Low copy numbers of complement C4 and C4A deficiency are risk factors for myositis, its subgroups and autoantibodies

BACKGROUND

Idiopathic inflammatory myopathies (IIM) are a group of autoimmune diseases characterised by myositis-related autoantibodies plus infiltration of leucocytes into muscles and/or the skin, leading to the destruction of blood vessels and muscle fibres, chronic weakness and fatigue. While complement-mediated destruction of capillary endothelia is implicated in paediatric and adult dermatomyositis, the complex diversity of complement C4 in IIM pathology was unknown.

METHODS

We elucidated the gene copy number (GCN) variations of total C4, C4A and C4B, long and short genes in 1644 Caucasian patients with IIM, plus 3526 matched healthy controls using real-time PCR or Southern blot analyses. Plasma complement levels were determined by single radial immunodiffusion.

RESULTS

The large study populations helped establish the distribution patterns of various C4 GCN groups. Low GCNs of C4T (C4T=2+3) and C4A deficiency (C4A=0+1) were strongly correlated with increased risk of IIM with OR equalled to 2.58 (2.28-2.91), p=5.0×10^-53 for C4T, and 2.82 (2.48-3.21), p=7.0×10^-57 for C4A deficiency. Contingency and regression analyses showed that among patients with C4A deficiency, the presence of HLA-DR3 became insignificant as a risk factor in IIM except for inclusion body myositis (IBM), by which 98.2% had HLA-DR3 with an OR of 11.02 (1.44-84.4). Intragroup analyses of patients with IIM for C4 protein levels and IIM-related autoantibodies showed that those with anti-Jo-1 or with anti-PM/Scl had significantly lower C4 plasma concentrations than those without these autoantibodies.

CONCLUSIONS

C4A deficiency is relevant in dermatomyositis, HLA-DRB1*03 is important in IBM and both C4A deficiency and HLA-DRB1*03 contribute interactively to risk of polymyositis.

Strong Association of Combined Genetic Deficiencies in the Classical Complement Pathway With Risk of Systemic Lupus Erythematosus and Primary Sjögren's Syndrome

OBJECTIVE

Complete genetic deficiency of the complement component C2 is a strong risk factor for monogenic systemic lupus erythematosus (SLE), but whether heterozygous C2 deficiency adds to the risk of SLE or primary Sjögren's syndrome (SS) has not been studied systematically. This study was undertaken to investigate potential associations of heterozygous C2 deficiency and C4 copy number variation with clinical manifestations in patients with SLE and patients with primary SS.

METHODS

The presence of the common 28-bp C2 deletion rs9332736 and C4 copy number variation was examined in Scandinavian patients who had received a diagnosis of SLE (n = 958) or primary SS (n = 911) and in 2,262 healthy controls through the use of DNA sequencing. The concentration of complement proteins in plasma and classical complement function were analyzed in a subgroup of SLE patients.

RESULTS

Heterozygous C2 deficiency-when present in combination with a low C4A copy number-substantially increased the risk of SLE (odds ratio [OR] 10.2 [95% confidence interval (95% CI) 3.5-37.0]) and the risk of primary SS (OR 13.0 [95% CI 4.5-48.4]) when compared to individuals with 2 C4A copies and normal C2. For patients heterozygous for rs9332736 with 1 C4A copy, the median age at diagnosis was 7 years earlier in patients with SLE and 12 years earlier in patients with primary SS when compared to patients with normal C2. Reduced C2 levels in plasma (P = 2 × 10^-9 ) and impaired function of the classical complement pathway (P = 0.03) were detected in SLE patients with heterozygous C2 deficiency. Finally, in a primary SS patient homozygous for C2 deficiency, we observed low levels of anti-Scl-70, which suggests a risk of developing systemic sclerosis or potential overlap between primary SS and other systemic autoimmune diseases.

CONCLUSION

We demonstrate that a genetic pattern involving partial deficiencies of C2 and C4A in the classical complement pathway is a strong risk factor for SLE and for primary SS. Our results emphasize the central role of the complement system in the pathogenesis of both SLE and primary SS.

Complement C4 Copy Number Variation is Linked to SSA/Ro and SSB/La Autoantibodies in Systemic Inflammatory Autoimmune Diseases

OBJECTIVE

Copy number variation of the C4 complement components, C4A and C4B, has been associated with systemic inflammatory autoimmune diseases. This study was undertaken to investigate whether C4 copy number variation is connected to the autoimmune repertoire in systemic lupus erythematosus (SLE), primary Sjögren's syndrome (SS), or myositis.

METHODS

Using targeted DNA sequencing, we determined the copy number and genetic variants of C4 in 2,290 well-characterized Scandinavian patients with SLE, primary SS, or myositis and 1,251 healthy controls.

