Apolipoprotein C3 induces inflammation and organ damage by alternative inflammasome activation.

NLRP3-inflammasome-driven inflammation is involved in the pathogenesis of a variety of diseases. Identification of endogenous inflammasome activators is essential for the development of new anti-inflammatory treatment strategies. Here, we identified that apolipoprotein C3 (ApoC3) activates the NLRP3 inflammasome in human monocytes by inducing an alternative NLRP3 inflammasome via caspase-8 and dimerization of Toll-like receptors 2 and 4. Alternative inflammasome activation in human monocytes is mediated by the Toll-like receptor adapter protein SCIMP. This triggers Lyn/Syk-dependent calcium entry and the production of reactive oxygen species, leading to activation of caspase-8. In humanized mouse models, ApoC3 activated human monocytes in vivo to impede endothelial regeneration and promote kidney injury in an NLRP3- and caspase-8-dependent manner. These data provide new insights into the regulation of the NLRP3 inflammasome and the pathophysiological role of triglyceride-rich lipoproteins containing ApoC3. Targeting ApoC3 might prevent organ damage and provide an anti-inflammatory treatment for vascular and kidney diseases.

Rheuma-VOR study: optimising healthcare of rheumatic diseases by multiprofessional coordinating centres.

OBJECTIVES: Early diagnosis of inflammatory arthritis is critical to prevent joint damage and functional incapacities. However, the discrepancy between recommendations of early diagnosis and reality is remarkable. The Rheuma-VOR study aimed to improve the time to diagnosis of patients with early arthritis by coordinating cooperation between primary care physicians, specialists and patients in Germany. METHODS: This prospective non-randomised multicentre study involved 2340 primary care physicians, 72 rheumatologists, 4 university hospitals and 4 rheumatology centres in 4 German Federal States. The two coprimary endpoints (time to diagnosis and screening performance of primary care physicians) were evaluated for early versus late implementation phase. Additionally, time to diagnosis and secondary endpoints (decrease of disease activity, increase in quality of life and overall well-being, improvement of fatigue, depression, functional ability, and work ability, reduction in drug and medical costs and hospitalisation) were compared with a reference cohort of the German Rheumatism Research Centre (DRFZ) reflecting standard care. RESULTS: A total of 7049 patients were enrolled in the coordination centres and 1537 patients were diagnosed with a rheumatic disease and consented to further participation. A follow-up consultation after 1 year was realised in 592 patients. The time to diagnosis endpoint and the secondary endpoints were met. In addition, the calculation of cost-effectiveness shows that Rheuma-VOR has a dominant cost-benefit ratio compared with standard care. DISCUSSION: Rheuma-VOR has shown an improvement in rheumatological care, patient-reported outcome parameters and cost savings by coordinating the cooperation of primary care physicians, rheumatologists and patients, in a nationwide approach.

Myeloperoxidase Modulates Inflammation in Generalized Pustular Psoriasis and Additional Rare Pustular Skin Diseases.

Generalized pustular psoriasis (GPP) is a severe multi-systemic inflammatory disease characterized by neutrophilic pustulosis and triggered by pro-inflammatory IL-36 cytokines in skin. While 19%-41% of affected individuals harbor bi-allelic mutations in IL36RN, the genetic cause is not known in most cases. To identify and characterize new pathways involved in the pathogenesis of GPP, we performed whole-exome sequencing in 31 individuals with GPP and demonstrated effects of mutations in MPO encoding the neutrophilic enzyme myeloperoxidase (MPO). We discovered eight MPO mutations resulting in MPO -deficiency in neutrophils and monocytes. MPO mutations, primarily those resulting in complete MPO deficiency, cumulatively associated with GPP (p = 1.85E-08; OR = 6.47). The number of mutant MPO alleles significantly differed between 82 affected individuals and >4,900 control subjects (p = 1.04E-09); this effect was stronger when including IL36RN mutations (1.48E-13) and correlated with a younger age of onset (p = 0.0018). The activity of four proteases, previously implicated as activating enzymes of IL-36 precursors, correlated with MPO deficiency. Phorbol-myristate-acetate-induced formation of neutrophil extracellular traps (NETs) was reduced in affected cells (p = 0.015), and phagocytosis assays in MPO-deficient mice and human cells revealed altered neutrophil function and impaired clearance of neutrophils by monocytes (efferocytosis) allowing prolonged neutrophil persistence in inflammatory skin. MPO mutations contribute significantly to GPP's pathogenesis. We implicate MPO as an inflammatory modulator in humans that regulates protease activity and NET formation and modifies efferocytosis. Our findings indicate possible implications for the application of MPO inhibitors in cardiovascular diseases. MPO and affected pathways represent attractive targets for inducing resolution of inflammation in neutrophil-mediated skin diseases.

