Overlap syndromes in the context of shared autoimmunity

The presence of autoimmune rheumatic diseases in several members of the same family, the concurrence of autoimmune rheumatic with non-rheumatic diseases in relatives of patients, the presence of autoantibodies in sera from healthy relatives of autoimmune-disease patients, the development of two or more autoimmune rheumatic diseases in one patient and the interplay of genetic and environmental factors leading to the presence of several autoimmune disease and/or their autoantibodies in families, is being termed "shared autoimmunity". Herein we analyzed autoimmune rheumatic overlap syndromes in this context. We performed a retrospective analysis of the clinical, serological and radiological characteristics of patients with overlap syndromes from the Clinic of Rheumatic Diseases at the Department of Immunology and Rheumatology of the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. We found 23 patients with overlap syndromes; 13 patients with rhupus, 5 with sclerodermatomyositis, 3 with scleroderma and SLE, one with sclerodermatomyositis and SLE and one with scleroderma and MPA. Rhupus tends to develop sequentially while sclerodermatomyositis tends to appear simultaneously. The other overlap syndromes are less common and their clinical course is rather aggressive, although clinical manifestations respond to standard treatment. The second and/or third disease appears while the first one is still active, even with adequate treatment. The coexistence of autoimmune rheumatic diseases may be partially explained by the interplay of environmental factors with genes that predispose to autoimmunity in general and to manifestations of specific diseases. This is part of the concept of Shared Autoimmunity.

Autoantibodies against the fibrinolytic receptor, annexin 2, in antiphospholipid syndrome

The association of thrombosis and gestational morbidity with antiphospholipid antibodies is termed antiphospholipid syndrome (APS). Annexin 2 (A2) is a profibrinolytic endothelial cell surface receptor that binds plasminogen, its tissue activator (tPA), and beta(2)-glycoprotein I (beta2GPI), the main antigen for antiphospholipid antibodies. Here, we evaluate A2 as a target antigen in APS. Serum samples from 434 individuals (206 patients with systemic lupus erythematosus without thrombosis, 62 with APS, 21 with nonautoimmune thrombosis, and 145 healthy individuals) were analyzed by enzyme-linked immunosorbent assay (ELISA) and immunoblot for antiphospholipid and A2 antibodies. Anti-A2 antibodies (titer > 3 SDs) were significantly more prevalent in patients with APS (22.6%; venous, 17.5%; arterial, 34.3%; and mixed thrombosis, 40.4%) than in healthy individuals (2.1%, P < .001), patients with nonautoimmune thrombosis (0%, P = .017), or patients with lupus without thrombosis (6.3%, P < .001). Anti-A2 IgG enhanced the expression of tissue factor on endothelial cells (6.4-fold +/- 0.13-fold SE), blocked A2-supported plasmin generation in a tPA-dependent generation assay (19%-71%) independently of beta2GPI, and inhibited cell surface plasmin generation on human umbilical vein endothelial cells (HUVECs) by 34% to 83%. We propose that anti-A2 antibodies contribute to the prothrombotic diathesis in antiphospholipid syndrome.

The different faces of shared autoimmunity

The concept of shared autoimmunity comprises various forms of disease: rheumatic diseases in several members of the same family, the coincidence of autoimmune rheumatic with non-rheumatic diseases in relatives of patients, the presence of autoantibodies in healthy relatives of autoimmune disease patients, and the development of two or more autoimmune rheumatic diseases in one patient, the so-called overlap syndromes. The genetic and environmental factors that lead to these phenomena interact in a complex fashion and influence the distinct phenotypic characteristics of each patient. In a previous case series, we described 23 Mexican Mestizo patients with overlap syndromes. Interestingly, rhupus tends to develop sequentially while sclerodermatomyositis tends to appear simultaneously. The clinical course of the other overlap syndromes is rather aggressive, although clinical manifestations respond to standard treatment. The second and/or third disease appears while the first one is still active, even with adequate treatment. The distinct course of overlap syndromes may be partially explained by the interplay of environmental factors with genes that predispose to autoimmunity in general and to manifestations of specific diseases. The analyses of genes that will help understand the pathophysiology of these diseases include several MHC complex genes, cytokines, AIRE, and PDCD1 amongst others.

Familial aggregation of systemic lupus erythematosus, rheumatoid arthritis, and other autoimmune diseases in 1,177 lupus patients from the GLADEL cohort

OBJECTIVE

To determine whether there is familial aggregation of systemic lupus erythematosus (SLE) and/or other autoimmune diseases in SLE patients and to identify clinical differences between patients with and those without familial autoimmunity.

METHODS

We interviewed members of the Grupo Latinoamericano de Estudio del Lupus Eritematoso (GLADEL) inception cohort of 1,214 SLE patients to ascertain whether they had relatives with SLE and/or other autoimmune diseases. Identified relatives were studied. Familial aggregation was tested using reported highest and intermediate population prevalence data for SLE, rheumatoid arthritis (RA), or all autoimmune diseases, and studies were performed to identify the genetic model applicable for SLE.

RESULTS

We identified 116 first-, second-, or third-degree relatives with SLE, 79 with RA, 23 with autoimmune thyroiditis, 3 with scleroderma, 1 with polymyositis, and 16 with other autoimmune diseases, related to 166 of the 1,177 SLE patients in the GLADEL cohort who agreed to participate. Forty-two SLE patients had 2 or more relatives with an autoimmune disease. We found a lambda(sibling) of 5.8 and 29.0 for SLE and of 3.2-5.3 for RA, when comparing with their reported high or intermediate population prevalence, respectively. We also found familial aggregation for autoimmune disease in general (lambda(sibling) = 1.5) and determined that for SLE, a polygenic additive genetic model, rather than a multiplicative one, is applicable.

CONCLUSION

In SLE there is familial aggregation of SLE, RA, and autoimmune disease in general. A polygenic additive model applies for SLE. American Indian-white Mestizo SLE patients and those with higher socioeconomic level were more likely to have familial autoimmunity.

