Monocytes from systemic lupus erythematous patients are severely altered in phenotype and lineage flexibility - PubMed (original) (raw)

Monocytes from systemic lupus erythematous patients are severely altered in phenotype and lineage flexibility

F Steinbach et al. Ann Rheum Dis. 2000 Apr.

Abstract

Objective: Cells of the myeloid lineage comprise a very heterogeneous population with many phenotypes and functional activities including macrophages and dendritic cells. To investigate the status, differentiative potential and lineage commitment of monocytic cells in systemic lupus erythematosus (SLE) patients, this study isolated and cultured peripheral blood monocytes from patients and healthy donors.

Methods: Monocytes were isolated by gradient centrifugation and adherence to plastic dishes. The cells were then cultured for three days, partially supplemented with GM-CSF and interleukin 4 (IL4) to obtain dendritic cells. The differentiation status was monitored by the expression of surface markers using flow cytometry and cytokine secretion.

Results: Monocytes from SLE patients expressed significantly lower numbers of the monocytic marker CD14 and HLA-DR while secreting significantly more tumour necrosis factor alpha (TNFalpha) than monocytes from healthy donors. The addition of GM-CSF and IL4 resulted in an inhibition of TNFalpha secretion, but was not sufficient to generate monocytederived dendritic cells.

Conclusion: Monocytes from SLE patients are severely altered in phenotype and function and have a limited differentiation flexibility towards the accessory type of monocytic cells.

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Figures

Figure 1

Representative examples of surface markers on monocytes from three patients with active SLE. Monocytes from healthy donors (control) showed an almost homogenous staining for CD14 (strong) and HLA-DR (weak). Monocytes from SLE patients showed various amounts of positive cells. In many cases, more cells were HLA-DR+ than CD14+ (see patient 1), but the expression of the two markers did not correlate. Cells expressed myeloid markers such as CD33, but the activation marker CD71 was also detected. The cells were analysed after scattergram gating of monocytic cells. Controls and patients did not react with isotype controls of irrelevant specificities. Control labelling revealed <15% of contaminating lymphocytes or neutrophils.

Figure 2

Cytokine secretion by monocytes from healthy donors (control) and SLE patients. Cytokine secretion was measured 24 hours after cell isolation. One group of SLE monocytes was supplemented with GM-CSF and IL4. Individual data and medians are presented.

Figure 3

Differentiation of monocytes after treatment with GM-CSF and IL4. At day 3, monocytes from healthy donors were CD1a+/CD14low/HLA-DR++, therefore representing monocyte derived dendritic cells. In contrast, monocytes from SLE patients were CD1a-/CD14+/HLA-DR++. This patient was representative for the six patients analysed. The differences in CD1 and CD14 expression were highly significant (both p=0.0007). Flow cytometric analysis was performed as in figure 1, isotype controls not shown.

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Monocytes from systemic lupus erythematous patients are severely altered in phenotype and lineage flexibility - PubMed (original) (raw)