VEGFR2 and VEGFA polymorphisms are not associated with an inferior prognosis in Caucasian patients with aggressive B-cell lymphoma.

PURPOSE: Previous published data showed an impact of single-nucleotide polymorphisms in the VEGF A and VEGFR2 genes on the survival of patients with various malignancies, among others diffuse large B-cell lymphoma (DLBCL). PATIENTS AND METHODS: We investigated the role of four VEGF-A and two VEGFR-2 gene polymorphisms on the outcome of 273 patients with diffuse large B-cell lymphoma who were treated with R-CHOP within a prospective, randomized trial of the German High-Grade Non-Hodgkin Lymphoma Study Group (DSHNHL). The genomic DNA samples were analyzed using commercial DNA Probes (Applied Biosystems, USA) to detect single-nucleotide polymorphisms in the VEGF A rs699947, rs1570360, rs2010963, rs3025039 and rs1870377, and rs2305948 in the VEGFR2 receptor. Hundred healthy blood donors served as a control. RESULTS: There was no difference between the SNP allele frequencies in lymphoma patients compared to the control group for all investigated SNPs. None of the investigated SNPs was significantly associated with EFS or OS. After adjusting for the International Prognostic Index risk factors in a multivariate analysis, these results could be confirmed. CONCLUSION: Single-nucleotide polymorphisms of the VEGF and VEGFR2 were not associated with a worse outcome in Caucasian patients with DLBCL.

Genetic variants in FBLIM1 gene do not contribute to SAPHO syndrome and chronic recurrent multifocal osteomyelitis in typical patient groups.

BACKGROUND: Syndrome of synovitis acne pustulosis hyperostosis osteitis (SAPHO) and chronic recurrent multifocal osteomyelitis (CRMO) present two diseases of a dermatologic and rheumatologic spectrum that are variable in manifestation und therapeutic response. Genetic risk factors have long been assumed in both diseases, but no single reliable factor has been identified yet. Therefore, we aimed to clinically characterize a patient group with syndrome of synovitis acne pustulosis hyperostosis osteitis (SAPHO) (n = 47) and chronic recurrent multifocal osteomyelitis (CRMO)/ chronic non-bacterial osteomyelitis (CNO) (n = 9) and analyze a CRMO candidate gene. METHODS: Clinical data of all patients were collected and assessed for different combinations of clinical symptoms. SAPHO patients were grouped into categories according to the acronym; disease-contribution by pathogens was evaluated. We sequenced coding exons of FBLIM1. RESULTS: Palmoplantar pustular psoriasis (PPP) was the most common skin manifestation in CRMO/CNO and SAPHO patients; most SAPHO patients had sterno-costo-clavicular hyperostosis. The most common clinical category of the acronym was S_PHO (n = 26). Lack of pathogen detection from bone biopsies was more common than microbial isolation. We did not identify autosomal-recessive FBLIM1 variants. CONCLUSIONS: S_PHO is the most common combination of symptoms of its acronym. Genetic analyses of FBLIM1 did not provide evidence that this gene is relevant in our patient group. Our study indicates the need to elucidate SAPHO's and CRMO/CNO's pathogenesis.

