Difference in CD22 molecules in human B cells and basophils

OBJECTIVE: CD22 is believed to be restricted to normal and neoplastic B cells. Human basophils were found to express CD22 molecules. Among the antibodies against CD22, Leu14, which recognized the ligand binding domain, reacted to basophils, and B3 and 4KB128, which recognized the amino terminus side and carboxy terminus side of the ligand binding epitope, respectively, did not. To clarify the difference of CD22 antigenicity in human B cells and basophils, we investigated RNA sequence and structures of CD22 molecules. MATERIALS AND METHODS: Purified B cells and basophils were obtained from normal human volunteers by using a MACS magnetic cell sorting system and anti-CD19 and anti-Fc epsilon R1 antibodies, respectively. RT-PCR and sequencing of CD22 mRNA were performed in the exons 3 to 8. Western blotting analysis of CD22 was also performed. RESULTS: The sequence of CD22 mRNA extracted from the basophils was the same as that of B cells in exons 3 to 8 (epitopes recognized by Leu14, B3, and 4KB128 were translated from exons 4 and 5). Reduced CD22 peptide extracted from the basophils reacted to Leu14 as well as B3 and 4KB128, and the molecular size of the reduced and nonreduced products was 130 kDa as expected. CONCLUSION: Disulfide bonds and the resulting 3D conformation of the CD22 molecules may have important roles in the difference of antigenicity of CD22 beta in B cells (CD22 beta 1) and basophils (CD22 beta 2). The difference in molecular structure surrounding the ligand-binding domain of CD22 may imply a specialization of the conformational forms of CD22 according to the ligand isoforms.     

Fenofibrate,a peroxisome proliferator-activated receptor alpha activator,suppresses experimental autoimmune myocarditis by stimulating the interleukin-10 pathway in rats

Experimental autoimmune myocarditis (EAM) in rats is an animal model of human giant cell myocarditis and postmyocarditis dilated cardiomyopathy. As the heart consumes large amounts of energy, heart diseases such as myocarditis and dilated cardiomyopathy are associated with abnormal fatty acid metabolism. Peroxisome proliferator-activated receptor alpha (PPARalpha) is a regulator of the oxidative degradation of fatty acids. To investigate the role of PPARalpha in EAM, fenofibrate (a PPARalpha activator) was administered to rats with EAM for 4 weeks. Reductions in the ratios of both ventricular weight to body weight and the area of inflammatory lesions to the total area of heart sections were observed in fenofibrate-treated rats when compared with controls. Fenofibrate ameliorated changes in serum albumin and sialic acid, which are markers of inflammation. Cardiac expression of interleukin-10 (IL-10) mRNA was more pronounced in the fenofibrate group than in the control group (1.3 +/- 0.2 vs 0.7 +/- 0.1; p < 0.01), and the area of intact myocardium correlated with the IL-10 mRNA level (p = 0.0297, r = 0.620). We suggest that PPARalpha activators may prevent the progression of myocarditis through increased expression of the gene encoding the anti-inflammatory cytokine IL-10, although the mechanisms involved remain to be determined.     

Electron microscopic identification of histidine decarboxylase-containing endocrine cells of the rat gastric mucosa. An immunohistochemical analysis

The localization of histidine decarboxylase-like immunoreactive structures in the mucosal cells of the rat stomach was studied by the peroxidase-antiperoxidase method. At the light microscopic level, histidine decarboxylase-like immunoreactivity-containing cells were concentrated in the basal part of the oxyntic region, whereas in other areas no immunoreactive cells were seen. Ultrastructural study showed that reaction end products were diffusely distributed within the cytoplasm of the enterochromaffinlike cells but other cell types such as A cells, G cells, and enterochromaffin cells were not labeled. These findings suggest that enterochromaffinlike cells synthesize histamine.     

Identification of simultaneous mutation of fibrinogen alpha chain and protein C genes in a Japanese kindred

Afibrinogenaemia usually induces a bleeding tendency during infancy, whereas protein C deficiency increases susceptibility to thrombosis in children or adolescence. Mutations of these genes have been, therefore, established as independent risk factors for coagulation disorders. We describe the homozygous mutation of the fibrinogen alpha chain gene and additional heterozygous mutation of the protein C gene in a male infant who showed prolonged umbilical bleeding after birth. On examination, the plasma fibrinogen was undetectable, and the activity and antigen level of protein C were reduced. The patient showed no fibrinogen Aalpha chain as well as Bbeta and gamma chains by Western blotting. The sequencing analysis showed the homozygous deletion of 1238 bases from intron 3 at position 2008 to intron 4 at position 3245 in the fibrinogen alpha chain gene. Both parents were heterozygous carriers of this mutation. In this patient, an additional mutation was also detected in the protein C gene: the heterozygous deletion of exon 7 at position 6161-6163 or 6164-6166, resulting the deletion of one amino acid (Lys150 or 151). His mother was also a carrier of this mutation. As the simultaneous mutation of the fibrinogen alpha chain and protein C genes has not been previously reported, the influence of the interaction between these two mutations on the clinical manifestations of this patient should be carefully monitored for a long period.     

Novel serum tumor marker, RCAS1, in pancreatic diseases

AIM: As tumor markers for pancreatic carcinoma, carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 have been used, but the sensitivity and specificity are not enough for the diagnosis of pancreatic carcinoma. METHODS: A novel serum tumor marker, RCAS1, was compared with two conventional serum tumor markers, CEA (highly specific for pancreatic cancer) and CA 19-9 (highly sensitive for pancreatic cancer), in 48 patients with pancreatic exocrine tumors. RESULTS: When the diagnosis of benign or malignant conditions was examined by one tumor marker, the sensitivity of RCAS1 alone (55%) was higher than that of CEA alone (27%) and the specificity of RCAS1 alone (92%) was greater than that of CA19-9 alone (78%). When examined by a combination of two markers, the sensitivity of a combination of RCAS1 and CA19-9 (95%) was superior to those of CA19-9 alone (78%), RCAS1 alone (55%, P = 0.002), CEA alone (27%) (P<0.001), RCAS1 and CEA (59%) and CA19-9 and CEA (82%). CONCLUSION: These results suggest that the combination of RCAS1 and CA19-9 is highly sensitive for pancreatic carcinoma.     

Autoimmune pancreatitis successfully treated with ursodeoxycholic acid

A 51-year-old woman with autoimmune pancreatitis is reported in whom treatment with ursodeoxycholic acid (UDCA) was beneficial. Complaining of epigastric discomfort, she presented with liver dysfunction of the cholestatic type, and diabetes mellitus. Pancreatic imaging revealed a diffuse swelling of the body, an irregular narrowing of the main pancreatic duct, and a terminal stricture of the common bile duct. Histologically, the biopsied pancreas was replaced by fibrous tissue with a small amount of mononuclear cell infiltration. She had anti-carbonic anhydrase-II antibody and anti-lactoferrin antibody. After treatment with UDCA, her liver dysfunction and diabetes mellitus improved and the pancreas size was reduced. Steroid therapy is usually indicated for this disorder, but UDCA may be given as an alternative choice.