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Aims: Idiopathic inflammatory myopathies (IIM) are autoimmune inflammatory disorders leading to skeletal muscle weakness and disability. The pathophysiology of IIM is poorly understood due to the scarcity of animal disease models. Genetic deletion of Icos or Icosl (inducible T cell co-stimulator/ligand) in non-obese diabetic (NOD) mice leads to muscle disease. Our aim was to characterise Icos -/- NOD myopathy and to search for novel autoantibodies (aAbs) in this model., Methods: Diabetes, weight, myopathy incidence/clinical score and grip strength were assessed over time. Locomotor activity was analysed with the Catwalk XT gait analysis system. Muscle histology was evaluated in haematoxylin/eosin and Sirius red-stained sections, and immune infiltrates were characterised by immunofluorescence and flow cytometry. 2D gel electrophoresis of muscle protein extracts and mass spectrometry were used to identify novel aAbs. NOD mice were immunised with troponin T3 (TNNT3) in incomplete Freund's adjuvant (IFA) and R848. An addressable laser bead immunoassay (ALBIA) was developed to measure aAb IgG serum levels., Results: Icos -/- NOD mice did not exhibit diabetes but developed spontaneous progressive myositis with decreased muscle strength and altered locomotor activity. Muscle from these mice exhibited myofibre necrosis, myophagocytosis, central nuclei, fibrosis and perimysial and endomysial cell infiltrates with macrophages and T cells. We identified anti-TNNT3 aAbs in diseased mice. Immunisation of NOD mice with murine TNNT3 protein led to myositis development, supporting its pathophysiological role., Conclusions: These data show that Icos -/- NOD mice represent a spontaneous model of myositis and the discovery of anti-TNNT3 aAb suggests a new autoantigen in this model., (© 2023 The Authors. Neuropathology and Applied Neurobiology published by John Wiley & Sons Ltd on behalf of British Neuropathological Society.)

Bispecific antibodies (BsAbs) represent an important advance in innovative therapeutic strategies. Among the countless formats of BsAbs, fusion with molecules such as anticalins linked to a monoclonal antibody (mAb), represents an easy and low-cost way to obtain innovative molecules. We fused an anticalin against human fibronectin to a molecule biosimilar to trastuzumab (H0) or rituximab (R0), in four different positions, two on the N terminal region of heavy or light chains and two on the C terminal region. The eight BsAbs (H family (HF) 1 to 4 and R family (RF) 1 to 4) were produced and their affinity parameters and functional properties evaluated. The presence of anticalin did not change the glycosylation of the BsAb, shape or yield. The antigenic recognition of each BsAb family, Her2 for HF1 to 4 and CD20 for RF1 to 4, was slightly decreased (HF) or absent (RF) for the anticalin N-terminal in the light chain position. The anticalin recognition of FN was slightly decreased for the HF family, but a dramatic decrease was observed for RF members with lowest affinity for RF1. Moreover, functional properties of Abs, such as CD16 activation of NK, CD32-dependent phagocytosis and FcRn transcytosis, confirmed that this anticalin position leads to less efficient BsAbs, more so for RF than HF molecules. Nevertheless, all BsAbs demonstrated affinities for CD16, CD32 and FcRn, which suggests that more than affinity for FcRs is needed for a functioning antibody. Our strategy using anticalin and Abs allows for rapid generation of BsAbs, but as suggested by our results, some positions of anticalins on Abs result in less functionality.

The neonatal Fc receptor (FcRn) is a ubiquitously expressed protein historically involved in IgG and albumin recycling. Recent data suggest an involvement in the pathophysiology of antibody-mediated autoimmune diseases. Among them, systemic lupus erythematosus (SLE) implies clinical and biological abnormalities of innate and adaptive circulating immune cells, potentially involving newly described functions of FcRn. In this study, FcRn expression was assessed by flow cytometry in peripheral blood leukocytes of 41 SLE patients with either active or inactive disease and 32 healthy donors. FcRn expression in B cells, natural killer cells, and T cells of SLE patients was statistically lower as compared to healthy donors. Conversely, FcRn level was statistically higher in non-classical monocyte subpopulations (CD14+CD16+ monocytes) of SLE patients versus healthy donors providing an interesting perspective to further explore its role in SLE pathophysiology.

