Luis R. Espinoza

Association of the IRF5 risk haplotype with high serum interferon-α activity in systemic lupus erythematosus patients

OBJECTIVE A haplotype of the interferon regulatory factor 5 (IRF5) gene has been associated with the risk of developing systemic lupus erythematosus (SLE), and our previous studies have demonstrated that high levels of serum interferon-alpha (IFNalpha) activity are a heritable risk factor for SLE. The aim of this study was to determine whether the IRF5 SLE risk haplotype mediates the risk of SLE by predisposing patients to the development of high levels of serum IFNalpha activity. METHODS IFNalpha levels in 199 SLE patients of European and Hispanic ancestry were measured with a sensitive functional reporter cell assay. The rs2004640, rs3807306, rs10488631, and rs2280714 single-nucleotide polymorphisms (SNPs) in IRF5 were genotyped in these patients. Haplotypes were categorized as SLE risk, neutral, or protective based on published data. RESULTS SLE patients with risk/risk and risk/neutral IRF5 genotypes had higher serum IFNalpha activity than did those with protective/protective and neutral/protective genotypes (P = 0.025). This differential effect of IRF5 genotype on serum IFNalpha levels was driven largely by SLE patients who were positive for either anti-RNA binding protein (anti-RBP) or anti-double-stranded DNA (anti-dsDNA) autoantibodies (P = 0.012 for risk/risk or risk/neutral versus protective/protective or neutral/protective). The rs3807306 genotype was independently associated with high serum IFNalpha in this autoantibody group. We found no difference in IFNalpha activity according to IRF5 genotype in patients lacking either type of autoantibody or in patients positive for both classes of autoantibody. CONCLUSION The IRF5 SLE risk haplotype is associated with higher serum IFNalpha activity in SLE patients, and this effect is most prominent in patients positive for either anti-RBP or anti-dsDNA autoantibodies. This study demonstrates the biologic relevance of the SLE risk haplotype of IRF5 at the protein level.

Pulmonary involvement in rheumatoid arthritis

Pulmonary involvement is one of the extra-articular manifestations of rheumatoid arthritis (RA) and includes pleurisy, parenchymal nodules, interstitial involvement, and airway disease. Rheumatoid pulmonary vasculitis is rare. Pulmonary disease also may be observed as a toxic event consequent to treatment for RA. Although RA is more common in women, rheumatoid lung disease occurs more frequently in men who have long-standing rheumatoid disease, positive rheumatoid factor and subcutaneous nodules. Pleural involvement, usually asymptomatic, is the most common manifestation of lung disease in RA and may occur concurrently with pulmonary nodulosis or interstitial disease. The clinical features and course of pulmonary fibrosis in RA are similar to those of idiopathic pulmonary fibrosis. Bronchiolitis obliterans organizing pneumonia (BOOP), which has been recently described in RA patients, has nonspecific clinical features. The histological patterns correspond to proliferative bronchiolitis in the airway and organizing pneumonia in the alveoli. Obstructive lung disease in RA includes obliterative bronchiolitis (OB) and bronchiectasis. OB is an acute illness characterized histologically by a constrictive bronchiolitis. It may be idiopathic or induced by D-penicillamine or intramuscular gold compounds. Methotrexate (MTX)-pneumonitis is an uncommon complication of MTX treatment. Its clinical presentation is not specific, and diagnosis must be made after exclusion of other causes of pulmonary diseases. It is uncertain if preexisting lung disease predisposes RA patients to MTX-pneumonitis. Treatment of lung disease in RA is empirical. Corticosteroids are usually administered and immunosuppressive drugs are often added when pulmonary disease progresses and/or steroid side-effects appear.

Abetimus sodium for renal flare in systemic lupus erythematosus: Results of a randomized, controlled phase III trial†

OBJECTIVE To investigate whether treatment with abetimus delays renal flare in patients with lupus nephritis. Secondary objectives included evaluation of the effect of abetimus on C3 levels, anti-double-stranded DNA (anti-dsDNA) antibody levels, use of high-dose corticosteroids and/or cyclophosphamide, and major systemic lupus erythematosus (SLE) flare. METHODS We conducted a randomized, placebo-controlled study of treatment with abetimus at 100 mg/week for up to 22 months in SLE patients. Three hundred seventeen patients with a history of renal flare and anti-dsDNA levels >15 IU/ml were randomized to a treatment group (158 abetimus, 159 placebo); 298 (94%) were enrolled in the intent-to-treat (ITT) population (145 abetimus, 153 placebo), based on the presence of high-affinity antibodies for the oligonucleotide epitope of abetimus at baseline screening. RESULTS Abetimus did not significantly prolong time to renal flare, time to initiation of high-dose corticosteroid and/or cyclophosphamide treatment, or time to major SLE flare. However, there were 25% fewer renal flares in the abetimus group compared with the placebo group (17 of 145 abetimus-treated patients [12%] versus 24 of 153 placebo-treated patients [16%]). Abetimus treatment decreased anti-dsDNA antibody levels (P < 0.0001), and reductions in anti-dsDNA levels were associated with increases in C3 levels (P < 0.0001). More patients in the abetimus group experienced > or =50% reductions in proteinuria at 1 year, compared with the placebo group (nominal P = 0.047). Trends toward reduced rates of renal flare and major SLE flare were noted in patients treated with abetimus who had impaired renal function at baseline. Treatment with abetimus for up to 22 months was well tolerated. CONCLUSION Abetimus at 100 mg/week significantly reduced anti-dsDNA antibody levels but did not significantly prolong time to renal flare when compared with placebo. Multiple positive trends in renal end points were observed in the abetimus treatment group.

