R409K mutation prevents acid-induced aggregation of human IgG4.

Human immunoglobulin G isotype 4 (IgG4) antibodies are suitable for use in either the antagonist or agonist format because their low effector functions prevent target cytotoxicity or unwanted cytokine secretion. However, while manufacturing therapeutic antibodies, they are exposed to low pH during purification, and IgG4 is more susceptible to low-pH-induced aggregation than IgG1. Therefore, we investigated the underlying mechanisms of IgG4 aggregation at low pH and engineered an IgG4 with enhanced stability. By swapping the constant regions of IgG1 and IgG4, we determined that the constant heavy chain (CH3) domain is critical for aggregate formation, but a core-hinge-stabilizing S228P mutation in IgG4 is insufficient for preventing aggregation. To identify the aggregation-prone amino acid, we substituted the CH3 domain of IgG4 with that of IgG1, changing IgG4 Arg409 to a Lys, thereby preventing the aggregation of the IgG4 variant as effectively as in IgG1. A stabilizing effect was also recorded with other variable-region variants. Analysis of thermal stability using differential scanning calorimetry revealed that the R409K substitution increased the Tm value of CH3, suggesting that the R409K mutation contributed to the structural strengthening of the CH3-CH3 interaction. The R409K mutation did not influence the binding to antigens/human Fcγ receptors; whereas, the concurrent S228P and R409K mutations in IgG4 suppressed Fab-arm exchange drastically and as effectively as in IgG1, in both in vitro and in vivo in mice models. Our findings suggest that the IgG4 R409K variant represents a potential therapeutic IgG for use in low-effector-activity format that exhibits increased stability.

A novel CC-chemokine receptor 3 antagonist, Ki19003, inhibits airway eosinophilia and subepithelial/peribronchial fibrosis induced by repeated antigen challenge in mice.

CC-chemokine receptor 3 (CCR3) is a chemokine receptor for which major ligands, CC-chemokine ligand (CCL) 11, CCL24, and CCL26, are known to be involved in chemotaxis for eosinophils. In the present study, we evaluated the effect of a low molecular weight CCR3-receptor antagonist, Ki19003 (4-[[5-(2,4-dichlorobenzylureido)pentyl][1-(4-chlorophenyl)ethyl]amino]butanoic acid), on airway remodeling in a mouse model of allergic asthma. BALB/c mice were sensitized twice by intraperitoneal injection of ovalbumin (OA) and exposed daily to 1% OA for 3 weeks. Twenty-four hours after the final antigen challenge, bronchoalveolar lavage and histological examinations were carried out. Ki19003 clearly inhibited antigen-induced increase in the number of eosinophils in bronchoalveolar lavage fluid (BALF), but did not affect the number of other cell types examined in this study. Ki19003 also inhibited the increased production of transforming growth factor-beta1 in BALF and the amount of hydroxyproline in the lungs in a dose-dependent manner. Furthermore, Ki19003 significantly attenuated allergen-induced subepithelial and peribronchial fibrosis. These findings indicate that CCR3 antagonism prevents not only the infiltration of eosinophils into the airways but also the development of allergen-induced subepithelial and peribronchial fibrosis. Therefore, a CCR3 antagonist may be useful in the treatment of airway remodeling, especially subepithelial and peribronchial fibrosis, in allergic asthma.

Analysis of clonality and HPV infection in benign, hyperplastic, premalignant, and malignant lesions of the vulvar mucosa.