[The future of medical investigation in Mexico]

The current situation of clinical research in Mexico is analyzed. The main findings are as follows: 10% of total number of researchers in Mexico are engaged in medical research; there is a highly centralized distribution in the Mexico City metropolitan area; there exists unequal academic development among disciplines, and there is an overwhelming number of researchers in public educational and health institutions. A substantial increase in medical publications during the last 15 years with reasonable citation impact was also found. Several urgent matters to attend were identified, such as financing problems, effect of health services descentralization completed in 1997, and the need to selectively support certain research areas such as accidents, mental health, addictions, geriatrics and chronic diseases.

Heterogeneity of antibodies to beta2-glycoprotein 1 from patients with systemic lupus erythematosus

We studied antibodies to beta2-glycoprotein 1 (anti-beta2GP1) from 72 patients with systemic lupus erythematosus (SLE) with or without antiphospholipid syndrome (APS) or with or without anticardiolipin antibodies (aCL). Fifteen patients had APS and positive antiphospholipid antibodies [clinical APS(+)/aPL(+)], 12 patients had APS, negative serum IgG and IgM aCL, antiphosphatidylethanolamine, anti-phosphatidylserine and no lupus anticoagulant [clinical APS(+)/ aPL(-)]. A third group included 16 patients without APS but high aCL levels [clinical APS(-)/ aPL(+)]. In a fourth group we studied 29 patients without clinical manifestations of APS or aCL [clinical APS(-)/aPL(-)]. One hundred anticardiolipin and VDRL-negative normal sera were studied as controls. IgG antibodies to cardiolipin proper in a bovine beta2GP-free system, to human beta2GP1 immobilized on cardiolipin or to human beta2GP1 alone were detected in all sera by ELISA using irradiated and nonirradiated plates from two manufacturers. Sera from APS(+)/aPL(+) patients showed IgG binding to CL, CL + beta2GP1 and beta2GP1 in irradiated and nonirradiated plates. APS(+)/ aPL(-) sera had more significant IgG binding to beta2GP1 than normal controls when studied in both irradiated or nonirradiated plates (P = 0.001). This binding was inhibited by solid-phase cardiolipin in a dose-dependent manner. Sera from the APS(-)/aPL(+) subgroup had comparable IgG activity in both the CL and CL + beta2GP1 assays, while no anti-beta2GP1 activity was detected in these sera. Sera from the clinical APS(-)/aPL(-) patients were negative in the three ELISA systems. Antibodies to human beta2GP1 from SLE patients recognize various epitopes. Those from APS(+)/ aPL(+) patients appear to react with an epitope boosted by cardiolipin in addition to another one present in the native protein. In contrast, anti-beta2GP1 from patients with APS(+)/aPL(-) are blocked by cardiolipin, suggesting that their epitope is the phospholipid-binding site.

Prevalence and factors associated with fibromyalgia in Mexican patients with systemic lupus erythematosus

In total, 189 consecutive women diagnosed with SLE were evaluated using the ACR 1990 criteria for fibromyalgia. Patients were classified into three subgroups. The fibromyalgia group (FM) included patients experiencing pain on palpation in at least 11 of the 18 tender points examined, as well as having a history of widespread pain for at least three months. Patients who were noted to have pain in fewer than four quadrants with less than 11 of 18 tender points were considered to have regional pain (RP). All patients who did not meet criteria for either FM or RP were classified as having no pain (NP). Measurement of SLE disease activity, sleep complaints, depression, fatigue severity and health status were performed. Only 18 of the SLE patients (9.5%) (95% CI 5.3-14%) fulfilled the ACR criteria for the classification of FM. Of the patients, 106 (56.1%) fulfilled criteria for RP and had a number of tender points of 5.4 +/- 3.4, and the rest of the patients (34.4%) had no tenderness at specific tender point sites. Age, body mass index, educational level and disease duration were comparable between the groups. FM and RP groups had different patterns of symptoms prevalence, with dysmenorrhea being more distinctive for FM. Sleep disturbances were more severe in the FM than in the RP group. Daytime complaints such as sleepiness, fatigue and depression were similar for RP and FM groups, but patients with FM reported more disability. Fibromyalgia is not common in Mexican patients with SLE and has a different pattern of symptoms in RP and NP patients. These data add evidence that ethnicity can play an important role in FM manifestations.

Neuroendocrine dopaminergic regulation of prolactin release in systemic lupus erythematosus: a possible role of lymphocyte-derived prolactin

Prolactin (PRL) secretion by the pituitary is under the control of dopamine. Hyperprolactinemia has been found in patients with systemic lupus erythematosus (SLE) and seems to be associated with clinical activity. T-lymphocytes express PRL and those from SLE patients appear to secrete more PRL than controls. In this study, immuno-(RIA) and bio-(BIO) assayable PRL in both serum and culture media of peripheral blood mononuclear cells (PBMNC) from SLE and control subjects were evaluated in the basal state and in response to 10 mg oral administration of metoclopramide, a dopamine receptor antagonist. Prolactin size heterogeneity in serum and culture media and PRL gene transcription in PBMNC were also studied. Basal serum RIA-PRL, BIO-PRL and the BIO/RIA ratio were similar in both groups. The serum BIO-PRL response after metoclopramide was higher than RIA-PRL in SLE, and this increment was also greater than in control subjects. PBMNC from SLE subjects secreted and produced more BIO-PRL. After metoclopramide, secretion and production of PRL increased only in PBMNC from control women and not in those from SLE patients. Our results demonstrated an increased central dopaminergic tone in SLE and suggest that lymphocyte-derived PRL might contribute to alter the functional activity of the hypothalamic dopaminergic system in SLE attempting to maintain serum PRL within a physiological range.

Systemic lupus erythematosus as a cause and prognostic factor of acute pancreatitis

OBJECTIVE

To perform a systematic analysis and case-control study of our patients with systemic lupus erythematosus (SLE) to determine the prevalence of acute pancreatitis (AP).

METHODS

All episodes of AP in SLE patients were identified (July 1984-July 2001). Prevalence was calculated. Etiology for each AP event was classified into mechanical, toxic-metabolic, or idiopathic. AP severity was defined based on Atlanta criteria. SLE disease activity was scored using Mex-SLEDAI index. A control group of non-SLE patients with AP was designed to establish the risk of developing severe or fatal idiopathic AP in patients with SLE.