Hyperprolactinemia in Systemic Lupus Erythematosus: Association with Disease Activity

This study was designed to determine the prevalence and clinical significance of hyperprolactinemia in systemic lupus erythematosus (SLE) and other rheumatic diseases. Basal levels of prolactin were determined in 130 nonselected sera from patients with rheumatic diseases including 45 with SLE, 31 with rheumatoid arthritis, 23 with osteoarthritis, 18 with fibromyalgia, and 13 with polymyalgia rheumatica. Serum samples of 28 healthy subjects were used as normal controls. Serum prolactin was measured by radioimmunoassay. ANA, anti-DNA, RNP, Sm, Ro, La, and anticardiolipin antibodies were determined by standard techniques. Elevated serum levels of prolactin (PRL greater than 20 ng/ml) were found in a subset of SLE patients. In addition, a direct correlation with clinical disease and serological (ANA) activity was also found. These findings suggest a potential role for this immunoregulatory hormone in SLE pathogenesis.

Combination Antibiotics as a Treatment for Chronic Chlamydia-Induced Reactive Arthritis A Double-Blind, Placebo-Controlled, Prospective Trial

OBJECTIVE Chlamydia trachomatis and Chlamydophila (Chlamydia) pneumoniae are known triggers of reactive arthritis (ReA) and exist in a persistent metabolically active infection state in the synovium, suggesting that they may be susceptible to antimicrobial agents. The goal of this study was to investigate whether a 6-month course of combination antibiotics is an effective treatment for patients with chronic Chlamydia-induced ReA. METHODS This study was a 9-month, prospective, double-blind, triple-placebo trial assessing a 6-month course of combination antibiotics as a treatment for Chlamydia-induced ReA. Eligible patients had to be positive for C trachomatis or C pneumoniae by polymerase chain reaction (PCR). Groups received 1) doxycycline and rifampin plus placebo instead of azithromycin; 2) azithromycin and rifampin plus placebo instead of doxycycline; or 3) placebos instead of azithromycin, doxycycline, and rifampin. The primary end point was the number of patients who improved by 20% or more in at least 4 of 6 variables without worsening in any 1 variable in both combination antibiotic groups combined and in the placebo group at month 6 compared with baseline. RESULTS The primary end point was achieved in 17 of 27 patients (63%) receiving combination antibiotics and in 3 of 15 patients (20%) receiving placebo. Secondary efficacy end points showed similar results. Six of 27 patients (22%) randomized to combination antibiotics believed that their disease went into complete remission during the trial, whereas no patient in the placebo arm achieved remission. Significantly more patients in the active treatment group became negative for C trachomatis or C pneumoniae by PCR at month 6. Adverse events were mild, with no significant differences between the groups. CONCLUSION These data suggest that a 6-month course of combination antibiotics is an effective treatment for chronic Chlamydia-induced ReA.

HLA-B27-Associated Reactive Arthritis: Pathogenetic and Clinical Considerations

SUMMARY Current evidence supports the concept that reactive arthritis (ReA) is an immune-mediated synovitis resulting from slow bacterial infections and showing intra-articular persistence of viable, nonculturable bacteria and/or immunogenetic bacterial antigens synthesized by metabolically active bacteria residing in the joint and/or elsewhere in the body. The mechanisms that lead to the development of ReA are complex and basically involve an interaction between an arthritogenic agent and a predisposed host. The way in which a host accommodates to invasive facultative intracellular bacteria is the key to the development of ReA. The details of the molecular pathways that explain the articular and extra-articular manifestations of the disease are still under investigation. Several studies have been done to gain a better understanding of the pathogenesis of ReA; these constitute the basis for a more rational therapeutic approach to this disease.

Prolactin and autoimmunity.

Prolactin (PRL) is a versatile hormone that is produced by the anterior pituitary gland and various extrapituitary sites including immune cells. Furthermore, PRL has widespread influences on proliferation and differentiation of a variety of cells in the immune system and is, in effect, a cytokine. PRL-receptors (PRL-R) are distributed throughout the immune system and are included as members of the cytokine receptor superfamily. PRL-R signal transduction is mediated by a complex array of signaling molecules of which JAK2, Stat1 and Stat5 pathway have been well studied. In PRL-stimulated T cells, the transcription factor gene, interferon regulatory factor-1 provides a mechanism whereby PRL can regulate the immune response. The human PRL gene is situated on the short arm of chromosome 6 close to the major histocompatibility complex. Polymorphisms of the human PRL gene have implications for production of lymphocyte PRL in SLE. Mild and moderate hyperprolactinemia (HPRL) has been demonstrated in 20-30% of SLE patients and is associated with active disease. HPRL may have a role in lupus nephritis and central nervous system involvement of SLE patients. HPRL stimulated the production of autoantibodies. These evidences support the important role of PRL in autoimmunity and autoimmune diseases, mainly SLE.