RESULTS

A prominent relationship was observed between C4A copy number and the presence of SSA/SSB autoantibodies, which was shared between the 3 diseases. The strongest association was detected in patients with autoantibodies against both SSA and SSB and 0 C4A copies when compared to healthy controls (odds ratio [OR] 18.0 [95% confidence interval (95% CI) 10.2-33.3]), whereas a weaker association was seen in patients without SSA/SSB autoantibodies (OR 3.1 [95% CI 1.7-5.5]). The copy number of C4 correlated positively with C4 plasma levels. Further, a common loss-of-function variant in C4A leading to reduced plasma C4 was more prevalent in SLE patients with a low copy number of C4A. Functionally, we showed that absence of C4A reduced the individuals' capacity to deposit C4b on immune complexes.

CONCLUSION

We show that a low C4A copy number is more strongly associated with the autoantibody repertoire than with the clinically defined disease entities. These findings may have implications for understanding the etiopathogenetic mechanisms of systemic inflammatory autoimmune diseases and for patient stratification when taking the genetic profile into account.

Four Systemic Lupus Erythematosus Subgroups, Defined by Autoantibodies Status, Differ Regarding HLA-DRB1 Genotype Associations and Immunological and Clinical Manifestations

Objective

The heterogeneity of systemic lupus erythematosus (SLE) constitutes clinical and therapeutical challenges. We therefore studied whether unrecognized disease subgroups can be identified by using autoantibody profiling together with HLA‐DRB1 alleles and immunological and clinical data.

Methods

An unsupervised cluster analysis was performed based on detection of 13 SLE‐associated autoantibodies (double‐stranded DNA, nucleosomes, ribosomal P, ribonucleoprotein [RNP] 68, RNPA, Smith [Sm], Sm/RNP, Sjögren's syndrome antigen A [SSA]/Ro52, SSA/Ro60, Sjögren's syndrome antigen B [SSB]/La, cardiolipin [CL]‐Immunoglobulin G [IgG], CL–Immunoglobulin M [IgM], and β₂ glycoprotein I [β₂GPI]–IgG) in 911 patients with SLE from two cohorts. We evaluated whether each SLE subgroup is associated with HLA‐DRB1 alleles, clinical manifestations (n = 743), and cytokine levels in circulation (n = 446).

Results

Our analysis identified four subgroups among the patients with SLE. Subgroup 1 (29.3%) was dominated by anti‐SSA/Ro60/Ro52/SSB autoantibodies and was strongly associated with HLA‐DRB1*03 (odds ratio [OR] = 4.73; 95% confidence interval [CI] = 4.52‐4.94). Discoid lesions were more common for this disease subgroup (OR = 1.71, 95% CI = 1.18‐2.47). Subgroup 2 (28.7%) was dominated by anti‐nucleosome/SmRNP/DNA/RNPA autoantibodies and associated with HLA‐DRB1*15 (OR = 1.62, 95% CI = 1.41‐1.84). Nephritis was most common in this subgroup (OR = 1.61, 95% CI = 1.14‐2.26). Subgroup 3 (23.8%) was characterized by anti‐ß₂GPI‐IgG/anti‐CL–IgG/IgM autoantibodies and a higher frequency of HLA‐DRB1*04 compared with the other patients with SLE. Vascular events were more common in Subgroup 3 (OR = 1.74, 95% CI = 1.2‐2.5). Subgroup 4 (18.2%) was negative for the investigated autoantibodies, and this subgroup was not associated with HLA‐DRB1. Additionally, the levels of eight cytokines significantly differed among the disease subgroups.

Conclusion

Our findings suggest that four fairly distinct subgroups can be identified on the basis of the autoantibody profile in SLE. These four SLE subgroups differ regarding associations with HLA‐DRB1 alleles and immunological and clinical features, suggesting dissimilar disease pathways.

Gene copy-number variations (CNVs) of complement C4 and C4A deficiency in genetic risk and pathogenesis of juvenile dermatomyositis

OBJECTIVE

Complement-mediated vasculopathy of muscle and skin are clinical features of juvenile dermatomyositis (JDM). We assess gene copy-number variations (CNVs) for complement C4 and its isotypes, C4A and C4B, in genetic risks and pathogenesis of JDM.

METHODS

The study population included 105 patients with JDM and 500 healthy European Americans. Gene copy-numbers (GCNs) for total C4, C4A, C4B and HLA-DRB1 genotypes were determined by Southern blots and qPCRs. Processed activation product C4d bound to erythrocytes (E-C4d) was measured by flow cytometry. Global gene-expression microarrays were performed in 19 patients with JDM and seven controls using PAXgene-blood RNA. Differential expression levels for selected genes were validated by qPCR.