RESULTS

Forty-nine AP episodes were identified in 35 SLE patients (30 +/- 14 yrs old, 94% female). Prevalence was 3.5%. A single episode was present in 26 patients. Identified AP causes were mechanical in 14 and toxic-metabolic in 10. Seventeen episodes were considered idiopathic. At least one drug related to AP was administered in 13 episodes. Corticosteroids were in use in 32 episodes, and as the only drug in 16. Mex-SLEDAI scores were significantly higher in idiopathic events. In the case-control analysis, idiopathic AP was more frequent in SLE cases (46% vs 14%). The strength of association of AP severity and related mortality was higher in SLE patients (OR 8.6 and 7.5, respectively).

CONCLUSION

AP is not a highly prevalent manifestation of SLE. Idiopathic cases predominate and show increased SLE activity. Drug consumption does not seem to participate in AP development. SLE episodes are more severe and frequently fatal.

Improvement in health-related quality of life in systemic lupus erythematosus patients enrolled in a randomized clinical trial comparing LJP 394 treatment with placebo

In a 76-week, randomized controlled trial, patients received 100 mg LJP 394 or placebo weekly for 16 weeks followed by three 12-week treatment cycles of 50 mg LJP 394 or placebo weekly each separated by eight-week periods when no therapy was administered. Health-related quality of life (HRQOL) was assessed using SF-36 at baseline, 16 weeks and every 12 weeks thereafter. Analyses populations included intent to treat (ITT) (n = 179) and patients with high-affinity anti-dsDNA antibody binding (HA): 157/179; 85% active, 90% placebo. In the ITT population, there were improvements in role emotional (RE) (+7.3 versus -8.2), social functioning (SF) (+4.3 versus +0.7), and role physical (RP) (+11.3 versus +6.0) domains in the active treatment group when compared with placebo, with similar changes observed in the HA population. In 37 patients with data pre- and post-renal flares, those receiving LJP 394 reported stabilization or improvement in all but one domain compared with deterioration in all domains with placebo. Changes in RE domain scores following a flare differed by 22.7 points between the two treatment groups, favouring LJP 394 treatment. Patients receiving LJP 394 reported stable or improved HRQOL with active treatment following renal flares compared with deterioration in placebo. Differences between treatment groups in RE and SF domains are clinically important and were replicated irrespective of the protocol population analysed.

Both risk alleles for FcγRIIA and FcγRIIIA are susceptibility factors for SLE: a unifying hypothesis

The aim of this study was to analyze in families with SLE for the presence of linkage and the structure and transmission of haplotypes containing alleles for the low-affinity Fcgamma receptors. The Fcgamma receptor polymorphisms FcgammaRIIA-131R/H, FcgammaRIIIA-176F/V and FcgammaRIIIB-NA1/2 and a polymorphism in the FcgammaRIIB gene were genotyped with RFLP, allele-specific PCR or pyrosequencing. Individual SNPs and haplotypes were tested for linkage in multicase families and for association using contingency tables, transmission disequilibrium test and affected family-based control groups in Swedish and Mexican single-case families. No linkage or association could be detected using the FcgammaR polymorphisms in the multicase families. However, an association was found for both FcgammaRIIA-131R and IIIA-176F alleles in the single-case families, but not for IIIB or IIB. Allelic association to SLE was found for a haplotype that included both risk alleles, but not in haplotypes where only one or the other was present. We propose that FcgammaRIIA-131R and FcgammaRIIIA-176F are both risk alleles for SLE transmitted primarily, but not exclusively on a single major haplotype that behaves functionally in a situation similar to that of compound heterozygozity.

Immunoregulatory defects in patients with systemic lupus erythematosus in clinical remission

Little is known about the immune system of patients with systemic lupus erythematosus (SLE) during periods of silent disease. To address this issue we analysed lymphoid populations andcytokine production of mononuclear cells obtained from SLE patients in remission. We studied 43 patients with inactive disease, 10 with active disease and 30 controls. Remission was defined as at least 1 year during which lack of clinical disease activity permitted withdrawal of all treatment. Remission length ranged from 1 to 30 years. Flow cytometry and ELISA were used to study lymphoid populations (CD4, CD8 and CD19) and cytokine production (IL-2, 4, 10, 12 and 18). Patients with short remission periods (up to 15 years) exhibited an increased percentage of B cells; production of IL-2, IL-10 and IL-12 was decreased; production of IL-18 was increased. Interestingly, patients from groups with long time of inactive disease had corrected most alterations, but had an impaired IL-18 expression. IL-12 production correlated strongly with the length of the remission period (r = 0.7565). The immune system of patients with inactive lupus has partially corrected the disturbances present during disease activity. This is accomplished gradually, sometimes until counter-regulatory alterations are developed. This may allow patients to remain without disease activity.

The GLADEL multinational Latin American prospective inception cohort of 1,214 patients with systemic lupus erythematosus: ethnic and disease heterogeneity among "Hispanics"

Clinical and laboratory manifestations and outcome of systemic lupus erythematosus (SLE) may vary in different populations. A prospective multinational inception cohort should prove useful in identifying the influence of ethnicity on the clinical characteristics of SLE. We therefore analyzed clinical, laboratory, and prognostic variables in Latin American SLE patients with disease of recent onset who were entered into a prospective cohort, and compared these variables in the cohort's 3 major ethnic groups. Thirty-four centers from 9 Latin American countries participated by randomly incorporating SLE patients within 2 years of diagnosis into a standardized database. Participating centers were selected for their expertise in diagnosing and managing SLE. We were then able to evaluate prospectively socioeconomic variables, ethnicity, type of medical care, clinical and laboratory features, disease activity, damage, and mortality at each site. A coordinating center controlled the quality of the information submitted. Of the 1,214 SLE patients included in the cohort, 537 were mestizos, 507 were white, and 152 were African-Latin American (ALA). (There were also small numbers of pure Amerindian and oriental individuals.) Significant differences were found between them in socioeconomic characteristics, type of care, and level of education favoring whites. Mestizos and ALA were younger at onset. Delay to diagnosis and disease duration was shorter in ALA. Fever was more frequent in whites; discoid lesions in ALA; renal disease and lymphopenia in mestizos and ALA. Although we found differences in background variables between ethnic groups from different countries, mestizos from 2 distant countries (Argentina and Mexico) were clinically akin and showed similar differences to whites. Mortality was associated with lower education, poor medical coverage, and shorter follow-up. In an exploratory model nonwhite ethnicity was associated with renal disease and lymphopenia, damage, and cumulative American College of Rheumatology criteria. These differences in clinical, prognostic, socioeconomic, educational, and access to medical care features in Latin American lupus patients of 3 major ethnic groups from 9 different countries may have an impact on the patients' disease. "Hispanics," as they have come to be generically termed on the basis of language, actually constitute a markedly heterogeneous group of subjects.