Refractory Nephrotic Syndrome in Lupus Nephritis: Favorable Response to Indomethacin Therapy

The effects of indomethacin on urinary protein excretion, levels of serum albumin and renal function were studied prospectively in six patients with systemic lupus erythematosus (SLE) and refractory nephrotic syndrome due to lupus nephritis. Two had membranoproliferative glomerulonephritis, two had diffuse proliferative glomerulonephritis, and one each had mesangioproliferative and membranous glomerulonephritis. All experienced a considerable reduction in urinary protein excretion and an increase in serum albumin. Indomethacin was discontinued in two patients because of side effects, and proteinuria recurred to pretreatment levels. The decrease of proteinuria continued during long-term treatment in three patients. Indomethacin did not cause a permanent decline in renal function. Our results suggest that therapy with indomethacin may be beneficial for the treatment of refractory nephrotic syndrome in selected SLE patients. However, because of potential side effects the administration of indomethacin should be monitored closely.

Chlamydiae as etiologic agents in chronic undifferentiated spondylarthritis.

OBJECTIVE The majority of patients with Chlamydia-induced reactive arthritis do not present with the classic triad of arthritis, conjunctivitis/iritis, and urethritis. Moreover, acute chlamydial infections are often asymptomatic. The aim of the present study was to assess the prevalence of synovial Chlamydia trachomatis and Chlamydia pneumoniae infections in patients with chronic undifferentiated spondylarthritis (uSpA). METHODS Study patients met the European Spondylarthropathy Study Group criteria for SpA, without evidence of ankylosing spondylitis, psoriasis, inflammatory bowel disease, or preceding dysentery. Symptoms were present for >or=6 months. Each patient underwent a synovial biopsy; tissue and concomitantly obtained peripheral blood mononuclear cells (PBMCs) were analyzed by polymerase chain reaction (PCR) for C trachomatis and C pneumoniae DNA. Other data collected on the day of the biopsy included standard demographic information and medical history, including any known history of C trachomatis or C pneumoniae. Physical examination (including joint count, evaluation for dactylitis and/or enthesitis, and skin examination) and HLA-B27 typing were performed. Synovial tissue (ST) samples from 167 patients with osteoarthritis (OA) were used as controls. RESULTS Twenty-six patients met the entry criteria and underwent synovial biopsy (25 knee, 1 wrist). Sixteen of them (62%) were positive for C trachomatis and/or C pneumoniae DNA (10 for C trachomatis, 4 for C pneumoniae, and 2 for both). PCR analysis of ST revealed the presence of Chlamydia significantly more frequently in patients with uSpA than in OA controls (P<0.0001). No specific clinical characteristics differentiated Chlamydia-positive from Chlamydia-negative patients. PBMCs from 4 of the 26 uSpA patients (15%) were positive for Chlamydia, and Chlamydia was found in ST from 2 of these 4 patients. No significant correlation between PCR positivity and HLA-B27 positivity was found. CONCLUSION The frequency of Chlamydia-positive ST samples, as determined by PCR, was found to be significantly higher in patients with uSpA than in patients with OA. Our results suggest that in many patients with uSpA, chlamydial infection, which is often occult, may be the cause.

Osteopontin and systemic lupus erythematosus association: a probable gene-gender interaction.

Osteopontin (SPP1) is an important bone matrix mediator found to have key roles in inflammation and immunity. SPP1 genetic polymorphisms and increased osteopontin protein levels have been reported to be associated with SLE in small patient collections. The present study evaluates association between SPP1 polymorphisms and SLE in a large cohort of 1141 unrelated SLE patients [707 European-American (EA) and 434 African-American (AA)], and 2009 unrelated controls (1309 EA and 700 AA). Population-based case-control association analyses were performed. To control for potential population stratification, admixture adjusted logistic regression, genomic control (GC), structured association (STRAT), and principal components analysis (PCA) were applied. Combined analysis of 2 ethnic groups, showed the minor allele of 2 SNPs (rs1126616T and rs9138C) significantly associated with higher risk of SLE in males (P = 0.0005, OR = 1.73, 95% CI = 1.28–2.33), but not in females. Indeed, significant gene-gender interactions in the 2 SNPs, rs1126772 and rs9138, were detected (P = 0.001 and P = 0.0006, respectively). Further, haplotype analysis identified rs1126616T-rs1126772A-rs9138C which demonstrated significant association with SLE in general (P = 0.02, OR = 1.30, 95%CI 1.08–1.57), especially in males (P = 0.0003, OR = 2.42, 95%CI 1.51–3.89). Subgroup analysis with single SNPs and haplotypes also identified a similar pattern of gender-specific association in AA and EA. GC, STRAT, and PCA results within each group showed consistent associations. Our data suggest SPP1 is associated with SLE, and this association is especially stronger in males. To our knowledge, this report serves as the first association of a specific autosomal gene with human male lupus.