Analysis of blood plasma cytokine profile in healthy residents of the Republic of Guinea

The cytokine system is a large group of humoral factors  produced by immune cells and involved in the  pathogenesis of most  human diseases.  To assess the  significance of changes  in cytokines/chemokines under  pathological conditions, appropriate reference values are required for healthy  people.  As known  from existing literature, most studies of various cytokine/chemokine concentrations in blood plasma were performed in healthy  subjects from Western Europe and North America.  Certain inter-population differences are known, with  respect  to production of distinct cytokines in different  racial  and  national groups.  Only  single studies concern normal levels of distinct cytokines in blood  plasma  of healthy  African  residents. The purpose  of this study was to determine the blood plasma cytokine profile in healthy  residents of the Republic of Guinea (RG), and to establish normal cytokine values.We have  examined 24  healthy  RG  residents and  23  residents of St.  Petersburg. Concentrations  of 40 cytokines/chemokines were determined in blood plasma.  The study was performed using multiplex analysis by xMAP technology.The  following  cytokine/chemokine levels  were  significantly   increased in  the  blood  plasma  of the  RG residents: IFNγ, IL-2, IL-4, IL-6, IL-10, TNFα, CCL1/I-309, CCL3/MIP-1α, CCL7/MCP-3, CCL17/ TARC, CCL19/MIP-3β,  CCL20/MIP-3α,  CCL21/6Ckine, CXCL2/Gro-β,  CXCL5/ENA-78, CXCL6/ GCP-2, CXCL9/MiG, CX3CL1/Fractalkine (р < 0.001).  For  the  CCL8/MCP-2, CCL22/MDC, CXCL1/ Gro-α and CXCL12/SDF-1α+β chemokines a trend for increased concentration was revealed, in comparison with residents of St. Petersburg (р < 0.05). Moreover, the levels of CCL23/MPIF-1 and MIF were significantly lower (р < 0.0001) in the RG residents. There was a tendency for decreased levels (р < 0.05) for CCL2/MCP-1 and CCL24/Eotaxin-2 chemokines in blood plasma taken from RG residents. There were no differences in levels of cytokines/chemokines for the studied  groups: GM-CSF, IL-1β, IL-16, CCL11/Eotaxin, CCL13/MCP-4, CCL15/Leukotactin-1, CCL25/TECK, CCL26/Eotaxin-3, CCL27/CTACK, CXCL8/IL-8, CXCL10/IP-10, CXCL11/I-TAC, CXCL13/BCA, and  CXCL16/SCYB16. Hence, this study  has presented for the  first time the normal limits for a wide range of cytokines/chemokines in blood plasma  of the African inhabitants. Interpopulation differences were found, including those  for constitutive chemokines. Different levels of CCL19/ MIP-3β and CCL21/6Ckine chemokines (the CCR7 receptor ligands) for the two populations may indirectly indicate the physiological features of T-cell maturation. Increased levels of CXCR2 receptor ligands in the blood plasma  of Guineans, i.e.,  CXCL2/Gro-β, CXCL5/ENA-78 and  CXCL6/GCP-2, may be due  to additional function of these chemokines as ligands for atypical DARC chemokine receptor, which neutralizes chemokines from the blood flow, whereas 95% of West Africans have mutations in the DARC gene and do not express this receptor. Increased levels of proinflammatory IL-6  and TNFα cytokines, and chemokine CCL20/MIP-3α in blood plasma  from RG  residents may suggest inflammatory processes  in the liver, since 100% of the examined Guineans had antibodies against the hepatitis A virus, 48% had antibodies to hepatitis B virus (anti-HBs), and 12% had antibodies against hepatitis C virus. In summary, the differences in cytokine/chemokine level may be related  to specific environment, circulation of infectious diseases, composition of intestinal, skin and mucosal microbiota, as well as distinct genetic  features

