Distinct characteristics of the gut virome in patients with osteoarthritis and gouty arthritis.

BACKGROUND/PURPOSE(S): The gut microbiota and its metabolites play crucial roles in pathogenesis of arthritis, highlighting gut microbiota as a promising avenue for modulating autoimmunity. However, the characterization of the gut virome in arthritis patients, including osteoarthritis (OA) and gouty arthritis (GA), requires further investigation. METHODS: We employed virus-like particle (VLP)-based metagenomic sequencing to analyze gut viral community in 20 OA patients, 26 GA patients, and 31 healthy controls, encompassing a total of 77 fecal samples. RESULTS: Our analysis generated 6819 vOTUs, with a considerable proportion of viral genomes differing from existing catalogs. The gut virome in OA and GA patients differed significantly from healthy controls, showing variations in diversity and viral family abundances. We identified 157 OA-associated and 94 GA-associated vOTUs, achieving high accuracy in patient-control discrimination with random forest models. OA-associated viruses were predicted to infect pro-inflammatory bacteria or bacteria associated with immunoglobulin A production, while GA-associated viruses were linked to Bacteroidaceae or Lachnospiraceae phages. Furthermore, several viral functional orthologs displayed significant differences in frequency between OA-enriched and GA-enriched vOTUs, suggesting potential functional roles of these viruses. Additionally, we trained classification models based on gut viral signatures to effectively discriminate OA or GA patients from healthy controls, yielding AUC values up to 0.97, indicating the clinical utility of the gut virome in diagnosing OA or GA. CONCLUSION: Our study highlights distinctive alterations in viral diversity and taxonomy within gut virome of OA and GA patients, offering insights into arthritis etiology and potential treatment and prevention strategies.

Cellular and Tissue Selectivity of AAV Serotypes for Gene Delivery to Chondrocytes and Cartilage.

Background: Despite several studies on the effect of adeno-associated virus (AAV)-based therapeutics on osteoarthritis (OA), information on the transduction efficiency and applicable profiles of different AAV serotypes to chondrocytes in hard cartilage tissue is still limited. Moreover, the recent discovery of additional AAV serotypes makes it necessary to screen for more suitable AAV serotypes for specific tissues. Here, we compared the transduction efficiencies of 14 conventional AAV serotypes in human chondrocytes, mouse OA models, and human cartilage explants obtained from OA patients. Methods: To compare the transduction efficiency of individual AAV serotypes, green fluorescent protein (GFP) expression was detected by fluorescence microscopy or western blotting. Likewise, to compare the transduction efficiencies of individual AAV serotypes in cartilage tissues, GFP expression was determined using fluorescence microscopy or immunohistochemistry, and GFP-positive cells were counted. Results: Only AAV2, 5, 6, and 6.2 exhibited substantial transduction efficiencies in both normal and OA chondrocytes. All AAV serotypes except AAV6 and rh43 could effectively transduce human bone marrow mesenchymal stem cells. In human and mouse OA cartilage tissues, AAV2, AAV5, AAV6.2, AAV8, and AAV rh39 showed excellent tissue specificity based on transduction efficiency. These results indicate the differences in transduction efficiencies of AAV serotypes between cellular and tissue models. Conclusions: Our findings indicate that AAV2 and AAV6.2 may be the best choices for AAV-mediated gene delivery into intra-articular cartilage tissue. These AAV vectors hold the potential to be of use in clinical applications to prevent OA progression if appropriate therapeutic genes are inserted into the vector.

Use of non-steroidal anti-inflammatory drugs and risk of death from COVID-19: an OpenSAFELY cohort analysis based on two cohorts.