RESULTS

Significantly lower GCNs and differences in distribution of GCN groups for total C4 and C4A were observed in JDM versus controls. Lower GCN of C4A in JDM remained among HLA DR3-positive subjects (p=0.015). Homozygous or heterozygous C4A-deficiency was present in 40.0% of patients with JDM compared with 18.2% of controls (OR=3.00 (1.87 to 4.79), p=8.2×10(-6)). Patients with JDM had higher levels of E-C4d than controls (p=0.004). In JDM, C4A-deficient subjects had higher levels of E-C4d (p=0.0003) and higher frequency of elevated levels of multiple serum muscle enzymes at diagnosis (p=0.0025). Microarray profiling of blood RNA revealed upregulation of type I interferon-stimulated genes and lower abundance of transcripts for T-cell and chemokine function genes in JDM, but this was less prominent among C4A-deficient or DR3-positive patients.

CONCLUSIONS

Complement C4A deficiency appears to be an important factor for the genetic risk and pathogenesis of JDM, particularly in patients with a DR3-positive background.

Agreement between ambulance nurses and physicians in assessing stroke patients

OBJECTIVES

If an ambulance nurse could bypass the emergency department (ED) and bring suspected stroke patients directly to a CT scanner, time to thrombolysis could be shortened. This study evaluates the level of agreement between ambulance nurses and emergency physicians in assessing the need for a CT scan, and interventions and monitoring beforehand, in patients with suspected stroke and/or a lowered level of consciousness.

METHODS

From October 2008 to June 2009, we compared the ambulance nurses' and ED physicians' judgement of 200 patients with stroke symptoms. Both groups answered identical questions on patients' need for a CT scan, and interventions and monitoring beforehand.

RESULTS

There was poor agreement between ambulance nurses and ED physicians in judging the need for a CT scan: κ = 0.22 (95% confidence interval (CI), 0.06-0.37). The nurses' ability to select the same patients as the physician for a CT scan had a sensitivity of 84% (95% CI, 77-89) and a specificity of 37% (95% CI, 23-53). Agreement concerning the need for interventions and monitoring was also low: κ = 0.32 (95% CI, 0.18-0.47). In 18% of cases, the nurses considered interventions before a CT scan unnecessary when the physicians' deemed them necessary.

CONCLUSIONS

Additional tools to support ambulance nurses decisions appear to be required before suspected stroke patients can be taken directly to a CT scanner.

Very high levels of anti-citrullinated protein antibodies are associated with HLA-DRB1*15 non-shared epitope allele in patients with rheumatoid arthritis

OBJECTIVE

Production of anti-citrullinated protein antibodies (ACPAs) is an important biomarker for rheumatoid arthritis (RA). We undertook this study to determine whether genetic factors (HLA-DRB1 alleles) are associated with extreme ACPA levels in individuals with ACPA-positive RA, and to ascertain whether there are any phenotypic characteristics associated with these subgroups of RA.

METHODS

HLA-DRB1 allelic groups were genotyped in 1,073 ACPA-positive RA patients from the Swedish Epidemiological Investigation of Rheumatoid Arthritis study. We found that 283 patients (26.4%) had high ACPA levels (defined as >1,500 units/ml using the Euro-Diagnostica anti-CCP2 test), while the rest of the patients had moderate ACPA levels and served as the comparison group. A replication group consisted of 235 RA patients.

RESULTS

No significant differences in baseline disease activity were observed between patients with high and those with moderate ACPA levels. However, the HLA-DRB1*15 allele was associated with high ACPA levels (P=0.0002). A similar trend was detected in HLA-DRB1*15-positive patients in the replication cohort, with meta-analysis of the discovery and replication cohorts demonstrating an overall effect of HLA-DRB1*15 on development of high ACPA levels in both the discovery and replication cohorts (P<0.0001 by Mantel-Haenszel test with a fixed-effects model).

CONCLUSION

Our data indicate that HLA-DRB1*15 may promote the production of high ACPA levels. Due to the high value of ACPA level scores in the 2010 American College of Rheumatology/European League Against Rheumatism classification criteria for RA, the presence of HLA-DRB1*15 may, at least in part, contribute to fulfilling the criteria for RA. This illustrates the complex nature of the genetic regulation of ACPA levels. Additional mechanistic studies of the regulation of ACPAs and ACPA-positive RA are pending.

