TNF-Induced Interstitial Lung Disease in a Murine Arthritis Model: Accumulation of Activated Monocytes, Conventional Dendritic Cells, and CD21+/CD23- B Cell Follicles Is Prevented with Anti-TNF Therapy.

Interstitial lung disease (ILD) is a well-known extra-articular manifestation of rheumatoid arthritis (RA). RA-associated ILD (RA-ILD) exists on a wide spectrum, with variable levels of inflammatory and fibrotic activity, although all subtypes are regarded as irreversible pathologic conditions. In both articular and pulmonary manifestations, TNF is a significant pathogenic factor. Whereas anti-TNF therapy alleviates joint pathologic conditions, it exacerbates fibrotic RA-ILD. The TNF-transgenic (TNF-Tg) murine model of RA develops both inflammatory arthritis and an ILD that mimics a cellular nonspecific interstitial pneumonia pattern dominated by an interstitial accumulation of inflammatory cells with minimal-to-absent fibrosis. Given the model's potential to elucidate the genesis of inflammatory RA-ILD, we aim to achieve the following: 1) characterize the cellular accumulations in TNF-Tg lungs, and 2) assess the reversibility of inflammatory ILD following anti-TNF therapy known to resolve TNF-Tg inflammatory arthritis. TNF-Tg mice with established disease were randomized to anti-TNF or placebo therapy and evaluated with imaging, histology, and flow cytometric analyses, together with wild-type controls. Flow cytometry of TNF-Tg versus wild-type lungs revealed significant increases in activated monocytes, conventional dendritic cells, and CD21+/CD23- B cells that are phenotypically distinct from the B cells in inflamed nodes, which are known to accumulate in joint-draining lymph nodes. In contrast to human RA-ILD, anti-TNF treatment significantly alleviated both joint and lung inflammation. These results identify a potential role for activated monocytes, conventional dendritic cells, and CD21+/CD23- B cells in the genesis of RA-ILD, which exist in a previously unknown, reversible, prefibrotic stage of the disease.

Rare high branching pattern from the first part of the right axillary artery.

A 77-year-old female cadaver was observed to have a rare branching pattern of the right axillary artery (AA). The first part of the AA typically gives off only a superior thoracic artery (STA) but was observed to give off three branches in the case: a lateral thoracic artery (LTA), a thoracoacromial trunk, and a large common trunk (CT). The LTA travelled to provide a variant STA to the 1st and 2nd intercostal spaces. The CT provided an accessory LTA and accessory thoracodorsal artery before bifurcating into a subscapular artery (SA) and posterior humeral circumflex artery. As expected, the SA further divided into the circumflex scapular artery and thoracodorsal artery. A pectoral artery and the anterior humeral circumflex artery originated directly from the second and third parts of the AA, respectively. Knowledge of AA branching variations is of great clinical significance to anatomists, radiologists, and surgeons due to the high rate of injury to this artery.