Evaluation of flow cytometry for cell count and detection of bacteria in biological fluids.

The analysis of biological fluids is crucial for the diagnosis and monitoring of diseases causing effusions and helps in the diagnosis of infectious diseases. The gold standard method for cell count in biological fluids is the manual method using counting chambers. The microbiological routine procedures consist of Direct Gram staining and culture on solid or liquid media. We evaluate the analytical performance of SYSMEX UF4000 (Sysmex, Kobe, Japan) and Sysmex XN10 (Sysmex, Kobe, Japan) in comparison with cytological and microbiological routine procedures. A total of 526 biological fluid samples were included in this study (42 ascitic, 31 pleural, 31 peritoneal, 125 cerebrospinal, 281 synovial, and 16 peritoneal dialysis fluids). All samples were analysed by flow cytometry and subsequently processed following cytological and/or microbiological routine procedures. With regards to cell counts, UF4000 (Sysmex, Kobe, Japan) showed a performance which was at least equivalent to those of the reference methods and superior to those of XN10 (Sysmex, Kobe, Japan). Moreover, the bacterial count obtained with UF4000 (Sysmex, Kobe, Japan) was significantly higher among culture or Direct Gram stain positive samples. We established 3 optimal cut-off points to predict Direct Gram stain positive samples for peritoneal (465.0 bacteria/µL), synovial (1200.0 bacteria/µL), and cerebrospinal fluids (17.2 bacteria/µL) with maximum sensitivity and negative predictive values. Cell count and detection of bacteria by flow cytometry could be used upstream cytological and microbiological routine procedures to improve and accelerate the diagnosis of infection of biological fluid samples.

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Effects of season, milking routine and cow cleanliness on bacterial and somatic cell counts of bulk tank milk

Journal of Dairy Research ◽

10.1017/s0022029911000598 ◽

2011 ◽

Vol 78 (4) ◽

pp. 436-441 ◽

Cited By ~ 27

Author(s):

Maddalena Zucali ◽

Luciana Bava ◽

Alberto Tamburini ◽

Milena Brasca ◽

Laura Vanoni ◽

...

Keyword(s):

Somatic Cell ◽

Cell Count ◽

Somatic Cell Count ◽

Bacterial Count ◽

Cold Season ◽

Plate Count ◽

Bulk Tank Milk ◽

Somatic Cell Counts ◽

Cell Counts ◽

Bulk Tank

The aim of the study was to investigate the effects of season, cow cleanliness and milking routine on bacterial and somatic cell counts of bulk tank milk. A total of 22 dairy farms in Lombardy (Italy) were visited three times in a year in different seasons. During each visit, samples of bulk tank milk were taken for bacterial and somatic cell counts; swabs from the teat surface of a group of cows were collected after teat cleaning and before milking. Cow cleanliness was assessed by scoring udder, flanks and legs of all milking cows using a 4-point scale system. Season affected cow cleanliness with a significantly higher percentage of non-clean (NC) cows during Cold compared with Mild season. Standard plate count (SPC), laboratory pasteurization count (LPC), coliform count (CC) and somatic cell count, expressed as linear score (LS), in milk significantly increased in Hot compared with Cold season. Coagulase-positive staphylococci on teat swabs showed higher counts in Cold season in comparison with the other ones. The effect of cow cleanliness was significant for SPC, psychrotrophic bacterial count (PBC), CC and Escherichia coli in bulk tank milk. Somatic cell count showed a relationship with udder hygiene score. Milking operation routine strongly affected bacterial counts and LS of bulk tank milk: farms that accomplished a comprehensive milking scheme including two or more operations among forestripping, pre-dipping and post-dipping had lower teat contamination and lower milk SPC, PBC, LPC, CC and LS than farms that did not carry out any operation.

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Persistent Sputum Cellularity and Neutrophils May Predict Bronchiectasis

Canadian Respiratory Journal ◽

10.1155/2011/920465 ◽

2011 ◽

Vol 18 (4) ◽

pp. 221-224 ◽

Cited By ~ 7

Author(s):

Nicole Drost ◽

Liesel D’silva ◽

Ryan Rebello ◽

Ann Efthimiadis ◽

Frederick E Hargreave ◽

...