CD32a receptor in health and disease

Low-affinity Fcγ-receptors that recognize the Fc portion of immunoglobulin (Ig) molecules, usually being in antigen-bound state, thus representing a link between innate and adaptive immunity. They play a significant role in inflammatory and infectious diseases. Among them, a separate FcγRII family (CD32) is discerned, which is characterized by transmission of intracellular signal independently of the common γ-chain, they have one α-chain containing two extracellular immunoglobulin-like domains. FcγRII receptors are present in almost all cells of the innate immune system: monocytes and macrophages, neutrophils, eosinophils, dendritic cells, as well as on B-lymphocytes and platelets. They perform two main functions: target recognition, facilitation of phagocytosis and destruction of antibody-opsonized cells by monocytes/ macrophages (including pathogenic cells). In parallel, the phagocytes are activated via the cytokine synthesis stimulation. The FcγRIIA (CD32a) and FcγRIIC (CD32c) activating receptors, like as FcγRIIB (CD32b) inhibiting receptors are present among the members of the FcγRII family. The low-affinity FcγRII receptors bind to IgG, with immune complexes being their natural ligands. High levels of immune complexes are usually found in both chronic viral infections and autoimmune diseases. There are shown polymorphic variants of the CD32a gene, which can affect the receptor function, and, thereby, causing susceptibility for different infections, influence the development of autoimmune diseases and primary immunodeficiencies. Activation of the CD32a receptor induces the production of pro-inflammatory cytokines, including TNFα and interferons, that are involved into inflammation in systemic lupus erythematosus, Kawasaki disease, Graves’ disease and rheumatoid arthritis. It has been shown that antibacterial activity of platelets is carried out via the CD32a receptor. The study of CD32a expression in people The CD32a receptor is considered a biomarker of cells that are a reservoir of HIV infection. At the present time, however, many questions remain regarding the mechanisms of CD32a expression of on HIV-infected cells and the role of CD32a in the formation of an HIV reservoir and/or development of appropriate resistance. In addition to HIV infection, the significance of FcγR receptors is shown in other infectious diseases, for example, with influenza and dengue virus infections. Better understanding of the CD32a structure and function will help to assess its role in immunopathogenesis of different conditions. This review focuses on the role of CD32a in development of the normal immune response in normal state and various diseases

Content of certain cytokines and chemokines in blood ofpatients with chronic hepatitis B in the early stages of liver fibrosis

Hepatitis B is an infectious viral disease in which damage or destruction of liver tissue occurs, and which can turn into a chronic form. In chronic hepatitis B (CHB), hepatocytes are replaced by connective tissue as they die, resulting in fibrosis, and then cirrhosis of the liver. Early diagnosis of liver fibrosis is an urgent task in the development of CHB. Already at this stage of the disease, the immune system is activated, which plays a leading role in liver damage in CHB. The main regulators of immune processes are cytokines, which mediate intercellular interactions. A separate group of cytokines are chemokines — proteins of cell migration. In CHB, they are responsible for infiltration of liver tissue by activated white blood cells. Cytokines and chemokines are active participants in fibrogenesis, so they can serve as biomarkers for the development of liver fibrosis, including in the early stages. The purpose of this study was to analyze the content of certain cytokines/chemokines in the peripheral blood of patients with CHB in order to search for potential biomarkers of the initial stages of liver fibrosis. The study included 30 patients with a confirmed diagnosis of CHB with stages of liver fibrosis F0-F1 on the Metavir scale, 36 patients with a diagnosis of chronic hepatitis C (F0-F1) and 37 conditionally healthy individuals as a control group. Concentrations of the following cytokines/chemokines were determined: IFNγ, TNFα, CCL2/MCP-1, CCL8/MCP-2, CCL20/MIP-3α, CXCL9/MIG, CXCL10/IP-10, CXCL11/I-TAC by multiplex analysis using xMAP technology (Luminex, USA). As a result of the study, it was found that in patients with CHB, the plasma content of cytokine TNFα and chemokines CCL2/MCP-1, CXCL9/MIG and CXCL10/IP-10 was increased, and the chemokine CCL8/MCP-2 was reduced, which indicates the possibility of using these cytokines/chemokines as biomarkers of liver damage in CHB. In the examined group of patients with CHB, there was no dependence of the concentrations of cytokines and chemokines in the blood plasma on the viral load, which may be explained by its low level. For plasma cytokines in patients with CHB, correlations were found between TNFα and CCL2/MCP-1 and CCL8/MCP-2 chemokines , which was not observed in the control group. At the same time, in the control group, a correlation was found between the content of TNFα and the chemokine CXCL9/MIG, which was not detected in the group of patients. For both groups, a correlation was found between the content of CXCL9/MIG and CXCL10/IP-10 chemokines. Based on the study data, an algorithm has been developed that allows us to establish chronic hepatitis B or chronic hepatitis C as the cause of the initial form of fibrosis F0-F1 in terms of the content of cytokines IFNγ, CCL2/MCP-1 and CCL8/MCP-2 in blood plasma with a diagnostic efficiency of 89.4%

