Matrix metalloproteinase gene polymorphisms and susceptibility to systemic sclerosis

The major pathological hallmark of the systemic sclerosis (SSc) is skin and internal organ fibrosis, which results from normal tissue architecture alterations and extracellular matrix (ECM) protein deposition. ECM components are degraded by matrix metalloproteinases (MMP). Promoter region polymorphisms in MMP genes may influence gene expression, resulting in an imbalance between ECM protein production and degradation. Here, we analyzed MMP1 -1607 1G/2G (rs1799750), MMP3 -1171 5A/6A (rs3025058), and MMP9 -1562 C/T (rs3918242) polymorphisms in relation to susceptibility to SSc and its clinical features. The patient group included 98 individuals with longstanding or recently diagnosed disease, meeting the American College of Rheumatology or LeRoy and Medsger criteria for SSc; the control group included 100 healthy blood donors. All participants were of European descent. Genotyping was performed by polymerase chain reaction followed by restriction digestion. Genotype and allele frequencies of MMP polymorphisms were similar between the two groups. In secondary analyses, significantly higher frequency of 1G/2G genotype from MMP1 polymorphism was observed for patients testing positive for antinuclear autoantibodies (P = 0.007), while 1G/1G genotype was associated with interstitial lung disease development (P = 0.018). The 6A/6A genotype from MMP3 polymorphism was absent in patients with calcinosis (P = 0.011), while the MMP3 5A/5A genotype correlated with the presence of anti-topoisomerase I antibodies (P = 0.009) and reduced diffusing capacity for carbon monoxide (P = 0.024). These results suggest that MMP polymorphisms are not associated with SSc susceptibility, although MMP1 and MMP3 variants are associated with specific SSc clinical and laboratory features.

Evaluation of polymorphic variants in apoptotic genes and their role in susceptibility and clinical progression to systemic lupus erythematosus

Background Systemic lupus erythematosus (SLE) is an autoimmune disease marked by the disruption of the immune homeostasis. Patients exhibit a wide range of clinical manifestations, and environmental and genetic factors are involved in SLE pathogenesis. Evidence suggests that abnormalities in the cellular and molecular events that coordinate apoptosis may favour the generation of autoantigens involved in autoimmunity. In this way, the apoptotic deregulation may be affected by polymorphic variants in apoptotic-related genes. Methods We analyzed FAS, FASL, BCL-2 and BAX polymorphisms in order to correlate to SLE susceptibility and clinical features. A total of 427 SLE patients from the Hospital de Clínicas de Porto Alegre and 543 controls from southern Brazil were evaluated. Results We observed higher frequencies of the FASL -844CC genotype and -844C allele, as well as of the FASL-844C/IVS2nt-124A haplotype in African-derived SLE patients when compared to controls ( P < 0.001). FASL -844C, which is related to high FasL expression, could contribute to increased apoptosis and to the breakdown of immunological tolerance, favouring autoantibody production and inflammation. On the other hand, the BAX -248GA genotype and the -248A allele , related to low protein expression, were observed as a protective factor against SLE in this same population. The rate of apoptosis and cell death was evaluated in peripheral lymphocytes, and SLE patients presented a higher percentage of dead lymphocytes (CD3⁺Annexin V⁺ 7-AAD⁺) compared to the control group. Conclusion Our data support a role for apoptosis in SLE susceptibility.

Assessment of anti-Müllerian hormone levels in premenopausal patients with systemic lupus erythematosus

OBJECTIVE

The ovarian reserve of patients with systemic lupus erythematosus (SLE) may be affected by disease activity and medication use. Studies have found that patients with SLE have similar fertility rates as healthy women of the same age. The goal of the present study was to investigate the ovarian reserve of patients with SLE by measuring anti-Müllerian hormone (AMH) levels, and compare it to that of healthy controls.

METHOD

This was a case-control study performed on 80 premenopausal women, of whom 40 fulfilled the 1997 American College of Rheumatology (ACR) criteria for SLE and 40 healthy controls paired by oral contraceptive use. Serum concentrations of AMH in peripheral venous blood were measured using a human AMH ELISA kit (CUSABIO, Wuhan, China).

RESULTS

AMH serum levels did not differ between patients with SLE and controls (22.79 ± 17.32 ng/ml versus 21.41 ± 16.22 ng/ml, respectively, p = 0.7), even after adjusting for age (21.03 ± 2.074 ng/ml versus 23.97 ± 2.71 ng/ml; p = 0.5). AHM levels were not significantly correlated with disease duration (r = 0.2; p = 0.3), body mass index (r = 0.2; p = 0.2) and disease activity (SLEDAI (r = 0.1; p = 0.7)) and damage indices (SLICC (r = 0.1; p = 0.7)). No associations were found between AMH and ethnicity, current smoking, as well as current or prior use of cyclophosphamide and other immunosuppressants.

CONCLUSION

In this cross-sectional study, women with SLE demonstrated similar AMH levels as healthy controls, suggesting preserved ovarian reserve in this population.

Electroconvulsive therapy as a treatment for refractory neuropsychiatric lupus with catatonia: three case studies and literature review

Neuropsychiatric disorders associated with systemic lupus erythematosus are very common. Treatment generally consists of glucocorticoids and immunosuppressive therapy; however, some cases are unresponsive. Electroconvulsive therapy (ECT) is a recognized treatment modality in psychiatry and is an option for refractory cases of neuropsychiatric lupus. This report describes three cases of neuropsychiatric lupus that improved with ECT after failure of antipsychotics and immunosuppressive therapy. All cases met DSM-5 criteria for catatonia (case 1: agitation, stereotypies, and grimacing; case 2: stupor, mutism, and grimacing; case 3: agitation, mutism, and stereotypies); therefore, ECT was indicated. This case series shows that ECT can be a therapeutic option in patients with neuropsychiatric lupus, especially when associated with catatonia and unresponsive to conventional treatment.

HLA-G +3142 polymorphism as a susceptibility marker in two rheumatoid arthritis populations in Brazil

In this study, we sought to investigate the genetic influence of two HLA-G 3'-untranslated region (3'-UTR) polymorphisms - 14 bp (rs66554220) and +3142C>G (rs1063320) and their compounding haplotypes in susceptibility to rheumatoid arthritis (RA) in a two-region Brazilian study comprising of 539 patients and 489 controls. All subjects were polymerase chain reaction (PCR) genotyped for the referred polymorphisms and logistic regression models controlling for sex, city and age were performed. Homozygozity for the +3142G allele was associated with an increased risk of RA [odds ratio (OR) = 1.45, 95% confidence interval (CI) = 1.075-1.959, P(Bonf)  = 0.030], whereas no association was observed for the 14 bp polymorphism. Haplotype comparisons between patients and controls showed a decreased frequency of the delC haplotype in patients (OR = 0.70, 95% CI = 0.521-0.946, P(Bonf)  = 0.040), which remained significant in the rheumatoid factor (RF)-positive group (OR = 0.66, 95% CI = 0.482-0.900, P(Bonf)  = 0.018), but not in the RF-negative group. These results corroborate the hypothesis of an involvement of HLA-G in the susceptibility of RA. The +3142G allele is associated with haplotype lineages that share high identity and are regarded as low producers. The presence of the G allele in homozygosis could be responsible for a low HLA-G expression profile that could favor the triggering of RA.