Prophylaxis of the antiphospholipid syndrome: a consensus report

Hypothetical circumstances that may require prophylaxis for a potential antiphospholipid syndrome (primary prophylaxis), or in some instances when there already had been some manifestations ofthe syndrome (secondary prophylaxis), were presented to a panel of experts for their consideration on potential prophylactic intervention. These were subsequently presented to the participants in the First International Consensus on Treatment of the Antiphospholipid Syndrome. In most instances there was consensus in adding low dose aspirin, an exception being aspirin allergy when other antiaggregants could be used in nonpregnant subjects. General measures to prevent thrombosis and other vasoprotective actions should also be provided. Higher risk of fetal loss or thrombosis called for anticoagulation with coumadin in nonpregnant subjects or subcutaneous low molecular weight heparin in pregnant ones. When indicated, prophylaxis of the antiphospholipid syndrome should be provided in systemic lupus erythematosus patients who are being treated for their disease. In no instance should corticosteroids or immunosuppresants be given as prophylactic of an antiphospholipid syndrome.

Antibody penetration into living cells: pathogenic, preventive and immuno-therapeutic implications

The dogmatic and at one time prevalent concept that intact antibody molecules were not able to enter into viable cells has now been modified due to the availability of a large amount of experimental findings and clinical observations that indicate otherwise. Penetration of mature autoantibodies into living cells might participate in the pathogenesis of diverse autoimmune diseases, through inducing apoptosis of healthy tissues and cells, but also by contributing to the breakdown of self-tolerance through presentation of self-antigens to the immune system. Conversely, the penetration of naturally occurring autoantibodies into immature lymphoid cells might have a physiological role in the edition of the immune repertoire in healthy individuals. Increasing interest is being paid to the potential immunotherapeutic role of penetrating antibodies as tools to deliver drugs, isotopes or genes into cells.

LJP 394 for the prevention of renal flare in patients with systemic lupus erythematosus: results from a randomized, double-blind, placebo-controlled study

OBJECTIVE

To determine whether LJP 394 delays or prevents renal flare in patients with systemic lupus erythematosus (SLE) and a history of renal disease.

METHODS

In a 76-week, double-blind, placebo-controlled study, 230 SLE patients were randomized to receive 16 weekly doses of 100 mg of LJP 394 or placebo, followed by alternating 8-week drug holidays and 12 weekly doses of 50 mg of LJP 394 or placebo. An assay measuring the affinity of the serum IgG fraction for the DNA epitope of LJP 394 identified a high-affinity population of patients (189 of 213 patients; 89% taking LJP 394 and 90% taking placebo). Analyses were performed on both the intent-to-treat population and the high-affinity population.

RESULTS

Anti-double-stranded DNA antibodies decreased and C3 levels tended to increase during treatment with LJP 394. In the intent-to-treat population, the time to renal flare was not significantly different between treatment groups, but patients taking LJP 394 had a longer time to institution of high-dose corticosteroids and/or cyclophosphamide (HDCC) and required 41% fewer treatments with HDCC. In the high-affinity population, the LJP 394 group experienced a longer time to renal flare, 67% fewer renal flares, longer time to institution of HDCC, and 62% fewer HDCC treatments compared with the placebo group. In patients with serum creatinine levels >/=1.5 mg/dl at study entry, those taking LJP 394 had 50% fewer renal flares; no renal flares were observed in the high-affinity group taking LJP 394. Serious adverse events were observed in 25 of the 114 LJP 394-treated patients (21.9%) and 34 of the 116 placebo-treated patients (29.3%).

CONCLUSION

Treatment with LJP 394 in patients with high-affinity antibodies to its DNA epitope prolonged the time to renal flare, decreased the number of renal flares, and required fewer HDCC treatments compared with placebo. The study drug appeared to be well tolerated.

Valine/valine genotype at position 247 of the beta2-glycoprotein I gene in Mexican patients with primary antiphospholipid syndrome: association with anti-beta2-glycoprotein I antibodies

OBJECTIVE

To determine the polymorphism at position 247 of the beta(2)-glycoprotein I (beta(2)GPI) gene in Mexican patients with antiphospholipid syndrome (APS) and to compare these data in patients with or without antibodies to beta(2)GPI and with the clinical manifestations of APS.

METHODS

We studied 39 patients with primary APS and compared them with 106 clinically healthy subjects. Polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism. The presence of "true" anticardiolipin (aCL) antibodies, beta(2)GPI-dependent aCL antibodies (IgG and IgM), and phospholipid-free anti-beta(2)GPI antibodies (IgG isotype) were detected by enzyme-linked immunosorbent assay (ELISA) utilizing nonirradiated ELISA plates. Clinical manifestations associated with antiphospholipid antibodies were also evaluated.

RESULTS

We found no significant differences in the genotype expression between the control group and the primary APS patients (13% with VV, 52% with VL, and 35% with LL versus 23% with VV, 51% with VL, and 26% with LL, respectively). In contrast, anti-beta(2)GPI-positive patients had significantly higher frequencies of the VV genotype and V allele expression than the control subjects and the anti-beta(2)GPI-negative patients. These genotype and allele frequencies were also significantly higher in patients with arterial thrombosis than in patients without it. Anti-beta(2)GPI-negative patients without arterial thrombosis did not express the VV genotype. We found no differences in the Val/Leu(247) polymorphism of the beta(2)GPI gene in primary APS patients with or without "true" aCL antibodies or in primary APS patients with or without beta(2)GPI-dependent aCL antibodies.