Plasma cytokines in patients with COVID-19 during acute phase of the disease and following complete recovery

COVID-19, an infection caused by the new coronavirus SARS-CoV-2, is associated with a number of pathophysiological mechanisms, mobilizing a wide spectrum of biomolecules, mainly, cytokines.The purpose of this study was to evaluate levels of multiple cytokines in blood plasma from the patients with COVID-19 during acute phase of the disease, and upon complete recovery. Samples of peripheral blood plasma of 56 patients with COVID-19, 69 convalescents and 10 healthy individuals were examined. Concentrations of 46 molecules, such as IL-1α, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-9, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-17A/CTLA8, IL-17-E/IL-25, IL-17F, IL-18, IL-22, IL-27, IFNα2, IFNγ, TNFα, TNFβ/ Lymphotoxin-α (LTA), CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1β, CCL7/MCP-3, CCL11/Eotaxin, CCL22/MDC, CXCL1/GROα, CXCL8/IL-8, CXCL9/MIG, CXCL10/IP-10, CX3CL1/Fractalkine, IL-1ra, IL-10, EGF, FGF-2/FGF-basic, Flt3 Ligand, G-CSF, M-CSF, GM-CSF, PDGF-AA, PDGF-AB/ BB, TGF-α, VEGF-A were measured via xMAP multiplexing technology. Significantly increased levels of 18 cytokines were found in blood plasma from COVID-19 patients during acute phase of the disease (as compared to control group), i.e., IL-6, IL-7, IL-15, IL-27, TNFα, TNFβ/Lymphotoxin-α (LTA), CCL2/MCP-1, CCL7/MCP-3, CXCL1/GROα, CXCL8/IL-8, CXCL10/IP-10, CXCL9/MIG, IL-1rа, IL-10, M-CSF, GM-CSF, VEGF-A. We found a significant decrease of nearly all the mentioned cytokines in recovered patients, in comparison with those who had moderate, severe/extremely severe disease. Moreover, we revealed a significantly decreased level of 8 cytokines in plasma from convalescents, as compared with control group, i.e., IL-1α, IL-2, IL-9, IL-12 p40, IL-18, CCL22/MDC, Flt3 Ligand, TGF-α. Immune response caused by SARS-CoV-2 infection involves multiple cytokines, mostly, with pro-inflammatory effects. We have shown for the first time that the convalescence phase is characterized by significantly lower levels of cytokines which regulate cellular differentiation and hematopoiesis (in particular, lymphocytes, T-cells and NK-cells). Over acute phase of the disease, the levels of these cytokines did not change. We revealed a significant decrease of most plasma cytokines upon recovery as compared to acute phase. On the contrary, acute phase of the disease is accompanied by significant increase of both pro- and antiinflammatory cytokines in blood plasma

Herd Immunity to SARS-CoV-2 among the Population in Saint-Petersburg during the COVID-19 Epidemic

