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- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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2. |
- Stockfelt, Marit, et al.
(author)
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Plasma interferon-alpha protein levels during pregnancy are associated with lower birth weight in systemic lupus erythematosus.
- 2024
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In: Rheumatology (Oxford, England). - 1462-0332.
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Journal article (peer-reviewed)abstract
- Adverse pregnancy outcomes are more common in women with systemic lupus erythematosus (SLE) compared with healthy women, but we lack prognostic biomarkers. Plasma interferon alpha (IFNα) protein levels are elevated in a subgroup of pregnant women with SLE, but whether this is associated with pregnancy outcomes is unknown. We investigated the relationship between IFNα, adverse pregnancy outcomes and the presence of autoantibodies in SLE pregnancy.We followed 76 women with SLE prospectively. Protein levels of IFNα were quantified in plasma collected in the 2nd and 3rd trimester with single-molecule array. Positivity for antinuclear and antiphospholipid antibodies was assessed during late pregnancy with multiplexed bead assay. Clinical outcomes included the adverse pregnancy outcomes small for gestational age (SGA), preterm birth, and preeclampsia.During SLE pregnancy, women with SGA infants compared with those without had higher levels of plasma IFNα protein, and IFNα positivity was associated with lower birth weight of the infant. Preterm birth was associated with autoantibodies against chromatin. IFNα protein levels associated positively with autoantibodies against chromatin, Smith/ribonucleoprotein (SmRNP) and RNP, but negatively with phospholipid antibodies.Elevated IFNα protein in plasma of women with SLE is a potential risk factor for lower birth weight of their infants. The association between IFNα and lower birth weight warrants further investigation regarding the pathophysiological role of IFNα during SLE pregnancy.
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3. |
- Stockfelt, Marit, et al.
(author)
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Plasma interferon-alpha protein levels during pregnancy are associated with lower birth weight in systemic lupus erythematosus
- 2024
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In: Rheumatology. - : OXFORD UNIV PRESS. - 1462-0324 .- 1462-0332.
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Journal article (peer-reviewed)abstract
- Objectives Adverse pregnancy outcomes are more common in women with SLE compared with healthy women, but we lack prognostic biomarkers. Plasma IFN-alpha protein levels are elevated in a subgroup of pregnant women with SLE, but whether this is associated with pregnancy outcomes is unknown. We investigated the relationship between IFN-alpha, adverse pregnancy outcomes and the presence of autoantibodies in SLE pregnancy.Methods We followed 76 women with SLE prospectively. Protein levels of IFN-alpha were quantified in plasma collected in the second and third trimester with single-molecule array. Positivity for ANA and aPL antibodies was assessed during late pregnancy with multiplexed bead assay. Clinical outcomes included the adverse pregnancy outcomes small for gestational age (SGA), preterm birth and preeclampsia.Results During SLE pregnancy, women with SGA infants compared with those without had higher levels of plasma IFN-alpha protein, and IFN-alpha positivity was associated with lower birth weight of the infant. Preterm birth was associated with autoantibodies against chromatin. IFN-alpha protein levels associated positively with autoantibodies against chromatin, Smith/RNP (SmRNP) and RNP, but negatively with aPL antibodies.Conclusion Elevated IFN-alpha protein in plasma of women with SLE is a potential risk factor for lower birth weight of their infants. The association between IFN-alpha and lower birth weight warrants further investigation regarding the pathophysiological role of IFN-alpha during SLE pregnancy. Graphical Abstract
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4. |
- Torell, Agnes, 1993, et al.
(author)
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Low CD4+T cell count is related to specific anti-nuclear antibodies, IFNα protein positivity and disease activity in systemic lupus erythematosus pregnancy.