CONCLUSION

Our results suggest that the VV genotype at position 247 of the beta(2)GPI gene may play a role in the generation of anti-beta(2)GPI antibodies and perhaps in the expression of arterial thrombosis in primary APS.

A regulatory polymorphism in PDCD1 is associated with susceptibility to systemic lupus erythematosus in humans

Systemic lupus erythematosus (SLE, OMIM 152700) is a complex autoimmune disease that affects 0.05% of the Western population, predominantly women. A number of susceptibility loci for SLE have been suggested in different populations, but the nature of the susceptibility genes and mutations is yet to be identified. We previously reported a susceptibility locus (SLEB2) for Nordic multi-case families. Within this locus, the programmed cell death 1 gene (PDCD1, also called PD-1) was considered the strongest candidate for association with the disease. Here, we analyzed 2,510 individuals, including members of five independent sets of families as well as unrelated individuals affected with SLE, for single-nucleotide polymorphisms (SNPs) that we identified in PDCD1. We show that one intronic SNP in PDCD1 is associated with development of SLE in Europeans (found in 12% of affected individuals versus 5% of controls; P = 0.00001, r.r. (relative risk) = 2.6) and Mexicans (found in 7% of affected individuals versus 2% of controls; P = 0.0009, r.r. = 3.5). The associated allele of this SNP alters a binding site for the runt-related transcription factor 1 (RUNX1, also called AML1) located in an intronic enhancer, suggesting a mechanism through which it can contribute to the development of SLE in humans.

A major susceptibility locus for systemic lupus erythemathosus maps to chromosome 1q31

A set of 87 multicase families with systemic lupus erythemathosus (SLE) from European (Iceland, Sweden, England, Norway, Italy, and Greece) and recently admixed (Mexico, Colombia, and the United States) populations were genotyped and analyzed for 62 microsatellite markers on chromosome 1. By parametric two-point linkage analysis, six regions (1p36, 1p21, 1q23, 1q25, 1q31, and 1q43) were identified that have LOD scores of Z>or=1.50, with different contributions, depending on the population of origin of the families (European or admixed American). All of the regions have been described previously and have therefore been confirmed in this analysis. The locus at 1q31 showed a significant three-point LOD score of Z=3.79 and was contributed by families from all populations, with several markers and under the same parametric model. Analysis of a known mutation in the CD45 gene did not support the role that this mutation plays in disease. We conclude that the locus at 1q31 contains a major susceptibility gene, important to SLE in general populations.

A regulatory polymorphism in PDCD1 is associated with susceptibility to systemic lupus erythematosus in humans

Systemic lupus erythematosus (SLE, OMIM 152700) is a complex autoimmune disease that affects 0.05% of the Western population, predominantly women. A number of susceptibility loci for SLE have been suggested in different populations, but the nature of the susceptibility genes and mutations is yet to be identified. We previously reported a susceptibility locus (SLEB2) for Nordic multi-case families. Within this locus, the programmed cell death 1 gene (PDCD1, also called PD-1) was considered the strongest candidate for association with the disease. Here, we analyzed 2,510 individuals, including members of five independent sets of families as well as unrelated individuals affected with SLE, for single-nucleotide polymorphisms (SNPs) that we identified in PDCD1. We show that one intronic SNP in PDCD1 is associated with development of SLE in Europeans (found in 12% of affected individuals versus 5% of controls; P = 0.00001, r.r. (relative risk) = 2.6) and Mexicans (found in 7% of affected individuals versus 2% of controls; P = 0.0009, r.r. = 3.5). The associated allele of this SNP alters a binding site for the runt-related transcription factor 1 (RUNX1, also called AML1) located in an intronic enhancer, suggesting a mechanism through which it can contribute to the development of SLE in humans.

Antiprothrombin Antibodies in Patients With Systemic Lupus Erythematosus or With Primary Antiphospholipid Syndrome

Some authors have found a strong statistical association of antibodies to prothrombin (aPT) with thrombosis in patients with antiphospholipid syndrome (APS); others have not confirmed this finding. It is unknown if the detection of aPT, in addition to anticardiolipin (aCL) and anti-beta2-glycoprotein-I (abeta2GP-I) antibodies, provides additional information in the clinical study of these patients. We studied 38 patients with primary antiphospholipid syndrome and 466 patients with systemic lupus erythematosus (SLE; 24 had a history of thrombosis and 69 had secondary APS). All were tested by ELISA for serum aPT (IgG and IgM) using irradiated and plain plates. We also detected aCL and anti-beta2GP-I by ELISA. One hundred sera from clinically healthy individuals were used as controls. Twenty-six percent and 11% primary APS sera were positive for IgG and IgM aPT, respectively, compared with 3% and 5% of controls (p < 0.001, both comparisons). We found no difference in the frequency of aPT in SLE patients and controls, but aPT were positive in 46% of lupus patients with a history of thrombosis (20% IgG, 33% IgM) and in 9% of those without thrombosis (6% IgG, 5% IgM; p < 0.001, both comparisons). Likewise, there was a significant difference in the frequency of aPT in SLE patients with (22%) or without (9%) secondary APS (p < 0.001). aPT titers decreased two- to sixfold when tested in plain plates. Thirty-five of 38 primary APS sera (92%) had IgG anti-beta2GP-I and 12 (31%) had aCL. No patient had aPT as the only antibody. The higher binding of aPT on irradiated plates suggests that aPT recognize a hidden epitope exposed by negative surfaces. The higher frequency of aPT found in patients with primary APS, SLE with thrombosis, or with secondary APS may suggest concerted pathogenic actions with other autoantibodies, but the detection of aPT does not seem to be of clinical value.

Anticardiolipin and anti-beta2-glycoprotein-I antibodies in hypertensive disorders of pregnancy

BACKGROUND

This study was undertaken in order to determine the frequency of anticardiolipin (aCL) and anti-beta2-glycoprotein-I antibodies (anti-beta2 GP-I) in patients with hypertensive disorders of pregnancy.