The first case of COVID-19 was diagnosed in St. Petersburg on March 2, 2020; the period of increase in the incidence lasted for 10 weeks, the maximum rates were recorded in mid-May, and subsequently there was a statistically significant decrease in the incidence.Objective: to determine the level and structure of community immunity to SARS-CoV-2 among the population of St. Petersburg during the period of intensive spread of COVID-19.Materials and methods. Selection of volunteers for the study was carried out through interviewing and randomization. The exclusion criterion was active COVID-19 infection at the time of the survey. 2713 people aged 1 to 70 years and above were  examined for the presence of specific antibodies to SARS-CoV-2. Antibodies were detected by enzyme immunoassay.Results and discussion. Studies have shown that in St. Petersburg, in the active phase of COVID-19 epidemic, there was a moderate seroprevalence to SARS-CoV-2, which amounted to 26 %, against the background of a high frequency (84.5 %) of asymptomatic infection in seropositive individuals who did not have a history of COVID-19 disease, positive PCR result and ARI symptoms on the day of examination. The maximum indicators of herd immunity were established in children 1–6 years old (31.1 %), 7–13 years old (37.7 %) and people over 70 years old (30.4 %). Differences in the level of seroprevalence in the age groups of 18–49 years are statistically significant. The highest level of seroprevalence was found among the unemployed (29.7 %), healthcare workers (27.1 %), education sector (26.4 %) and business sector personnel (25 %). In convalescents, COVID-19 antibodies are produced in 75 % of cases. In individuals with positive result of PCR analysis carried out earlier, antibodies are detected in 70 % of the cases. The results of the study of herd immunity to SARS-CoV-2 are essential to forecast the development of the epidemiological situation, as well as to plan measures for specific and non-specific prevention of COVID-19

Assessment of the Herd Immunity to SARS-CoV-2 among the Population of the Leningrad Region during the COVID-19 Epidemic

The first case of COVID-19 was registered in the Leningrad Region on March 13, 2020. The period of increasing intensity of the epidemic process lasted 8 weeks. One month after reaching the maximum incidence rate, a study was organized to determine seroprevalence to COVID-19 among the population of the Region.Objective of the study was to determine the level and structure of community immunity to SARS-CoV-2 virus in the population of the Leningrad Region in the period of intensive COVID-19 transmission.Materials and methods. The work was carried out within the framework of the Rospotrebnadzor project on assessment of community immunity to the SARS-CoV-2 virus in the population of the Russian Federation. The content of antibodies to SARS-CoV-2 was determined applying ELISA using a kit for the analysis of human serum or blood plasma for the presence of specific IgG to the nucleocapsid of the SARS-CoV-2 virus , manufactured by the State Scientific Center of Applied Microbiology and Biotechnology (Obolensk) in accordance with the instructions for use.Results and discussion. The study has showed that the herd immunity of the population of the Leningrad Region was 20.7 %. The maximum level has been established in children 1–6 years old (42.3 %) and people over 70 years old (29.0 %). The highest level of seropositivity, except for children and older people, was found among the unemployed (25.1 %). The lowest level of seroprevalence was detected in civil servants (12.8 %) and military personnel (16.7 %). It has been shown that the risk of infection increases by 1.5 times in case of contacts with COVID-19 patients. After exposure to COVID-19 virus, antibodies are produced in 82.1 % of the cases. In individuals with a positive PCR test result obtained earlier, antibodies are detected in 82.8 % of cases. The share of asymptomatic forms among seropositive residents of the Leningrad Region was 86.9 %. The results of assessing the herd immunity to SARS-CoV-2 in the population of the Leningrad Region indicate that during the period of intensive COVID-19 transmission, an average level of seroprevalence was formed. A significant proportion of asymptomatic forms of infection characterizes the high intensity of the latently developing epidemic process. The results obtained should be taken into account when organizing preventive measures, including vaccination, and predicting morbidity rates