Progranulin-autoantibodies in sera of rheumatoid arthritis patients negative for rheumatoid factor and anti-citrullinated peptide antibodies.

OBJECTIVES: Previously we discovered antibodies against progranulin (PGRN-abs) in a protein array-based screening of sera from various rheumatic diseases. Here we conducted a study to evaluate the prevalence of PGRN-abs in seropositive and seronegative rheumatoid arthritis (RA). METHODS: PGRN-abs were determined in the sera from 257 RA patients being seropositive for RF-IgM and/or ACPA-IgG and from 224 seronegative RA patients who were prospectively included in this study (total RA cohort n=481). All serum samples from the included participants were tested for RF-IgM as well as for ACPA-IgG, and PGRN-abs were determined using a previously described ELISA. Statistics was performed using the χ2 test for evaluating differences in clinical data; to evaluate independent statistical effects on the frequency of PGRN-abs status a logistic regression model with Wald-test was performed. RESULTS: PGRN-abs were detected in 25.3% from seropositive RA and in 21.0% from RF- and ACPA-negative RA resulting in a prevalence of 23.7% for both cohorts together. Comparing mean DAS28 values in the PGRN-abs positive cohort with the PGRN-abs negative cohort, the DAS28 value was significantly higher in PGRN-abs positive RA patients (3.81 vs. 3.50, p=0.038). A trend for higher frequencies of PGRN-abs in sera of RA patients with unfavourable characteristics such as erosive disease or requiring TNFi medication was observed. CONCLUSIONS: These data suggest that the determination of PGRN-abs in seronegative RA patients may reduce their seronegative status. Further studies are required to evaluate PGRN-abs as a potential diagnostic marker in RA.

Autoantibodies against lamin C, NA14 and CK15 in primary vasculitides or autoimmune diseases with secondary vasculitis.

OBJECTIVES: Autoantibodies may play a role in the pathogenesis of primary vasculitides (PVs) like giant cell arteritis (GCA). We recently identified 3 cytoskeletal proteins (lamin C [laC], nuclear autoantigen of 14kD [NA14] and cytokeratin 15 [CK15]) as autoantigens in GCA and postulated a frequent autoantibody response against these antigens in PVs. METHODS: To test this hypothesis we studied a cohort of patients with PVs (n=61) and healthy individuals (n=27) for the presence of these autoantibodies using a recombinant cDNA expression library. To define their specifity for PV, we also examined patients with other autoimmune diseases such as rheumatoid arthritis (RA) and connective tissue diseases (CTD). RESULTS: We found no statistically significant differences in autoantibody responses between patients with PV and healthy controls, although there was a trend for an association between PVs and the occurrence of antibodies against laC and CK15. However, in patients with RA (n=33) or Sjögren's syndrome (SS, n=11) with vasculitides we observed more frequently autoantibodies against NA14, laC and CK15 compared to healthy controls. In patients with systemic lupus erythematosus (SLE, n=23) autoantibodies against laC were more frequent. The presence of autoantibodies in RA, SS and SLE was associated with systemic secondary vasculitis (SSV). In RA, laC- and NA14-seropositive patients were in a more advanced disease stage than seronegative patients with more frequent extraarticular manifestations (p=0.004). In SLE laC-autoantibody-positive patients had a higher SLE activity index (p<0.001). CONCLUSIONS: Serum autoantibodies against laC and NA14 are frequent in patients with RA and CTD and are associated with extensive disease and SSV. The potential pathogenic and prognostic role of these antibodies should be further investigated.

Altered phenotype and functionality of varicella zoster virus-specific cellular immunity in individuals with active infection.

