Serum glycylproline p-nitroanilidase activity in rheumatoid arthritis and systemic lupus erythematosus

Lowered Serum Dipeptidyl Peptidase IV Activity is Associated with Depressive Symptoms and Cytokine Production in Cancer Patients Receiving Interleukin-2-Based Immunotherapy

“…The results that the changes in serum DPP IV are inversely correlated to serum IL-6 and IL-2R suggest that serum DPP IV activity is sensitive to graded differences in IRS activation. These findings are in accordance with previous studies showing that lower serum DPP IV activity accompanies inflammatory disorders, such as rheumatoid arthritis, colitis ulcerosa, autoimmune chronic hepatitis, and systemic lupus erythematosus (Fujita et al 1978;De Meester 1992;De Meester et al 1993).…”

“…Conditions accompanied by activation of the IRS, such as inflammatory and autoimmune disorders (rheumatoid arthritis, autoimmune chronic hepatitis, and systemic lupus erythematosus (Fujita et al 1978;De Meester 1992;De Meester et al 1993) and major depression (Maes et al 1991;Elgun et al 1999) are characterized by lowered serum activity of dipeptidyl peptidase IV (DPP IV; EC 3.4.14.5). The ectoenzyme DPP IV is a membrane-bound serine protease that catalyses the cleavage of dipeptides from the amino-terminus of oligo-and polypeptides under definite structural conditions (De Meester 1992;De Meester et al 1999;HopsuHavu and Glenner 1966;Van Hoof et al 1992).…”

Decreased Dipeptidyl Peptidase IV Enzyme Activity of Plasma Soluble CD26 and Its Inverse Correlation with HIV-1 RNA in HIV-1 Infected Individuals

“…CD26 is present on various cell types, including T cells and epithelial cells of the liver, kidney, and intestine (33). DPPIV enzyme activity has been found in plasma, serum, and urine (34 -36) and levels in all these samples have been found to vary considerably with changes in immune status (37)(38)(39), in particular during autoimmune processes such as RA and SLE. However, the precise source and mechanism of the production of plasma sCD26/DPPIV remains unclear.…”

Streptokinase Promotes Development of Dipeptidyl Peptidase IV (CD26) Autoantibodies after Fibrinolytic Therapy in Myocardial Infarction Patients

“…In both RA and SLE there is a reduction in serum DPP IV activity (11,29,30,41). In a recent report (6), we demonstrated that reduction of serum DPP IV activity in RA patients was due to hypersialylation of the enzyme, whereas in SLE patients a similar reduction in activity was possibly the result of increased clearance of DPP IV from circulation due to the high titers of circulating anti-DPP IV autoantibodies of the immunoglobulin A (IgA) class (6).…”