METHODS

We studied aCL (IgG and IgM) and IgG anti-beta 2 GP-I by ELISA in the serum and IgG aCL and anti-beta 2 GP-I in the urine of 125 women with hypertensive disorders of pregnancy (cases) (75 had preeclampsia, 25 had eclampsia, and 25 had chronic hypertension). One hundred and twenty seven normal women were used as controls. Antibody positivity was defined as above the 90(th) percentile of the controls.

RESULTS

We found no differences in frequency of serum anti-beta 2 GP-I or serum and urinary aCL between cases and controls. In contrast, we found that frequency of IgG anti-beta 2 GP-I was higher in the urine of cases (26.1%) compared to controls (9.4%, p = 0.001). Strength of association was stronger for urinary anti-beta2-glycoprotein-I in women with preeclampsia (odds ratio [OR] = 4.3, 95% confidence limit [CI 95%] = 1.95-9.62, p <0.0001). Cases and the subgroup of preeclamptic patients also had higher titers of urinary IgG anti-beta 2 GP-I than control women (p <0.0001).

CONCLUSIONS

Our work suggests that urine testing is necessary in order to ascertain whether antibodies to beta(2)GP-I are associated with preeclampsia.

Novel facts about an old marker: the LE cell

For more than fifty years, lupus erythematosus (LE) cells were believed to result from in vitro opsonization of bare nuclei by serum antinuclear antibodies and their ultimate phagocytosis by neutrophils. Twenty years ago, we described that certain antinuclear antibodies could enter into viable cells, and later on, it was proved that penetration of anti-DNA antibodies into cells results in protracted active cell death. Recent findings indicate that the material engulfed by LE cells are apoptotic blebs as residuals of cells dying after penetration of anti-DNA antibodies. These observations not only change the interpretation of the presence of the LE cell phenomenon, but also stress the potential pathophysiological role of antibodies to intracellular antigens in autoimmune diseases.

Anti-cardiolipin, anti-cardiolipin plus bovine, or human beta(2)glycoprotein-I and anti-human beta(2)glycoprotein-I antibodies in a healthy infant population

BACKGROUND

Pathogenic antiphospholipid antibodies studies are usually conducted on populations of adults. Studies involving normal children are scant.

METHODS

Antibody reactivity against CL alone (true aCL), CL-complexed to bovine beta(2)GP-I (aCL-bovine beta(2)GP-I), or human (aCL-human beta(2)GP-I) beta(2)GP-I, or to phospholipid-free human beta(2)GP-I (anti-human beta(2)GP-I) was determined by ELISA in serum samples from 360 Mexican children ranging from 1 month through 8 years of age.

RESULTS

Statistical analysis of variance and rankings of Kruskal-Wallis demonstrated no significant difference in all tested antibody activities between ages and genders of the study population. Values are presented as a percentile distribution included between 5 and 99, corresponding to the percentages of the studied population. Normal arbitrary units (AU) for IgG, IgA, and IgM true aCL that correspond to the 95 and 99 percentiles are as follows: 2.15 and 3.5; 2.35 and 5.0, and 3.15 and 4.5, respectively. IgG, IgA, and IgM aCL-bovine beta(2)GP-I activities are 2.6 and 5.0, 3.0 and 5.0, and 2.7 and 6.0 AU, respectively, while IgG activities of aCL-bovine and human beta(2)GP-I are 1.45 and 1.80, respectively. Normal values for IgG anti-human beta(2)GP-I are 1.85 AU.

CONCLUSIONS

While elevated serum levels of antibodies to CL and/or beta(2)GP-I have been associated with thrombotic and hematologic manifestations, the majority of reports deal with adult populations. We report the cut-off values (in AU, international PL units, and international units for beta(2)GP-I) of the specific serologic response of true aCL, aCL-bovine beta(2)GP-I, aCL-human beta(2)GP-I, and anti-human beta(2)GP-I in healthy Mexican children.

Characterization of anti-phosphatidylcholine polyreactive natural autoantibodies from normal human subjects

In 1990 our group reported a patient with autoimmune hemolytic anemia and high titers of IgM anticardiolipin antibodies that cross-reacted with phosphatidylcholine (PTC). These autoantibodies also recognized bromelain-treated erythrocytes (BrE) and in vitro aged erythrocytes. The epitope exposed with this treatment is PTC. To detect and characterize antiphosphatidylcholine antibodies (anti-PTC) in a normal human population, we studied by ELISA the presence of serum anti-PTC (IgG and IgM) in clinically healthy human subjects. The most representative samples were also studied for IgG or IgM activity against BrE by flow cytometry, rheumatoid factor activity, anti-dsDNA, anti-ssDNA by ELISA and by indirect immunofluorecence (IIF) using HEp-2 line and a healthy human fibroblast strain as substratum. Eighty five percent of sera had IgM anti-PTC and none had IgG. IgM antibodies against BrE were inhibited by PTC micelles (mPTC). Anti-PTC were also inhibited by phosphorylcholine and phosphatidic acid. Aggregated gammaglobulin (AGG) reactivity was inhibited by dsDNA and mPTC. The IgM anti-dsDNA activity was inhibited by soluble dsDNA, AGG and mPTC. All sera gave intermediate filaments pattern by IIF and reacted against purified vimentin by dot blot and Western blot.Our study shows hemolytic IgM anti-PTC present in normal human serum. The main epitope recognized by these autoantibodies is phosphorylcholine. The physicochemical characteristics, crossreactivity with self-antigens and functional properties are typical features of natural autoantibodies.

Distribution of class I and class III MHC antigens in the Tarasco Amerindians

Class I and class III major histocompatibility complex (MHC) antigen frequencies were analyzed in 130 haplotypes from 33 families belonging to a group of Amerindians culturally and linguistically isolated for more than 12 centuries in Mexico: the Tarascos. The most frequent antigens in this ethnic group of the HLA-A locus are: A2 (gf 0.353), A24 (gf = 0.223), A31 (gf = 0.184), and A28 (gf = 0.161); and the most frequent of the HLA-B locus are: B35 (gf = 0.230), B39 (gf = 0.192), B15 (gf = 0.146), and B5 (gf = 0.123). On the other hand, class III antigens demonstrated relatively high frequencies of the SC31 (frequency = 0.561), SC01 (frequency = 0.076), and SC42 (frequency = 0.069) complotypes. Also important was the relatively high frequency of the HLA-B27 antigen (gf 0.061) and the SC33 complotype (frequency = 0.046), which are either absent or found infrequently in other Amerindian groups. Analysis of MHC haplotypes revealed that four of them have relatively high frequencies, these were the following: [B39;SC31] (11.6%), [B35;SC31] (11.6%), [B15;SC31] (8.0%), and [B5;SC31] (5.8%). Other MHC haplotypes had frequencies lower than 5.0%. The decreased frequency of BF alleles other than BF*S and the presence of the SC33 and SC32 complotypes suggest long time preservation from genetic admixture. This information withstands the basis for population genetic analysis and disease association studies in Mexican mestizos.