HLA-DRB1*04/*13 alleles are associated with vascular disease and antiphospholipid antibodies in systemic lupus erythematosus

BACKGROUND AND OBJECTIVES

Vascular disease is common in systemic lupus erythematosus (SLE) and patients with antiphospholipid antibodies (aPL) are at high risk to develop arterial and venous thrombosis. Since HLA class II genotypes have been linked to the presence of pro-thrombotic aPL, we investigated the relationship between HLA-DRB1 alleles, aPL and vascular events in SLE patients.

METHODS

665 SLE patients of Caucasian origin and 1403 controls were included. Previous manifestations of ischaemic heart disease, ischaemic cerebrovascular disease (ICVD) and venous thromboembolism (together referred to as any vascular events (AVE)) were tabulated. aPL were measured with ELISA. Two-digit HLA-DRB1 typing was performed by sequence-specific primer-PCR.

RESULTS

HLA-DRB1*04 was more frequent among SLE patients with ICVD compared to unaffected patients. This association remained after adjustment for known traditional cardiovascular risk factors. HLA-DRB1*13 was associated with AVE. All measured specificities of aPL-cardiolipin IgG and IgM, β2-glycoprotein-1 IgG, prothrombin (PT) IgG and a positive lupus anticoagulant test were associated with HLA-DRB1*04-while HLA-DRB1*13 was associated with IgG antibodies (β2-glycoprotein-1, cardiolipin and PT). In patients with the combined risk alleles, HLA-DRB1*04/*13, there was a significant additive interaction for the outcomes AVE and ICVD.

CONCLUSIONS

The HLA-DRB1*04 and HLA-DRB1*13 alleles are associated with vascular events and an aPL positive immune-phenotype in SLE. Results demonstrate that a subset of SLE patients is genetically disposed to vascular vulnerability.

Shared epitope alleles remain a risk factor for anti-citrullinated proteins antibody (ACPA)--positive rheumatoid arthritis in three Asian ethnic groups

Background

To investigate the associations between HLA-DRB1 shared epitope (SE) alleles and rheumatoid arthritis in subsets of rheumatoid arthritis defined by autoantibodies in three Asian populations from Malaysia.

Methods

1,079 rheumatoid arthritis patients and 1,470 healthy controls were included in the study. Levels of antibodies to citrullinated proteins (ACPA) and rheumatoid factors were assessed and the PCR-SSO method was used for HLA-DRB1 genotyping.

Results

The proportion of ACPA positivity among Malay, Chinese and Indian rheumatoid arthritis patients were 62.9%, 65.2% and 68.6%, respectively. An increased frequency of SE alleles was observed in ACPA-positive rheumatoid arthritis among the three Asian ethnic groups. HLA-DRB1*10 was highly associated with rheumatoid arthritis susceptibility in these Asian populations. HLA-DRB1*0405 was significantly associated with susceptibility to rheumatoid arthritis in Malays and Chinese, but not in Indians. HLA-DRB1*01 did not show any independent effect as a risk factor for rheumatoid arthritis in this study and HLA-DRB1*1202 was protective in Malays and Chinese. There was no association between SE alleles and ACPA- negative rheumatoid arthritis in any of the three Asian ethnic groups.

Conclusion

The HLA-DRB1 SE alleles increase the risk of ACPA-positive rheumatoid arthritis in all three Asian populations from Malaysia.

Protection against anti-citrullinated protein antibody-positive rheumatoid arthritis is predominantly associated with HLA-DRB1*1301: a meta-analysis of HLA-DRB1 associations with anti-citrullinated protein antibody-positive and anti-citrullinated protein antibody-negative rheumatoid arthritis in four European populations

OBJECTIVE

The protective effect of HLA-DRB1 alleles on the development of rheumatoid arthritis (RA) is poorly understood. The aim of this study was to perform a meta-analysis of 4 European populations to investigate which HLA-DRB1 alleles are associated with protection in anti-citrullinated protein antibody (ACPA)-positive RA and ACPA-negative RA.

METHODS

Data for >2,800 patients and >3,000 control subjects for whom information on HLA-DRB1 typing and ACPA status was available were collected from 4 European countries: Norway, Sweden, The Netherlands, and Spain. The odds ratios (ORs) and 95% confidence intervals (95% CIs) associated with the different HLA-DRB1 alleles were analyzed in a combined meta-analysis focused on protective alleles and classifications. The analysis of ACPA-positive RA was stratified for the shared epitope (SE) alleles, to correct for skewing due to this association.

RESULTS

In ACPA-positive RA, the only alleles that conveyed protection after stratification for SE were HLA-DRB1*13 alleles (OR 0.54 [95% CI 0.38-0.77]). The protective effect of the allele classifications based on the DERAA and D70 sequences was no longer present after exclusion of DRB1*13 (for D70, OR 0.97 [95% CI 0.75-1.25]), indicating that DRB1*13, rather than the DERAA or D70 sequence as such, is associated with protection. Among the DRB1*13 alleles, only DRB1*1301 was associated with protection (OR 0.24 [95% CI 0.09-0.59]). Protection appeared to follow a north-to-south gradient, with the strongest association in northern European countries. In ACPA-negative RA, there were no robust associations with HLA-DRB1 alleles.