Keyword(s):

Cell Count ◽

Roc Curves ◽

Total Cell ◽

Total Cell Count ◽

High Resolution Computed Tomography ◽

Predictive Values ◽

Retrospective Survey ◽

Cell Counts ◽

Airway Diseases ◽

Computed Tomography Scans

BACKGROUND: Quantitative cell counts in sputum provide an accurate assessment of the type and severity of bronchitis.OBJECTIVE: To examine whether sputum cell counts could identify bronchiectasis in patients with recurrent bronchitis.METHODS: A retrospective survey of a clinical database (January 2004 to January 2005) of quantitative cell counts from sputum selected from expectorate in patients with obstructive airways diseases was used to identify predictors of bronchiectasis using ROC curves. This was prospectively evaluated (February 2005 to April 2008) using high-resolution computed tomography scans of thorax that were independently scored by a radiologist who was blinded to the clinical details.RESULTS: The retrospective survey identified 41 patients with bronchiectasis among 490 patients with airway diseases. Total cell count of 60×106/g or greater of the selected sputum with predominant neutrophils on two occasions had a sensitivity of 86.7%, a specificity of 87.5%, and positive and negative predictive values of 93% and 78%, respectively, to identify bronchiectasis. In the prospective study, 10 of 14 (71%) patients who met these criteria were identified to have bronchiectasis. Both total cell count and the percentage of neutrophils correlated with radiographic bronchiectasis severity.CONCLUSIONS: Persistent or recurrent intense sputum cellularity with neutrophilia is suggestive of bronchiectasis.

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Treatment Free Survival of Patients with MBL and Early CLL: Follow-up of 405 Patients at Mayo Clinic.

Blood ◽

10.1182/blood.v112.11.2063.2063 ◽

2008 ◽

Vol 112 (11) ◽

pp. 2063-2063

Author(s):

Tait Shanafelt ◽

Neil E. Kay ◽

Kari Rabe ◽

Timothy G. Call ◽

Clive S. Zent ◽

...

Keyword(s):

Flow Cytometry ◽

Natural History ◽

B Cell ◽

Cell Count ◽

Mayo Clinic ◽

Lymphocytic Leukemia ◽

Peripheral Blood Flow ◽

Time To Treatment ◽

Cell Counts

Abstract BACKGROUND: The diagnosis of monoclonal B-cell lymphocytosis (MBL) is used to characterize patients who have a circulating population of clonal B-cells, a total B-cell count of <5 x 109/L, and no other features of another B-cell lymphoproliferative disorder. In most patients the immunophenotype is similar to that of chronic lymphocytic leukemia with co-expression of CD19 and CD5. The natural history of CLL-phenotype MBL is unclear. We used the Mayo Clinic hematopathology database to identify patients with CLL-phenotype MBL and abstracted clinical information on natural history and prognostic parameters from clinical and research records. METHODS: Using hematopathology records, we identified a cohort of 1820 patients seen at Mayo Clinic between August 1998 and May 2006 who underwent investigation using peripheral blood flow cytometry and who were found to have a clonal B-cell population of CLL phenotype. After elimination of patients with advanced stage (Rai I-IV), previously treated CLL, and individuals with an established diagnosis of CLL/MBL >1 year prior to flow, 636 unique patients with isolated lymphocytosis were identified. Based on our prior analysis (Leukemia Research 32:1458) demonstrating that nearly all patients with an ALC >10x109/L have a B-cell count >5x109/L, we focused the remaining analysis on the 405/636 patients who had an ALC <10x109/L and the necessary raw data from flow cytometry analysis to determine the B-cell count. RESULTS: Among the 405 individuals with an ALC <10x109/L, 306 (76%) had a B-cell count <5x109/L at the time of flow and met the current criteria for the diagnosis of MBL (BJH 130:325). Median age at the time of MBL diagnosis was 70 years (range 34 – 93). A slight male preponderance was observed (59% male). B-cell counts ranged from 0.02 to 4.99x109/L and ALC ranged from 0.3–9.6 x109/L. CD38 status was available for 268 (88%) MBL patients of whom 20% were CD38 positive using the 30% threshold. Cytogenetic analysis by fluorescent in situ hybridization (FISH) was available in 130 (42%) MBL patients. Using the hierarchical classification system of Dohner and colleagues, 57 (44%) were 13q-, 23 (18%) were trisomy 12, 5 (4%) were 11q-, 4 (3%) were 17p-, and 39 (30%) had no defect detected. ZAP-70 status was available for 77 (25%) patients of whom 13% were ZAP-70+ positive. Patients underwent sequential monitoring with a median follow-up of 1.7 yrs (range 0–8.1 yrs). Time from diagnosis to treatment for patients meeting criteria for MBL (n=306) as compared to Rai stage 0 CLL patients with B-cell counts between 5.0 and 10.0 x109/L (n=99) was not significantly different and is shown in Figure 1 (p=0.87). For individuals with MBL, survival free of treatment was 98% (95%CI: 96–100%) at 1 year, 93% (95%CI: 89–98%) at 2 years, and 77% (95%CI: 67–89%) at 5 years. While gender (p=0.10), and B-cell count as a continuous variable (p=0.15) were not found to be associated with time to treatment (TTT) among MBL patients, age (p=0.02, HR=0.94, 95% CI: 0.89–0.99) and CD38 status (p<0.02, HR: 3.3, 95% CI: 1.2–9.2) did show a relationship with TTT. CONCLUSIONS: Although we observed a low rate of progression among individuals meeting criteria for MBL, TFS was similar to individuals meeting current criteria for Rai stage 0 CLL who had B-cell counts between 5.0 – 10.0 x109/L . Among individuals meeting criteria for MBL, younger patients and those who were CD38 positive had a shorter time to treatment. Additional studies are needed to determine what B-cell count or other characteristics should be used to distinguish between MBL and Rai stage 0 CLL. FIGURE: FIGURE:.