Objectives: In autoimmunity, autoantibodies (aAb) may be simple biomarkers of disease or true pathogenic effectors. A form of idiopathic inflammatory myopathy associated with anti-signal recognition particle (SRP) or anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) aAb has been individualised and is referred to as immune-mediated necrotising myopathy (IMNM). The level of aAb correlates with IMNM activity and disease may respond to immunosuppression, suggesting that they are pathogenic. We aimed to evaluate the pathogenicity of IgG from patients with anti-SRP or anti-HMGCR aAb in vivo by developing the first mouse model of IMNM., Methods: IgG from patients suffering from anti-SRP or anti-HMGCR associated IMNM were passively transferred to wild-type, Rag2 -/- or complement C3 -/- mice. Muscle deficiency was evaluated by muscle strength on electrostimulation and grip test. Histological analyses were performed after haematoxylin/eosin staining or by immunofluorescence or immunohistochemistry analysis. Antibody levels were quantified by addressable laser bead assay (ALBIA)., Results: Passive transfer of IgG from patients suffering from IMNM to C57BL/6 or Rag2 -/- mice provoked muscle deficiency. Pathogenicity of aAb was reduced in C3 -/- mice while increased by supplementation with human complement. Breakage of tolerance by active immunisation with SRP or HMGCR provoked disease., Conclusion: This study demonstrates that patient-derived anti-SRP + and anti-HMGCR + IgG are pathogenic towards muscle in vivo through a complement-mediated mechanism, definitively establishing the autoimmune character of IMNM. These data support the use of plasma exchanges and argue for evaluating complement-targeting therapies in IMNM., Competing Interests: Competing interests: OBo is member of the Scientific Committee of CSL Behring Foundation (France) and received consulting fees from Inova Diagnostics., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To characterize muscle fiber necrosis in immune-mediated necrotizing myopathies (IMNM) with anti-signal recognition particle (SRP) or anti-3-hydroxy-3-methylglutarylcoenzyme A reductase (HMGCR) antibodies and to explore its underlying molecular immune mechanisms., Methods: Muscle biopsies from patients with IMNM were analyzed and compared to biopsies from control patients with myositis. In addition to immunostaining and reverse transcription PCR on muscle samples, in vitro immunostaining on primary muscle cells was performed., Results: Creatine kinase levels and muscle regeneration correlated with the proportion of necrotic fibers ( r = 0.6, p < 0.001). CD68 + iNOS + macrophages and a Th-1 immune environment were chiefly involved in ongoing myophagocytosis of necrotic fibers. T-cell densities correlated with necrosis but no signs of cytotoxicity were detected. Activation of the classical pathway of the complement cascade, accompanied by deposition of sarcolemmal immunoglobulins, featured involvement of humoral immunity. Presence of SRP and HMGCR proteins on altered myofibers was reproduced on myotubes exposed to purified patient-derived autoantibodies. Finally, a correlation between sarcolemmal complement deposits and fiber necrosis was observed ( r = 0.4 and p = 0.004). Based on these observations, we propose to update the pathologic criteria of IMNM., Conclusion: These data further corroborate the pathogenic role of anti-SRP and anti-HMGCR autoantibodies in IMNM, highlighting humoral mechanisms as key players in immunity and myofiber necrosis., (© 2018 American Academy of Neurology.)

Background: Immune-mediated necrotizing myopathy (IMNM) is a newly identified subgroup of idiopathic inflammatory myopathies. It is defined as a rare and severe disease, with symmetrical and proximal muscle weakness and a characteristic histology. An autoimmune aspect of IMNM is suggested by its association with autoantibodies directed against signal recognition particle (SRP) and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in the majority of patients. Statin use is strongly associated with anti-HMGCR-positive IMNM. The pathophysiological mechanisms of this disease are still poorly understood, and as a result, no therapeutic strategy has been validated to date., Objective: The aim of this article is to provide an overview of the current knowledge about epidemiology, clinical features, and pathophysiology of IMNM, as well as treatment strategies., Results and Conclusion: IMNM is a subject of widespread interest, with quick and meaningful advances being made. In recent years, huge progress has been made in terms of diagnosis and patient management. However, the understanding of pathophysiological mechanisms and treatment strategies still requires further investigation.