CONCLUSION

Our data do not support any of the classifications of protective alleles and indicate that protection against ACPA-positive RA is predominantly associated with HLA-DRB1*1301.

Gene-environment interaction between the DRB1 shared epitope and smoking in the risk of anti-citrullinated protein antibody-positive rheumatoid arthritis: all alleles are important

OBJECTIVE

An interaction effect for developing rheumatoid arthritis (RA) was previously observed between HLA-DRB1 shared epitope (SE) alleles and smoking. We aimed to further investigate this interaction between distinct SE alleles and smoking regarding the risk of developing RA with and without anti-citrullinated protein antibodies (ACPAs).

METHODS

We used data regarding smoking habits and HLA-DRB1 genotypes from 1,319 patients and 943 controls from the Epidemiological Investigation of Rheumatoid Arthritis, in which 972 patients and 488 controls were SE positive. Subsequently, 759 patients and 328 controls were subtyped for specific alleles within the DRB1*04 group. Odds ratios with 95% confidence intervals (95% CIs) were calculated by means of logistic regression. Interaction was evaluated by calculating attributable proportion due to interaction, with 95% CIs.

RESULTS

A strong interaction between smoking and SE alleles in the development of ACPA-positive RA was observed for all DRB1*04 SE alleles taken as a group (relative risk [RR] 8.7 [95% CI 5.7-13.1]) and for the *0401 and *0404 alleles (RR 8.9 [95% CI 5.8-13.5]) and the *01 and *10 alleles (RR 4.9 [95% CI 3.0-7.8]) as specific, separate groups, with similar strength of interaction for the different groups (attributable proportion due to interaction 0.4 [95% CI 0.2-0.6], 0.5 [95% CI 0.3-0.7], and 0.6 [95% CI 0.4-0.8], respectively).

CONCLUSION

There is a statistically significant interaction between distinct DRB1 SE alleles and smoking in the development of ACPA-positive RA. Interaction occurs with the *04 group as well as the *01/*10 group, demonstrating that regardless of fine specificity, all SE alleles strongly interact with smoking in conferring an increased risk of ACPA-positive RA.

Testosterone addition during menopausal hormone therapy: effects on mammographic breast density

OBJECTIVE

To study the effect on mammographic breast density of testosterone addition during combined estrogen/progestogen therapy in postmenopausal women.

METHODS

A prospective, randomized, double-blind, placebo-controlled trial. A total of 99 women were given 2 mg 17beta-estradiol and 1 mg norethisterone acetate in combination with either a testosterone patch (300 mug/24 h) or a placebo patch. Mammographic breast density at baseline and after 6 months was assessed by visual classification scales and by digitized quantification. A standardized questionnaire was used to quantify subjective breast symptoms.

RESULTS

Visual classifications showed an increase in mammographic density in 18-30% of the women, with no significant differences between the treatment groups. The mean increase of the area of dense breast during treatment according to digitized assessment was 7.4% in the placebo group and 5.4% in the testosterone group. Breast symptoms showed a positive association with the increase in density (r(s) = 0.34; p < 0.01). Symptoms were most pronounced at 2 months of treatment. Density, both at baseline (r(s) = -0.35; p < 0.01) and change during treatment (r(s) = -0.28; p < 0.01) showed a negative association with free testosterone levels.

CONCLUSION

The addition of testosterone does not appear to influence mammographic breast density in women concurrently treated with a common oral estrogen/progestogen regimen for a period of 6 months.

Expression of syndecan-1 in histologically normal breast tissue from postmenopausal women with breast cancer according to mammographic density

OBJECTIVE

To analyze the expression of Syndecan-1 in dense and non-dense human breast tissue.

METHODS

Specimens of histologically normal tissue were obtained from postmenopausal women undergoing surgery for breast cancer. Each tissue block was subject to radiological examination and pair-wise samples of dense and non-dense tissue were collected. Semi-quantitative assessment of immunohistochemical staining intensity for Syndecan-1 and estrogen receptor subtypes was performed.

RESULTS

The expression of Syndecan-1 in all tissue compartments was significantly higher in dense than in non-dense specimens. The strongest staining was recorded in stromal tissue. There was a strong correlation between epithelial estrogen receptor alpha and stromal cell Syndecan-1 expression in dense tissue (rs = 0.7; p = 0.02). This association was absent in non-dense tissue.