Assessment of nailfold capillaroscopy in systemic sclerosis by different optical magnification methods

BACKGROUND

Systemic sclerosis (SSc) is characterized by target-organ fibrosis and microvascular dysfunction, which can be assessed using nailfold capillaroscopy. Dermoscopy is a useful and easily performed method for diagnosing skin lesions.

AIM

To compare conventional capillaroscopy, using the gold-standard method (conventional stereomicroscope nailfold capillaroscopy; SNFC), with polarized light noncontact dermoscopy (PNCD) and nonpolarized light contact dermoscopy (NPCD), and to evaluate their accuracy in diagnosing characteristic SSc-related alterations.

METHODS

The study enrolled 45 patients with SSc. Capillaroscopy images and photographs were taken with three devices, SNFC, NPCD and PNCD, and these images were randomly analysed by a blinded observer.

RESULTS

The scleroderma pattern was found in 83% of patients. PNCD and NPCD were highly sensitive in identifying the presence of focal capillary loss (96.4% and 100%, respectively), haemorrhage (96.2% and 92%, respectively), and scleroderma (91.9%, 94.6%), and showed high specificity for haemorrhage and enlarged loops. The intra-observer kappa values for detection of the scleroderma pattern by SNFC images, NPCD and PNCD were moderate to good: (κ = 0.71 (95% CI 0.44-0.95), κ = 0.60 (95% CI 0.35-0.83) and κ = 0.60 (95% CI 0.32-0.86), respectively. Evaluation of haemorrhage presence gave high kappa values for all methods: κ = 0.77 (95% CI 0.57-0.95), κ = 0.90 (95% CI 0.76-1.00) and κ = 0.95 (95% CI 0.85-1.00), respectively.

CONCLUSIONS

Both polarized and nonpolarized dermoscopy are reliable methods for valuation of nailfold capillaroscopy in patients with SSc. They are easy to perform, with good rates of accuracy and results that are comparable with traditional capillaroscopy.

CCR5delta32 in systemic lupus erythematosus: implications for disease susceptibility and outcome in a Brazilian population

The aim of this study was to analyze the allelic and genotypic frequencies of the CCR5delta32 polymorphism in systemic lupus erythematosus (SLE) patients and to investigate a possible association of this allele with SLE susceptibility and clinical outcome. A total of 367 SLE patients and 435 healthy controls were genotyped for the CCR5delta32 polymorphism. We observed that, in European-derived individuals, the frequency of the CCR5delta32 allele was smaller in patients than in controls (2.7% vs. 7.5%, OR 0.34, 95% CI 0.17-0.65, p Bonf=0.002), suggesting that this allele could be considered a protective factor for the disease. Regarding clinical manifestations, we observed that CCR5delta32 female African-derived carrier patients presented a higher predisposition to class IV nephritis when compared with absent nephritis/other class group (13.8% vs. 3.8%, OR 37.1, 95% CI 2.8-1854.7, p Bonf=0.030). A multivariate analysis including all female patients and controlling for the presence or absence of anti-dsDNA antibodies, ethnicity and age at diagnosis showed an increased relative risk of 3.9 times for patients carrying the CCR5delta32 allele to develop class IV nephritis as compared with noncarriers. Our data suggest that the CCR5delta32 allele is a protective factor for the disease in European-derived patients and a susceptibility factor to class IV nephritis in African-derived female patients.

Protective effect of RC-3095, an antagonist of the gastrin-releasing peptide receptor, in experimental arthritis

OBJECTIVE

To evaluate the antiinflammatory effects of RC-3095 in 2 experimental models of arthritis, collagen-induced arthritis (CIA) and antigen-induced arthritis (AIA), and to determine the mechanisms of action involved.

METHODS

RC-3095 was administered daily to mice with CIA and mice with AIA, after induction of disease with methylated bovine serum albumin. Disease incidence and severity were assessed using a clinical index and evaluation of histologic features, respectively. In mice with CIA, gastrin-releasing peptide receptor (GRPR) was detected by immunohistochemical analysis, while in mice with AIA, migration of neutrophils, presence of glycosaminoglycans, and lymphocyte proliferation, determined using the MTT assay, were assessed. Expression of cytokines interleukin-17 (IL-17), IL-1β, and tumor necrosis factor α (TNFα) was evaluated in all mouse knees using enzyme-linked immunosorbent assay. Treg cell production was assessed by flow cytometry in the joints of mice with AIA.

RESULTS

In mice with AIA, administration of RC-3095 reduced neutrophil migration, mechanical hypernociception, and proteoglycan loss. These findings were associated with inhibition of the levels of all 3 proinflammatory cytokines, decreased lymphocyte proliferation, and increased Treg cell numbers. In the CIA model, treatment with RC-3095 led to a significant reduction in arthritis clinical scores and the severity of disease determined histologically. Synovial inflammation, synovial hyperplasia, pannus formation, and extensive erosive changes were all dramatically reduced in the arthritic mice treated with RC-3095. Furthermore, arthritic mice treated with RC-3095 showed a significant reduction in the concentrations of IL-17, IL-1β, and TNFα, and showed a diminished expression of GRPR.

CONCLUSION

These findings suggest that the GRP pathway has a significant role in chronic arthritis, and its inhibition can be explored as a possible therapeutic strategy in rheumatoid arthritis.

Metabolic syndrome prevalence is increased in rheumatoid arthritis patients and is associated with disease activity

OBJECTIVES

To evaluate the prevalence of metabolic syndrome (MetS) in patients with rheumatoid arthritis (RA) vs. controls, and to verify possible associations of MetS with specific disease-related factors.

METHODS

The subjects were 283 RA patients and 226 healthy controls, frequency matched by age and sex. MetS was defined according to National Cholesterol Education Program (NCEP) criteria. Disease activity was evaluated with the Disease Activity Score using 28 joints (DAS28). A standardized clinical evaluation was performed and cardiovascular risk factors were assessed.