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Monoclonal B-Cell Lymphocytosis (MBL) in Blood Donors: Age- and Sex-Specific Prevalence, Clone Size, and IGHV-IGHD-IGHJ Rearrangements

Blood ◽

10.1182/blood.v118.21.2840.2840 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2840-2840

Author(s):

Youn K. Shim ◽

Jane Rachel ◽

Paolo Ghia ◽

Jeff Boren ◽

Antonis Dagklis ◽

...

Keyword(s):

Risk Factors ◽

Flow Cytometry ◽

B Cells ◽

B Cell ◽

Cell Count ◽

Blood Donors ◽

Prevalence Ratio ◽

Age Group ◽

Cell Counts ◽

Donated Blood

Abstract Abstract 2840 Recent studies using sensitive flow cytometry methods have reported up to 14% MBL prevalence among older adults. Although MBL has been detected in donated blood, a systematic study of MBL prevalence in blood donors is lacking. We initiated the first such study, using high sensitivity immunophenotyping and ensuring exclusion of repeat donors. Here we report results from the first ten months. Starting in May 2010, samples from 1090 blood donors over 44 years old were collected at a regional U.S. blood center. Samples were immunophenotyped by flow cytometry with a six-color antibody cocktail (CD19, CD20, CD5, CD45 and κ/λ immunoglobulin light chains). At least 500, 000 events were collected on a FACS Canto II flow cytometer. Histograms were examined for phenotypic patterns consistent with B cell clonality. Samples were classified as MBL when at least 50 clonal B cells were detected. MBL immunophenotypes were categorized into typical chronic lymphocytic leukemia (CLL)-like, atypical CLL-like, or non-CLL-like (CD5 negative). Samples from MBL cases underwent PCR amplification, and IGHV- IGHD- IGHJ gene rearrangements were sequenced when possible. The overall MBL prevalence (Table 1) was 7.7% (84/1090). The sex-specific prevalence was 4.2% in women and 10.2% in men. The prevalence increased with increasing age for men. In women the prevalence increased sharply from the 45–54 age group to the 55–64 age group. The prevalence in the >64 age group of women appeared to drop, but this estimate is unreliable due to the small number of observations. Multivariate log-binomial regression modeling showed that male sex and increasing age are independent risk factors for MBL: the age-adjusted prevalence ratio for sex (men/women) was 2.3 (95%CI 1.4–3.7; p=0.001), while the sex-adjusted prevalence ratio for age group 65 and older compared to the youngest age group (45–54) was 2.1 (95%CI 1.2–3.7; p=0.006). The median absolute B-cell count was comparable in blood donors with and without MBL (167/μl vs. 160/μl). The clonal B-cell count in donors with MBL was low (median 11/μl, 10th-90th percentiles 1–122). However, the clonal count was much higher (median 333/μl, 10th-90th percentiles 90–2887) in the subset of MBL donors in whom more than 80% of the B-cells were clonal. Moreover, the clonal B-cell counts in atypical CLL-like and non-CLL-like MBL were higher (median 37/μl, n=31) than in typical CLL-like MBL (median 4/μl, n=53) (p=0.0002). Of the 84 MBL cases, 82 were PCR-amplified and examined for monoclonal bands reflecting IGHV-IGHD-IGHJ rearrangement. In the 29 samples where monoclonal banding was detected, the median clonal count was 40/μl, while it was only 8/μl in 53 samples where no monoclonal banding was detected. Of the 29 samples