OBJECTIVES: To assess the association between routinely prescribed non-steroidal anti-inflammatory drugs (NSAIDs) and deaths from COVID-19 using OpenSAFELY, a secure analytical platform. METHODS: We conducted two cohort studies from 1 March to 14 June 2020. Working on behalf of National Health Service England, we used routine clinical data in England linked to death data. In study 1, we identified people with an NSAID prescription in the last 3 years from the general population. In study 2, we identified people with rheumatoid arthritis/osteoarthritis. We defined exposure as current NSAID prescription within the 4 months before 1 March 2020. We used Cox regression to estimate HRs for COVID-19 related death in people currently prescribed NSAIDs, compared with those not currently prescribed NSAIDs, accounting for age, sex, comorbidities, other medications and geographical region. RESULTS: In study 1, we included 536 423 current NSAID users and 1 927 284 non-users in the general population. We observed no evidence of difference in risk of COVID-19 related death associated with current use (HR 0.96, 95% CI 0.80 to 1.14) in the multivariable-adjusted model. In study 2, we included 1 708 781 people with rheumatoid arthritis/osteoarthritis, of whom 175 495 (10%) were current NSAID users. In the multivariable-adjusted model, we observed a lower risk of COVID-19 related death (HR 0.78, 95% CI 0.64 to 0.94) associated with current use of NSAID versus non-use. CONCLUSIONS: We found no evidence of a harmful effect of routinely prescribed NSAIDs on COVID-19 related deaths. Risks of COVID-19 do not need to influence decisions about the routine therapeutic use of NSAIDs.

Inflammatory Cytokine-Producing Cells and Inflammation Markers in the Synovium of Osteoarthritis Patients Evidenced in Human Herpesvirus 7 Infection.

A direct association between joint inflammation and the progression of osteoarthritis (OA) has been proposed, and synovitis is considered a powerful driver of the disease. Among infections implicated in the development of joint disease, human herpesvirus 7 (HHV-7) infection remains poorly characterized. Therefore, we assessed synovitis in OA patients; determined the occurrence and distribution of the HHV-7 antigen within the synovial membrane of OA-affected subjects; and correlated plasma levels of the pro-inflammatory cytokines tumor necrosis factor (TNF), interleukin-6 (IL-6), and TNF expressed locally within lesioned synovial tissues with HHV-7 observations, suggesting differences in persistent latent and active infection. Synovial HHV-7, CD4, CD68, and TNF antigens were detected immunohistochemically. The plasma levels of TNF and IL-6 were measured by an enzyme-linked immunosorbent assay. Our findings confirm the presence of persistent HHV-7 infection in 81.5% and reactivation in 20.5% of patients. In 35.2% of patients, virus-specific DNA was extracted from synovial membrane tissue samples. We evidenced the absence of histopathologically detectable synovitis and low-grade changes in the majority of OA patients enrolled in the study, in both HHV-7 PCR+ and HHV-7 PCR‒ groups. The number of synovial CD4-positive cells in the HHV-7 polymerase chain reaction (PCR)+ group was significantly higher than that in the HHV-7 PCR‒ group. CD4- and CD68-positive cells were differently distributed in both HHV-7 PCR+ and HHV-7 PCR‒ groups, as well as in latent and active HHV-7 infection. The number of TNF+ and HHV-7+ lymphocytes, as well as HHV-7+ vascular endothelial cells, was strongly correlated. Vascular endothelial cells, especially in the case of infection reactivation, appeared vulnerable. The balance between virus latency and reactivation is a long-term relationship between the host and infectious agent, and the immune system appears to be involved in displaying overreaction when a shift in the established equilibrium develops.

Epstein-Barr virus infection and variants of Epstein-Barr nuclear antigen-1 in synovial　tissues of rheumatoid arthritis.

OBJECTIVE: The objective of the present study was to investigate Epstein-Barr virus (EBV) infection as an environmental factor for the development of rheumatoid arthritis (RA). METHODS: Synovial tissues were collected during surgery from 128 RA and 98 osteoarthritis (OA) patients. DNA was extracted from synovial tissues. The EBV gene was assessed by nested PCR for the amplification of EBV nuclear antigen-1 (EBNA-1). The nucleotide sequence of the PCR product was elucidated. HLA-DRB1 genotyping was also performed. RESULTS: EBV DNA was more frequently detected in the synovial tissues of RA patients (32.8%) than OA patients (15.3%) (p<0.01). The frequency of EBNA-1 variants did not significantly differ between RA and OA (RA: 17%, OA: 13%). The population with the HLA-DRB1 shared epitope (SE) was significantly higher in RA patients (70.3%) than in OA patients (44.9%) (p<0.001). In RA patients, the presence of EBV DNA was similar among SE-positive and -negative patients (SE-positive: 34.4%, -negative: 28.9%). The population with the EBNA-1 variant did not significantly differ between SE-positive and -negative patients (SE-positive: 12.9%, -negative: 27.3%). DISCUSSION: The present results indicate that EBV infection contributes to the onset of RA and chronic inflammation in synovial tissues. The frequency of EBNA-1 gene variants was low and not significantly different between RA and OA, suggesting that EBNA-1 gene variants are not a risk factor for RA. HLA-DRB1 with SE is a genetic risk factor for the development of RA. However, neither the presence of EBV nor EBNA-1 gene variants differed between SE-positive and -negative RA patients. Therefore, these two risk factors, SE and EBV, may be independent. CONCLUSION: EBV infection may be an environmental risk factor for the development of RA, while nucleotide variants of EBNA-1 do not appear to contribute to its development.