RESULTS

The criteria for MetS were met by 39.2% RA patients vs. 19.5% in the control group (p < 0.001). Increased waist circumference, elevated blood pressure (BP), and fasting glucose were more frequent in RA patients than controls (p < 0.001 for all associations). By multiple logistic regression analysis (adjusted for age, sex, and years at school), the risk of having MetS was significantly higher for RA patients than for controls [odds ratio (OR) 1.87, 95% confidence interval (CI) 1.17-3.00, p = 0.009]. The DAS28 was significantly higher in RA patients with MetS than in those without MetS (3.59 ± 1.27 vs. 3.14 ± 1.53; p = 0.01). Disease duration, the presence of rheumatoid factor, and extra-articular manifestations were similar for patients with and without MetS.

CONCLUSIONS

MetS frequency was higher in RA patients than in controls. Among RA patients, MetS was associated with disease activity. The higher prevalence of cardiovascular risk factors in RA suggests that inflammatory processes play a notable role in the development of cardiovascular disease (CVD), and indicates that tight control of systemic inflammatory activity and CVD modifiable risk factors should be recommended.

A combined enrichment/polymerase chain reaction based method for the routine screening of Streptococcus agalactiae in pregnant women

Group B Streptococcus (GBS) is the most common cause of life-threatening infection in neonates. Guidelines from CDC recommend universal screening of pregnant women for rectovaginal GBS colonization. The objective of this study was to compare the performance of a combined enrichment/PCR based method targeting the atr gene in relation to culture using enrichment with selective broth medium (standard method) to identify the presence of GBS in pregnant women. Rectovaginal GBS samples from women at ≥36 weeks of pregnancy were obtained with a swab and analyzed by the two methods. A total of 89 samples were evaluated. The prevalence of positive results for GBS detection was considerable higher when assessed by the combined enrichment/PCR method than with the standard method (35.9% versus 22.5%, respectively). The results demonstrated that the use of selective enrichment broth followed by PCR targeting the atr gene is a highly sensitive, specific and accurate test for GBS screening in pregnant women, allowing the detection of the bacteria even in lightly colonized patients. This PCR methodology may provide a useful diagnostic tool for GBS detection and contributes for a more accurate and effective intrapartum antibiotic and lower newborn mortality and morbidity.

TLR7/8/9 polymorphisms and their associations in systemic lupus erythematosus patients from Southern Brazil

Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease and can affect several organs and systems. It is characterized by high production of autoantibodies against nuclear compounds. TLR7/8/9 are responsible for nucleic acid recognition and they trigger proinflammatory responses through activation of NK-kappaB and Type I IFN production, making a bridge between the innate and the adaptative immune systems. We analyzed the frequency of TLR7 rs179008, TLR8 rs3764880, TLR9 rs5743836 and rs352140 in 370 patients with SLE and 415 healthy controls from southern Brazil. All analyses were conducted with regard to gender and ethnicity. Genotypic and allelic frequencies were different for TLR7 rs179008 (0.253 vs. 0.163, p = 0.020 and p = 0.003, OR for T allele: 1.74 CI 95% 1.12–2.70) and TLR9 rs5743836 (0.174 vs. 0.112, p = 0.045 and p = 0.017, OR for C allele: 1.59, CI 95% 0.99–2.57) between European-derived female groups. A higher frequency was observed for the presence of Anti-SSa/Ro for TRL9 rs5743836 C allele carriers (0.228 vs 0.126, Bonferroni corrected p = 0.06). No statistical differences were found for TLR9 haplotypic analyses. We suggest that TLR7 rs179008 and TLR9 rs5743836 can be considered SLE susceptibility factors for women of European descent in our population.

The role of BsmI and FokI vitamin D receptor gene polymorphisms and serum 25-hydroxyvitamin D in Brazilian patients with systemic lupus erythematosus

Vitamin D deficiency has been described in systemic lupus erythematosus (SLE). BsmI VDR (vitamin D receptor) gene polymorphism was associated with SLE in Asian patients. Studies in Brazilian populations have not been realized. A case-control study with 195 SLE patients and 201 healthy controls was conducted to investigate the influence of BsmI and FokI VDR gene polymorphisms on susceptibility to SLE. In addition, 25-hydroxyvitamin D [25(OH)D] was measured in SLE patients to evaluate possible associations with VDR polymorphic variants and clinical and laboratory expressions of disease. Genotyping was performed by RFLP-PCR. The measurement of 25(OH)D was performed by chemiluminescence. There was no statistically significant difference in genotype and allelic frequencies of BsmI and FokI polymorphisms between European-derived cases and controls. The mean serum levels of 25(OH)D were 25.51 ± 11.43 ng/ml in SLE patients. According to genotype distribution, 25(OH)D concentrations were significantly higher in patients carrying the FokI f/f genotype compared with patients carrying the F/F genotype (31.6 ± 14.1 ng/ml versus 23.0 ± 9.2 ng/ml, p = 0.004), reinforcing its role in the functional activity of VDR. This feature may be considered in future clinical and experimental studies involving vitamin D measurements. Therefore, genetic-specific definitions of ideal levels of vitamin D in SLE need to be established in future studies.

Association of the HLA-G gene +3142C>G polymorphism with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease that affects several organs and systems. Its etiology remains unknown, although it is probably multifactorial. The human leukocyte antigen G (HLA-G) is a nonclassic major histocompatibility complex I molecule characterized by restricted expression and low DNA polymorphism. HLA-G plays a role in immunosuppression through different mechanisms. In inflammatory diseases, it has been postulated that HLA-G expression may be a possible mechanism of tissue protection against exacerbated inflammatory response. On the 3' untranslated region (3' UTR) of the HLA-G gene, there is an insertion/deletion polymorphism of 14 bp (rs1704) that was shown to influence the mRNA stability. The influence of this polymorphism in disease susceptibility is controversial. Also in the 3' UTR there is a single nucleotide polymorphism C/G (rs1063320) on the position +3142, at a possible binding site for microRNAs (miRNAs) and having an influence on miRNA affinity. In this study, we analyzed the +3142C>G and the 14 bp polymorphisms in 195 SLE European-derived female patients. Our findings show a significant increase of the +3142G allele frequency among patients as compared with controls (0.58 vs 0.47, P = 0.011). Also, patients presented a higher frequency of the GG genotype (OR = 1.90, 95% CI: 1.08-3.42). Double heterozygotes for the two polymorphisms presented a milder mean systemic lupus erythematosus disease activity index (SLEDAI) than heterozygotes for only one of the variants or non-heterozygous individuals (1.56 vs 3.15 and 3.26, respectively, corrected P = 0.044). These results suggest the involvement of the HLA-G molecule on SLE susceptibility and outcome.

