Reduced Circulating Natural Killer T Cells and γ/δ T Cells in Patients with Systemic Sclerosis

VALERIA RICCIERI, GILBERTO PARISI, ANTONIO SPADARO, ROSSANA SCRIVO, FRANCESCA BARONE, TIZIANA MORETTI, GRAZIELLA BERNARDINI, ROBERTO STROM, EGISTO TACCARI, and GUIDO VALESINI

ABSTRACT.

Objective. To evaluate peripheral blood mononuclear cells (PBMC) expressing natural killer (NK) cell surface markers (CD16 and CD56, in both CD3– and CD3+ cells) and g/d T cell receptors (TCR) involved in non-MHC-restricted cytotoxicity, assessing their possible relationship with clinical and laboratory variables in patients with systemic sclerosis (SSc).

Methods. We submitted 50 patients with SSc to detailed clinical and laboratory assessment, and also performed PBMC subset analyses by direct dual immunofluorescence and flow cytometry.

Results. No statistically significant differences were found in the percentages or the absolute numbers of total lymphocytes, of B cells, and of CD4+ T cells. The absolute number of CD8+ cells was lower (p < 0.03), while HLA-DR+ elements were higher in frequency (p < 0.03) in SSc patients than in healthy controls. SSc patients had lower values (both percentage and absolute number) of NK-T cells (p < 0.01 and p < 0.003, respectively) and of T cells expressing g/d TCR (p < 0.01 and p < 0.005, respectively); whereas NK cells were marginally but not significantly decreased. The absolute number of NK-T cells showed an inverse correlation to erythrocyte sedimentation rate values (p < 0.03; r_s = –0.306), percentage of g-globulins (p < 0.01; r_s = –0.353), and serum concentrations of IgG (p < 0.02; r_s = –0.334).

Conclusion. Impairment of NK-T cells and of T cells expressing g/d TCR may lead to downregulation of normal immune response, and seems to be important for immunological and inflammatory aspects of SSc. (J Rheumatol 2005;32:283-6)

Key Indexing Terms:

SYSTEMIC SCLEROSIS
NON-MHC-RESTRICTED CYTOTOXICITY
NATURAL KILLER CELLS
T CELLS
g/d T CELLS

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From the Dipartimento di Clinica e Terapia Medica Applicata, Cattedra di Reumatologia; and the Dipartimento di Biotecnologie Cellulari ed Ematologia, Università degli Studi di Roma "La Sapienza," Rome, Italy.

V. Riccieri, MD; G. Parisi, MD; A. Spadaro, MD; R. Scrivo, MD; F. Barone, MD; E. Taccari, MD; G. Valesini, MD, Dipartimento di Clinica e Terapia Medica Applicata; T. Moretti, PhD; G. Bernardini, PhD; R. Strom, MD, Dipartimento di Biotecnologie Cellulari ed Ematologia.

Address reprint requests to Dr. V. Riccieri, Divisione di Reumatologia, Dipartimento di Clinica e Terapia Medica Applicate, Università degli Studi di Roma "La Sapienza," Policlinico Umberto I, 00161 Rome, Italy. E-mail: valeria.riccieri@uniroma1.it

Submitted January 15, 2004; revision accepted September 22, 2004.

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