Class II allele and haplotype frequencies in Mexican systemic lupus erythematosus patients: the relevance of considering homologous chromosomes in determining susceptibility

The aim of the present study was to determine the relevant major histocompatibility complex (MHC) class II alleles in the genetic susceptibility to systemic lupus erythematosus (SLE) in Mexican Mestizo patients. We examined the gene and haplotype frequencies of the HLA-DRB1, DQA1 and DQB1 alleles by polymerase chain reaction-sequence-specific oligonucleotide probes in 81 Mexican SLE Mestizo patients and 99 ethnically matched controls. We found a significantly increased frequency of the HLA-DRB1*0301 (p(c) = 0.031, odds ratio = 2.63) allele and significantly decreased frequencies of the DRB1*0802 (p(c) = 0.035) and DRB1*1101 (p(c) = 0.037) alleles in the SLE group. Haplotype analysis showed increased frequencies of DRB1*0301-DQA1*0501-DQB1*0201 (p(c) = 0.017, odds ratio = 2.97), and decreased frequency of DRB1*0802-DQA1*0401-DQB1*0402 (p(c) = 0.034) in SLE patients. The most frequently detected haplotypes in SLE patients showed different haplotypic combinations in the homologous chromosome from those found in controls. Thus, the combinations detected in SLE patients were either not detected in the control group or infrequently found. The results suggest that the DRB1*0301 is the principal class II allele associated with the genetic susceptibility to SLE in Mexican patients and that the presence of a specific haplotype of the homologous chromosome in patients with DRB1*0407-DQA1*03-DQB1*0302 and DRB1*1501-DQA1*0102-DQB1*0602 haplotypes could have an additive effect on the susceptibility to the disease. Finally, the low frequency of the DRB1*0301 and DRB1*1501 alleles in the control population suggests that the genetic admixture between Mexican Indians and Caucasian populations was an event that could have increased the risk of Mexicans to develop SLE.

Anetoderma in systemic lupus erythematosus: relationship to antiphospholipid antibodies

Anetoderma is an elastolytic disorder where multiple patches of slack skin are formed. Twelve patients with anetoderma associated with systemic lupus erythematous have been described, all in the dermatological literature. Recently, a role for antiphospholipid antibodies has been proposed with microthromboses as its pathogenic mechanism. We present herein a 20-year-old female patient who developed anetoderma soon after sun exposure. She was found to have a false positive VDRL and gradually developed other manifestations of SLE, including interstitial cystitis. She has had repeatedly positive antiphospholipid antibodies. Although there are patients who may have a primary form, diagnosis of anetoderma should trigger a search for SLE and/or antiphospholipid antibodies.

The future of treatment for systemic lupus erythematosus

The future promises good news for the treatment of systemic lupus erythematosus, some of which can already be foreseen. Increased knowledge on genes that participate in the predisposition, pathogenesis, pharmacogenetics of, and protection against this disease may permit intervention at this level. Also, better understanding about the role of sex hormones has allowed trials of weak androgens or prolactin inhibitors. New immunomodulators or immunosuppressors may enable more precise treatment at the immunoregulatory level, and greater knowledge on the disturbance of circuits has already provided hints and even allowed trials of anti-interleukin-10 antibodies, an IL-10 decreasing agent, tolerance-induction strategies or intervention at the level of T cell co-stimulation, as well as immune ablation with subsequent stem cell transplantation. Autoantibodies can be removed, controlled by means of anti-idiotypes, which are blocked from reaching their target antigen or uncoupled from the tissues they have reached. All these treatment strategies will gradually become decanted in order to achieve the optimal treatment of SLE, which may tum out to be its cure.

Penetration of autoantibodies into living cells, 2000

The formerly prevalent concept that intact autoantibodies could not penetrate into viable cells has been defeated by a large amount of experimental findings and clinical observations that indicate otherwise. The penetration of autoantibodies into living cells seems to participate in the pathogenesis of diverse autoimmune diseases, but it may also play a physiological role in healthy individuals. Although the fine mechanisms of the phenomenon remain to be elucidated, the potential use of penetrating autoantibodies as vectors to deliver molecules into cells, with diverse therapeutic purposes, has gained growing interest during the last few years.

Are there "Attenuated" Forms of Evans Syndrome?

Indirect evidence of hemolysis has been described in patients with autoimmune thrombocytopenic purpura. In order to collect more data, another method to assess red blood cell destruction in these patients was employed: measurement of free haptoglobin levels. In 17 individuals with autoimmune thrombocytopenic purpura the levels of free haptoglobins were assessed after carefully ruling out microangiopathic hemolysis, systemic lupus erythematosus or overt Evans syndrome. Abnormally low levels of free haptoglobins were found in five individuals (29%) as indirect evidence of hemolysis. The long-term thrombocytopenia-free status was lower in patients with low haptoglobin levels than in those with normal levels (40 versus 58%). These data, added to previous evidence, support the observation of Evans made 50 years ago: "there is a spectrum-like relationship between primary thrombocytopenia and haemolytic anemia".". Accordingly, the concept of "attenuated" variants of the Evans syndrome could be entertained.