Multinational evidence-based recommendations on how to investigate and follow-up undifferentiated peripheral inflammatory arthritis: integrating systematic literature research and expert opinion of a broad international panel of rheumatologists in the 3E Initiative

Objective

To develop evidence-based recommendations on how to investigate and follow-up undifferentiated peripheral inflammatory arthritis (UPIA).

Methods

697 rheumatologists from 17 countries participated in the 3E (Evidence, Expertise, Exchange) Initiative of 2008–9 consisting of three separate rounds of discussions and modified Delphi votes. In the first round 10 clinical questions were selected. A bibliographic team systematically searched Medline, Embase, the Cochrane Library and ACR/EULAR 2007–2008 meeting abstracts. Relevant articles were reviewed for quality assessment, data extraction and synthesis. In the second round each country elaborated a set of national recommendations. Finally, multinational recommendations were formulated and agreement among the participants and the potential impact on their clinical practice was assessed.

Results

A total of 39 756 references were identified, of which 250 were systematically reviewed. Ten multinational key recommendations about the investigation and follow-up of UPIA were formulated. One recommendation addressed differential diagnosis and investigations prior to establishing the operational diagnosis of UPIA, seven recommendations related to the diagnostic and prognostic value of clinical and laboratory assessments in established UPIA (history and physical examination, acute phase reactants, autoantibodies, radiographs, MRI and ultrasound, genetic markers and synovial biopsy), one recommendation highlighted predictors of persistence (chronicity) and the final recommendation addressed monitoring of clinical disease activity in UPIA.

Conclusions

Ten recommendations on how to investigate and follow-up UPIA in the clinical setting were developed. They are evidence-based and supported by a large panel of rheumatologists, thus enhancing their validity and practical use.

Killer cell immunoglobulin-like receptor (KIR) genes in systemic sclerosis

A previous study has suggested that the combination KIR2DS2(+)/KIR2DL2(-) was related to increased risk for systemic sclerosis (SSc), while others have failed to reproduce this finding. Our objective was to study this matter further and test the association of other KIR genes with SSc. One hundred and ten SSc patients and 115 healthy bone marrow donors were enrolled in a case-control study. Blood was collected for DNA extraction; typing of 15 KIR genes and human leucocyte antigen-C (HLA-C) was made by polymerase chain reaction with sequence specific primers (PCR-SSP), followed by electrophoresis on agarose gel. Patients underwent clinical evaluation, serology, Doppler echocardiography and chest high-resolution computed tomography. The frequency of the inhibitory KIR2DL2 was significantly lower in patients [29.1% versus 65.2% in controls, P < 0.0001; odds ratio (OR) = 0.22, 95% confidence interval 0.12-0.40]. When combinations of activating and inhibitory KIR genes were analysed, the presence of KIR2DS2 in the absence of KIR2DL2 (KIR2DS2(+)/KIR2DL2(-)) was more frequent in patients than in controls (25.5% versus 1.7%, respectively; P < 0.0001; OR = 19.29, 4.24-122.26). However, the presence of both KIR2DS2 and KIR2DL2 (KIR2DS2(+)/KIR2DL2(+)) was more frequent in controls (57.4%) than in patients (28.2%, P < 0.0001), suggesting a preponderant protective effect of KIR2DL2 over KIR2DS2. Stratification for HLA-C1 status did not change these results. No statistically significant associations were found between KIR phenotypes and clinical and laboratory features of SSc. Our results suggest a protective role of KIR2DL2(+) phenotype and confirmed the association of the combination KIR2DS2(+)/KIR2DL2(-) with increased risk for SSc.

Mannose-binding lectin gene polymorphisms in Brazilian patients with systemic lupus erythematosus

The mannose-binding lectin gene (MBL-2) has emerged as a candidate for systemic lupus erythematosus susceptibility, but studies in Brazilian population have not been conducted. To examine potential associations of mannose-binding lectin alleles G57E, G54D, IVSnt5, R52C and R52H with susceptibility to and clinical expression of systemic lupus erythematosus in southern Brazilian patients, we conducted a case—control study with 327 consecutive patients with diagnosis of systemic lupus erythematosus and 345 healthy controls. Genotyping was performed by restriction fragment length polymorphism—polymerase chain reaction assay. A statistically significant difference in the frequencies of allele R52C was observed in European-derived systemic lupus erythematosus patients when compared with controls (9.6% vs. 3.3%, p < 0.001, odds ratio: 3.15, 95% confidence interval: 1.76—5.62, p < 0.05). The frequencies of alleles G54D and G57E were not different between European-derived systemic lupus erythematosus patients and controls. There were no differences between clinical and laboratory features in systemic lupus erythematosus patients according to the presence or absence of mannose-binding lectin allelic variants. These results support an increased risk of systemic lupus erythematosus in European-derived individuals carrying allele R52C. Patients carrying this allele have an approximately three-fold higher odds ratio of developing systemic lupus erythematosus when compared with controls. Our data do not support associations between the mannose-binding lectin allelic variants studied and clinical expression of systemic lupus erythematosus. Lupus (2010) 19, 280—287.

Association of the HLA-G 14 bp polymorphism with systemic lupus erythematosus

Human leukocyte antigen-G (HLA-G) is a nonclassical class I major histocompatibility complex molecule which is induced at the course of inflammatory pathologies, and its expression has been suggested as a possible mechanism of tissue protection against autoimmune inflammatory responses, therefore acting as a mechanism of immune surveillance. We investigated the influence of the 14 bp polymorphism of the HLA-G gene on systemic lupus erythematosus (SLE) by analyzing 293 patients with SLE and 460 healthy controls. The patient's group was not in Hardy-Weinberg equilibrium, presenting an excess of heterozygotes (P = 0.014). The heterozygote group exhibited lower systemic lupus erythematosus disease activity indexes than the homozygous deletion group and the homozygous insertion group (mean value = 2.29 against 2.97 and 3.4, respectively, P = 0.035). Photosensitive patients showed a higher frequency of heterozygotes and an equivalent lower frequency of homozygotes for deletion; on the other hand, patients without arthritis presented a higher frequency of heterozygotes than the arthritis group and also a lower frequency of the del/del genotype. Overall, our results support the idea of a role of the HLA-G insertion/deletion polymorphism and therefore a role for the HLA-G molecule, on the pathology of SLE.

