Detection of a soluble form of the leukocyte surface antigen CD48 in plasma and its elevation in patients with lymphoid leukemias and arthritis

• Published in: Journal of clinical immunology Vol. 17; no. 6; pp. 502 - 509
• Main Authors: SMITH, G. M, BIGGS, J, NORRIS, B, ANDERSON-STEWART, P, WARD, R
• Format: Journal Article
• Language: English
• Published: New York, NY Kluwer/Plenum 01.11.1997; Springer Nature B.V
• Subjects: Adult; Aged; Aged, 80 and over; Amino Acid Sequence; Animals; Antibodies, Monoclonal - immunology; Antigens, CD - analysis; Antigens, CD - blood; Antigens, CD - immunology; Antigens, Surface - blood; Arthritis - blood; Biological and medical sciences; CD48 Antigen; Cell Line; Female; Flow Cytometry; Hematologic and hematopoietic diseases; Herpesviridae Infections - immunology; Herpesviridae Infections - physiopathology; Herpesvirus 4, Human - immunology; Humans; Immunoassay; Leukemia, Lymphocytic, Chronic, B-Cell - blood; Leukemia, Lymphoid - blood; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Leukocytes - immunology; Leukocytes, Mononuclear - chemistry; Leukocytes, Mononuclear - cytology; Leukocytes, Mononuclear - immunology; Lymphoma, Non-Hodgkin - blood; Male; Medical sciences; Mice; Mice, Inbred BALB C; Mice, Inbred CBA; Mice, Nude; Middle Aged; Molecular Sequence Data; Sensitivity and Specificity; Human; Leukocyte; Diseases of the osteoarticular system; Hodgkin disease; Malignant hemopathy; Arthritis; Soluble form; Non Hodgkin lymphoma; Lymphoma; Cell surface; Antigen; Chronic lymphocytic leukemia; Lymphoproliferative syndrome; Serum
• ISSN: 0271-9142; 1573-2592
• DOI: 10.1023/A:1027327912204

Proteins with glycosylphosphatidylinositol (GPI) anchors exhibit a range of activities and some of these proteins exist in both a membrane-associated and a soluble form. CD48 is a 47-kd GPI-linked glycoprotein which is expressed on T and B lymphocytes, monocytes, and many lymphoid malignancies. The biological function of CD48 is unknown. We describe the detection of a soluble form of CD48 in plasma and serum. Its level was quantified by an immunoenzymometric assay (IEMA) specific for soluble CD48. While soluble CD48 was detected in the plasma of healthy individuals (median = 29 ng/ml; range, 15-48 ng/ml), elevated levels were detected in some patients with lymphoproliferative disease (median = 41 ng/ml; range, 9-213 ng/ml, arthritis (median = 42 ng/ml; range, 13-67 ng/ml), and acute EBV infection (174 ng/ml). Soluble CD48 was also detectable in tissue culture supernatants from the Raji lymphoid cell line. The mechanism of CD48 release from cells is unclear. The finding of significant levels of soluble CD48 in plasma and the development of a sensitive IEMA for its measurement will facilitate further studies on its normal function and its role in disease.