title: Antigen-specific T-cell activation in hyperplastic thymus in myasthenia gravis.
abstract: In order to determine whether antigen-specific T-cell activation by dendritic cells (DCs) is accelerated in thymuses exhibiting lymphofollicular hyperplasia (TLFH) among patients with early-onset myasthenia gravis (EOMG), we investigated the expression levels of phosphorylated protein kinase C (PKC)theta and the local relationship between the presence of phosphorylated PKCtheta and the homing receptor CD44 or CD83, a marker for mature DCs, in samples taken from EOMG patients with early improvement following thymectomy, in remnant thymuses from late-onset MG patients, and in non-MG control thymuses. Antigen-specific T-cell activation was markedly accelerated in TLFH from EOMG patients. Activated T cells and adjacent DCs appeared to be components of a CD44(high) cell population circulating from the blood to the thymus. Although there is no convincing evidence that thymectomy is of benefit in MG, in some EOMG patients with early improvement following thymectomy, blockade of CD44-associated circulation mechanisms is probably the cause for the early benefits of thymectomy and is a potential alternative to thymectomy.
authors.affiliation: Department of Neurology, Hanamaki General Hospital, Kajoh-chou 4-28, Hanamaki 025-0075, Japan. kutsugi@s4.dion.ne.jp
authors.forename: Kimiaki
authors.initials: K
authors.lastname: Utsugisawa
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Nagane
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Suzuki
authors.forename: Ryushi
authors.initials: R
authors.lastname: Kondoh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000276:immunology; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D007136:Immunoglobulins / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000150:complications* / Q000276:immunology / Q000473:pathology*; D011493:Protein Kinase C / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D013934:Thymectomy; D013952:Thymus Hyperplasia / Q000209:etiology* / Q000276:immunology / Q000473:pathology* / Q000601:surgery; D000097802:CD83 Antigen; D000099221:Protein Kinase C zeta
chemical_list: D015703:Antigens, CD; D018960:Hyaluronan Receptors; D007136:Immunoglobulins; D008562:Membrane Glycoproteins; D011493:Protein Kinase C; D000097802:CD83 Antigen; D000099221:Protein Kinase C zeta