Lower Monocyte Research Articles

Cytotoxic activity of monocytes against Toxoplasma gondii in acute, chronic and reactivated murine toxoplasmosis.

The phagocytic activity and cytotoxicity of peripheral blood monocytes (against toxoplasma tachyzoites) was studied in acute, chronic and reactivated toxoplasma infected Swiss albino mice. During acute infection, a low phagocytic activity was observed on the 4th day post infection (dpi) (P less than 0.01) and a low monocyte cytotoxicity was noticed after the 2nd dpi (P less than 0.01) which further decreased till the 8th dpi. In contrast, both the parameters were significantly increased during chronic infection. Increase in monocytic cytotoxicity was manifested on the 3rd dpi (P less than 0.001) whereas phagocytosis showed an increase on the 12th dpi (P less than 0.05). The reactivated group showed no change in both the parameters when compared with the control immunosuppressed group (P greater than 0.05).

Cell density-dependent expression of chondroitin sulfate proteoglycan in cultured human monocytes.

Monocytes were isolated and established in vitro at different cell densities. The incorporation of [35S]sulfate into macromolecules in monocytes (day 1 in culture) and monocyte-derived macrophages (day 5 in culture) was found to increase with decreasing cell density in approximately the same way in both day 1 and day 5 cell cultures. [35S]Sulfate was found to be incorporated almost exclusively into chondroitin sulfate proteoglycan (CSPG) in both high and low density monocyte and monocyte-derived macrophage cultures. The molecular size of the [35S]CSPGs produced by the high and low cell density cultures were not found to differ as judged by gel chromatography elution patterns. The molecular size and the structure of the glycosaminoglycan chains were found to be almost similar in high and low density day 1 and day 5 cultures. Only a small degree of proteoglycan degradation could be observed in both high and low density cultures. Furthermore, cell density-dependent differences in CSPG biosynthesis could be observed already 2 h after the establishment of the cultures, indicating that a process of "down-regulation" in high density cultures was already in operation. The glycosaminoglycan synthesis in high cell density day 1 cultures could be increased slightly following exposure to 0.5 mM benzyl-beta-D-xyloside, but not to the same level as that observed in untreated low cell density cultures. By contrast, the expression of 35S-macromolecules by cells cultured at high cell density for 5 days could be increased by xyloside treatment almost to the same level as that observed in the low density cultures.

Prognostic features of chronic myelomonocytic leukaemia: a modified Bournemouth score gives the best prediction of survival.

We have studied the clinical and laboratory features of 53 cases of chronic myelomonocytic leukaemia (CMML) defined according to the FAB criteria. A granulocyte count of greater than 16 X 10(9)/l or a monocyte count of greater than 2.6 X 10(9)/l correlated with a poorer survival, but the best predictor of poor survival was the modified 'Bournemouth' score in which one point each was allocated for Hb less than 10 g/dl, neutrophils less than 2.5 X 10(9)/l or greater than 16 X 10(9)/l, platelets less than 100 X 10(9)/l and bone marrow blasts greater than 5%. A score of 2 or more was predictive of poor survival (Chi2 = 10.25; P less than 0.001). Those patients with low monocyte and neutrophil counts and a low modified Bournemouth score tended to have a clinical course similar to refractory anaemia (RA) with an indolent course not requiring treatment and long survival whereas those with high monocyte and neutrophil counts and a high modified 'Bournemouth' score have a clinical course resembling that of refractory anaemia with excess of blasts (RAEB).