Increased prevalence and severity of radiographic hand osteoarthritis in patients with HIV-1 infection associated with metabolic syndrome: data from the cross-sectional METAFIB-OA study.

OBJECTIVE: To determine radiographic hand osteoarthritis (HOA) prevalence in patients with HIV-1 infection in comparison with the general population and to address whether metabolic syndrome (MetS) may increase the risk of HOA during HIV-1 infection. PATIENTS: Patients with HIV-1 infection and MetS (International Diabetes Federation, IDF criteria) aged 45-65 years were matched by age and gender to HIV-1-infected subjects without MetS and underwent hand radiographs. Framingham OA cohort was used as general population cohort. METHODS: Radiographic HOA was defined as Kellgren-Lawrence (KL) score ≥2 on more than one joint. Radiographic severity was assessed by global KL score and number of OA joints. HOA prevalence was compared with that found in the Framingham study, stratified by age and sex. Logistic and linear regression models were used to determine the risk factors of HOA in patients with HIV-1 infection. RESULTS: 301 patients (88% male, mean age 53.4±5.0 years) were included, 152 with MetS and 149 without it. Overall, HOA prevalence was 55.5% and was higher for those with MetS than those without it (64.5% vs 46.3%, p=0.002). When considering men within each age group, HOA frequency was greater in patients with HIV-1 infection than the general population (all ages: 55.8% vs 38.7%; p<0.0001), due to the subgroup with MetS (64.9%; p<0.0001), as well as the subgroup without MetS, although not significant (46.6%; p=0.09). Risk of HOA was increased with MetS (OR 2.23, 95% 95% CI 1.26% to 3.96%) and age (OR 1.18, 95% CI 1.12 to 1.25). HOA severity was greater for patients with MetS than those without. HOA was not associated with previous or current exposure to protease inhibitors or HIV infection-related markers. CONCLUSIONS: HOA frequency is greater in patients with HIV-1 infection, especially those with MetS, than the general population. TRIAL REGISTRATION NUMBER: NCT02353767.

Occasional presence of herpes viruses in synovial fluid and blood from patients with rheumatoid arthritis and axial spondyloarthritis.

Viral agents have been suspected as participants of immune-mediated disorders. In the case of rheumatic diseases, the synovial joint cavity represents a secluded area of inflammation which could harbor etiological agents. We analyzed by polymerase chain reaction the possible presence of DNA from various herpes viruses in blood and synovial fluid from patients with either rheumatoid arthritis (n = 18), axial spondyloarthritis (n = 11), or osteoarthritis (n = 8). Relevant findings were as follows: DNA from varicella zoster virus was found in synovial fluid but not in blood mononuclear cells from 33 % of patients with rheumatoid arthritis and in 45 % of patients with axial spondyloarthritis but not in patients with osteoarthritis. Also, DNA from herpes simplex viruses 1 and 2 was found both in the blood and in the synovial fluid from 33 % of patients with rheumatoid arthritis. Our results indicate the occasional presence of DNA from herpes viruses in patients with rheumatoid arthritis or with axial spondyloarthritis. However, these findings might represent a parallel epiphenomenon of viral activation associated either with immunosuppressive therapy or with primary immune disturbances, rather than the etiological participation of herpes viruses in these disorders.

Human endogenous retrovirus W activity in cartilage of osteoarthritis patients.