To elucidate the pathogenesis of vulvar carcinomas, we studied clonality and human papillomavirus (HPV) infection in vulvar epithelial diseases. Monoclonal composition was demonstrated in all 9 invasive tumors (squamous cell carcinoma [SCC], 6; basal cell carcinoma, 1; malignant melanoma, 2), 15 of 20 cases of vulvar intraepithelial neoplasia (VIN), 7 of 9 cases of Paget disease, 2 of 6 cases of lichen sclerosus (LS), and 2 of 3 cases of squamous cell hyperplasia (SCH); high-risk type HPV was revealed in 5 of 6 SCCs and 17 of 20 VINs. These observations might imply that a subset of cases of LS and SCH result from a neoplastic proliferation, similar to VINs but not related to infection with high-risk type HPV. In 1 case of SCC with concurrent VIN 3 in an adjacent lesion, both lesions showed the same pattern of X chromosome inactivation and the presence of HPV-16 in episomal and integrated forms, suggesting that monoclonal expansion triggered by high-risk type HPV integration is an early event for carcinogenesis of HPV-associated SCC.

Portal thrombosis due to intrahepatic cholangiocarcinoma following successful treatment for hepatocellular carcinoma.

A 57-year-old man, who had undergone hepatic arterial infusion chemotherapy with right portal occlusion for hepatocellular carcinoma was admitted to our hospital because of severe abdominal pain. Contrast-enhanced computed tomograms revealed that most areas of the liver were not enhanced, a finding suspicious for perfusion disturbance in the liver. Angiography revealed an interrupted right hepatic artery. Arterial portograms revealed complete obstruction of the right portal vein and a small left branch of the portal vein. Despite anticoagulant therapy with urokinase for portal vein thrombosis, the patient died from hepatorenal failure. Autopsy revealed that cholangiocarcinoma occupied almost the entire parenchyma of the right lobe, although the treated hepatocellular carcinoma lesion was completely necrotic. The right hepatic artery was obstructed due to direct invasion of tumor. There were diffuse thrombi in the left portal branches surrounded by tumor infiltrating along Glisson's sheath to the peripheral portion of the left lobe.

Comparison of growth hormone-producing and non-growth hormone-producing pituitary adenomas: imaging characteristics and pathologic correlation.

PURPOSE: To identify characteristic features of growth hormone (GH)-producing pituitary adenomas. MATERIALS AND METHODS: A total of 174 pathologically proven pituitary adenomas were evaluated retrospectively on magnetic resonance (MR) images to determine the signal intensity (on T2-weighted images), maximum diameter, and amount of suprasellar and infrasellar extension. For microadenomas, sellar depth was also measured. GH-producing adenomas were classified at histologic evaluation as densely or sparsely granulated. Specimens from 38 adenomas were stained to assess the amounts of fibrous tissue, iron, and amyloid they contained. Results were correlated with the size and hormonal activity of adenomas by using the chi2, unpaired t, and Mann-Whitney U tests. RESULTS: Among 174 pituitary adenomas, 42 were GH-producing adenomas. Of these, 16 were densely granulated, and 24 were sparsely granulated (two histologic specimens were lost). Signal intensity was evaluated among 153 adenomas. On T2-weighted MR images, hypointensity was seen more commonly in adenomas that produced GH (16 of 40 cases [40%]; P <.001) than in those that did not; hypointensity was nearly exclusive to densely granulated GH-producing adenomas. The amounts of amyloid, fibrous tissue, and iron contained in adenomas demonstrated little relationship with signal intensity. Average suprasellar extension was significantly smaller in adenomas that produced GH (-0.8 mm) than in those that did not (5.3 mm) (P <.001). GH-producing adenomas tended to demonstrate infrasellar extension rather than suprasellar extension. Average sellar depth associated with GH-producing microadenomas (13.3 mm) was significantly greater than for non-GH-producing microadenomas (9.7 mm; P <.001). CONCLUSION: Characteristic features regarding growth direction and T2 signal intensity can be identified for GH-producing adenomas.

Well-differentiated papillary mesothelioma in the pelvic cavity. A case report.