CONCLUSION

An increase of Syndecan-1 in all tissue compartments and a redistribution from epithelium to stroma may be a characteristic feature for dense breast tissue.

Neutral effect of ultra-low-dose continuous combined estradiol and norethisterone acetate on mammographic breast density

OBJECTIVE

To compare the effects of two different ultra-low doses of continuous combined hormone therapy and placebo on mammographic breast density in postmenopausal women.

METHODS

A subpopulation of 255 postmenopausal women from the CHOICE trial were randomly assigned to 0.5 mg 17beta-estradiol (E2) + 0.25 mg norethisterone acetate (NETA), 0.5 mg E2 + 0.1 mg NETA, or placebo. Women using hormone replacement therapy (HRT) up to 2 months prior to the study were excluded; 154 women fulfilled the inclusion criteria. Mammograms were performed at baseline and after 6 months. Breast density was evaluated by visual classification scales and a computer-assisted digitized technique.

RESULTS

No significant differences were detected between the active treatment groups and the placebo group in the digitized quantification. The mean baseline values for density around 20% were unchanged after 6 months. Also, visual classifications showed no increase in breast density in any study group.

CONCLUSION

In contrast to currently available bleed-free regimens, the new ultra-low-dose combination of 0.5 mg E2 and 0.1 mg NETA seems to have very little or even a neutral effect on the breast. Both digitized quantification and visual assessment of breast density were unchanged after 6 months. Larger prospective studies should be performed to confirm this new finding.

Opposing effects of HLA-DRB1*13 alleles on the risk of developing anti-citrullinated protein antibody-positive and anti-citrullinated protein antibody-negative rheumatoid arthritis

OBJECTIVE

The effect of non-shared epitope HLA-DRB1 alleles on rheumatoid arthritis (RA) is poorly understood. This study was undertaken to investigate the effects of several HLA-DRB1 alleles, independent of the shared epitope, on the risk of developing anti-citrullinated protein antibody (ACPA)-positive or ACPA-negative RA in a large case-control study.

METHODS

HLA typing for the DRB1 gene was performed in 1,352 patients with RA and 922 controls from the Swedish Epidemiological Investigation of Rheumatoid Arthritis study. Relative risks (RRs) and 95% confidence intervals (95% CIs) were calculated.

RESULTS

DRB1*13 was found to protect against ACPA-positive RA when stratifying for the shared epitope and using a dominant genetic model (RR 0.41 [95% CI 0.26-0.64]). Furthermore, DRB1*13 neutralized the effect of the shared epitope in ACPA-positive RA (RR 3.91 [95% CI 3.04-5.02] in patients who had the shared epitope but not DRB1*13, and RR 1.22 [95% CI 0.81-1.83] in patients with both the shared epitope and DRB1*13, as compared with patients negative for both the shared epitope and DRB1*13). However, we did not replicate the previous published risk of ACPA-negative RA conferred by DRB1*03 when a dominant genetic model was used (RR 1.29 [95% CI 0.91-1.82]). Similarly, no significant effect of DRB1*03 on RR for ACPA-negative RA was seen using the recessive genetic model (RR 1.18 [95% CI 0.6-2.4]). In contrast, the combination of DRB1*03 and DRB1*13 was significantly associated with increased risk of developing ACPA-negative RA (RR 2.07 [95% CI 1.17-3.67]).

CONCLUSION

Our findings indicate that the DRB1*13 allele plays a dual role in the development of RA, by protecting against ACPA-positive RA but, in combination with DRB1*03, increasing the risk of ACPA-negative RA.

Different patterns of associations with anti-citrullinated protein antibody-positive and anti-citrullinated protein antibody-negative rheumatoid arthritis in the extended major histocompatibility complex region

OBJECTIVE

To identify additional variants in the major histocompatibility complex (MHC) region that independently contribute to risk in 2 disease subsets of rheumatoid arthritis (RA) defined according to the presence or absence of antibodies to citrullinated protein antigens (ACPAs).

METHODS

In a multistep analytical strategy using unmatched as well as matched analyses to adjust for HLA-DRB1 genotype, we analyzed 2,221 single-nucleotide polymorphisms (SNPs) spanning 10.7 Mb, from 6p22.2 to 6p21.31, across the MHC. For ACPA-positive RA, we analyzed samples from the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA) and the North American Rheumatoid Arthritis Consortium (NARAC) studies (totaling 1,255 cases and 1,719 controls). For ACPA-negative RA, we used samples from the EIRA study (640 cases and 670 controls). Plink and SAS statistical packages were used to conduct all statistical analyses.