The etiology of viruses in osteoarthritis remains controversial because the prevalence of viral nucleic acid sequences in peripheral blood or synovial fluid from osteoarthritis patients and that in healthy control subjects are similar. Until now the presence of virus has not been analyzed in cartilage. We screened cartilage and chondrocytes from advanced and non-/early osteoarthritis patients for parvovirus B19, herpes simplex virus-1, Epstein Barr virus, cytomegalovirus, human herpes virus-6, hepatitis C virus, and human endogenous retroviruses transcripts. Endogenous retroviruses transcripts, but none of the other viruses, were detected in 15 out the 17 patients. Sequencing identified the virus as HERV-WE1 and E2. HERV-W activity was confirmed by high expression levels of syncytin, dsRNA, virus budding, and the presence of virus-like particles in all advanced osteoarthritis cartilages examined. Low levels of HERV-WE1, but not E2 envelope RNA, were observed in 3 out of 8 non-/early osteoarthritis patients, while only 3 out of 7 chondrocytes cultures displayed low levels of syncytin, and just one was positive for virus-like particles. This study demonstrates for the first time activation of HERV-W in cartilage of osteoarthritis patients; however, a causative role for HERV-W in development or deterioration of the disease remains to be proven.

Epstein-Barr virus persistence and infection of autoreactive plasma cells in synovial lymphoid structures in rheumatoid arthritis.

OBJECTIVES: Rheumatoid arthritis (RA) is associated with an increased Epstein-Barr virus (EBV) blood DNA load, a robust immune response to EBV and cross-reactive circulating antibodies to viral and self-antigens. However, the role of EBV in RA pathogenesis remains elusive. Here, we investigated the relationship between synovial EBV infection, ectopic lymphoid structures (ELS) and immunity to citrullinated self and EBV proteins. METHODS: Latent and lytic EBV infection was investigated in 43 RA synovial tissues characterised for presence/absence of ELS and in 11 control osteoarthritis synovia using RT-PCR, in situ hybridisation and immunohistochemistry. Synovial production of anti-citrullinated protein (ACPA) and anti-citrullinated EBV peptide (VCP1/VCP2) antibodies was investigated in situ and in vivo in the severe combined immunodeficiency (SCID)/RA chimeric model. RESULTS: EBV dysregulation was observed exclusively in ELS+ RA but not osteoarthritis (OA) synovia, as revealed by presence of EBV latent (LMP2A, EBV-encoded small RNA (EBER)) transcripts, EBER+ cells and immunoreactivity for EBV latent (LMP1, LMP2A) and lytic (BFRF1) antigens in ELS-associated B cells and plasma cells, respectively. Importantly, a large proportion of ACPA-producing plasma cells surrounding synovial germinal centres were infected with EBV. Furthermore, ELS-containing RA synovia transplanted into SCID mice supported production of ACPA and anti-VCP1/VCP2 antibodies. Analysis of CD4+ and CD8+ T-cell localisation and granzyme B expression suggests that EBV persistence in ELS-containing synovia may be favoured by exclusion of CD8+ T cells from B-cell follicles and impaired CD8-mediated cytotoxicity. CONCLUSIONS: We demonstrated active EBV infection within ELS in the RA synovium in association with local differentiation of ACPA-reactive B cells.

Increase in human endogenous retrovirus HERV-K (HML-2) viral load in active rheumatoid arthritis.

To study the viral loads of human endogenous retrovirus HERV-K (HML-2) type 1 and type 2 in rheumatoid arthritis (RA), we measured the viral loads of HERV-K (HML-2) type 1 and type 2 using nucleic acid sequence-based amplification (NASBA) technology. We analyzed plasma samples from RA patients (n = 79) and healthy volunteers (HV, n = 46) and synovial fluid samples from RA (n = 10) and osteoarthritis (OA, n = 10) patients. HERV-K type 1 and type 2 viruses were detected and quantified for the majority of plasma and synovial fluid samples from RA patients. HERV-K type 1 and type 2 viral loads were significantly elevated in RA patients compared with HV in plasma (P < 0.0001) and from RA patients compared with OA patients in synovial fluid (type 1: P = 0.0007; type 2: P = 0.023). Moreover, an association was observed between the HERV-K type 1 viral load in plasma and the disease activity in RA patients (RA patients with low activity versus high activity P = 0.0129; RA patients with intermediate activity versus high activity P = 0.037). Our findings showed that HERV-K (HML-2) viral load can be detected in plasma samples from RA patients, with higher levels observed for those with active disease. There was an association of HERV-K type 1 levels with the disease activity.

