s34_ab13

T and NK cell subset changes with microbial extracts and human HSP60-derived peptides in Behçet's disease

A. Kibaroglu¹, E. Eksioglu-Demiralp¹, T. Akoglu¹, H. Direskeneli²

Departments of ¹Hematology-Immunology and ²Rheumatology, Marmara University Medical School, Istanbul, Turkey.

ABSTRACT
Objective
Microorganisms such as streptococcus and autoantigens such as 60 kD heat-shock protein (HSP60) are implicated in the etiopathogenesis of Behçet's disease (BD).

Methods
Peripheral blood mononuclear cells from patients with BD (n = 16) and healthy controls (HC) (n = 11) were cultured for 5 days with extracts of S. sanguis-KTH-1 (SS), E. coli (EC) and a mixed peptide combination from human HSP60 (aa 136-50, 179-97, 224-58 and 336-51) reported to be associated with BD. T and NK cell subset changes were determined by flow cytometry.

Results
In unstimulated 5-day cultures gd+ (both CD4+gd+ and CD8+gd+), CD8+ab+, CD4+CD56+ and CD8+CD- 11b+ cells were increased in BD compared to HC. In antigen-stimulated cultures of BD patients CD3+ and ab+ T cells responded to HSP60 peptides whereas EC stimulated only CD16/ CD56+ NK cells. In the control group, similar to BD, ab+ and CD4+ T cells responded to HSP60 peptides, however SS and EC mainly activated cytotoxic T cell subsets (CD8+CD11b and CD4+-CD56+ T cells).

Conclusion
Significant increases in unstimulated T cell subsets suggest the presence of an in vivo T cell activation in BD. In both patients and controls similar patterns of responses were observed against different microorganisms, however the role of human HSP60 peptides as immunodominant, cross-reactive antigens could not be demonstrated.

Key words
Behçet's disease, streptococcus, Escherichia coli, human HSP60.

This study was supported by the Turkish Scientific and Technical Research Council (TUBITAK, SBAG-1844).
Please address correspondence to: H. Direskeneli, MD, Department of Rheumatology, Marmara University Medical School Hospital, Tophanelioglu Cad. 13/15, 81190 Altunizade, Istanbul, Turkey.
E-mail: direskeneli@superonline.com