poblation, must be considered.

Antibodies to citrullinated peptides in tuberculosis.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by symmetric polyarthritis, rheumatoid factor (RF) positivity, and bone erosions. Recently, research has been conducted on anti-citrullinated peptide antibodies (ACPAs) to which there are greater sensitivity and specificity than RF. However, these antibodies have also been described in infectious diseases, particularly tuberculosis (TB), placing the high specificity of the test in doubt. The aim of this research was to study the prevalence of ACPAs in TB, RA, and healthy controls. Patients with bacteriologically confirmed pulmonary tuberculosis, RA (ACR criteria), in addition to healthy controls were included. ACPAs were researched by: anti-cyclic citrullinated peptide (CCP), anti-modified citrullinated vimentin (MCV), and RF by ELISA. The study was conducted in 50 TB patients, 50 with RA, and 20 controls. Anti-CCP antibodies were found in 39 (78 %) of the RA patients (median titer, 128 U), whereas anti-MCV antibodies were found in 25 (50 %). Of the patients with TB, two (4 %) had positivity for anti-CCP and anti-MCV and no patient in the control group tested positive for these antibodies. Sensitivity of anti-CCP for RA was 78 % (confidence interval (CI), 63 to 88 %) and specificity was 97 % (CI, 89 to 99 %) while the sensitivity of anti-MCV was 50 % (CI, 35-64 %) and specificity was 97 % (CI, 89 to 99 %). RF was positive in 40 samples (80 %) of RA, in 30 (60 %) of TB, and in 1 (5 %) of the controls. Our findings showed high sensitivity of anti-CCP and high specificity of both anti-CCP and anti-MCV antibodies for RA, even in a population with high incidence of tuberculosis. The higher frequency of positivity of ACPA in TB observed in previous studies may be attributed to methodological factors.

Neonatal antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is a clinical entity characterized by arterial and venous thrombosis, adverse obstetric outcome and the presence of antibodies against phospholipids in serum or plasma. The objective of the present study is to describe a rare case of APS that occurred in a neonate born from a patient previously diagnosed as primary APS. A male, preterm born twin infant, whose mother had been diagnosed as primary APS, developed thrombocytopenia, livedo reticularis, pericardial effusion and thrombosis of the left subclavian and external jugular veins concomitantly with severe respiratory tract infection soon after his delivery, that culminated with his death two months after the birth, in spite of the large spectrum antibiotic therapy and all supportive measures. Laboratory findings included high titers of IgM anticardiolipin antibodies and moderate titers of IgG isotype and negative antinuclear antibody, configuring a case of neonatal APS. Neonatal APS is a rare clinical condition, with only a few cases described in the literature. Its occurrence may depend on the passage of antibodies through the placenta or, as it seems to have occurred in the present case, by the production of de novo antibodies by the fetus. The present case illustrates the necessity of a higher surveillance of the neonates born from mothers with primary APS or systemic lupus erythematosus (SLE) for the eventual development of such complication.

Complement activation by anticardiolipin antibodies.

A haemolytic assay was used to test the complement fixation ability of 16 serum samples with high concentrations of anti-cardiolipin antibodies. Fourteen patients had clinical complications usually associated with these antibodies--namely, recurrent abortions, thrombosis, or thrombocytopenia. Complement fixation by anticardiolipin antibodies was shown in only four of these patients and was not directly related to the antibody concentration. Because anticardiolipin antibodies in most of these patients did not activate the complement pathway it is unlikely that the complement cascade has an important role in the clinical complications associated with these antibodies.