The ubiquitin-proteasome pathway and viral infections in articular cartilage of patients with osteoarthritis.

Many viruses can evolve different strategies to exploit the ubiquitin-proteasome pathway (UPP) for their own benefit. Some data have recently established connections between UPP and osteoarthritis (OA). The aim of this study was to determine the possible involvement of viral infections linked with the UPP in the physiopathology of OA. Samples of human cartilage were obtained from 12 patients with clinical and radiological features of OA and from 12 normal controls. DNA was extracted from cultured chondrocytes from these patients, and quantitative real-time PCR was performed to analyse the DNA/RNA prevalence and viral loads of HSV, EBV, HCMV, enterovirus, and HTLV-1. The prevalence of total viral DNA/RNA among patients with OA was 16.7% (mean viral load of 7.86 copies/mug DNA), EBV being responsible for the two positive samples, while the prevalence in controls was 0%. We did not detect any positive samples for HSV, CMV, enterovirus, and HTLV-1 among patients with OA and controls. This first approach to the study of the prevalence of viruses linked to the UPP in articular cartilage of end-stage OA patients provides evidences supporting the risk of EBV transmission or reactivation in a subset of patients with disorders requiring tissue regeneration.

Hepatitis C virus infection in Italian patients with fibromyalgia.

We evaluated the prevalence of hepatitis C virus (HCV) infection in Italian patients suffering from fibromyalgia (FM), in comparison with patients affected by non-HCV related rheumatic degenerative disorders. Consecutive patients with FM and a statistically comparable group of patients suffering from peripheral osteoarthritis (OA) or sciatica due to L4-L5 or L5-S1 herniated disc were tested for HCV infection with a third-generation microparticle enzyme immunoassay (MEIA). In the positive cases, a third-generation recombinant immunoblot assay (RIBA) confirmatory test and serum HCV-RNA test were performed. Fisher's exact test was performed to compare the prevalence of HCV infection (MEIA- and RIBA-positive results) obtained in the two enrolled groups. Enrolled were 152 subjects suffering from FM and 152 patients with peripheral OA or sciatica. Anti-HCV antibodies were found in 7/152 (4.6%) patients suffering from FM and in 5/152 (3.3%) of control subjects. No statistically significant differences in HCV prevalence were detected between cases and controls. Our present report does not confirm previous data indicating an increased prevalence of HCV in FM patients and does not seem to support a significant pathogenetic role of HCV under this condition.

Detection of parvovirus B19 in synovial fluids of patients with osteoarthritis.

We aimed to determine the possible role of parvovirus B19 (PVB19) in the etiology of osteoarthritis. PVB19 DNA, anti-VP1 IgM and IgG, and interleukin IL-6 levels were also assayed in synovial fluids of 42 patients with osteoarthritis and 10 controls. PVB19 DNA was detected in 28 of 42 (66.66%) in patients and in 3 of 10 (30%) in controls. IgG and IgM response were detected in 21 of 42 (50.00%) and in 2 of 42 (4.76%) patients, respectively. IL-6 were positive in 15 of 42 (36%) patients and in 3 of 10 (30%) controls. All IgG (+) samples had PVB19 DNA (100%, P < 0.001). Eleven of 15 IL-6 (+) samples had PVB19 DNA (+) (73.33%, P < 0.05). Moreover, all IL-6 (+) samples (n = 5) in stage IV had PVB19 DNA (+) (100%, P < 0.001). We have detected a significant association between the stages of osteoarthritis and PVB19 DNA (P < 0.05). These findings support the presence of PVB19 acting as a transactivator of IL-6 expression as reported earlier. Our results also suggest that the higher stages of osteoarthritis might be related to the increased inflammation and cell damage on joint cartilage due to PVB19.

Human parvovirus B19, varicella zoster virus, and human herpesvirus-6 in mesenchymal stem cells of patients with osteoarthritis: analysis with quantitative real-time polymerase chain reaction.

