Pam16 and Pam18 were repurposed during Trypanosoma brucei evolution to regulate the replication of mitochondrial DNA.

Protein import and genome replication are essential processes for mitochondrial biogenesis and propagation. The J-domain proteins Pam16 and Pam18 regulate the presequence translocase of the mitochondrial inner membrane. In the protozoan Trypanosoma brucei, their counterparts are TbPam16 and TbPam18, which are essential for the procyclic form (PCF) of the parasite, though not involved in mitochondrial protein import. Here, we show that during evolution, the 2 proteins have been repurposed to regulate the replication of maxicircles within the intricate kDNA network, the most complex mitochondrial genome known. TbPam18 and TbPam16 have inactive J-domains suggesting a function independent of heat shock proteins. However, their single transmembrane domain is essential for function. Pulldown of TbPam16 identifies a putative client protein, termed MaRF11, the depletion of which causes the selective loss of maxicircles, akin to the effects observed for TbPam18 and TbPam16. Moreover, depletion of the mitochondrial proteasome results in increased levels of MaRF11. Thus, we have discovered a protein complex comprising TbPam18, TbPam16, and MaRF11, that controls maxicircle replication. We propose a working model in which the matrix protein MaRF11 functions downstream of the 2 integral inner membrane proteins TbPam18 and TbPam16. Moreover, we suggest that the levels of MaRF11 are controlled by the mitochondrial proteasome.

Influenza vaccine with adjuvant on disease activity in psoriatic arthritis patients under anti-TNF-α therapy.

OBJECTIVES: To evaluate the effects on disease activity of seasonal influenza vaccination with adjuvant in psoriatic arthritis (PsA) patients in stable disease activity on anti-TNF-α drugs as compared to not vaccinated PsA patients adequately matched. METHODS: An observational study was conducted on a cohort of PsA patients in stable disease activity who underwent administration of an adjuvanted vaccine for seasonal influenza. Cases (Group 1) were matched for age, sex, disease activity and therapy with not vaccinated PsA patients (Group 2). Analysis included patients data before vaccination (T0), and one month (T1) and three months (T3) after administration of the vaccination for Group 1 and at correspondent intervals for Group 2. Assessment of disease activity parameters was performed at each visit. RESULTS: Twenty-five vaccinated and 25 not vaccinated patients were included in the study. As a first approach, we analysed the data within groups. At T1, as compared to baseline, the group of vaccinated patients had a statistically significant increase in TJC (tender joint count) and ESR (erythrocyte sedimentation rate). At T3, a statistically significant difference from baseline characteristics was found only for the TJC. In Group 2, all the observed variables showed no significant differences when comparing baseline to T1 and T3. Analysis of the data between groups at T1, Group 1, as compared to Group 2, showed a significant increase of TJC, ESR, HAQ (Health Assessment Questionnaire), PtGA (patient global assessment) and PhGA (physician global assessment). These findings were also confirmed when comparing the two groups at T3 for ESR and PtGA, while they were not confirmed for TJC, HAQ and PhGA. CONCLUSIONS: Influenza vaccination is clinically efficacious in PsA patients under anti-TNF-α therapy, but it could trigger a short-lasting exacerbation of the disease.

Enteropathic spondyloarthritis: from diagnosis to treatment.

Enteropathic arthritis (EA) is a spondyloarthritis (SpA) which occurs in patients with inflammatory bowel diseases (IBDs) and other gastrointestinal diseases. Diagnosis is generally established on the medical history and physical examination. It was, generally, made according to the European Spondyloarthropathy Study Group (ESSG) criteria. Rheumatic manifestations are the most frequent extraintestinal findings of IBD with a prevalence between 17% and 39%, and IBD is associated, less frequently, with other rheumatic disease such as rheumatoid arthritis, Sjogren syndrome, Takayasu arteritis, and fibromyalgia. Although the pathogenesis of EA has not been plainly clarified, the most popular theory supposes that joint inflammation occurs in genetically predisposed subjects with bacterial gut infections, provided an important evidence for a possible relationship between inflammation of the gut mucosa and arthritis. The management of patients with EA requires an active cooperation between the gastroenterologist and rheumatologist.

