Volume 7 Supplement 1

25th European Workshop for Rheumatology Research

Open Access

Expression of programmed death (PD)-1 and PD-1 ligands (PD-L1, PD-L2) in peripheral blood mononuclear cells of patients with systemic lupus erythematosus

  • G Bertsias1,
  • A Raptopoulou1,
  • E Coutala1,
  • M Mamoulaki1,
  • H Kritikos1,
  • P Sidiropoulos1 and
  • DT Boumpas1
Arthritis Research & Therapy20057(Suppl 1):P153

DOI: 10.1186/ar1674

Received: 11 January 2005

Published: 17 February 2005

Background

Programmed death (PD)-1 is a newly described member of the immunoglobulin super-family that is expressed on activated T lymphocytes and B lymphocytes. Engagement of PD-1 with its specific ligands, PD-L1 (B7-H1) and PD-L2 (B7-DC), inhibits lymphocyte proliferation and cytokine expression, and may play a role in peripheral tolerance and negative regulation of T-cell and B-cell responses in vivo. We sought to investigate the expression profiles of PD-1 and PD-1 ligands in peripheral blood cells of patients with systemic lupus erythematosus (SLE).

Materials and methods

Blood was drawn from patients with SLE (n = 16), rheumatoid arthritis (n = 16), other inflammatory disease (n = 4), and healthy controls (n = 9). Peripheral blood mononuclear cells were separated on a ficoll-density gradient, and flow cytometry analysis was performed using monoclonal antibodies against CD3, CD19, CD14, CD25, CD69, PD-1, PD-L1, and PD-L2.

Results

See Table 1.

Table 1

 

Disease group

 

Healthy controls

Systemic lupus erythematosus

Rheumatoid arthritis

Inflammatory disease

 

Mean

SEM

Mean

SEM

Mean

SEM

Mean

SEM

PD-1+ (%)

        

   in CD3+

0.6

0.2

0.4

0.1

1.6

0.6

0.5

0.1

   in CD19+

1.7

0.9

1.4

0.3

0.9

0.4

1.1

0.4

   in CD25+

3.0

1.0

2.4

0.7

3.3

1.6

8.5

3.4

PD-L1+ (%)

        

   in CD3+

2.8

1.2

4.1

0.9

2.3

0.5

2.0

0.6

   in CD19+

3.9

1.3

5.1

0.9

3.7

1.0

11.3

8.0

   in CD14+

5.1

2.0

14.0

5.4

2.9

0.9

5.7

3.2

PD-L2+ (%)

        

   in CD3+

0.6

0.2

0.5

0.1

0.5

0.2

0.4

0.0

   in CD14+

2.0

0.5

1.4

0.3

1.1

0.5

1.2

0.1

SEM, standard error of the mean. No statistically significant differences were observed.

Conclusions

In this preliminary report, SLE patients showed a trend for lower expression of PD-1 and higher expression of PD-L1 in unstimulated peripheral blood mononuclear cells compared with other disease controls. These results corroborate findings linking SLE with polymorphism of the PD-1 gene resulting in putative altered expression of the PD-L2 [1]. Lower expression of PD-1 in SLE lymphocytes could be related to ineffective suppression of autoreactive lymphocytes and thus to disease evolution. Currently, we investigate expression of PD-1 and its ligands on subpopulations of lymphocytes (CD45RO+, CD27+), as well as the kinetics of expression upon stimulation.

Authors’ Affiliations

(1)
Department of Rheumatology, Clinical Immunology and Allergy, Medical School, University of Crete

References

  1. Prokunina L, Castillejo-Lopez C, Oberg F, Gunnarsson I, Berg L, Magnusson V, et al: A regulatory polymorphism in PDCD1 is associated with susceptibility to systemic lupus erythematosus in humans. Nat Genet. 2002, 32: 666-669. 10.1038/ng1020.View ArticlePubMedGoogle Scholar

Copyright

© BioMed Central Ltd 2005

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