with monoclonal banding, 19 were heavily mutated (<97% germline), 6 minimally mutated (97–99%), and 4 unmutated (100%); 21 (72%) were IGHV3, and the remaining 8 (28%) were IGHV4 (Figure 1). CLL-related IGHV genes were uncommon. This study has so far revealed a much higher prevalence of MBL in donated blood than previously reported. The majority of MBL in this population are mutated, CLL-like, low count MBL, which has also been seen in residential population studies. These findings suggest that MBL in donated blood typically represents indolent MBL rather than clinical MBL. However, the biology of MBL is still being elucidated. Given the reported association (Castillo et al, Blood 2010) between red blood cell transfusions and non-Hodgkin lymphoma (particularly the aggregate category CLL/SLL), our findings underscore the need to ascertain long-term outcomes in recipients of blood from MBL donors. In addition, these results will be important in interpreting findings from other studies of MBL prevalence and risk factors. Disclosures: No relevant conflicts of interest to declare.

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Performance evaluation of automated cell counts compared with reference methods for body fluid analysis

Diagnosis ◽

10.1515/dx-2021-0088 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Michela Seghezzi ◽

Giulia Previtali ◽

Valentina Moioli ◽

Maria Grazia Alessio ◽

Giovanni Guerra ◽

...

Keyword(s):

Cell Count ◽

Body Fluid ◽

Mononuclear Cells ◽

Area Under The Curve ◽

Roc Curves ◽

Polymorphonuclear Cells ◽

Roc Curve Analysis ◽

Gold Standard Method ◽

Cellular Analysis ◽

Cell Counts

Abstract Objectives Cellular analysis of body fluids (BFs) can assist clinicians for the diagnosis of many medical conditions. The aim of this work is the evaluation of the analytical performance of the UF-5000 body fluid mode (UF-BF) analyzer compared to the gold standard method (optical microscopy, OM) and to XN-1000 (XN-BF), another analyzer produced by the same manufacturer (Sysmex) and with a similar technology for BF analysis. Methods One hundred BF samples collected in K3EDTA tubes were analyzed by UF-BF, XN-BF and OM. The agreement was evaluated using Passing and Bablok regression and Bland–Altman plot analysis. The receiver operating characteristic (ROC) curves were selected for evaluating the diagnostic agreement between OM classification and UF-BF parameters. Results Comparison between UF-BF and OM, in all BF types, showed Passing and Bablok’s slope comprised between 0.99 (polymorphonuclear cells count, PMN-BF) and 1.39 (mononuclear cells count, MN-BF), the intercepts ranged between 26.47 (PMN-BF parameter) and 226.80 (white blood cell count). Bland–Altman bias was comprised between 7.3% (total cell count, TC-BF) and 52.9% (MN-BF). Comparison between UF-BF and XN-BF in all BF showed slopes ranged between 1.07 (TC-BF and PMN-BF) and 1.16 (MN-BF), intercepts ranged between 8.30 (PMN) and 64.78 (WBC-BF). Bland–Altman bias ranged between 5.8 (TC-BF) and 21.1% (MN-BF). The ROC curve analysis showed an area under the curve ranged between 0.9664 and 1.000. Conclusions UF-BF shows very good performance for the differential counts of cells in ascitic, pleural and synovial fluids and therefore it is useful to screen and count cells in this type of BF.