BACKGROUND: Varicella zoster virus (VZV) establishes lifelong persistence and may reactivate in individuals with impaired immune function. To investigate immunologic correlates of protection and VZV reactivation, we characterized specific immunity in 207 nonsymptomatic immunocompetent and 132 immunocompromised individuals in comparison with patients with acute herpes zoster. METHODS: VZV-specific CD4 T cells were quantified flow cytometrically after stimulation and characterized for expression of interferon-γ, interleukin 2, and tumor necrosis factor α and surface markers for differentiation (CD127) and anergy (cytotoxic T lymphocyte antigen 4 [CTLA-4] and programmed death [PD]-1). Immunoglobulin G and A levels were quantified using an enzyme-linked immunosorbent assay. RESULTS: In healthy individuals, VZV-specific antibody and T-cell levels were age dependent, with the highest median VZV-specific CD4 T-cell frequencies of 0.108% (interquartile range, 0.121%) during adolescence. VZV-specific T-cell profiles were multifunctional with predominant expression of all 3 cytokines, CD127 positivity, and low expression of CTLA-4 and PD-1. Nonsymptomatic immunocompromised patients had similar VZV-specific immunologic properties except for lower T-cell frequencies (P<.001) and restricted cytokine expression. In contrast, significantly elevated antibody- and VZV-specific CD4 T-cell levels were found in patients with zoster. Their specific T cells showed a shift in cytokine expression toward interferon γ single positivity, an increase in CTLA-4 and PD-1, and a decrease in CD127 expression (all P<.001). This phenotype normalized after resolution of symptoms. CONCLUSIONS: VZV-specific CD4-T cells in patients with zoster bear typical features of anergy. This phenotype is reversible and may serve as adjunct tool for monitoring VZV reactivations in high-risk patients.

The molecular basis for development of proinflammatory autoantibodies to progranulin.

Recently we identified in a wide spectrum of autoimmune diseases frequently occurring proinflammatory autoantibodies directed against progranulin, a direct inhibitor of TNFR1 & 2 and of DR3. In the present study we investigated the mechanisms for the breakdown of self-tolerance against progranulin. Isoelectric focusing identified a second, differentially electrically charged progranulin isoform exclusively present in progranulin-antibody-positive patients. Alkaline phosphatase treatment revealed this additional progranulin isoform to be hyperphosphorylated. Subsequently Ser81, which is located within the epitope region of progranulin-antibodies, was identified as hyperphosphorylated serine residue by site directed mutagenesis of candidate phosphorylation sites. Hyperphosphorylated progranulin was detected exclusively in progranulin-antibody-positive patients during the courses of their diseases. The occurrence of hyperphosphorylated progranulin preceded seroconversions of progranulin-antibodies, indicating adaptive immune response. Utilizing panels of kinase and phosphatase inhibitors, PKCß1 was identified as the relevant kinase and PP1 as the relevant phosphatase for phosphorylation and dephosphorylation of Ser81. In contrast to normal progranulin, hyperphosphorylated progranulin interacted exclusively with inactivated (pThr320) PP1, suggesting inactivated PP1 to cause the detectable occurrence of phosphorylated Ser81 PGRN. Investigation of possible functional alterations of PGRN due to Ser81 phosphorylation revealed, that hyperphosphorylation prevents the interaction and thus direct inhibition of TNFR1, TNFR2 and DR3, representing an additional direct proinflammatory effect. Finally phosphorylation of Ser81 PGRN alters the conversion pattern of PGRN. In conclusion, inactivated PP1 induces hyperphosphorylation of progranulin in a wide spectrum of autoimmune diseases. This hyperphosphorylation prevents direct inhibition of TNFR1, TNFR2 and DR3 by PGRN, alters the conversion of PGRN, and is strongly associated with the occurrence of neutralizing, proinflammatory PGRN-antibodies, indicating immunogenicity of this alternative secondary modification.

Autoantibody mediated deficiency of IL-36-receptor antagonist in a subset of patients with psoriasis and psoriatic arthritis.

