Intra-articular nodular fasciitis of the knee: a rare cause of recurrent hemarthrosis

A 20-year-old man presented with pain and recurrent hemarthrosis in the right knee. Magnetic resonance imaging of the knee showed a lesion with homogeneous low signal intensity on T1-weighted images and a heterogeneous, low to high signal intensity on T2-weighted images. At arthroscopy, the mass was located between the posterior cruciate ligament and the posterior knee joint capsule. The tumor was excised through a posterior approach and histologically diagnosed as a nodular fasciitis. Intra-articular nodular fasciitis is a very rare clinicopathologic entity. The current case showed the unique clinical feature of recurrent hemarthrosis at initial presentation, which has not been previously reported.     

Association of gene expression involving innate immunity and genetic variation in interleukin 28B with antiviral response

Innate immunity plays an important role in host antiviral response to hepatitis C viral (HCV) infection. Recently, single nucleotide polymorphisms (SNPs) of IL28B and host response to peginterferon α (PEG-IFNα) and ribavirin (RBV) were shown to be strongly associated. We aimed to determine the gene expression involving innate immunity in IL28B genotypes and elucidate its relation to response to antiviral treatment. We genotyped IL28B SNPs (rs8099917 and rs12979860) in 88 chronic hepatitis C patients treated with PEG-IFNα-2b/RBV and quantified expressions of viral sensors (RIG-I, MDA5, and LGP2), adaptor molecule (IPS-1), related ubiquitin E3-ligase (RNF125), modulators (ISG15 and USP18), and IL28 (IFNλ). Both IL28B SNPs were 100% identical; 54 patients possessed rs8099917 TT/rs12979860 CC (IL28B major patients) and 34 possessed rs8099917 TG/rs12979860 CT (IL28B minor patients). Hepatic expressions of viral sensors and modulators in IL28B minor patients were significantly up-regulated compared with that in IL28B major patients (≈ 3.3-fold, P < 0.001). However, expression of IPS-1 was significantly lower in IL28B minor patients (1.2-fold, P = 0.028). Expressions of viral sensors and modulators were significantly higher in nonvirological responders (NVR) than that in others despite stratification by IL28B genotype (≈ 2.6-fold, P < 0.001). Multivariate and ROC analyses indicated that higher RIG-I and ISG15 expressions and RIG-I/IPS-1 expression ratio were independent factors for NVR. IPS-1 down-regulation in IL28B minor patients was confirmed by western blotting, and the extent of IPS-1 protein cleavage was associated with the variable treatment response. CONCLUSION: Gene expression involving innate immunity is strongly associated with IL28B genotype and response to PEG-IFNα/RBV. Both IL28B minor allele and higher RIG-I and ISG15 expressions and RIG-I/IPS-1 ratio are independent factors for NVR.     

Plasma cells and the chronic nonsuppurative destructive cholangitis of primary biliary cirrhosis

There has been increased interest in the role of B cells in the pathogenesis of primary biliary cirrhosis (PBC). Although the vast majority of patients with this disease have anti-mitochondrial antibodies, there is no correlation of anti-mitochondrial antibody titer and/or presence with disease severity. Furthermore, in murine models of PBC, it has been suggested that depletion of B cells may exacerbate biliary pathology. To address this issue, we focused on a detailed phenotypic characterization of mononuclear cell infiltrates surrounding the intrahepatic bile ducts of patients with PBC, primary sclerosing cholangitis, autoimmune hepatitis, chronic hepatitis C, and graft-versus-host disease, including CD3, CD4, CD8, CD20, CD38, and immunoglobulin classes, as well as double immunohistochemical staining for CD38 and IgM. Interestingly, CD20 B lymphocytes, which are a precursor of plasma cells, were found in scattered locations or occasionally forming follicle-like aggregations but were not noted at the proximal location of chronic nonsuppurative destructive cholangitis. In contrast, there was a unique and distinct coronal arrangement of CD38 cells around the intrahepatic ducts in PBC but not controls; the majority of such cells were considered plasma cells based on their expression of intracellular immunoglobulins, including IgM and IgG, but not IgA. Patients with PBC who manifest this unique coronal arrangement were those with significantly higher titers of anti-mitochondrial antibodies. CONCLUSION: These data collectively suggest a role for plasma cells in the specific destruction of intrahepatic bile ducts in PBC and confirm the increasing interest in plasma cells and autoimmunity.     

Reversal of slow growth and heartbeat through the restoration of mitochondrial function in clk-1-deficient mouse embryos by exogenous administration of coenzyme Q10

The longevity gene clk-1/coq7 encodes an enzyme that is essential for the biosynthesis of coenzyme Q (CoQ) in mitochondria and regulates the lifespan and behavioral timing in Caenorhabditis elegans and the chronological lifespan in fission yeast. However, whether the mammalian clk-1/coq7 ortholog (clk-1) regulates these phenotypes in mammals remains to be fully evaluated due to the embryonic lethality of clk-1-deficient (clk-1(-/-)) mice. To investigate whether clk-1 regulates biological functions, such as growth and heartbeat, through CoQ in mouse embryos, we cultivated the cells and hearts of clk-1(-/-) mouse embryos at embryonic day 10.5 (E10.5) for at least 10 days in the presence of fetal bovine serum. In embryonic cells, cardiomyocytes, and hearts, the growth and heart rates were significantly slowed in clk-1(-/-) compared with wild-type or heterozygous mouse tissues. Moreover, frequent apoptosis and a significant reduction in mitochondrial functions, including membrane potential and ATP production, were observed in the clk-1(-/-) cells and hearts. The slowed growth and heart rates and the reduced mitochondrial function of clk-1(-/-) embryonic cells and hearts in culture were almost completely rescued by the administration of exogenous CoQ(10). The results indicate that clk-1 regulates growth and heart rates through CoQ-mediated mitochondrial functions in mouse embryos.