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A quantitative evaluation of some factors affecting the non-fatty solids of cow's milk

Journal of Dairy Research ◽

10.1017/s0022029900010086 ◽

1960 ◽

Vol 27 (1) ◽

pp. 19-32 ◽

Cited By ~ 5

Author(s):

W. H. Alexander ◽

F. B. Leech

Keyword(s):

Cell Count ◽

Residual Effect ◽

Clinical Mastitis ◽

High Cell ◽

Factors Affecting ◽

Stage Of Lactation ◽

Cell Counts ◽

Satisfactory Analysis ◽

The Difference ◽

Image Position

SummaryTen farms in the county of Durham took part in a field study of the effects of feeding and of udder disease on the level of non-fatty solids (s.n.f.) in milk. Statistical analysis of the resulting data showed that age, pregnancy, season of the year, and total cell count affected the percentage of s.n.f. and that these effects were additive and independent of each other. No effect associated with nutritional changes could be demonstrated.The principal effects of the factors, each one freed from effects of other factors, were as follows:Herds in which s.n.f. had been consistently low over a period of years were compared with herds in which s.n.f. had been satisfactory. Analysis of the data showed that about 70% of the difference in s.n.f. between these groups could be accounted for by differences in age of cow, stage of lactation, cell count and breed.There was some evidence of a residual effect following clinical mastitis that could not be accounted for by residual high cell counts.The within-cow regression of s.n.f. on log cell count calculated from the Durham data and from van Rensburg's data was on both occasions negative.The implications of these findings are discussed, particularly in relation to advisory work.

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Frequency of Cytomegalovirus Viral Load in Iranian Human Immunodeficiency Virus-1-Infected Patients with CD4+ Counts <100 Cells/mm3

Intervirology ◽

10.1159/000514385 ◽

2021 ◽

pp. 1-5

Author(s):

Mohammad Reza Jabbari ◽

Hoorieh Soleimanjahi ◽

Somayeh Shatizadeh Malekshahi ◽

Mohammad Gholami ◽

Leila Sadeghi ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Viral Load ◽

Cell Count ◽

Previous History ◽

Cd4 Count ◽

Cd4 Cell Count ◽

Cell Counts ◽

Immunodeficiency Virus ◽

Cd4 Cell ◽

Hiv 1

Objectives: The aim of present work was to assess cytomegalovirus (CMV) viremia in Iranian human immunodeficiency virus (HIV)-1-infected patients with a CD4+ count <100 cells/mm3 and to explore whether CMV DNA loads correlate with CD4+ cell counts or associated retinitis. Methods: This study was conducted at the AIDS research center in Iran on HIV-1-infected patients with CD4+ count <100 cells/mm3, antiretroviral therapy-naive, aged ≥18 years with no previous history of CMV end-organ disease (CMV-EOD). Results: Thirty-nine of 82 patients (47.56%) had detectable CMV viral load ranging from 66 to 485,500 IU/mL. CMV viral load in patients with retinitis ranges from 352 to 2,720 IU/mL, and it was undetectable in 2 patients. No significant associations between CMV viremia and CD4+ cell count was found (p value = 0.31), whereas significant association of CMV viremia in HIV-infected patients with retinitis was found (p < 0.02). Conclusions: We estimated the frequency of CMV viral load infection in Iranian HIV-1-infected patients with a CD4+ cell count <100 mm3/mL in the largest national referral center for HIV-1 infection in Iran. Further research is required on the relevance of CMV viral load in diagnostic and prognostic value of CMV-EOD.

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CD19 Cell Count at Baseline Predicts B Cell Repopulation at 6 and 12 Months in Multiple Sclerosis Patients Treated with Ocrelizumab

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18158163 ◽

2021 ◽

Vol 18 (15) ◽

pp. 8163

Author(s):

Gianmarco Abbadessa ◽

Giuseppina Miele ◽

Paola Cavalla ◽

Paola Valentino ◽

Girolama Alessandra Marfia ◽

...