OBJECTIVE: Psoriatic arthritis (PsA) is known as a seronegative form of spondylarthropathy. The interleukin-36 cytokine family may have a major role in disease pathogenesis and particularly the related cutaneous manifestations. In light of our recent observations on (transient) autoantibody phenotypes neutralizing endogenous anti-inflammatory receptor antagonists (progranulin, IL-1Ra) in different inflammatory conditions, we set out to investigate the potential role of such antibodies targeting IL-36 cytokine family members in PsA and psoriasis without arthritic manifestations (Pso). METHODS: In the present study we screened for hypothetic autoantibodies against the anti-inflammatory mediators IL-36 receptor antagonist (IL-36Ra) and anti-inflammatory IL-38 in PsA, Pso and inflammatory and healthy controls. Serum samples of patients with PsA (n = 254), Pso (n = 100), systemic lupus erythematosus (SLE, n = 50), rheumatoid arthritis (RA, n = 100), ulcerative colitis (UC, n = 50), Crohn´s disease (CD, n = 50), and healthy controls (n = 237) were screened for autoantibodies against IL-36Ra and IL-38 as well as IL-36Ra levels by ELISA. Biochemical analysis for immune complexes and atypic protein isoforms as well as IL-36 signaling reporter assays were performed. RESULTS: Anti-IL-36Ra antibodies were detected in five out of 100 (5.0 %) patients with Pso, in 12 of 254 (4.72 %) patients with PsA and in one of 50 (2 %) patients with CD, but in none of the other investigated inflammatory or healthy controls. The IL-36Ra autoantibodies belonged to the IgG1 subclass and their titers ranged between 1:200 to 1:1600. They resulted in immune-complex formation, depletion of serum IL-36Ra levels and were functional in terms of facilitating unrestricted IL-36 signaling. CONCLUSION: IL-36Ra autoantibodies were found in subgroups of patients with Pso and PsA and may drive respective pathology.

Genetic polymorphism of the OPG gene associated with breast cancer.

BACKGROUND: The receptor activator of NF-κB (RANK), its ligand (RANKL) and osteoprotegerin (OPG) have been reported to play a role in the pathophysiological bone turnover and in the pathogenesis of breast cancer. Based on this we investigated the role of single nucleotide polymorphisms (SNPs) within RANK, RANKL and OPG and their possible association to breast cancer risk. METHODS: Genomic DNA was obtained from Caucasian participants consisting of 307 female breast cancer patients and 396 gender-matched healthy controls. We studied seven SNPs in the genes of OPG (rs3102735, rs2073618), RANK (rs1805034, rs35211496) and RANKL (rs9533156, rs2277438, rs1054016) using TaqMan genotyping assays. Statistical analyses were performed using the χ2-tests for 2 x 2 and 2 x 3 tables. RESULTS: The allelic frequencies (OR: 1.508 CI: 1.127-2.018, p=0.006) and the genotype distribution (p=0.019) of the OPG SNP rs3102735 differed significantly between breast cancer patients and healthy controls. The minor allele C and the corresponding homo- and heterozygous genotypes are more common in breast cancer patients (minor allele C: 18.4% vs. 13.0%; genotype CC: 3.3% vs. 1.3%; genotype CT: 30.3% vs. 23.5%). No significantly changed risk was detected in the other investigated SNPs. Additional analysis showed significant differences when comparing patients with invasive vs. non-invasive tumors (OPG rs2073618) as well as in terms of tumor localization (RANK rs35211496) and body mass index (RANKL rs9533156 and rs1054016). CONCLUSIONS: This is the first study reporting a significant association of the SNP rs3102735 (OPG) with the susceptibility to develop breast cancer in the Caucasian population.

GWAS meta-analysis of psoriasis identifies new susceptibility alleles impacting disease mechanisms and therapeutic targets.