Fine mapping of the SLEB2 locus involved in susceptibility to systemic lupus erythematosus

We have previously reported linkage of systemic lupus erythematosus to chromosome 2q37 in multicase families from Iceland and Sweden. This locus (SLEB2) was identified by linkage to the markers D2S125 and D2S140. In the present study we have analyzed additional microsatellite markers and SNPs covering a region of 30 cM around D2S125 in an extended set of Nordic families (Icelandic, Swedish, and Norwegian). Two-point linkage analysis in these families gave a maximum lod score at the position of markers D2S2585 and D2S2985 (Z = 4.51, PIC = 0.65), by applying a "model-free" pseudo-marker linkage analysis. Based on multipoint linkage analysis in the Nordic families, the most likely location of the SLEB2 locus is estimated to be in the interval between D2S125 and the position of markers D2S2585 and D2S2985, with a peak multipoint lod score of Z = 6.03, assuming a dominant pseudo-marker model. Linkage disequilibrium (LD) analysis was performed using the data from the multicase families and 89 single-case families of Swedish origin, using the same set of markers. The LD analysis showed evidence for association in the single-case and multicase families with locus GAAT3C11 (P < 0.0003), and weak evidence for association was obtained for several markers located telomeric to D2S125 in the multicase families. Thirteen Mexican families were analyzed separately and found not to have linkage to this region. Our results support the presence of the SLEB2 locus at 2q37.

Vasculitis in the connective tissue diseases

Vasculitides in the setting of connective tissue diseases are generally thought to be infrequent and relatively little is written about them. They are, however, important both because they may pose diagnostic and therapeutic challenges and affect prognosis. In each of the connective tissue diseases, vasculitis can present in various clinical and pathologic forms adding to their diagnostic and therapeutic difficulties. This article reviews recent information on the frequency, characteristics, and possible pathogenic mechanisms of the vasculitides occurring in patients with the main connective tissue diseases.

Clinical and biologic effects of anti-interleukin-10 monoclonal antibody administration in systemic lupus erythematosus

OBJECTIVE

To evaluate the safety and clinical efficacy of administering an anti-interleukin-10 (anti-IL-10) monoclonal antibody (mAb) to systemic lupus erythematosus (SLE) patients with active and steroid-dependent disease. In addition, we sought to assess the effects of in vivo IL-10 neutralization on biologic markers of SLE.

METHODS

Treatment consisted of 20 mg/day intravenous administration of an anti-IL-10 murine mAb (B-N10) for 21 consecutive days, with a followup period of 6 months. Six patients were studied.

RESULTS

Treatment was safe and well tolerated. All patients developed antibodies against B-N10. Cutaneous lesions and joint symptoms improved in all patients beginning during B-N10 administration and continuing to month 6. The SLE Disease Activity Index decreased from a mean +/- SEM of 8.83+/-0.91 on day 1 to 3.67+/-0.67 on day 21 (P = 0.001), 1.50+/-0.84 at month 2, and 1.33+/-0.80 at month 6 (P<0.001). At the end of followup, the disease was clinically inactive in 5 of the 6 patients. Prednisone administration was decreased from a mean +/- SEM of 27.9+/-5.7 mg/day on day 1 to 9.6+/-2.0 mg/day at month 6 (P<0.005). Activity of immune and endothelial cells rapidly decreased, as assessed by the early evolution of several biologic markers.

CONCLUSION

This is the first report of IL-10 antagonist administration to humans. The study shows the involvement of IL-10 in the pathogenesis of SLE, and indicates that the use of IL-10 antagonists may be beneficial in the management of refractory SLE.

Association analysis with microsatellite and SNP markers does not support the involvement of BCL-2 in systemic lupus erythematosus in Mexican and Swedish patients and their families

We have described suggestive linkage between microsatellite markers within the cytogenetic region 18q21-23 and SLE, a region where linkage with other autoimmune diseases has also been detected. The Bcl-2 gene located within this region, is a candidate gene because of its role in apoptosis, a physiological mechanism that could be deregulated in autoimmune disease. Furthermore, several studies have found abnormalities of Bcl-2 expression in SLE patients. We therefore sought to determine if the Bcl-2 gene is involved in SLE by studying members of a large cohort of Mexican SLE patients (n = 378) and 112 Swedish simplex families. Using a microsatellite marker and two single nucleotide polymorphisms located within the gene, we were unable to detect association between Bcl-2 and SLE in either population. We also tested whether combinations of alleles of the Bcl-2 and IL-10.G microsatellites would increase the risk for SLE. Our results do not support such hypothesis. Our findings suggest that linkage between SLE and the 18q21-23 region is due to a gene other than Bcl-2.

The anti-phospholipid antibody syndrome: clinical and serological aspects

The association of thromboses and/or cytopenias with anti-phospholipid antibodies (aPL), the anti-phospholipid syndrome (APS), is well recognized. The syndrome may be primary or occur within systemic lupus erythematosus (SLE). The notion of the syndrome occurring within SLE is important since patients found to have aPL may be at risk for developing APS manifestations, those who develop some manifestations may be at risk for developing others and, finally, SLE patients with this syndrome may need special treatment. There are subtle differences between the primary and the secondary forms, mostly due to the frequently higher and more persistent autoantibody levels in the primary and the influence of lupus in the secondary. These syndromes may be related to various antigen/antibody systems in which phospholipids participate either directly or through their effect on the proteins that bind them. Similar clinical manifestations also occur in patients who have serum antibodies to such proteins (e.g. beta2-glycoprotein-I) in the absence of phospholipid. Some of these antibodies may even be more important pathogenically than the antibodies against cardiolipin that were originally described. Testing for the latter is, however, still the first choice when suspecting an antiphospholipid syndrome. If this is negative in this situation, a search for the other autoantibodies is indicated.

Genetic analysis of the contribution of IL10 to systemic lupus erythematosus

OBJECTIVE

To study the contribution of the IL10 gene to the susceptibility to systemic lupus erythematosus (SLE).

METHODS

Analysis by fluorescent-semiautomated genotyping of a dinucleotide repeat located in the promoter region of the IL10 locus (microsatellite G).

RESULTS

No significant difference was found in the frequencies of the microsatellite alleles of 330 Mexican patients with SLE compared to 368 controls from the same population. Two-point linkage analyses were carried out using 13 Mexican, 13 Swedish, and 8 Icelandic families with 2 or more cases with SLE. No linkage was revealed between IL10 and SLE, using a variety of parameter settings.

CONCLUSION

Our results do not support that the IL10 gene contributes to the susceptibility to SLE in the populations we studied.