Prognostic value of initial mononucleated cell percentages in patients with epidermoid carcinoma of the head and neck

It has been established that staging of squamous cell carcinoma of the head and neck at the time of diagnosis carries the most significant prognostic factor. Searching for other prognostic factors at the time of diagnosis, the percentages of lymphocytes and monocytes in the peripheral blood were studied. The results revealed that there were significantly higher lymphocyte values in patients without regional lymph node metastasis compared with those with such metastasis (p = 0.0064). On the other hand, higher monocyte values correlated with advanced stages of the disease. Patients with regional lymph node metastasis had higher monocyte values than those without nodal metastases. Furthermore, the incidence of recurrences and metastases during the first year was significantly lower in patients who had lymphocyte values of 30 percent or more when compared with those with values of less than 30 percent (p = 0.0003). In addition, all patients with early stages (I and II) of disease had less than 10 percent monocytes. These data suggest that initial high lymphocyte and low monocyte percentages carry a better prognosis. It seems that the percentage of mononucleated cells in the peripheral blood may have the second most important prognostic value.

Analysis of the monocyte Fc receptors and antibody-mediated cellular interactions required for the induction of T cell proliferation by anti-T3 antibodies.

The induction of human T cell proliferation by antibodies that cross-link T3 antigens is dependent on functional interactions of anti-T3 antibodies with monocyte Fc receptors. In this report, we used a panel of anti-T3 antibodies of differing heavy chain isotype and a variety of other monoclonal antibodies to analyze several features of the antibody-mediated interactions between T cells and monocytes that are required for mitogenesis. Whereas three IgG2a anti-T3 antibodies were mitogenic for cells from all individuals, IgM and IgG2b anti-T3 antibodies did not induce T cell proliferation in any donor and could block the proliferative responses induced by other mitogenic anti-T3 antibodies. Dose-response analyses with four IgG1 anti-T3 antibodies demonstrated donor heterogeneity as reported by other investigators. However, in contrast to these previous reports, high concentrations of IgG1 anti-T3 antibodies were found to be mitogenic for all donors, indicating that this heterogeneity is based on relative rather than absolute defects in low responder monocytes. Cell mixing experiments in which monocytes from two different low responder donors were co-cultured with T cells and IgG1 anti-T3 antibodies did not identify any complementary defects, suggesting that the low responder phenotype results from a relatively restricted polymorphism. To assess the nature of the signals required for inducing T cell proliferation, nonmitogenic anti-T3 antibodies were co-cultured with other pan-T cell antibodies having the IgG2a isotype. The combination of signals from T3 antigen cross-linkage and those independently generated by other IgG2a antibodies bound to monocyte Fc receptors did not induce T cell proliferation. Hence, it appears that the T3 antigen or closely associated structures must be clustered at the monocyte membrane for mitogenesis. Finally, in competitive inhibition experiments, the isotype specificity of monocyte Fc receptors involved in the induction of T cell proliferation was examined. Two distinct Fc receptor sites, one that binds murine IgG2a and IgG3 antibodies and a second that binds murine IgG1 antibodies, were identified. Murine IgM or IgG2b did not appear to bind either of these receptor sites. Taken together, these data indicate that human monocytes have two distinct Fc receptor sites, which must specifically and directly interact with T cell-bound anti-T3 antibodies for mitogenesis.

Human T lymphocyte proliferation induced by a pan-T monoclonal antibody (anti-Leu 4): heterogeneity of response is a function of monocytes.

Anti-Leu-4 is a murine monoclonal antibody that defines a molecule of 20,000 to 25,000 daltons present on all mature T lymphocytes in man. When cultured in the presence of 10 to 1000 ng/ml anti-Leu-4, the T cells of most individuals proliferate with peak responses on the third day of culture. T cells of both helper and suppressor lineages proliferate, but only in the presence of monocytes. Approximately 40% of individuals tested responded weakly or not at all to anti-Leu-4, despite normal responses to other stimuli. The variation in responsiveness between individuals could not be explained by differences in Leu-4 antigen density on the surface of T cells, differences in the rate of Leu-4 antigen modulation, or structural differences in the Leu-4 molecule as defined by the method of two-dimensional polyacrylamide gel electrophoresis. In the presence of monocytes from high responders, the T cells from low responders proliferated vigorously to anti-Leu-4, whereas monocytes from low responders failed to support proliferation by high responder T cells. On the other hand, low responder monocytes did not prevent T cells from proliferating in the presence of high responder monocytes. These results suggest that the failure of some individuals to respond to anti-Leu-4 is due to the absence or dysfunction of an essential monocyte population.