Psoriasis is a common, debilitating immune-mediated skin disease. Genetic studies have identified biological mechanisms of psoriasis risk, including those targeted by effective therapies. However, the genetic liability to psoriasis is not fully explained by variation at robustly identified risk loci. To move towards a saturation map of psoriasis susceptibility we meta-analysed 18 GWAS comprising 36,466 cases and 458,078 controls and identified 109 distinct psoriasis susceptibility loci, including 45 that have not been previously reported. These include susceptibility variants at loci in which the therapeutic targets IL17RA and AHR are encoded, and deleterious coding variants supporting potential new drug targets (including in STAP2, CPVL and POU2F3). We conducted a transcriptome-wide association study to identify regulatory effects of psoriasis susceptibility variants and cross-referenced these against single cell expression profiles in psoriasis-affected skin, highlighting roles for the transcriptional regulation of haematopoietic cell development and epigenetic modulation of interferon signalling in psoriasis pathobiology.

Different apoptotic responses of RA synoviocytes depending on different genotypes of the mdm2 SNP T309G.

Mdm2 is an ubiquitin ligase, which binds p53 and blocks its function as a transcription factor in the pathway of apoptosis. Recently we have showed that the SNP mdm2 T309G has a protective effect of the minor allele in rheumatoid arthritis (RA). However, a functional impact on apoptosis by the different genotypes of the mdm2 SNP has not been investigated. Genomic DNA was obtained from 49 cell lines of synoviocytes derived from 49 patients with RA, and the mdm2 SNP309 was genotyped by polymerase chain reaction and restriction enzyme analysis. Seven cell lines were identified as homozygous for TT (major allele of mdm2 SNP309), and four as homozygous for GG (minor allele). All 11 cell lines were stimulated with 5 ng/ml of TNF alpha and 2.5 ng/ml of Il-1beta. After staining with propidium iodide (25 µg/ml) DNA fluorescence was measured with FACS; the rate of apoptosis was defined as the percentage of cells with a sub-2n DNA content (= less than haploid DNA-content). The cell-lines genotyped with mdm2 SNP 309TT showed a significantly different apoptosis rate in percent compared with GG for both conditions with stimulation (19.4 ± 3.6 vs. 26.9 ± 1.8; P = 0.02) and without stimulation by TNF alpha and Il-1beta (27.4 ± 8.8 vs. 43.9 ± 2.4; P = 0.0002). In the cell culture in vitro model RA synoviocytes homozygous for mdm2 SNP 309GG had a higher apoptotic activity compared to TT, possibly identifying a protective effect of the minor allele.

[When a urological emergency indicates an internal medical crisis : Priapism as the first clinical manifestation of leukemia]. / Wenn ein urologischer Notfall auf eine internistische Krise hinweist : Priapismus als klinische Erstmanifestation einer Leukämie.

Priapism as a sign of a severe hematological disease is a rare event, which has to be considered as both a urological and a hematological emergency that requires immediate treatment. This article describes a clinical case of priapism as the first clinical manifestation of a hitherto undiagnosed chronic myeloid leukemia (CML) and discusses the results of a literature review on this topic.

Contrasting association of a non-synonymous leptin receptor gene polymorphism with Wegener's granulomatosis and Churg-Strauss syndrome.

OBJECTIVE: There is evidence that the leptin/ghrelin system is involved in T-cell regulation and plays a role in (auto)immune disorders such as SLE, RA and ANCA-associated vasculitides (AAVs). Here, we evaluate the genetic background of this system in WG. METHODS: We screened variations in the genes encoding leptin, ghrelin and their receptors, the leptin receptor (LEPR) and the growth hormone secretagogue receptor (GHSR). Three single nucleotide polymorphisms (SNPs) in each gene region were analysed in 460 German WG cases and 878 ethnically matched healthy controls. RESULTS: A three-SNP haplotype of GHSR was significantly associated with WG [P = 0.0067; corrected P-value (P(c)) = 0.026; odds ratio (OR) = 1.30; 95% CI 1.08, 1.57], as was one non-synonymous SNP in LEPR (Lys656Asn, P = 0.0034; P(c) = 0.013; OR = 0.72; 95% CI 0.58, 0.90). These four SNPs were re-analysed in independent cohorts of 226 German WG cases and 519 controls. While the GHSR association was not confirmed, allele frequencies of the LEPR SNP were virtually identical to those from the initial cohorts. Analysis of this SNP in the combined WG and control panels revealed a significant association of the LEPR 656Lys allele with WG (P = 0.00032; P(c) = 0.0013; OR = 0.72; 95% CI 0.60, 0.86). Remarkably, the Lys656Asn SNP showed contrasting allele distribution in two cohorts of 108 and 88 German cases diagnosed with Churg-Strauss syndrome (CSS, combined P = 0.0067; OR = 1.41; 95% CI 1.10, 1.81), whereas identical allele frequencies were revealed when comparing British WG and microscopic polyangiitis cases. CONCLUSIONS: While GHSR has to be further evaluated, these data provide profound evidence for an association of the LEPR Lys656Asn SNP with AAV, resulting in opposing effects in WG and CSS.