ABCB1 C1236T, G2677T/A and C3435T polymorphisms in systemic lupus erythematosus patients

P-glycoprotein (Pgp), the ABCB1 gene product, acts as an efflux pump that transports a large variety of substrates and is a mechanism of cell protection against xenobiotics. An increasing number of studies have shown that some ABCB1 polymorphisms may affect Pgp expression and activity, as well as affecting the development and susceptibility to diseases and pharmacological response. High activity of Pgp has been detected in systemic lupus erythematosus (SLE) patients. The C1236T, G2677T/A, and C3435T are the most commonly studied single nucleotide polymorphisms in the ABCB1 gene. Therefore, their frequencies were determined in Brazilian individuals with European ancestry (N = 143) and in SLE patients (N = 137). Genotyping was performed by PCR-RFLP analysis using specific primers followed by incubation with the appropriate restriction enzymes. The resulting DNA fragments were visualized on agarose or polyacrylamide gels. No statistically significant differences were observed in allelic and genotypic frequencies between SLE and healthy subjects (Fisher exact test). Nevertheless, the 2677A allelic frequency was lower in SLE patients with malar rash (0.007) compared with patients without this feature (0.04; P = 0.0054), while the frequency of this variant was higher in SLE patients with pleuritis (0.07) compared with patients without this feature (0.01; P = 0.0156). We suggest that although the ABCB1 polymorphisms do not directly interfere in SLE susceptibility, their evaluation, especially the 2677A allele, in other immunological processes may be interesting since they can interfere in clinical features of this disease.

Glu298Asp eNOS polymorphism is not associated with SLE

To examine potential associations of the Glu298Asp polymorphism in the coding region of the endothelial nitric oxide synthase (eNOS) gene with susceptibility to and clinical expression of systemic lupus erythematosus (SLE). One hundred thirteen consecutive patients of European ancestry with diagnosis of SLE, satisfying the American College of Rheumatology criteria, from the outpatient clinic of the Serviço de Reumatologia of the Hospital de Clínicas de Porto Alegre, and 206 healthy controls from the same geographic area were genotyped by polymerase chain reaction for the Glu298Asp polymorphism in the coding region of the eNOS gene. Clinical, demographic, and laboratorial data were collected. Clinical manifestations of SLE and related diseases were evaluated for the association with specific genotypes. The allelic and genotypic distribution of the Glu298Asp did not differ significantly between SLE patients and controls. We found no association of the polymorphism with lupus nephritis, antiphospholipid syndrome, cardiovascular disease (CVD), and risk factors to CVD. The presented results in this study do not provide support for a major role of eNOS Glu298Asp neither in the susceptibility for SLE or clinical manifestations, although there was low statistical power for the latter evaluation.

Effects of an antagonist of the bombesin/gastrin-releasing peptide receptor on complete Freund's adjuvant-induced arthritis in rats

OBJECTIVE

To determine the effects of RC-3095 in clinical and histopathologic parameters and inflammatory mediators on complete Freund's adjuvant-induced arthritis (CFA).

METHODS

The arthritis was induced by injection of CFA into the left hind footpad. The animals were divided into control, vehicle injected control, placebo group (saline subcutaneously 50ml/kg, once daily for 8 days after modeling), treatment group (0.3mg/kg of RC-3095 subcutaneously, once daily for 8 days after induction). Clinical evaluation was accomplished daily, through scoring of the paw edema. The animals were sacrificed 15 days after induction for collection of hind foot joints for histology. We used a histological scoring system which was previously described, and interferon (INF)-gamma, interleukin (IL)-1beta, tumor necrosis factor (TNF), interleukin (IL)-6 and interleukin (IL)-10 were measured by ELISA.

RESULTS

There was a significant inhibition of joint histological findings in the RC-3095 treated group, including synovial inflammatory infiltration and hyperplasia, cartilage and bone erosion. IFN-gamma, IL-1beta, TNF, IL-6 and IL-10 serum levels were significantly lower in the treated group. Paw swelling and subcutaneous inflammation, evaluated clinically, were not different between CFA-induced groups.

CONCLUSIONS

RC-3095 was able to improve experimental arthritis, attenuate joint damage and decrease serum levels of IFN-gamma, IL-1beta, TNF, IL-6 and IL-10. These data indicate that interference with GRP pathway is a potential new strategy for the treatment of RA that needs further investigational studies.

Redox signalling and the inflammatory response in rheumatoid arthritis

Reactive oxygen species (ROS) are produced mainly during oxidative phosphorylation and by activated phagocytic cells during oxidative burst. The excessive production of ROS can damage lipids, protein, membrane and nucleic acids. They also serve as important intracellular signalling that enhances the inflammatory response. Many studies have demonstrated a role of ROS in the pathogenesis of inflammatory chronic arthropathies, such as rheumatoid arthritis. It is known that ROS can function as a second messenger to activate nuclear factor kappa-B, which orchestrates the expression of a spectrum of genes involved in the inflammatory response. Therefore, an understanding of the complex interactions between these pathways might be useful for the development of novel therapeutic strategies for rheumatoid arthritis.

GSTT1, GSTM1 and GSTP1 polymorphisms and susceptibility to juvenile idiopathic arthritis

OBJECTIVE

In this study we have analyzed GSTM1, GSTT1 and GSTP1 polymorphisms in patients with juvenile idiopathic arthritis (JIA), to investigate a possible role of these genes as genetic components of the disease.

METHODS

A total of 103 individuals (49 oligoarticular, 41 polyarticular and 13 systemic) were analyzed for the three polymorphisms, using a PCR/RFLP methodology.

RESULTS

We have observed significantly increased frequencies of individuals with GSTT1 null genotype in JIA patients comparing to controls (37% x 21%; p=0.0183). There was a 2-fold increased risk (OR 2.2, 95% CI 1.2-4.1) associating the disease with the GSTT1 null genotype. Considering the subgroups (oligoarticular, polyarticular and systemic), the results indicated an association between polyarticular and systemic patients and the GSTT1 null genotype. There was a 2-fold increased risk for polyarticular patients (OR 2.4, 95%, CI 1.1-5.4), and a 4-fold increased risk for systemic patients (OR 4.4, 95%, 1.3-14.5).

CONCLUSION

The GSTT1 null genotype seems to be involved in polyarticular and systemic JIA.

The chemokine receptor CCR5 genetic polymorphism and expression in rheumatoid arthritis patients

OBJECTIVES

To identify the genetic polymorphism of the chemokine receptor CCR5 (the Delta32 allelic variant) in patients with rheumatoid arthritis (RA) and compare the findings with healthy controls. To compare the CCR5 phenotypic expression in T cells and monocytes isolated from the peripheral blood and synovial fluid in a subgroup of RA patients.

METHODS

CCR5 genes of 92 RA patients and 160 healthy controls were genotyped using specific primers flanking the region of deletion. The ethnic distribution was similar between the groups. Flow cytometric analysis was used for immunophenotyping the T cells and monocytes isolated from the peripheral blood and synovial fluid of eight RA patients. The isolated cells were triple stained with CD4 or CD8, CD25 and CCR5 monoclonal antibodies.