OBJECTIVE: To investigate whether there is a possible viral transmission using mesenchymal stem cells (MSCs) in autologous or allogeneic transplantation in the context of osteoarthritis (OA) patients. The presence of parvovirus B19 (B19), varicella zoster virus (VZV), and human herpesvirus-6 (HHV-6) was studied in MSCs from bone marrow of patients with OA and healthy controls. METHODS: MSCs were prepared from bone marrow aspirates obtained from 18 patients undergoing joint replacement as a result of OA and from 10 healthy controls. DNA was extracted from primary MSCs' culture established from these cells and quantitative real-time polymerase chain reaction was performed to analyse the prevalence and viral load of B19, VZV and HHV-6. RESULTS: The prevalence of total viral DNA among patients with OA was 16.7% (3/18), with a mean viral load of 29.7 copies/microg of DNA. One out of 18 was positive for B19 (viral load, 61.2 copies/microg of DNA), two for VZV (mean viral load, 14.4 copies/microg of DNA), and none for HHV-6. The prevalence of total viral DNA in the control group was 20% (2/10), with a mean viral load of 13.4 copies/microg of DNA. Both positive results were of B19 parvoviruses. There were no statistically significant differences among patients and controls. CONCLUSIONS: This first approach to the viral prevalence in MSCs of bone marrow in OA patients and healthy controls seems to show a very low risk of viral transmission or reactivation in a possible MSCs' transplantation.

Lack of detection of human retrovirus-5 proviral DNA in synovial tissue and blood specimens from individuals with rheumatoid arthritis or osteoarthritis.

OBJECTIVE: Prior studies have suggested an association of human retrovirus 5 with rheumatoid arthritis. The purpose of this study was to determine if human retrovirus-5 proviral DNA is present in synovial tissue and blood specimens from patients with rheumatoid arthritis or osteoarthritis, or those without joint disease. METHODS: Synovial tissue and whole blood from 75 patients with rheumatoid arthritis, 75 patients with osteoarthritis, and 50 patients without a primary arthritis diagnosis were assayed by real-time quantitative polymerase chain reaction (PCR) using primers that amplify a 186-bp fragment of human retrovirus-5 proviral DNA. RESULTS: A total of 200 tissue specimens, 200 mononuclear cells, and 196 of 200 granulocyte specimens tested negative for human retrovirus-5 proviral DNA. No association between human retrovirus 5 and rheumatoid arthritis or osteoarthritis (P = 0.516) was identified. Granulocyte specimens from 4 patients, 2 with rheumatoid arthritis and 2 with osteoarthritis, yielded a low positive human retrovirus-5 proviral DNA signal (83-1,365 copies of human retrovirus-5 proviral DNA/ml blood). CONCLUSION: Contrary to prior reports, we did not find an association between human retrovirus 5 and rheumatoid arthritis or osteoarthritis using a real-time PCR assay. Our findings are consistent with the recent finding that human retrovirus 5 is actually rabbit endogenous retrovirus H.

Human endogenous retrovirus HERV-K(HML-2) Rec expression and transcriptional activities in normal and rheumatoid arthritis synovia.

OBJECTIVE: Despite abundance in the genome, the possible functions of human endogenous retrovirus (HERV) sequences are not well understood. The involvement of HERV in various disease conditions, such as germ cell tumors or autoimmune diseases like rheumatoid arthritis (RA), has been suggested. We investigated expression of HERV-K(HML-2) env-derived transcripts in normal and RA synovia. METHODS: We analyzed HERV-K(HML-2) expression on the mRNA and protein level by RT-PCR analysis and immunofluorescence labeling of the HERV-K(HML-2) Rec (formerly cORF) protein. We examined synovial cell cultures from normal synovia (n = 9), from patients with RA (n = 26), and osteoarthritis (OA, n = 4), and uncultured synovial tissues (RA, n = 12; normal synovia, n = 1). RESULTS: HERV-K Rec protein was expressed in all normal synovial specimens, and in the majority of RA and OA cases. We demonstrate for the first time expression of HERV-K protein in synovial tissue. RT-PCR and sequence analysis of cloned RT-PCR products confirmed expression of spliced HERV-K(HML-2) env transcripts in normal and in arthritic synovia. In addition to rec mRNA, several alternatively spliced transcripts, including np9, were identified. However, different amounts of the various RT-PCR products indicate different expression levels of HERV-K(HML-2) env-derived transcripts in RA compared to normal synovia, with apparently lower expression levels in arthritic synovia. CONCLUSION: These findings imply a physiological role of HERV-K(HML-2) Rec in synovial tissue. Differences in the expression of HERV-K env-derived transcripts in RA synovia may be caused by disease-specific changes in the general expression pattern.