Rituximab in patients with rheumatoid arthritis and vasculitis-associated cutaneous ulcers.

OBJECTIVES: To test the efficacy of treatment with rituximab in refractory rheumatoid vasculitis in patients with rheumatoid arthritis (RA). METHODS: Retrospective study of four female patients with histologically proven RA associated vasculitic cutaneous ulcers. All patients developed the lesions on long term treatment with methotrexate or leflunomide, and three of them with tumour necrosis factor alpha (TNF) blockers. All patients were refractory to prednisolone in the dosage between 0.5 and 1 mg/kg body weight for at least 4 weeks prior to rituximab. Rituximab were administered in two intravenous applications in the interval of 14 days accompanied by continued treatment with methotrexate or leflunomide and prednisolone. RESULTS: Three out of four patients achieved a rapid clinical remission of the lesions within 4 to 6 weeks after rituximab therapy continuing at least for four months with a successful corticoid reduction till prednisolone 10 mg a day. One patient showed no remission of the skin lesions accompanied by increasing levels for ESR and CRP. CONCLUSIONS: Rituximab treatment seems to be very effective in several cases of vasculitis-associated cutaneous ulcers in RA patients. However, the effectiveness of rituximab in cases with this indication remains to be shown in larger number of patients.

Single-nucleotide polymorphisms p53 G72C and Mdm2 T309G in patients with psoriasis, psoriatic arthritis, and SAPHO syndrome.

Psoriasis (Ps), psoriatic arthritis (PsA), and SAPHO syndrome are diseases of unknown etiology that share common clinical features; however, family studies support the hypothesis of a genetic background for each of these diseases. To study the two common single-nucleotide polymorphisms (SNP) in the murine-double-minute-2-(Mdm2) and p53 genes in patients with Ps, PsA, and SAPHO syndrome. Genomic DNA was obtained from 187 patients with Ps, 50 with PsA, and 36 with SAPHO as well as 478 healthy controls. Mdm2-gene SNP T309G and p53-gene SNP G72C genotypes were determined by the polymerase chain reaction. Genotype and allele frequencies were analyzed with chi(2)-tests. Among the patients with Ps and PsA, no differences in allele or genotype frequencies of the p53-gene SNP G72C and Mdm2-gene SNP T309G were detected. However, in the SAPHO patients group, the frequencies of the Mdm2 SNP309 G allele and the genotype SNP 309 GG were significantly increased compared with the controls (G allele: 51.4 vs. 38.7%, P = 0.034; genotype GG: 36.1 vs. 14.2%, P = 0.002). In addition, the frequencies of the p53 SNP72 C allele and the genotype SNP 72 CC were also increased in the SAPHO patients cohort (C allele: 36.1 vs. 25.6%, P = 0.05; genotype CC: 16.7 vs. 6.3%, P = 0.05). SAPHO syndrome may be linked to an imbalance between MDM2 and p53 regulation with a "weak" p53-response associated with the Mdm2 SNP 309 G allele. In contrast, the p53 network does not seem to play a major role in pathogenesis of Ps or PsA.