s34_ab9

The level of soluble Granzyme A is elevated in the plasma and in the Vg 9/Vd2 T cell culture supernatants of patients with active Behçet's disease

A. Accardo-Palumbo^1,3, A. Ferrante¹, M. Cadelo¹, F. Ciccia¹, G. Parrinello², L. Lipari¹, A.R. Giardina¹, M. Riili¹, E. Giardina¹, F. Dieli³, G. Triolo¹

¹Section of Rheumatology and Clinical Immunology and ²Section of Internal Medicine Department of Internal Medicine; and ³Section of General Pathology, Department of Biopathology, University of Palermo, Italy.

ABSTRACT
Objective
Gramzyme A (GrA) is a serine proteinase with trypsin-like activity that is released extracellularly during the degranulation of cytotoxic cells. Among the cytotoxic cells, g/d T cells participate in the early phases of the immune response and are known to express perforin and granzymes constitutively in agreement with their cytolytic pontential.

Methods
GrA activity was detected using the synthetic substrate N-a-benzyloxycarbonyl-L-lysine thiobenzyl ester in the plasma and supernatants of peripheral blood mononuclear cell cultured in the presence of Dimethylallyl pyrophosphate to obtain Vg9/Vd2 T cell expansion.

Results
Significantly high levels of GrA were found in the serum and supernatants of lymphocytes from patients with active Behçet's disease cultured in the presence of DMAPP. Levels were found to be significantly lower after remission. A positive correlation was observed between GrA levels in the supernatants and the Vg9/Vd2 T cell expansion factor.

Conclusion
These results strongly suggest that Vg9/Vd2 T cells are active participants in the pathogenesis of the disease through their degranulation and granzyme release.

Key words
Granzyme A, Vg9/Vd2 T cell, Behçet's disease.

Supported in part by a grant from the Ministero della Istruzione, della Universitá e della Ricerca (MIUR). Angelo Ferrante is a PhD student and recipient of a fellow-ship from MIUR.
Please address correspondence and reprint requests to: Prof. Giovanni Triolo, Cattedra di Reumatologia, Dipartimento Biomedico di Medicina Interna e Specialistica, Istituto di Clinica Medica, Policlinico Universitario, Piazza Cliniche 2, 90127 Palermo, Italy.
E-mail: triolog@tiscalinet.it