RESULTS

A total of 299 SNPs reached locus-wide significance (P<2.3x10(-5)) for ACPA-positive RA, whereas surprisingly, no SNPs reached this significance for ACPA-negative RA. For ACPA-positive RA, we adjusted for known DRB1 risk alleles and identified additional independent associations with SNPs near HLA-DPB1 (rs3117213; odds ratio 1.42 [95% confidence interval 1.17-1.73], Pcombined=0.0003 for the strongest association).

CONCLUSION

There are distinct genetic patterns of MHC associations in the 2 disease subsets of RA defined according to ACPA status. HLA-DPB1 is an independent risk locus for ACPA-positive RA. We did not identify any associations with SNPs within the MHC for ACPA-negative RA.

Prevalence of disabling spasticity 1 year after first-ever stroke

OBJECTIVE

To estimate the prevalence of disabling spasticity (DS) 1 year after first-ever stroke.

DESIGN

Cross-sectional survey 1 year after first-ever stroke.

METHODS

Patients above 18 years from one county with first-ever stroke were identified by use of the national stroke registry. A representative sample of 163 patients was created and 140 of these were followed up. Assessments of motor function and ability with the modified Ashworth Scale, the modified Rankin Scale (mRS), the Barthel Index (BI) and clinical evaluation were performed in order to identify patients with spasticity-related disability.

RESULTS

The observed prevalence of any spasticity was 17% and of DS 4%. Patients with DS scored significantly worse than those with no DS on the mRS (P = 0.009) and the BI (P = 0.005). DS was more frequent in the upper extremity, correlated positively with other indices of motor impairment and inversely with age. There was an independent effect of severe upper extremity paresis (OR 22, CI 3.9-125) and age below 65 years (OR 9.5, CI 1.5-60).

CONCLUSIONS

The prevalence of DS after first-ever stroke is low but corresponds to a large number of patients and deserves further attention with regards to prevention and treatment.

Using high-power lasers for detection of elastic photon-photon scattering

The properties of four-wave interaction via the nonlinear quantum vacuum is investigated. The effect of the quantum vacuum is to generate photons with new frequencies and wave vectors, due to elastic photon-photon scattering. An expression for the number of generated photons is derived, and using state-of-the-art laser data it is found that the number of photons can reach detectable levels. In particular, the prospect of using the high-repetition Astra Gemini system at the Rutherford Appleton Laboratory is discussed. The problem of noise sources is reviewed, and it is found that the noise level can be reduced well below the signal level. Thus, detection of elastic photon-photon scattering may for the first time be achieved.

Objective assessment of cervical dystonia: a pilot study

OBJECTIVES

The aims were to characterize the movements in cervical dystonia (CD) by using an estimate of the mechanical power and work involved in the movements and to describe this through a movement energy index (MEI).

MATERIALS AND METHODS

The subjects (patients n = 6, controls n = 6) were seated in front of a screen with a laser pointer attached to a headband while they performed standardized movements. A three-dimensional motion capture system was used and a test-retest was performed.

RESULTS

The mean value of MEI was significantly higher for the patients than for the controls. There was no significant difference between MEI from test to retest for the patients but there was a significant difference between MEI from test to retest for the controls.

CONCLUSION

This study suggests that MEI could be a useful measure for the quantification of movement dysfunction in CD and thus an objective outcome measure in comparison of different therapies.

Increased prevalence of atherosclerosis in patients with medium term rheumatoid arthritis

OBJECTIVE

To measure the extent of atherosclerosis in patients with rheumatoid arthritis (RA) with a disease duration of considerable length, and in age and sex matched individuals.

METHODS

Thirty-nine patients with RA (30 women, 9 men) with disease onset occurring between 1974 and 1978, and less than 65 years of age at the time of investigation, were enrolled together with 39 sex and age matched controls. Quantitative measurement of intima-media thickness (IMT) and semiquantitative assessment of the presence of plaque were undertaken by B-mode ultrasound of the common carotid artery (CCA-IMT) and the common femoral artery on the right-hand side. Echo Doppler cardiography was performed with an Accuson Aspen. The results were related to disease activity variables and accumulated disease activity, to lipid levels [i.e., cholesterol, high density lipoproteins, low density lipoproteins, triglycerides (TG)], to hemostatic factors [tissue plasminogen activator antigen (tPAag), plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor (vWF)], and to soluble adhesion molecules (sICAM-1 and sE-selectin).

