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Effect of natalizumab treatment on circulating plasmacytoid dendritic cells: a cross-sectional observational study in patients with multiple sclerosis.

Kivisäkk P, Francois K, Mbianda J, Gandhi R, Weiner HL, Khoury SJ - PLoS ONE (2014)

Bottom Line: We observed that NTZ treatment was associated with a 25-50% reduction in PDC frequency in peripheral blood as compared to untreated MS patients, while the frequency of MDCs was unchanged.In contrast, in vitro treatment with NTZ did not increase markers of PDC activation or their ability to induce T cell differentiation.Our study shows that NTZ treatment is associated with a reduced frequency of PDCs in the peripheral circulation, but that PDCs in NTZ-treated individuals display an activated phenotype.

View Article: PubMed Central - PubMed

Affiliation: Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.

ABSTRACT

Objectives: Dendritic cells (DCs) serve a critical role both in promoting and inhibiting adaptive immunity. The goal of this study was to investigate the effect of natalizumab (NTZ) treatment on DC numbers, phenotype, and function in patients with multiple sclerosis (MS).

Methods: Frequency and phenotype of myeloid and plasmacytoid DCs (MDCs and PDCs, respectively) were analyzed in blood from two separate cohorts of untreated, interferon-treated, or NTZ-treated MS patients. In addition, PDCs were stimulated with CpG-containing oligonucleotides or co-cultured with homologous T cells in the presence or absence of NTZ in vitro to determine functional effects of NTZ treatment.

Results: We observed that NTZ treatment was associated with a 25-50% reduction in PDC frequency in peripheral blood as compared to untreated MS patients, while the frequency of MDCs was unchanged. PDCs in NTZ-treated patients displayed a mature, activated phenotype with increased expression of HLA-DR, TLR9, CCR7, IL-6 and IL-12. In contrast, in vitro treatment with NTZ did not increase markers of PDC activation or their ability to induce T cell differentiation.

Conclusion: Our study shows that NTZ treatment is associated with a reduced frequency of PDCs in the peripheral circulation, but that PDCs in NTZ-treated individuals display an activated phenotype. Taken together the data suggests that transmigration of activated PDCs is preferentially affected by blockade of integrin α4 leading to an increased frequency of activated PDCs in blood.

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Phenotype and cytokine expression of plasmacytoid dendritic cells.Frequency of plasmacytoid dendritic cells (PDCs) expressing TLR9 (A), HLA-DR (B), and CCR7 (C) in peripheral blood from untreated MS patients (UNT) and MS patients treated with natalizumab (NTZ) or interferon-β (IFN) determined using flow cytometry. Representative histograms showing TLR9 (D) and HLA-DR (E), staining on PDCs from an UNT (blue open) and a NTZ-treated (red filled) patient. Flow plots showing CCR7 staining on CD49dhi and CD49dlow PDCs from an UNT (F) and a NTZ-treated (G) patient. Expression of IL-6 (H) and IL-12 (p35) (I) mRNA in PDCs isolated from the patients described in A-C using FACS sorting and rt-PCR without ex-vivo stimulation. Graph shows mean, interquartile range, and min-max range (A–C) or mean and SD (H–I).
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pone-0103716-g003: Phenotype and cytokine expression of plasmacytoid dendritic cells.Frequency of plasmacytoid dendritic cells (PDCs) expressing TLR9 (A), HLA-DR (B), and CCR7 (C) in peripheral blood from untreated MS patients (UNT) and MS patients treated with natalizumab (NTZ) or interferon-β (IFN) determined using flow cytometry. Representative histograms showing TLR9 (D) and HLA-DR (E), staining on PDCs from an UNT (blue open) and a NTZ-treated (red filled) patient. Flow plots showing CCR7 staining on CD49dhi and CD49dlow PDCs from an UNT (F) and a NTZ-treated (G) patient. Expression of IL-6 (H) and IL-12 (p35) (I) mRNA in PDCs isolated from the patients described in A-C using FACS sorting and rt-PCR without ex-vivo stimulation. Graph shows mean, interquartile range, and min-max range (A–C) or mean and SD (H–I).

Mentions: PDCs from NTZ-treated patients expressed higher levels of HLA-DR, CCR7 and Toll-like receptor-9 (TLR9), three markers associated with cellular activation, maturation and trafficking abilities in PDCs, compared to untreated patients (Fig. 3A–G), while the expression of the anti-apoptotic Bcl-2 and Bcl-xL were comparable in the two groups (data not shown). PDCs isolated directly ex vivo using FACS sorting of blood from NTZ-treated patients expressed significantly higher levels of IL-6 and IL-12 (p35) mRNA compared to PDCs isolated from untreated patients (Fig. 3H–I), while we observed no differences in the expression of IL-1β, IL-10, IL-23, IL-27 or TGF-β mRNA (data not shown). We did not observe any changes in the expression of these markers in PDCs from IFN-β treated patients (Fig. 2, 3); neither was NTZ- or IFN-β treatment associated with changes in the surface phenotype or cytokine expression in MDCs (data not shown).