BACKGROUND: Well-differentiated papillary mesothelioma (WDPM) is considered to be a distinct subtype of peritoneal mesothelioma. It occurs in the peritoneum, is most commonly seen in young women and is found incidentally at laparotomy for other indications. Clinically, WDPM is considered to be benign or to have low malignancy potential. CASE: A 48-year-old female with no history of asbestos exposure presented with hypermenorrhea. An operation was performed for adenomyosis, and six papillary nodules, 2 cm or less, were found in the serosa of the pelvic cavity. Peritoneal lavage fluid and imprint material from the tumor were obtained for cytologic examination. The cytologic specimens showed many scattered cells and sheetlike clusters and some papillary clusters. These cells had abundant, polygonal, cyanophilic cytoplasm; clearly outlined borders; and slitlike intercellular spaces. The cell arrangement was orderly. The nuclei were uniform in size, with a single centrally located nucleolus, and there were no binucleated forms or mitosis. There was no increase in chromatin. On the luminal surface of the cells, a brush border was observed. CONCLUSION: It is important to differentiate WDPM from diffuse malignant mesothelioma or other peritoneal malignant tumors to avoid treating them as malignant tumors.

Cytologic diagnosis of estrogen and progesterone receptors in breast imprints.

OBJECTIVE: To investigate estrogen receptor (ER) and progesterone receptor (PR) levels in imprint specimens obtained at breast surgery and to compare their correlation with that of standard methods. STUDY DESIGN: Imprint specimens for cytology were obtained from 101 mass-forming lesions in 66 patients, and specimens were frozen in liquid nitrogen for later assay. The imprint specimens were immunocytochemically (ICC) stained by monoclonal antibody to ER or PR; diaminobenzidine-stained cell nuclei in clusters were regarded as positive. Tissue specimens were assayed by the standard method of dextran-coated charcoal assay (DCC) and enzyme immunoassay. RESULTS: Forty-five primary breast cancer lesions, 2 contralateral breast cancer, 49 dissected nodes and 5 benign breast lesions were collected. The correlation between DCC and ICC was 81% (82/101) for ER and 74% (66/101) for PR. That between EIA and ICC was 88% (88/99) for ER and 80% (79/100) for PR, higher than that between DCC and ICC for ER and PR. CONCLUSION: ICC assessment of ER or PR on imprint cytology is a promising clinical test with an acceptable correlation.

Transcervical needle biopsy for the differential diagnosis between uterine sarcoma and leiomyoma.

BACKGROUND: The clinical differential diagnosis between uterine sarcoma and benign leiomyoma is difficult even with magnetic resonance imaging (MRI). Therefore, a considerable number of patients have undergone hysterectomies due to an indication of "suspected malignancy" based on tumor size alone. However, approximately 80% of these hysterectomies have been judged to have been recommended inappropriately. In such situations, reliable preoperative diagnostic tests are required. The authors have evaluated the accuracy of needle biopsy for uterine myoma-like tumors, a procedure that to the authors' knowledge has been performed infrequently. METHODS: Transcervical needle biopsy was performed in 435 patients with uterine myoma-like tumors. The biopsy specimens were scored for degree of malignancy according to the histopathologic criteria proposed by Bell et al. Histopathologic evaluation of surgical specimens and clinical outcome after 2 years of follow-up were used as the reference standards. RESULTS: Of 435 patients, 7 had uterine sarcomas, 4 of which were scored as > or = 4 points and were diagnosed as "sarcoma" by needle biopsy alone. No sarcoma cases were included in the group of patients with a score of 0. The cutoff score combining the highest sensitivity and specificity with respect to distinguishing uterine leiomyosarcoma from uterine leiomyoma was 2; sensitivity, specificity, and positive and negative predictive values were 100%, 98.6%, 58%, and 100.0%, respectively. CONCLUSIONS: Transcervical needle biopsy using histopathologic scoring is a reliable diagnostic test for the differential diagnosis between uterine sarcoma and leiomyoma. This diagnostic method, combined with MRI screening, could reduce the number of patients currently undergoing unnecessary surgery.

Quiste ciliado cutáneo en la mejilla de unvarón / Cutaneous ciliated cyst on the cheek in a male

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