Role of insulin receptors in obesity-related diabetes.

Insulin binding to monocytes was assessed before and after plasma insulin suppression by diazoxide in 14 obesity-related diabetic subjects. Four of the five patients with mild carbohydrate intolerance (FBS less than 150 mg%) and hyperinsulinism exhibited low monocyte insulin binding. Despite an increase in insulin binding after 7 days of diazoxide therapy, no improvement in carbohydrate tolerance could be demonstrated. Lack of improvement may have been related to persistent diazoxide effect. An additional group of 4 patients with low plasma insulin values and more severe carbohydrate intolerance (FBS greater than 150 mg%) had high monocyte insulin binding. This group, as well as a group of patients with intermediate insulin responses, tolerated diazoxide poorly and developed moderate ketonuria or severe hyperglycemia (plasma glucose greater than 350 mg%) necessitating discontinuation of the drug after 3-6 days. The studies in these patients suggest that obesity-related diabetes may be characterized early by mild elevation of plasma glucose, hyperinsulinism and impaired monocyte insulin binding. As beta cell exhaustion occurs, more severe hyperglycemia intervenes and insulin binding to monocytes increases.

Factors influencing monocyte recognition of human erythrocyte autoantibodies in vitro.

Erythrocytes, serum, and blood monocytes from patients with erythrocyte autoantibodies were examined by in vitro serologic and cell culture procedures in order to evaluate factors modulating patient mononuclear phagocyte activity. Monocyte recognition of autoantibody-coated erythrocytes was influenced both by antibody titer score and by the monocyte source. The results suggest that patients with low serum autoantibody titer scores and normal monocyte behavior are less likely to destroy autologous or normal donor erythrocytes than are patients with high-serum antibody titer scores or enhanced monocyte activity. We conclude that patient, rather than normal donor monocytes, must be used in cellular assays designed to predict the fate of erythrocytes transfused into patients with erythrocyte autoantibodies.

In vitro monocyte maturation as a prediction of survival in squamous cell carcinoma of the lung.

In vitro monocyte maturation was studied in patients with squamous cell carcinoma of the lung--limited to the ipsilateral hemithorax in 30 and more extensive in 40. The patients were studied prospectively and initial monocyte maturation was correlated with survival. Monocyte maturation in patients with limited disease before treatment ranged from 3.1 to 57.6% with a median value of 21.4%. The survival of those patients in whom monocyte maturation was less than the normal range (less than 30.4%) was significantly shorter than the survival in those with normal maturation ( p less than 0.05). Four of the five patients whose initial maturation was less than 10% proved to be inoperable at surgery. Patients with extensive disease had monocyte maturation ranging from 2.4 to 52.9% with a median value of 13.2%, significantly lower than in those with limited disease (p less than 0.025). Patients with extensive disease and low monocyte maturation survived a significantly shorter time than those with normal maturation ( p less than 0.005). The depression of monocyte development may explain the finding of negative delayed hypersensitivity skin reactions in many patients with lung carcinoma and may prove useful as an index of prognosis.

USE OF A MODIFIED MINICOIL FOR CONTINUOUS DIALYSIS.