RESULTS

There was no difference in the CCR5Delta32 genotypic frequency between the RA patients and the control group (0.055 and 0.063, respectively, p = 0.989). No homozygote for the CCR5Delta32 allele was seen in either group. Five heterozygotes were identified in the RA patient group, whose disease was shown to be aggressive. A significant enrichment of activated CCR5+ monocytes was seen in the synovial fluid of the RA patients subjected to arthrocentesis, who were all homozygotes for the CCR5 wild-type genotype.

CONCLUSION

A protective role for the CCR5 allelic variant in RA development was not observed. Disease severity in the heterozygotes suggests that other proinflammatory mechanisms might overcome this mutation in vivo. The activated CCR5+ monocyte enrichment in the rheumatoid synovial fluid might indicate that this cell population has an important role in the pathogenesis of the disease.

Oesophageal dysmotility in systemic sclerosis: comparison of HRCT and scintigraphy

The aim of this study was to compare oesophageal abnormalities observed in high-resolution CT with radionuclide transit in patients with systemic sclerosis. 76 patients with systemic sclerosis were evaluated by high-resolution CT and oesophageal transit scintigraphy. Residual activity > or =20% (in relation to peak activity) at 15 s after the beginning of the swallow of the labelled liquid (in supine position) was considered indicative of oesophageal dysfunction. Supra-aortic and infra-aortic oesophageal coronal diameters were measured in high-resolution CT. Oesophageal dilatation was deemed present when the diameters exceeded 10 mm. 19 patients (25%) had supra-aortic oesophageal dilatation and 48 patients (63.1%) had infra-aortic dilatation. The prevalence of radionuclide transit delay was 77.6%. All patients (19/19) with supra-aortic dilatation had oesophageal dysfunction, compared with 70.2% (40/57) of the patients with no supra-aortic dilatation (p = 0.004). Oesophageal dysfunction was present in 97.9% (47/48) of patients with infra-aortic dilatation, compared with 42.9% (12/28) in patients without it (p < 0.001). Receiver operating characteristic (ROC) curves have demonstrated that the supra-aortic and infra-aortic diameters had good discriminatory capacity for oesophageal dysfunction in systemic sclerosis (area under the curve, 95% confidence interval: 0.80, 0.70-0.89 and 0.92, 0.86-0.98, respectively). There is a clinically significant association between oesophageal dysmotility and high-resolution CT findings of oesophageal coronal dilatation. The evaluation of infra-aortic oesophageal coronal diameter can provide additional useful information about the functional and anatomic conditions of the oesophagus in systemic sclerosis.

Raised serum S100B protein levels in neuropsychiatric lupus

OBJECTIVE

To test serum S100B protein levels in patients with and without neuropsychiatric systemic lupus erythematosus (NPSLE) and controls.

METHODS

87 patients with SLE, 23 with and 64 without neuropsychiatric involvement, and 25 control subjects were prospectively evaluated. NPSLE diagnosis was made according to the American College of Rheumatology nomenclature and case definitions for neuropsychiatric lupus syndromes. Serum S100B protein levels were determined with a luminescence immunoassay. Statistical analysis was performed using Mann-Whitney and Kruskal-Wallis tests.

RESULTS

Among the patients with NPSLE, 9 presented psychosis; 4, cranial neuropathy; 3, cerebrovascular disease; 1, seizures; 1, chorea; 1, peripheral polyneuropathy; 1, multiplex mononeuropathy; 3, dementia. Serum concentrations of S100B protein were significantly higher in patients with NPSLE (median 0.164 ng/ml, interquartile range 0.113-0.332) than in non-NPSLE patients (0.062 ng/ml, 0.026-0.109) and controls (0.088 ng/ml, 0.013-0.124) (p<0.001). Patients with anti-dsDNA antibodies had higher S100B protein levels (p = 0.001). No significant associations were found of lupus activity (among non-NPSLE cases), antiphospholipid antibodies, and reduced complement levels with S100B concentration.

CONCLUSIONS

Serum S100B protein level is raised in NPSLE, reflecting continuing neurological damage. The association of anti-dsDNA antibodies with higher S100B protein concentration deserves further study.

Nailfold capillaroscopic findings in primary Sjögren's syndrome: clinical and serological correlations

OBJECTIVE

To describe the capillaroscopic abnormalities observed in patients with primary Sjögren's Syndrome (pSS), associating them with clinical and serologic features, and comparing these findings to those observed in normal controls.

METHODS

Sixty-one consecutive patients with pSS were studied by clinical evaluation, serology, and nailfold capillary microscopy (NCM). Twenty-one normal controls were also examined. Capillaroscopic findings were recorded in a standardized way by a blinded observer Capillary loss on NCM was evaluated using a deletion score.

RESULTS

NCM was normal in 59.0% of pSS patients; 29.5% had non-specific abnormalities, and 11.5% presented a SD-like pattern. Patients presented a higher deletion score than controls (p < 0.001). Other capillaroscopic parameters (number of dilated, bizarre, and meandering capillaries; capillary hemorrhages; venous plexus visibility) did not differ significantly between patients and controls. Among patients, the deletion score was higher in those with systemic manifestations (p = 0.022) and Raynaud's phenomenon (p = 0.050). No association between the presence of antinuclear antibodies, rheumatoid factor, anti-SSA/Ro and anti-SSB/La with qualitative or quantitative NCM findings was found. Among the 7 patients with SD-like pattern on NCM, 6 had Raynaud's phenomenon, but only 2 presented autoantibodies related to systemic sclerosis (1 with anticentromere and 1 with low titer antitopoisomerase I). None of these patients met the ACR criteria for SSc.

CONCLUSIONS

SD-like pattern on NCM is observed in a small but significant proportion of pSS patients. The association of systemic involvement with a higher deletion score may be related to the hypothesis that these manifestations represent clinical expressions of systemic vasculitis.