- 2024
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In: Arthritis research & therapy. - : BioMed Central (BMC). - 1478-6362 .- 1478-6354. ; 26:1
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Journal article (peer-reviewed)abstract
- Lymphopenia, autoantibodies and activation of the type I interferon (IFN) system are common features in systemic lupus erythematosus (SLE). We speculate whether lymphocyte subset counts are affected by pregnancy and if they relate to autoantibody profiles and/or IFNα protein in SLE pregnancy.Repeated blood samples were collected during pregnancy from 80 women with SLE and 51 healthy controls (HC). Late postpartum samples were obtained from 19 of the women with SLE. Counts of CD4+and CD8+T cells, B cells and NK cells were measured by flow cytometry. Positivity for anti-nuclear antibodies (ANA) fine specificities (double-stranded DNA [dsDNA], Smith [Sm], ribonucleoprotein [RNP], chromatin, Sjögren's syndrome antigen A [SSA] and B [SSB]) and anti-phospholipid antibodies (cardiolipin [CL] and β2 glycoprotein I [β2GPI]) was assessed with multiplexed bead assay. IFNα protein concentration was quantified with Single molecule array (Simoa) immune assay. Clinical data were retrieved from medical records.Women with SLE had lower counts of all lymphocyte subsets compared to HC throughout pregnancy, but counts did not differ during pregnancy compared to postpartum. Principal component analysis revealed that low lymphocyte subset counts differentially related to autoantibody profiles, cluster one (anti-dsDNA/anti-Sm/anti-RNP/anti-Sm/RNP/anti-chromatin), cluster two (anti-SSA/anti-SSB) and cluster three (anti-CL/anti-β2GPI), IFNα protein levels and disease activity. CD4+T cell counts were lower in women positive to all ANA fine specificities in cluster one compared to those who were negative, and B cell numbers were lower in women positive for anti-dsDNA and anti-Sm compared to negative women. Moreover, CD4+T cell and B cell counts were lower in women with moderate/high compared to no/low disease activity, and CD4+T cell count was lower in IFNα protein positive relative to negative women. Finally, CD4+T cell count was unrelated to treatment.Lymphocyte subset counts are lower in SLE compared to healthy pregnancies, which seems to be a feature of the disease per se and not affected by pregnancy. Our results also indicate that low lymphocyte subset counts relate differentially to autoantibody profiles, IFNα protein levels and disease activity, which could be due to divergent disease pathways.
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5. |
- Torell, Agnes, 1993, et al.
(author)
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Low-density granulocytes are related to shorter pregnancy duration but not to interferon alpha protein blood levels in systemic lupus erythematosus.
- 2023
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In: Arthritis research & therapy. - : BMC. - 1478-6362 .- 1478-6354. ; 25
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Journal article (peer-reviewed)abstract
- An increased risk of pregnancy complications is seen in women with systemic lupus erythematosus (SLE), but the specific immunopathological drivers are still unclear. Hallmarks of SLE are granulocyte activation, type I interferon (IFN) overproduction, and autoantibodies. Here we examined whether low-density granulocytes (LDG) and granulocyte activation increase during pregnancy, and related the results to IFNα protein levels, autoantibody profile, and gestational age at birth.Repeated blood samples were collected during pregnancy in trimesters one, two, and three from 69 women with SLE and 27 healthy pregnant women (HC). Nineteen of the SLE women were also sampled late postpartum. LDG proportions and granulocyte activation (CD62L shedding) were measured by flow cytometry. Plasma IFNα protein concentrations were quantified by single molecule array (Simoa) immune assay. Clinical data were obtained from medical records.Women with SLE had higher LDG proportions and increased IFNα protein levels compared to HC throughout pregnancy, but neither LDG fractions nor IFNα levels differed during pregnancy compared to postpartum in SLE. Granulocyte activation status was higher in SLE relative to HC pregnancies, and it was increased during pregnancy compared to after pregnancy in SLE. Higher LDG proportions in SLE were associated with antiphospholipid positivity but not to IFNα protein levels. Finally, higher LDG proportions in trimester three correlated independently with lower gestational age at birth in SLE.Our results suggest that SLE pregnancy results in increased peripheral granulocyte priming, and that higher LDG proportions late in pregnancy are related to shorter pregnancy duration but not to IFNα blood levels in SLE.
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