<h3>Background</h3> Eftilagimod alpha (efti; IMP321) is a soluble LAG-3 protein (LAG-3Ig) that binds to a subset of MHC class II molecules and mediates activation of antigen-presenting cells followed by CD8 T-cells. Weekly paclitaxel is a standard of care chemo-regimen after failure of endocrine-based therapy for metastatic breast carcinoma (MBC). AIPAC (Active Immunotherapy PAClitaxel) investigated the addition of efti to weekly paclitaxel in these patients (pts). <h3>Methods</h3> This placebo-controlled, double-blinded, 1:1 randomized phase IIb trial enrolled pts with measurable disease, HR+ HER2- MBC after endocrine-based therapy. Pts received paclitaxel (80 mg/m² IV on D1, D8, D15) + efti (30 mg) or placebo on D2, D16 (every 2 weeks) for up to 24 weeks following efti/placebo for up to 52 weeks. The primary endpoint (EP) was progression-free survival (RECIST1.1) by BICR. Secondary EPs included overall survival (OS), PFS (local read), overall response rate (ORR), biomarker, quality of life. Exploratory EPs included univariate/multivariate analyses. <h3>Results</h3> 227 pts were randomized (Jan2017-Jul2019). All except 1 received ≥1 treatment and were included in the full analysis set [efti (n=114); placebo (n=112)]. Data cut-off was 14May2021 (min. follow-up= 22 months). Median age was 60 yrs with ECOG 0 in 61.5%. 91.6% had visceral disease. Pts were mostly endocrine resistant (84%) and partially pre-treated with CDK4/6 inhibitors (44.2%). Post-study treatment was similar. Median OS was 20.4 (95% CI: 14.3-25.1) months in the efti group vs. 17.5 (95% CI: 12.9-21.9) in the placebo group. HR was 0.88 (95%CI: 0.64-1.19; p=0.197). In predefined univariate analyses, younger pts, low baseline monocytes and luminal B showed significant/clinically meaningful improvement in OS (table 1). Efti increased PBMC/T cell (CD4/CD8) count vs. placebo, correlating with improved OS (Spearman Rho=0.6, p=0.02 for CD8 T cells). In a whole population multivariate cox regression model, increasing BMI and prior treatment with CDK4/6 were independent significant poor prognostic markers for PFS and OS. TEAEs leading to discontinuation were similar at 5.3%(efti) &amp; 6.3%(placebo). PFS (Primary EP) and safety were reported at SABCS 2020 (Abstract#132). <h3>Conclusions</h3> Efti added to paclitaxel led to a non-significant 2.9 months median OS increase in HR+ HER2- MBC pts after endocrine-based therapy. Effects were significant in pts &lt;65yrs, with low monocytes and more aggressive disease (luminal B). Efti increased circulating CD4/CD8 T cells, which significantly correlated to improved OS. Weekly paclitaxel + efti should be further investigated in MBC. <h3>Trial Registration</h3> The trial identifiers are IMP321-P011 (code for sponsor), 2015-002541-63 (EudraCT) and NCT02614833 (ClinicalTrials.gov). <h3>Ethics Approval</h3> The study was approved by relevant ethic committees and institutional review boards.

STUDIES ON THE BLOOD CYTOLOGY OF THE RABBIT

1. The blood cytology of 91 rabbits was studied prior to inoculation with a transplantable malignant neoplasm. The following statements refer in each instance to the mean values of the pre-inoculation counts. 2. The animals which were most resistant to the malignant disease had, before inoculation, normal red and white cell counts, normal hemoglobin percentages, high eosinophile counts, and low counts of monocytes and lymphocytes. The relations of the neutrophile and basophile counts were irregular, but normal values also appeared to be associated with greater resistance. 3. The most susceptible animals were those which had, before inoculation, red cell counts above 5,500,000 or below 5,000,000 per c.mm.; hemoglobin above 70 per cent or below 60 per cent (Newcomer); white cell counts below 6,000 or above 8,500 per c.mm.; low eosinophile, high monocyte, or high lymphocyte counts. 4. No animal with any of the following findings prior to inoculation recovered completely from the tumor as determined by autopsy examination: red cells above 5,500,000 per c.mm. of blood; hemoglobin above 70 per cent; total white cells above 10,000 per c.mm.; eosinophiles below 120 per c.mm., or below the relative value of 1.5 per cent; basophiles below 400 per c.mm., or below the relative value of 6 per cent; lymphocytes above 3,600 per c.mm.; monocytes above 1,500 per c.mm.; neutrophiles above 5,000 per c.mm.; and total granular cells above 5,700 per c.mm. In the case of each of the following pre-inoculation values, only 1 animal was completely free from tumor at autopsy: hemoglobin below 60 per cent; red cells below 4,800,000 per c.mm.; total granular cells below 3,300 per c.mm.; total non-granular cells below 2,300 per c.mm.; total non-granular cells above 3,700 per c.mm. No animal with pre-inoculation eosinophiles above 3.9 per cent, or basophiles above 16 per cent died from the tumor. 5. The blood findings before inoculation could be related to the character and outcome of the malignant disease, from the standpoint of animal groups as well as in the case of individual rabbits. 6. From the results of the experiments here reported, it seems possible to predict with an accuracy of between 80 and 90 per cent the individual resistance or susceptibility of rabbits to the tumor by a study of their blood cells before inoculation.