RESULTS

Patients with RA had higher maximal and mean IMT values compared with controls. The difference concerning mean CCA-IMT reached statistical significance in patients with RA and correlated significantly with lipids (cholesterol, LDL, LDL/HDL ratio, TG) and tPAag. The prevalence of plaques, as well as of aortic cusp sclerosis, was higher in RA but only the difference in aortic cusp sclerosis was statistically significant. Patients with plaques had significantly higher levels of lipids (cholesterol, LDL, LDL/HDL ratio) than patients without plaques, while patients with cusp sclerosis had significantly higher cholesterol and TG levels. sICAM-1 was significantly higher both in patients with plaques and in those with aortic cusp sclerosis compared to patients without.

CONCLUSION

Our results suggest an accelerated atherosclerosis in patients with RA that is related mainly to lipid levels.

Mammographic breast density during hormone replacement therapy: effects of continuous combination, unopposed transdermal and low-potency estrogen regimens

OBJECTIVE

The aim of this study was to evaluate the impact of different hormone replacement therapy (HRT) regimens on mammographic breast density.

STUDY DESIGN

Mammographic density was recorded in women participating in a population-based screening program. At first mammogram, all women were non-users of HRT, and thereafter reported continuous use of the same HRT regimen. The study population comprised 158 women: a total of 52 women were using continuous combined HRT (conjugated equine estrogen 0.625 mg plus medroxyprogesterone acetate 5 mg); 51 women were using low-dose oral estrogen alone (estriol 2 mg daily); and 55 women were using unopposed transdermal estrogen given as a patch (estradiol 50 micrograms/24 h). Films were coded and analyzed for mammographic density by an independent radiologist blinded to treatments. Mammographic density was classified according to Wolfe.

RESULTS

An increase in mammographic density was much more common among women taking continuous combined HRT (40%) than for those using oral low-dose estrogen (6%) and transdermal (2%) treatment. The increase in density was already apparent at the first visit after starting HRT. During long-term follow-up, there was very little change in mammographic status.

CONCLUSION

HRT regimens were shown to have different effects on the normal breast. There is an urgent need to clarify the biological nature and significance of a change in mammographic density during treatment and, in particular, its relation to symptoms and breast cancer risk.

Mammographic breast density during hormone replacement therapy: differences according to treatment

OBJECTIVE

Our purpose was to investigate the effects of various hormone replacement regimens on mammographic breast density.

STUDY DESIGN

Mammographic density was recorded in women participating in a population-based screening program. All women were nonusers of hormone replacement therapy at first mammogram and thereafter reported continuous use of the same treatment: estrogen alone (n = 50) or estrogen in cyclic (n = 75) or continuous (n = 50) combination with progestogen. Mammographic density was quantified according to the Wolfe classification.

RESULTS

An increase in mammographic density was much more common among women receiving continuous combination hormone replacement therapy (52%) than among those receiving cyclic (13%) and estrogen-only (18%) treatment. The increase in density was apparent already at first visit after the start of hormone replacement therapy. There was little change in mammographic status during long-term follow-up.

CONCLUSION

Regimens of hormone replacement therapy were shown to have different effects on the normal breast. There is an urgent need to clarify the biologic nature and significance of a change in mammographic density during treatment and, in particular, its relation to symptoms and breast cancer risk.

Acoustic and perceptual evaluation of voice and speech quality: a study of patients with laryngeal cancer treated with laryngectomy vs irradiation

OBJECTIVE

To compare voice and speech function in patients who underwent laryngectomy with that of 2 control groups.

DESIGN

A cross-sectional study comparing acoustic and temporal variables with perceptual evaluations in 3 subject groups.

SETTING

University hospital in Göteborg, Sweden.

SUBJECTS

Two groups of patients with laryngeal carcinoma were examined: 12 male patients who had laryngectomy and were using a tracheoesophageal prosthesis and 12 male patients treated with radical radiotherapy who had a preserved larynx. The third group consisted of 10 normal controls without laryngeal disease.

MAIN OUTCOME MEASURES

Acoustic variables were fundamental frequency, absolute fundamental frequency perturbation, speech rate, and maximum phonation time. Perceptual evaluation included 15 listeners' perceptual evaluation and the patients' self-assessment of speech intelligibility, voice quality, and speech acceptability.

RESULTS

No significant acoustic or temporal differences were found between the laryngectomy and radical radiotherapy groups. There was a significant difference between the patient groups in perceptual evaluation. Both groups of patients differed from normal controls in acoustic and temporal measures, where the laryngectomy group generally deviated more from the normal controls than the patient group treated with radiotherapy. There was a weak, but significant, correlation between absolute fundamental frequency perturbation and perceived voice quality.

CONCLUSIONS

Perceptual evaluations could indicate significant differences between the patients who underwent laryngectomy and irradiated patients, where the acoustic analysis failed to reflect these differences. Both patient groups could be distinguished according to acoustic and temporal measures when compared with normal controls. The acoustic analyses were more sufficient in voices without severe dysfunction.