Background: Secondary hyperparathyroidism (SHPT) is a relevant problem in patients undergoing dialysis, and cinacalcet hydrochloride seems to be the best option for controlling it. After kidney transplantation (KTx), moderate to severe SHPT may persist and cause hypercalcemia and hypophosphatemia, among other deleterious effects. The number of patients receiving cinacalcet before KTx is increasing., Objective: To evaluate the evolution of calcemia, phosphatemia, and intact parathyroid hormone (iPTH) after KTx in patients with SHPT receiving cinacalcet on dialysis., Patients and Methods: The study included 19 patients (15 men and 4 women; mean [SD] age, 52 [13] years) undergoing dialysis and receiving cinacalcet before KTx. Mean duration of dialysis before KTx was 33 (25) months, and cinacalcet dose was 45 (15) mg/d. Creatinine, calcium, phosphorus, alkaline phosphatase, and iPTH concentrations were evaluated at baseline (day of surgery), at 15 days after surgery, and then monthly for 6 months. In all patients, cinacalcet therapy was discontinued on the day of surgery., Results: After the first month post-KTx, mean (SD) serum creatinine concentration was 1.6 (0.4) mg/dL and remained stable during follow-up. Calcium and phosphorus concentrations were normal in 13 patients after KTx; however, in 6 patients, hypercalcemia (calcium concentration, 11 [1.3] mg/dL) or hypophosphatemia (phosphorus concentration, 1.7 [0.6] mg/dL) developed, with iPTH concentration of 557 (400) pg/mL and alkaline phosphatase concentration of 307 (114) IU/mL. Treatment with cinacalcet resulted in correction of calcium and phosphorus concentrations (10.1 [0.4] mg/dL and 1.7 [0.7] mg/dL, respectively). Patients in whom hypercalcemia or hypophosphatemia developed were receiving cinacalcet, 60 mg/d or more, during dialysis therapy. Patients who received cinacalcet, 30 mg/d, before KTx did not exhibit hypercalcemia or hypophosphatemia after KTx., Conclusion: In patients with HPT undergoing dialysis and receiving cinacalcet, 60 mg/d or more, this drug therapy should be continued after KTx to avert development of hypercalcemia or hypophosphatemia.

Background: Persistent secondary hyperparathyroidism (SHP) is the most frequent cause of hypercalcemia observed in approximately 10% of renal transplanted (RT) patients 1 year after surgery. Persistent SHP with hypercalcemia is an important factor of bone loss after renal transplantation. This study prospectively evaluates the effects of cinacalcet therapy on serum calcium (SCa) and parathyroid hormone (PTH) blood levels, and basically on bone mineral density (BMD) in RT patients with persistent hyperparathyroidism., Methods: Nine RT patients (eight women, one man) with allograft function more than 6 months were included based on total SCa more than 10.5 mg/dL and intact parathyroid hormone (iPTH) concentration more than 65 pg/mL. After inclusion, patients started on a single daily oral dose of 30 mg of cinacalcet. At inclusion and every study visit blood levels of creatinine, Ca, P, alkaline phosphatase, iPTH 1,25- dihydroxyvitamin D3, and 25-hydroxyvitamin D3 were assessed. Baseline and at the end of study radial BMD were measured. Study follow-up was 12 months., Results: During the study period, SCa decreased from 11.72+/-0.39 to 10.03+/-0.54 mg/dL (P<0.001). iPTH decreased from 308.85+/-120.12 to 214.66+/-53.75 mg/dL (P<0.05). The mean serum creatinine decreased from 1.58+/-0.34 to 1.25+/-0.27 mg/dL (P=0.03) and the mean radial BMD increased from 0.881+/-0.155 to 0.965+/-0.123 gr/cm2 (P<0.05). There were no significant changes in the other parameters assessed. One patient was excluded for gastrointestinal intolerance., Conclusions: In RT patients with hypercalcemia secondary to persistent SHP, cinacalcet corrects hypercalcemia and PTH, simultaneously improving BMD.