An Address on the Pathology of Syphilis: Being an Introduction to a Debate at the Pathological Society of London

<h3>Abstract</h3> <h3>Rationale</h3> whether systemic dissemination of SARS-CoV-2 has any impact on COVID-19 severity and also on the immunological alterations observed in this disease is largely unknown. <h3>Objectives</h3> We determined the association of plasma SARS-CoV-2 RNA with clinical severity, laboratory findings and immunological parameters in a cohort of 250 patients with confirmed COVID-19 infection. <h3>Methods</h3> Three groups of patients were studied: 50 outpatients, 100 hospitalised ward patients, and 100 critically ill. The association between plasma SARS-CoV-2 RNA and severity was evaluated using multivariate ordinal logistic regression analysis and Generalized Linear Model (GLM) analysis with a binomial distribution. The association between plasma SARS-CoV-2 RNA and laboratory parameters was evaluated using multivariate GLM with a gamma distribution. <h3>Measurements and Main Results</h3> The prevalence of SARS-CoV-2-RNA viremia increased in parallel with severity of infection (22% in outpatients, 36 % in those hospitalised in wards, and 82% in those at the ICU). In hospitalised patients, the presence of SARS-CoV-2-RNA viremia was independently associated to critical illness: (adjusted OR= 8.30 [CI95%=4.21 - 16.34], <i>p</i> &lt; 0.001). SARS-CoV-2-RNA viremia was an independent predictor of higher levels of ferritin, LDH and cytokines (involving CXCL10, CCL-2, IL-15, IL-10, IL-1ra and GCS-F), and lower of lymphocytes, monocytes and platelets counts <h3>Conclusions</h3> SARS-CoV-2-RNA viremia is a robust marker of critical illness in COVID-19. Our findings support that hypercytokinemia in COVID-19 is a reactive event in response to the dissemination of viral material at the systemic level. <h3>“At a Glance Commentary”</h3> <h3>Scientific Knowledge on the Subject</h3> there is a limited number of works evaluating the presence of SARS-CoV-2 RNA in the serum or plasma of patients with COVID-19, involving few patients, most of them with non-severe disease. In consequence, the impact that the presence of SARS-CoV-2 RNA viremia has on disease biology and severity is largely unknown. <h3>What This Study Adds to the Field</h3> to our knowledge, this is the first study comparing the prevalence of SARS-CoV-2-RNA viremia in outpatients (n=50), patients admitted to the ward (n=100), and critically ill patients (n=100) with COVID-19. Multivariate analysis demonstrates that the presence of SARS-CoV-2-RNA viremia in those COVID-19 patients needing hospitalization translates into an 8-fold increase in the risk of presenting critical illness. Presence of viremia in COVID-19 patients is associated with high levels of ferritin and LDH, hypercytokinemia (increased levels of CXCL10, CCL2, IL-10, IL-1ra, G-CSF &amp; IL-15), lymphopenia and low monocyte and platelet counts. These data indicate that SARS-CoV-2-RNA viremia could be a driver of immunological dysregulation and severe disease in COVID-19 This article has an online data supplement, which is accessible from this issue’s table of content online at www.atsjournals.org