Effect of natalizumab treatment on circulating plasmacytoid dendritic cells: a cross-sectional observational study in patients with multiple sclerosis.

Kivisäkk P, Francois K, Mbianda J, Gandhi R, Weiner HL, Khoury SJ - PLoS ONE (2014)

Phenotype and cytokine expression of plasmacytoid dendritic cells.Frequency of plasmacytoid dendritic cells (PDCs) expressing TLR9 (A), HLA-DR (B), and CCR7 (C) in peripheral blood from untreated MS patients (UNT) and MS patients treated with natalizumab (NTZ) or interferon-β (IFN) determined using flow cytometry. Representative histograms showing TLR9 (D) and HLA-DR (E), staining on PDCs from an UNT (blue open) and a NTZ-treated (red filled) patient. Flow plots showing CCR7 staining on CD49dhi and CD49dlow PDCs from an UNT (F) and a NTZ-treated (G) patient. Expression of IL-6 (H) and IL-12 (p35) (I) mRNA in PDCs isolated from the patients described in A-C using FACS sorting and rt-PCR without ex-vivo stimulation. Graph shows mean, interquartile range, and min-max range (A–C) or mean and SD (H–I).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4116240&req=5

pone-0103716-g003: Phenotype and cytokine expression of plasmacytoid dendritic cells.Frequency of plasmacytoid dendritic cells (PDCs) expressing TLR9 (A), HLA-DR (B), and CCR7 (C) in peripheral blood from untreated MS patients (UNT) and MS patients treated with natalizumab (NTZ) or interferon-β (IFN) determined using flow cytometry. Representative histograms showing TLR9 (D) and HLA-DR (E), staining on PDCs from an UNT (blue open) and a NTZ-treated (red filled) patient. Flow plots showing CCR7 staining on CD49dhi and CD49dlow PDCs from an UNT (F) and a NTZ-treated (G) patient. Expression of IL-6 (H) and IL-12 (p35) (I) mRNA in PDCs isolated from the patients described in A-C using FACS sorting and rt-PCR without ex-vivo stimulation. Graph shows mean, interquartile range, and min-max range (A–C) or mean and SD (H–I).
Mentions: PDCs from NTZ-treated patients expressed higher levels of HLA-DR, CCR7 and Toll-like receptor-9 (TLR9), three markers associated with cellular activation, maturation and trafficking abilities in PDCs, compared to untreated patients (Fig. 3A–G), while the expression of the anti-apoptotic Bcl-2 and Bcl-xL were comparable in the two groups (data not shown). PDCs isolated directly ex vivo using FACS sorting of blood from NTZ-treated patients expressed significantly higher levels of IL-6 and IL-12 (p35) mRNA compared to PDCs isolated from untreated patients (Fig. 3H–I), while we observed no differences in the expression of IL-1β, IL-10, IL-23, IL-27 or TGF-β mRNA (data not shown). We did not observe any changes in the expression of these markers in PDCs from IFN-β treated patients (Fig. 2, 3); neither was NTZ- or IFN-β treatment associated with changes in the surface phenotype or cytokine expression in MDCs (data not shown).

Bottom Line: We observed that NTZ treatment was associated with a 25-50% reduction in PDC frequency in peripheral blood as compared to untreated MS patients, while the frequency of MDCs was unchanged.In contrast, in vitro treatment with NTZ did not increase markers of PDC activation or their ability to induce T cell differentiation.Our study shows that NTZ treatment is associated with a reduced frequency of PDCs in the peripheral circulation, but that PDCs in NTZ-treated individuals display an activated phenotype.

View Article: PubMed Central - PubMed

Affiliation: Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.

ABSTRACT

Objectives: Dendritic cells (DCs) serve a critical role both in promoting and inhibiting adaptive immunity. The goal of this study was to investigate the effect of natalizumab (NTZ) treatment on DC numbers, phenotype, and function in patients with multiple sclerosis (MS).

Methods: Frequency and phenotype of myeloid and plasmacytoid DCs (MDCs and PDCs, respectively) were analyzed in blood from two separate cohorts of untreated, interferon-treated, or NTZ-treated MS patients. In addition, PDCs were stimulated with CpG-containing oligonucleotides or co-cultured with homologous T cells in the presence or absence of NTZ in vitro to determine functional effects of NTZ treatment.

Results: We observed that NTZ treatment was associated with a 25-50% reduction in PDC frequency in peripheral blood as compared to untreated MS patients, while the frequency of MDCs was unchanged. PDCs in NTZ-treated patients displayed a mature, activated phenotype with increased expression of HLA-DR, TLR9, CCR7, IL-6 and IL-12. In contrast, in vitro treatment with NTZ did not increase markers of PDC activation or their ability to induce T cell differentiation.

Conclusion: Our study shows that NTZ treatment is associated with a reduced frequency of PDCs in the peripheral circulation, but that PDCs in NTZ-treated individuals display an activated phenotype. Taken together the data suggests that transmigration of activated PDCs is preferentially affected by blockade of integrin α4 leading to an increased frequency of activated PDCs in blood.

Show MeSH
Related in: MedlinePlus