Insulin resistance is supposed to be the basis of metabolic syndrome (MS), although it is difficult to measure. The ratio of triglyceride (TG) to high-density lipoprotein (HDL) has been proposed as a surrogate marker of insulin resistance in overweight subjects. The aim of the present study was to assess the accuracy of the TG/HDL ratio for the diagnosis of MS. Data of 18,778 active workers (77.6% men) enrolled in 3 insurance companies in Spain were collected from their annual health examinations. Mean age was 42.2 +/- 10.7 years. MS was assessed according to modified Adult Treatment Panel III criteria. Prevalences of MS were 18.8% in men and 6.1% in women. Mean value of the TG/HDL ratio was 2.50 +/- 2.2 and increased in parallel to the number of MS components present. Subjects with MS had a ratio that was 2 times higher compared with those without (5.10 vs 2.03, p <0.001). Receiver operating characteristic curves were performed to assess the capability of the TG/HDL ratio to contribute to a diagnosis of MS and 80% sensitivity and 78% specificity were obtained for values >2.75 in men and >1.65 in women. In conclusion, the TG/HDL ratio is a feasible and accurate measurement for assessment of MS in healthy subjects. We propose cut-off values of 2.75 for men and 1.65 for women for a diagnosis of MS.

Persistent hyperparathyroidism is the most frequent cause of hypercalcemia after renal transplantation, namely, hypercalcemia is observed in about 10% of patients at 1 year. This prospective study evaluated the effect of cinacalcet, a second-generation calcimimetic, on serum calcium and parathyroid hormone (PTH) blood levels among recipients with hypercalcemia due to persistent hyperparathyroidism. Thirteen renal transplanted patients (10 women and 3 men) were included based upon: a total serum calcium >10.5 mg/dL; intact PTH (iPTH) blood levels >65 pg/mL; graft function >6 months, and stable maintenance immunosuppressive therapy. After inclusion, patients initially received 30 mg of cinacalcet once daily. The mean time of initiation was 64 +/- 7 months after transplantation. The follow-up was 6 months. The median dose of cinacalcet was 30 mg/d (5 patients received 60 mg/d). During the study period, renal function remained stable. Serum calcium levels decreased significantly from 11.7 +/- 0.39 to 10.35 +/- 0.8 mg/dL (P < .001). Serum phosphate levels increased from 2.82 +/- 0.34 mg/dL to 3.2 +/- 0.41 mg/dL (P < .05). The mean iPTH levels significantly decreased from 308 +/- 120 to 210 +/- 80 pg/mL (P < .05). There were no significant change in 25-hydroxyvitamin D3 blood levels (from 17.7 +/- 9 to 17.4 +/- 6 ng/mL), but the 1,25-dihydroxyvitamin D3 blood levels decreased from 53.8 +/- 18.2 to 32.6 +/- 9.2 pg/mL (P < .01). There were no significant changes in blood levels of alkaline phosphatase, magnesium, bicarbonate, calciuria, phosphaturia, and immunosuppressive drugs. Cinacalcet was well tolerated in all patients except one who had gastrointestinal discomfort. In summary, cinacalcet corrected hypercalcemia and improved phosphatemia in patients with persistent hyperparathyroidism after transplantation with no negative effects on renal function.

We studied the behaviour of 56 clinical isolates of Pseudomonas aeruginosa strains against the following beta-lactam antibiotics: cefotaxime, cefoperazone, cefsulodin, lamoxactam, Ro 13-9904, azlocillin, mezlocillin and ticarcillin. Twenty-six strains were resistant to gentamicin and 30 to gentamicin and/or carbenicillin. The MICs were measured by the serial dilution test on solid agar. Cefsulodin was the most active cephalosporin against carbenicillin-resistant strains (MIC greater than or equal to 128 mg/l); it inhibited 56.6% of these strains at a concentration of 8 mg/l. Azlocillin was the most active penicillin, inhibiting 79.96% of the same strains at a concentration of 64 mg/l. Cefsulodin was the most active cephalosporin against the gentamicin-resistant group of Pseudomonas aeruginosa strains (MIC greater than or equal to 8 mg/l) which were sensitive to carbenicillin (MIC less than or equal to 64 mg/l). It inhibited 100% of the strains at a concentration of 4 mg/l. All of the penicillins studied inhibited all of the strains in this group. The required concentrations were the following: 16 mg/l for azlocillin, 32 mg/l for mezlocillin and 64 mg/l for ticarcillin.