Osteoporosis and psoriatic arthritis.

Osteoporosis (OP) is a skeletal disorder characterized by compromised bone strength that predisposes to an increased risk of fracture. The prevalence of OP in the general population is very high as established in several studies, and OP represents one of the possible aspects of bone involvement in arthritis. In psoriatic arthritis this involvement is particularly complex because it affects not only mechanisms of bone loss but also of bone formation. We will discuss these aspects and the available epidemiological data.

Characterization of QuantiFERON-TB-Plus results in latent tuberculosis infected patients with or without immune-mediated inflammatory diseases.

OBJECTIVES: Screening for latent tuberculosis infection (LTBI) diagnosis is mandatory in patients with immune-mediated inflammatory diseases (IMID) requiring biologics. QuantiFERON-TB-Plus (QFT-P), an LTBI diagnostic test, measures IFN-γ after M. tuberculosis-stimulation in TB1 and TB2 tubes in which a "CD4" or a "CD4 and CD8" response is respectively elicited. Aim of this study is to compare the response to QFT-P of IMID-LTBI patients candidates to a new biological therapy vs LTBI-subjects without IMID. METHODS: We prospectively enrolled 167 subjects: 61 IMID-LTBI and 106 NON-IMID-LTBI. RESULTS: All subjects were mitogen-responders. IFN-γ production was significantly lower in IMID-LTBI-patients compared to NON-IMID-LTBI-subjects. We observed discordant TB1 and TB2 results in 6.5% of IMID-LTBI-patients and in 8% of NON-IMID-LTBI-subjects. Applying a logistic regression analysis, we found that IMID-LTBI patients had a higher probability (TB1 stimulation OR 3.32; TB2 stimulation OR 4.33) to have IFNγ results ≤0.7 IU/mL compared to NON-IMID-LTBI-subjects. Interestingly, IMID-treatment did not interfere with the distribution of IFNγ-values. CONCLUSIONS: These results indicate that IMID-LTBI-patients have a low IFN-γ response to QFT-P, a high proportion of results ranging in the grey zone and a distribution of IFNγ-values independent from the IMID-treatment. These results are important for the management of LTBI screening in IMID patients.

Large Vessel Vasculitis Occurring in Rheumatoid Arthritis Patient under Anti-TNF Therapy.

Vasculitis is a heterogeneous group of disorders characterized by the presence of necrotic inflammatory phenomena and destruction of blood vessels. Vasculitis is classified as primary (idiopathic) or secondary to infections, connective tissue diseases and drugs but can also be considered as a paraneoplastic phenomenon. Evidence shows that the increasing use of biological agents results in a growing number of reports of autoimmune diseases induced by these therapies. An inflammatory articular chronic disease such as rheumatoid arthritis may be complicated by extra-articular manifestations, such as cutaneous or systemic vasculitis. Herewith, we describe the case of a great vessels arteritis in a patient affected by rheumatoid arthritis in therapy with an anti-TNF agent (etanercept).

Comparison of the TaqMan and LightCycler systems in pharmacogenetic testing: evaluation of CYP2C9*2/*3 polymorphisms.

BACKGROUND: Pharmacogenetic testing for drug-metabolizing enzymes is not yet widely used in clinical practice. METHODS: In an attempt to facilitate the application of this procedure, we have compared two real-time PCR-based methods, the TaqMan and the LightCycler for the pharmacogenetic evaluation of CYP2C9*2/*3 polymorphisms. RESULTS AND CONCLUSION: Both procedures are suitable for pharmacogenetic studies. The TaqMan procedure was less expensive in terms of cost per sample, but the TaqMan apparatus is more expensive than the LightCycler apparatus.