Lung clearance of 99mTc-DTPA in systemic lupus erythematosus

The early demonstration of lung involvement in systemic lupus erythematosus (SLE) patients is a difficult but important task. In the present study we attempted to identify abnormalities in pulmonary clearance of 99mTc-DTPA in SLE, correlating their clearance data with clinical findings and disease activity. Forty-six consecutive SLE patients with and without active disease (LACC score) and 30 normal volunteers were studied. All subjects were submitted to pulmonary scintigraphy with 99mTc-DTPA to evaluate the pulmonary clearance, and to a chest X-ray, and SLE patients were submitted to tests of disease activity, spirometry, arterial blood gases and tests to assess acute-phase proteins. Pulmonary clearance was faster in SLE patients with active disease when compared to normal controls [half-life of 67.04 min (51.52-82.55 min) in active SLE versus 85.87 min (78.85-92.87 min) in controls, P<0.05] and there was a higher frequency of abnormal clearance rates in patients with active disease (11 of 26 patients, 42.3%) when compared with SLE patients without disease activity (2 of 20 patients, 10%) (P = 0.04). A significant correlation was observed between the clearance rates and cough (P<0.05), but not between the clearance rates and dyspnea symptoms or radiological findings, duration of SLE disease, antinuclear antibody titers and patterns, C-reactive protein or anti-double stranded DNA antibodies. We conclude that the pulmonary clearance of 99mTc-DTPA is increased in SLE patients with active disease.

Ubiquitin-like moiety of the monoclonal nonspecific suppressor factor beta is responsible for its activity

Monoclonal nonspecific suppressor factor (MNSF), a lymphokine produced by murine T cell hybridoma, possesses pleiotrophic Ag-nonspecific suppressive functions. Most recently, a cDNA clone encoding MNSF beta (a subunit of MNSF) was isolated and characterized. The MNSF beta cDNA encodes a 14.5-kDa fusion protein with MNSF-like activity consisting of an 8-kDa ubiquitin-like segment (ubi-L) and the ribosomal protein S30 (6.5 kDa). To determine whether ubi-L itself has biologic activity, cDNA encoding the ubi-L region was expressed in bacteria and the recombinant product was tested for the activity. Ubi-L showed MNSF-like biologic activity without any cytotoxic action. Interestingly, the addition of ubiquitin to the assay inhibited ubi-L-induced suppression. IFN-gamma, which is known to enhance the expression of MNSF receptor, induced splenocytes to secrete ubi-L by increasing mRNA. Ubi-L has species-specific action and the ability to selectively inhibit the B cell proliferative response stimulated by soluble but not by Sepharose-bound anti-Ig Ab. In addition, okadaic acid, a serine/threonine phosphatase 1 and 2A inhibitor, showed a synergistic inhibitory action with ubi-L, indicative of the possible involvement of phosphatase(s) in the regulation of ubi-L action.

Ubiquitin-like moiety of the monoclonal nonspecific suppressor factor beta is responsible for its activity

Monoclonal nonspecific suppressor factor (MNSF), a lymphokine produced by murine T cell hybridoma, possesses pleiotrophic Ag-nonspecific suppressive functions. Most recently, a cDNA clone encoding MNSF beta (a subunit of MNSF) was isolated and characterized. The MNSF beta cDNA encodes a 14.5-kDa fusion protein with MNSF-like activity consisting of an 8-kDa ubiquitin-like segment (ubi-L) and the ribosomal protein S30 (6.5 kDa). To determine whether ubi-L itself has biologic activity, cDNA encoding the ubi-L region was expressed in bacteria and the recombinant product was tested for the activity. Ubi-L showed MNSF-like biologic activity without any cytotoxic action. Interestingly, the addition of ubiquitin to the assay inhibited ubi-L-induced suppression. IFN-gamma, which is known to enhance the expression of MNSF receptor, induced splenocytes to secrete ubi-L by increasing mRNA. Ubi-L has species-specific action and the ability to selectively inhibit the B cell proliferative response stimulated by soluble but not by Sepharose-bound anti-Ig Ab. In addition, okadaic acid, a serine/threonine phosphatase 1 and 2A inhibitor, showed a synergistic inhibitory action with ubi-L, indicative of the possible involvement of phosphatase(s) in the regulation of ubi-L action.

Monoclonal nonspecific suppressor factor beta inhibits interleukin-4 secretion by a type-2 helper T cell clone

Monoclonal nonspecific suppressor factor (MNSF) is a lymphokine product of a murine T cell hybridoma that inhibits the generation of lipopolysaccharide-induced immunoglobulin secreting cells in an antigen-nonspecific manner. Most recently, a cDNA clone encoding MNSF beta, a subunit of MNSF, was isolated and sequenced (Nakamura et al., Proc. Natl. Acad. Sci. USA 1995. 92: 3463). The MNSF beta cDNA encodes a 14.5-kDa ubiquitin-like protein showing several MNSF activities. We have previously observed that hybridoma-derived native MNSF can inhibit interleukin (IL)-4 secretion by bone marrow-derived mast cells. Therefore, we studied whether MNSF beta is also able to inhibit IL-4 secretion by the type-2 helper T cell clone D10. G4.1. MNSF beta inhibited both the IL-4 secretion and the proliferation of concanavalin A-activated D10 cells, although neither effect was complete.

HLA class II genotyping by polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP) in systemic lupus erythematosus patients

Recently, genotyping of HLA class II alleles by digestion of polymerase chain reaction (PCR) amplified polymorphic DNA region with restriction endonucleases (PCR-RFLP) has been reported and claimed to be a simple and reliable technique. We tested the use of PCR-RFLP for genotyping of DQA 1, DQB 1, DPB 1 and DRB 1 alleles of 40 normal individuals and 19 patients with systemic lupus erythematosus (SLE). In agreement with previous reports, we observed an association of SLE with the DRB 1*1501-DQA 1*0102-DQB 1*0602 haplotype and noted an unreported association with DPB 1*0501. Although these observations must be confirmed with larger sample sizes, we believe that the PCR-RFLP is simpler and more practical than the sequence-specific oligonucleotides (PCR-SSO) for genotyping and can be invaluable to the more widespread molecular determination of HLA-class II specificities, including in non-specialized laboratories.

Molecular cloning and characterization of a cDNA encoding monoclonal nonspecific suppressor factor

The monoclonal nonspecific suppressor factor (MNSF) is a lymphokine product of a murine T-cell hybridoma that inhibits the generation of lipopolysaccharide-induced immunoglobulin-secreting cells in an antigen-nonspecific manner. A cDNA clone encoding MNSF beta (an isoform of MNSF) was isolated and expressed in bacteria. The sequence obtained is virtually identical to the Fau protein, a product of the ubiquitously expressed fau gene with unknown function. Northern blot analysis demonstrated a single, 0.6-kb transcript. Specific polyclonal antibodies against synthetic peptides corresponding to the deduced amino acid sequences were elicited in rabbits. Immunoprecipitation experiments with these antibodies showed that MNSF beta is released extracellularly in an aggregate form, albeit it lacks a signal peptide sequence. The anti-MNSF beta affinity eluate from the MNSF-producing murine hybridoma (E17) and concanavalin A-activated splenocyte culture supernatants inhibited the immunoglobulin production by lipopolysaccharide-activated splenocytes. Recombinant MNSF beta also showed a similar biologic activity. Thus, ubiquitin-like protein(s) may be involved in the regulation of the immune responses.