The potential role of human endogenous retrovirus K10 in the pathogenesis of rheumatoid arthritis: a preliminary study.

OBJECTIVE: To examine whether human endogenous retrovirus K10 is associated with autoimmune rheumatic disease. DESIGN: A novel multiplex reverse transcription polymerase chain reaction (RT-PCR) system was developed to investigate HERV-K10 mRNA expression in patients with rheumatoid arthritis. METHODS: 40 patients with rheumatoid arthritis, 17 with osteoarthritis, and 27 healthy individuals were recruited and total RNA was extracted from peripheral blood mononuclear cells (PBMCs) and analysed using multiplex RT-PCR for the level of HERV-K10 gag mRNA expression. Southern blot and DNA sequencing confirmed the authenticity of the PCR products. RESULTS: Using the histidyl tRNA synthetase (HtRNAS) gene as a housekeeping gene in the optimised multiplex RT-PCR, a significantly higher level of HERV-K10 gag mRNA expression was found in rheumatoid arthritis than in osteoarthritis (p = 0.01) or in the healthy controls (p = 0.02). CONCLUSION: There is enhanced mRNA expression of the HERV-K10 gag region in rheumatoid arthritis compared with osteoarthritis or healthy controls. This could contribute to the pathogenesis of rheumatoid arthritis.

Hepatitis C virus infection in psoriatic arthritis.

OBJECTIVE: To evaluate the prevalence of hepatitis C virus (HCV) infection in patients with psoriatic arthritis (PsA), compared with patients affected by non HCV-related rheumatic degenerative disorders. METHODS: One-hundred consecutive subjects with PsA, and a statistically comparable group of 100 consecutive patients with peripheral osteoarthritis (OA) or sciatica due to L4-L5 or L5-S1 herniated disc were tested for HCV infection with a third-generation microparticle enzyme immunoassay (MEIA). Positive cases were submitted to a third-generation recombinant immunoblot assay (RIBA) confirmatory test. Comparison between the HCV prevalence obtained in the 2 enrolled groups was performed using Fisher's exact test. RESULTS: Anti-HCV antibodies were found with the MEIA method, in 1 patient with PsA, and in 4 patients with OA or sciatica. The RIBA method confirmed MEIA results in all positive patients. The difference in HCV prevalence detected in the PsA group and in the control group was not statistically significant (P = 0.68). Furthermore, HCV prevalence in PsA patients was lower than the ones reported in different geographic areas of Italy. CONCLUSION: Our present report does not confirm previous data that indicated an increased prevalence of HCV in PsA patients, and as a consequence, does not sustain a possible trigger role of HCV in cases of PsA. The absence of clinical or instrumental resources that consent a definite differential diagnosis between PsA and HCV-related arthritis was outlined and analyzed.

The relationship between arthritis and human parvovirus B19 infection.

In order to evaluate the role of human parvovirus B19 in the etiopathogenesis of autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), synovial fluid and blood specimens were collected at 1-month intervals from 20 patients with early synovitis (ES) and 31 with RA. Blood specimens were also collected from 25 patients with SLE, 25 with osteoarthritis (OA) as the diseased control group, and 50 healthy blood donors (HBD) as the healthy control group. Detection of B19 IgM and B19 IgG were performed by enzyme-linked immunosorbent assay from serum specimens, and B19 DNA was detected by polymerase chain reaction from synovial fluid samples. B19 IgM, B19 IgG, and B19 DNA were found in the three patients of the ES group. Subsequently, two of them were diagnosed with RA and one with SLE. B19 DNA was also detected in the synovial fluid of eight patients in the RA group. Of them, all were positive for B19 IgG and half were positive for B19 IgM. B19 IgM was not detected in either of the control groups. To define the role of B19 in the etiopathogenesis and prognosis of undiagnosed arthritis and other chronic inflammatory diseases such as RA and SLE, we need broader serial and prospective studies based on clinical and laboratory collaboration. In conjunction with case reports, these studies would also serve to detect other possible factors in the etiopathogenesis of chronic inflammatory diseases.