Implementation of in vivo high-resolution micro-computed tomography (µCT), a powerful tool for longitudinal analysis of murine lung disease models, is hampered by the lack of data on cumulative low-dose radiation effects on the investigated disease models. We aimed to measure radiation doses and effects of repeated µCT scans, to establish cumulative radiation levels and scan protocols without relevant toxicity. Lung metastasis, inflammation and fibrosis models and healthy mice were weekly scanned over one-month with µCT using high-resolution respiratory-gated 4D and expiration-weighted 3D protocols, comparing 5-times weekly scanned animals with controls. Radiation dose was measured by ionization chamber, optical fiberradioluminescence probe and thermoluminescent detectors in a mouse phantom. Dose effects were evaluated by in vivo µCT and bioluminescence imaging read-outs, gold standard endpoint evaluation and blood cell counts. Weekly exposure to 4D µCT, dose of 540–699 mGy/scan, did not alter lung metastatic load nor affected healthy mice. We found a disease-independent decrease in circulating blood platelets and lymphocytes after repeated 4D µCT. This effect was eliminated by optimizing a 3D protocol, reducing dose to 180–233 mGy/scan while maintaining equally high-quality images. We established µCT safety limits and protocols for weekly repeated whole-body acquisitions with proven safety for the overall health status, lung, disease process and host responses under investigation, including the radiosensitive blood cell compartment.

Inhibitors of tumor necrosing factor alpha (TNF-a) have proven to be highly effective in the treatment of rheumatoid arthritis (RA). Concerns, however, are raised about the possible association between these treatments and an increased development of malignancies. The objective of this paper was to compare the risk of hematologic and solid malignancies in patients treated for RA with anti-TNF therapy, with the risk in the general population. From January 2000 until January 2012, all RA patients that started treatment with anti-TNF agents were included in this single-center cohort study. The primary outcome of this study was the incidence of malignancy after starting anti-TNF treatment. In our cohort of 365 patients, 34 malignancies were discovered in 30 patients after the start of anti-TNF treatment; 20 patients developed a solid malignancy, 6 a hematologic, 2 a solid and a hematologic malignancy, and 2 patients developed 2 solid malignancies. The overall incidence rate (IR) of malignancy was 1379.1 per 100.000 patient years. The risk or standardized incidence ratio (SIR) of solid malignancy, calculated by comparison with the age-adjusted population in Flanders, was 120.1 in female and 136.7 in male patients. The calculated SIR of hematologic malignancy was 450.8 for women and 473.9 for men. Some immune modulation-related lymphoproliferative disorders regressed spontaneously when stopping TNF blockers. Overall, the malignancy risk in our rheumatoid arthritis patients treated with anti-TNF therapy was slightly higher than in the normal population; the risk of hematologic malignancies was more important.

In spite of many compounds identified as antifibrotic in preclinical studies, pulmonary fibrosis remains a life-threatening condition for which highly effective treatment is still lacking. Towards improving the success-rate of bench-to-bedside translation, we investigated in vivo µCT-derived biomarkers to repeatedly quantify experimental silica-induced pulmonary fibrosis and assessed clinically relevant readouts up to several months after silicosis induction. Mice were oropharyngeally instilled with crystalline silica or saline and longitudinally monitored with respiratory-gated-high-resolution µCT to evaluate disease onset and progress using scan-derived biomarkers. At weeks 1, 5, 9 and 15, we assessed lung function, inflammation and fibrosis in subsets of mice in a cross-sectional manner. Silica-instillation increased the non-aerated lung volume, corresponding to onset and progression of inflammatory and fibrotic processes not resolving with time. Moreover, total lung volume progressively increased with silicosis. The volume of healthy, aerated lung first dropped then increased, corresponding to an acute inflammatory response followed by recovery into lower elevated aerated lung volume. Imaging results were confirmed by a significantly decreased Tiffeneau index, increased neutrophilic inflammation, increased IL-13, MCP-1, MIP-2 and TNF-α concentration in bronchoalveolar lavage fluid, increased collagen content and fibrotic nodules. µCT-derived biomarkers enable longitudinal evaluation of early onset inflammation and non-resolving pulmonary fibrosis as well as lung volumes in a sensitive and non-invasive manner. This approach and model of non-resolving lung fibrosis provides quantitative assessment of disease progression and stabilization over weeks and months, essential towards evaluation of fibrotic disease burden and antifibrotic therapy evaluation in preclinical studies.

Objectives: To review the therapeutic option of Rituximab, a chimeric anti-CD20 antibody, in systemic autoimmune rheumatic diseases (SARDs) such as systemic lupus erythematosus, systemic sclerosis, primary Sjögren syndrome and idiopathic inflammatory myopathy. Methods: A non-systematic review was conducted. Results: The specific role and indication of rituximab in SARDs has been the subject of multiple trials in recent years. Evidence supports the use of rituximab in moderate-to-severe refractory systemic lupus erythematosus, diffuse skin involvement in systemic sclerosis and systemic involvement in primary Sjögren syndrome. Several guidelines have adopted these indications. In addition, there is a consensus about the use of rituximab in refractory myositis. The role of rituximab in interstitial lung disease associated with these SARDs needs to be further explored. Conclusion:Rituximab is a treatment option in several SARDs. Upcoming trials, use in daily practice and the safety profile are elaborated on.

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