Expression of OX40 and OX40 ligand (gp34) in the normal and myasthenic thymus

• Published in: Acta neurologica Scandinavica Vol. 102; no. 4; pp. 236 - 243
• Main Authors: Onodera, J., Nagata, T., Fujihara, K., Ohuchi, M., Ishii, N., Sugamura, K., Itoyama, Y.
• Format: Journal Article
• Language: English
• Published: Copenhagen Munksgaard International Publishers 01.10.2000; Blackwell
• Subjects: Adolescent; Adult; Antibodies, Monoclonal - metabolism; Antigens, CD - metabolism; Biological and medical sciences; Cerebral Cortex - metabolism; Diseases of striated muscles. Neuromuscular diseases; Female; Flow Cytometry; flowcytometry; gp34; HLA-DR Antigens - metabolism; Humans; immunocytochemistry; Ligands; Male; Medical sciences; Medulla Oblongata - metabolism; Middle Aged; myasthenia gravis; Myasthenia Gravis - genetics; Myasthenia Gravis - metabolism; Neurology; OX40; OX40 ligand; Receptors, Tumor Necrosis Factor - genetics; Receptors, Tumor Necrosis Factor - metabolism; thymus; Thymus Gland - metabolism; Thymus Gland - pathology; Human; Pathology; Flow cytometry; Neuromuscular diseases; Nervous system diseases; Myasthenia gravis; Immunocytochemistry; Ligand; T-Lymphocyte; Exploration
• ISSN: 0001-6314; 1600-0404
• DOI: 10.1034/j.1600-0404.2000.102004236.x

Objectives– To examine the expression of OX40, an activated memory T‐cell marker, and its ligand (OX40L), a set of molecules for T‐cell–B‐cell interaction, and other lymphocyte activation markers in the thymuses of myasthenia gravis (MG) and controls. Material and methods– We studied the expression of OX40, OX40L, IL‐2Rα and HLA‐DR in the thymic tissues of MG and controls using immunocytochemistry and flowcytometry. Results– In both hyperplastic thymus of MG and control thymus, OX40+ cells were scattered mainly in the medulla with much fewer OX40L+ cells being distributed in the corticomedullary junctions. IL‐2Rα and HLA‐DR were expressed in the medulla at higher frequencies as compared with OX40 in controls as well as MG. In contrast, the numbers of OX40+ cells around the germinal centers (GC) were significantly greater than those of control thymuses, and some mononuclear cells in GC were OX40L+. A considerable number of OX40+ cells were seen in the thymic tissues adjacent to thymomas. OX40+ cells were CD4+CD8− or CD4+CD8+ and were mostly HLA‐DR−. (The coexpression of OX40 and IL‐2Rα on activated CD4+ T cells was previously reported.) Conclusion– OX40, expressed in a fraction of activated CD4+ T cells, may be upregulated in thymic tissues adjacent to GC and thymoma in MG, and OX40 may interact with OX40L in GC to enhance anti‐acetylcholine receptor antibody production in MG.