Keyword(s):

B Cell ◽

Cell Count ◽

Considerable Proportion ◽

Cell Counts ◽

Time Scheduling ◽

Magnetic Resonance Imaging Mri ◽

Multiple Sclerosis Patients ◽

Kinetics Of ◽

Cell Repopulation

Background: The kinetics of B cell repopulation in MS patients treated with Ocrelizumab is highly variable, suggesting that a fixed dosage and time scheduling might be not optimal. We aimed to investigate whether B cell repopulation kinetics influences clinical and radiological outcomes and whether circulating immune asset at baseline affects B cell repopulation kinetics. Methods: 218 MS patients treated with Ocrelizumab were included. Every six months we collected data on clinical and magnetic resonance imaging (MRI) activity and lymphocyte subsets at baseline. According to B cell counts at six and twelve months, we identified two groups of patients, those with fast repopulation rate (FR) and those with slow repopulation rate (SR). Results: A significant reduction in clinical and radiological activity was found. One hundred fifty-five patients had complete data and received at least three treatment cycles (twelve-month follow-up). After six months, the FR patients were 41/155 (26.45%) and 10/41 (29.27%) remained non-depleted after twelve months. FR patients showed a significantly higher percentage of active MRI scan at twelve months (17.39% vs. 2.53%; p = 0,008). Furthermore, FR patients had a higher baseline B cell count compared to patients with an SR (p = 0.02 and p = 0.002, at the six- and twelve-month follow-ups, respectively). Conclusion: A considerable proportion of MS patients did not achieve a complete CD19 cell depletion and these patients had a higher baseline CD19 cell count. These findings, together with the higher MRI activity found in FR patients, suggest that the Ocrelizumab dosage could be tailored depending on CD19 cell counts at baseline in order to achieve complete disease control in all patients.

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Lymphocyte subset analysis to evaluate the prognosis of HIV-negative patients with pneumocystis pneumonia

BMC Infectious Diseases ◽

10.1186/s12879-021-06124-5 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Fan Jin ◽

Jing Xie ◽

Huan-ling Wang

Keyword(s):

T Cell ◽

Cell Count ◽

Lymphocyte Subsets ◽

Nk Cell ◽

Cd8 T Cell ◽

Pneumocystis Pneumonia ◽

Lymphocyte Subset ◽

Cd4 T Cell ◽

Cell Counts ◽

Hiv Negative

Abstract Objectives We analysed the peripheral blood lymphocyte subsets of human immunodeficiency virus (HIV)-negative patients infected with pneumocystis pneumonia (PCP) to determine the relationships between the levels of different types of lymphocytes and the prognosis of patients. Methods We retrospectively reviewed HIV-negative patients with PCP diagnosed in our department. All the eligible patients underwent lymphocyte subset analysis on admission. Results A total of 88 HIV-negative PCP patients were enrolled in the study. In univariate analyses, low CD4+ T cell count, low CD8+ T cell count, and low natural killer cell (NK cell) count were associated with higher in-hospital mortality. CD8+ T cell count ≤300/μL was found to be an independent risk factor for poor prognosis in multivariate logistical regression analysis (p = 0.015, OR = 11.526, 95% CI = 1.597–83.158). Although low CD4+ T cell and NK cell counts were not independent risk factors, the mortality rates of PCP patients decreased as the CD4+ T cell and NK cell counts increased. Conclusion The immune process of Pneumocystis jirovecii infection is complex but important. We propose that lymphocyte subsets could give clinicians a better understanding of patient immune status, helping with the early identification of potentially lethal infections and treatment decision making, such as adjusting the immunosuppressive regimen and choosing an appropriate patient monitoring level.

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FRI0015 PHENOTYPE AND FUNCTION OF THE PERIPHERAL BLOOD DENDRITIC CELLS OF PSORIASIS PATIENTS WITH AND WITHOUT ARTHRITIS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.4296 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 578.1-579

Author(s):

S. Schnitte ◽

A. Fuchs ◽

T. Funk ◽

A. C. Pecher ◽

D. Dörfel ◽

...