The role of cyclic AMP in the lipopolysaccharide-induced suppression of thymidine kinase activity in macrophage

We observed that lipopolysaccharide (LPS, 1 micrograms/ml) can suppress [3H]thymidine incorporation into acid-insoluble fraction in a mouse macrophage cell line J774 (over 70% at 6 h) without affecting the uptake of [3H]thymidine or DNA polymerase activity. Paralleling this suppression, a decrease in the thymidine kinase (TK) activity, but not of thymidine monophosphate (TMP) kinase and thymidine diphosphate (TDP) kinase, was observed. LPS dose-dependently increased intracellular cAMP levels to about 3.5-times basal at 6 h, proportionally to the decrease of the TK activity. Elevation of intracellular cAMP by several reagents also decreased TK activity. Apparently LPS treatment elevates cAMP concentration by decreasing the low Km cAMP phosphodiesterase activity (58% at 6 h). The time course of cAMP-dependent protein kinase (PK-A) activity during the first 6 h after LPS treatment correlated with that of cAMP concentration. Treatment with a PK-A inhibitor restored about 63% of LPS-induced reduction of TK activity at 6 h. At longer times, however, there was a discrepancy between the change of cAMP concentration or PK-A activity and the reduction of TK activity. Therefore, protein kinase activation caused by the accumulation of intracellular cAMP probably triggers some mechanism responsible for the reduction of the TK activity.

Antinuclear antibodies in healthy aging people: a prospective study

In order to evaluate the expression of antinuclear antibodies (ANA) in normal elderly individuals over time and clinical significance, a cross-sectional ANA testing in healthy Japanese was performed, followed by annual evaluations of ANA positive aged (> or = 65 years) and a control group. ANA was more prevalent in the aged (11.4% vs. 3.8%) and most were persistent after 4 years. Anti-ssDNA and anti-histone antibodies were increased in aged ANA positive as compared to ANA negative controls. Except for a history of spontaneous abortion, there was no differences in clinical findings. HLA DRB1*0901 and the DQB1*0602 + 0302 + 0303 set of alleles were increased in ANA positive. Therefore, ANA in the aged were persistent, apparently directed toward chromatin elements, and shared MHC associations with autoimmune diseases. Longer follow-up may be necessary to improve the evaluation of clinical significance of ANA in the aged.

Isolation and characterization of a human nonspecific suppressor factor from ascitic fluid of systemic lupus erythematosus. Evidence for a human counterpart of the monoclonal nonspecific suppressor factor and relationship to the T cell receptor alpha-chain

The monoclonal nonspecific suppressor factor (MNSF) is a lymphokine produced by a murine T cell hybridoma capable of suppressing Ab production by LPS-stimulated B cells. The existence of a human counterpart of MNSF, designated as the human nonspecific suppressor factor (hNSF), was likely because the anti-MNSF mAb (MO6) recognizes a similar suppressive activity in supernatants of Con A-stimulated human PBMC. By using the MO6 mAb, we investigated the presence of hNSF in the ascitic fluid of a patient with SLE. A small amount of cross-reactive hNSF was isolated from concentrated ascitic fluid fractionated with the MO6-affinity column, and a specific anti-hNSF mAb (P2) was produced. The hNSF eluted from the P2-affinity column could suppress up to 80% of the PWM-induced IgG production of human PBMC in a dose-dependent manner, even when added in late culture periods. Moreover, hNSF could inhibit proliferation of PBMC triggered by either PWM or Con A, which also implies an effect on T cells. On SDS-PAGE, the isolated hNSF resolved as a single peak of about 66 kDa and probably represents an aggregate of hydrophobic subunits. On reverse-phase HPLC, the bioactivity could be recovered from a single peak at 18.3 min. The suppression of IgG production induced by hNSF could be partly neutralized by preincubation with an anti-TCR-alpha mAb, whereas an anti-TCR-beta did not have any effect. Anti-TCR-alpha could also directly bind to the isolated nNSF, demonstrating some serologic relationship, as has been reported for several Ag-specific suppressor systems.

Isolation and characterization of a human nonspecific suppressor factor from ascitic fluid of systemic lupus erythematosus. Evidence for a human counterpart of the monoclonal nonspecific suppressor factor and relationship to the T cell receptor alpha-chain

The monoclonal nonspecific suppressor factor (MNSF) is a lymphokine produced by a murine T cell hybridoma capable of suppressing Ab production by LPS-stimulated B cells. The existence of a human counterpart of MNSF, designated as the human nonspecific suppressor factor (hNSF), was likely because the anti-MNSF mAb (MO6) recognizes a similar suppressive activity in supernatants of Con A-stimulated human PBMC. By using the MO6 mAb, we investigated the presence of hNSF in the ascitic fluid of a patient with SLE. A small amount of cross-reactive hNSF was isolated from concentrated ascitic fluid fractionated with the MO6-affinity column, and a specific anti-hNSF mAb (P2) was produced. The hNSF eluted from the P2-affinity column could suppress up to 80% of the PWM-induced IgG production of human PBMC in a dose-dependent manner, even when added in late culture periods. Moreover, hNSF could inhibit proliferation of PBMC triggered by either PWM or Con A, which also implies an effect on T cells. On SDS-PAGE, the isolated hNSF resolved as a single peak of about 66 kDa and probably represents an aggregate of hydrophobic subunits. On reverse-phase HPLC, the bioactivity could be recovered from a single peak at 18.3 min. The suppression of IgG production induced by hNSF could be partly neutralized by preincubation with an anti-TCR-alpha mAb, whereas an anti-TCR-beta did not have any effect. Anti-TCR-alpha could also directly bind to the isolated nNSF, demonstrating some serologic relationship, as has been reported for several Ag-specific suppressor systems.

Monoclonal non-specific suppressor factor (MNSF) inhibits the IL4 secretion by bone marrow-derived mast cell (BMMC)

We investigated whether monoclonal non-specific suppressor factor (MNSF) has an effect on the IL4 secretion by BMMC sensitized with anti-DNP IgE monoclonal antibody. The sensitized BMMC showed a maximum increase of IL4 secretion at 10 ng/ml antigen activation. When MNSF (10 U) was added, it remarkably suppressed the IL4 secretion (82 +/- 3%). MNSF also suppressed the IL4 secretion by the mast cell line, CFTL-15, but not CFTL-12. Northern blot analysis showed that, when the same amounts of MNSF were added, IL4 mRNA expression was decreased, suggesting that the suppression results from the inhibition of a transcript.