Cartilage destruction is partly induced by the internal proteolytic enzymes and apoptotic phenomenon of chondrocytes in relapsing polychondritis.

OBJECTIVE: We analyzed 9 cases by immunohistochemical studies in order to elucidate the mechanisms of cartilage destruction in relapsing polychondritis (RP), which often involves the external auricle and respiratory tract through immunological disorder. METHODS: Cartilage tissues were obtained during surgical operations. Cell species in the granulation tissues, especially near the cartilage, were identified by cell-surface markers [CD3, CD4, CD8, CD20, CD45 (LCA), and CD68]. The proteolytic enzymes expressed in the cells in the perichondral granulation and in chondrocytes themselves were analyzed by immunohistochemical studies using anti-matrix metalloproteinase (MMP) -1, -3, -8, -9, and -13, and cathepsin D, K, L, and elastase antibodies. Apoptosis and nitric oxide (NO), an apoptosis-related factor, were also examined using ApopTag and antinitrotyrosine antibody, respectively. RESULTS: Among cell species that infiltrated in perichondral granulation, LCA, CD68 (monocytes/macrophages), and CD4 cells were dominant in number; MMP-8, MMP-9, and elastase were expressed only in the perichondral granulation; whereas MMP-3 and cathepsin K and L were detected in both chondrocytes and granulations. Out of 9 cases examined, 6 revealed apoptotic cells in excess of 50% of chondrocytes. There was a strong correlation between the number of apoptotic cells and the number of MMP-3-positive (r = 0.83) and cathepsin K-positive cells (r = 0.92). Abundant NO-expressing cells were observed in the chondrocytes in degenerated cartilage, similar to apoptosis. CONCLUSION: Cartilage destruction in polychondritis is induced not only by perichondral inflammation, but also by intrinsic factors expressed in chondrocytes themselves, including certain kinds of proteolytic enzymes and apoptosis.

Hypereosinophilia with systemic thrombophlebitis.

A 34-year-old Japanese woman developed subcutaneous induration in the left thigh, then showed extreme eosinophilia, and died of hemorrhagic infarction of the brain. Autopsy revealed endocarditis with eosinophil infiltration and systemic thrombophlebitis, including pulmonary veins and intrahepatic branches of the portal vein. Arterial structure was relatively preserved. She had no clinical history of asthma and had anti-ascarid IgE antibody at postmortem serological examination; thus, her disease does not fulfill the diagnostic criteria of Churg-Strauss syndrome and idiopathic hypereosinophilic syndrome (HES). Her organ involvement is, however, consistent with that of HES; thus, her pathophysiological conditions would resemble those of HES. Systemic thrombophlebitis without arterial lesion in patients with hypereosinophilia has never been reported, and this case would broaden the spectrum of vascular lesions in these patients.