Keyword(s):

Risk Factors ◽

Flow Cytometry ◽

Dendritic Cells ◽

Psoriatic Arthritis ◽

T Lymphocytes ◽

Peripheral Blood ◽

Surface Proteins ◽

Research Support ◽

Cross Sectional ◽

Cell Counts

Background:Psoriasis is a frequent skin disease that can appear with an arthritic manifestation in approximately 30% of the cases [1]. The underlying excessive immune reaction caused by pro-inflammatory cytokines can be triggered by several risk factors [2]. Various subgroups of Dendritic cells (DCs) in the skin play a crucial role in the induction of the dermal inflammatory response [3].Objectives:As the role of peripheral blood DCs remains unknown and the cause of an arthritic manifestation is still not completely understood [4], this project aimed to detect differences in phenotype or function of peripheral blood DCs in psoriatic patients with or without arthritis.Methods:We analyzed peripheral blood cells of 60 psoriasis patients with and without arthritis. Different DC subpopulations were detected by flow cytometry. Monocyte-derived DCs were cultured with or without Lipopolysaccharides to gain immature (iDC) and mature (mDC) cells. The DC phenotype was determined by staining with CD80, CD83, CD86, CD206, CCR7, CD1a, HLA-DR, CD40, GPN-MB, DC209 and CD14. Their T-cell stimulatory capability was analyzed by co-incubation with Carboxyfluorescein succinimidyl ester stained lymphocytes and the quantification of CD4+ T-lymphocytes afterwards. To measure the migration capacity DCs were seated into transwell chambers with a semipermeable membrane and partly supplemented with Macrophage Inflammatory Protein 3 Beta (Mip3b). Migrated cells were detected by flow cytometry. Measured cell counts were normalized to cell counts without Mip3b stimulation.Results:Comparing the factor of increase of migrated mDC counts due to mip3b stimulation, we detected a significant lower rate in samples of patients with arthritis (PsA) compared to those of patients without (Ps). Assays of mDCs without mip3b stimulation showed a significant higher count of migrated cells in the samples of the arthritic group [Figure 1]. Cell counts with Mip3b stimulation did vary slightly in the groups. The DC subpopulations and the expression of analyzed cell surface proteins did not show significant differences. The amounts of stimulated T-Lymphocytes did not differ significantly.Figure 1.Migration essay showing mDCs following Mip3b (+miß3b) as multiples of mDCs without stimulation (-mip3b). The factor of increase is significantly lower in patients with arthritis (PsA) compared to patients without (Ps). Absolute counts of migrated mDCs without Mip3b are significantly higher in the arthritic group. Cell counts with stimulation do not differ significantly (data not shown). N=24, p<0.05Conclusion:CCL19 (Mip3b) is a potent ligand to the CCR7 receptor inducing migration of DCs towards the lymphatic node [5]. The CCR7 amounts on the DC surface did not differ significantly in the groups. The mDCs without CCL19 stimulation migrated in higher amounts in samples of arthritic patients. Cell counts of stimulated DCs showed only slight differences. These results could be generated by a different appearance of the DCs of arthritic patients that might facilitate migration. Further experiments focusing on this aspect should be performed. A possible effect of disruptive factors (age, sex, medication…) needs to be clarified.References:[1]Henes, J.C., et al.,High prevalence of psoriatic arthritis in dermatological patients with psoriasis: a cross-sectional study.Rheumatol Int, 2014.34(2): p. 227-34.[2]Lee, E.B., et al.,Psoriasis risk factors and triggers.Cutis, 2018.102(5s): p. 18-20.[3]Kim, T.G., S.H. Kim, and M.G. Lee,The Origin of Skin Dendritic Cell Network and Its Role in Psoriasis.Int J Mol Sci, 2017.19(1).[4]Veale, D.J. and U. Fearon,The pathogenesis of psoriatic arthritis.Lancet, 2018.391(10136): p. 2273-2284.[5]Ricart, B.G., et al.,Dendritic cells distinguish individual chemokine signals through CCR7 and CXCR4.J Immunol, 2011.186(1): p. 53-61.Acknowledgments:This project was financially supported by Novartis Pharma GmbH.Disclosure of Interests:Sarah Schnitte Grant/research support from: Reaserch grant by Novartis, Alexander Fuchs: None declared, Tanja Funk: None declared, Ann-Christin Pecher: None declared, Daniela Dörfel: None declared, Jörg Henes Grant/research support from: Novartis, Roche-Chugai, Consultant of: Novartis, Roche, Celgene, Pfizer, Abbvie, Sanofi, Boehringer-Ingelheim,

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