Guardians of immunity: NK cell-mediated defense in COVID-19 and post-COVID scenarios.

The COVID-19 pandemic has left a lasting impact on global health, challenging communities, healthcare systems, and researchers worldwide. As we navigate this unprecedented crisis, this paper embarks on a multifaceted exploration of the pivotal role played by natural killer (NK) cells in the context of COVID-19. A significant portion of this paper is devoted to dissecting the nuanced role that NK cells assume in the context of COVID-19.

A concise review of flow cytometric methods for minimal residual disease assessment in childhood B-cell precursor acute lymphoblastic leukemia.

Minimal residual disease refers to a leukemia cell population that is resistant to chemotherapy or radiotherapy and leads to disease relapse. The assessment of MRD is crucial for making an accurate prognosis of the disease and for the choice of optimal treatment strategy. Here, we review the advantages and disadvantages of the available genetic and phenotypic methods and focus on the multiparametric flow cytometry as a promising method with greater sensitivity, speed, and standardization options.

Conversion and Obsessive-Phobic Symptoms Predict IL-33 and IL-28A Levels in Individuals Diagnosed with COVID-19.

The first epidemiological wave of the incidence of COVID-19 in Bulgaria was registered in June 2020. After the wave peak, we conducted a study in persons diagnosed with COVID-19 (N = 52). They were assessed with the anxiety-depressive scale (ADS), including basic (BS), vegetative (VS), conversion (CS), obsessive-phobic (OPS), and depressive (DS) symptoms.

HIV-1 genetic diversity and demographic characteristics in Bulgaria.

HIV-1 strain diversity in Bulgaria is extensive and includes contributions from nearly all major subtypes and the Circulating Recombinant Forms (CRF): 01_AE, 02_AG, and 05_DF. Prior to this study, HIV-1 sequence information from Bulgaria has been based solely on the pro-RT gene, which represent less than 15% of the viral genome. To further characterize HIV-1 in Bulgaria, assess participant risk behaviors, and strengthen knowledge of circulating strains in the region, the study "Genetic Subtypes of HIV-1 in Bulgaria (RV240)" was conducted.

Detailed molecular epidemiologic characterization of HIV-1 infection in Bulgaria reveals broad diversity and evolving phylodynamics.

Limited information is available to describe the molecular epidemiology of HIV-1 in Bulgaria. To better understand the genetic diversity and the epidemiologic dynamics of HIV-1 we analyzed 125 new polymerase (pol) sequences from Bulgarians diagnosed through 2009 and 77 pol sequences available from our previous study from persons infected prior to 2007. Epidemiologic and demographic information was obtained from each participant and phylogenetic analysis was used to infer HIV-1 evolutionary histories.

Antigen-specific CD4- and CD8-positive signatures in different phases of Mycobacterium tuberculosis infection.

Current diagnostic standards for Mycobacterium tuberculosis (MTB) infection do not distinguish between active and latent tuberculosis (TB). To identify specific biomarkers characterizing the different forms of TB infection, we investigated in parallel with the QuantiFERON -TB Gold In-Tube (QFT-IT) the use of flow cytometry measuring CD4 and CD8 MTB-specific immune response in 17 active-TB patients, 21 health care workers (HCW), 14 recent contacts of TB patients (RC-TB), and 10 bacille Calmette Guerin (BCG)-vaccinated healthy controls (BCG-HC). A correlation (r = 0.

A particular expression pattern of CD13 epitope 7H5 in chronic lymphocytic leukaemia--a possible new therapeutic target.

A total of 50 patients with chronic lymphocytic leukaemia (CLL), as well as the B-cell leukaemia cell lines MEC-1, JVM-3, and BV-173 were studied in order to assess the incidence of CD13/aminopeptidase N (APN) immunolabelling with a monoclonal antibody 7H5 compared to LeuM7 and to CD13 mRNA levels, and to correlate these data with the cytotoxic and apoptosis-induction activity of the natural phenolic APN inhibitor curcumin. CD13/APN was detected in a significant proportion of B-CLL patients (42/50, 84%), immunolabelled by 7H5 (42/50) ± LeuM7 (10/50). Molecular analysis for CD13 transcripts confirmed these data, resulting in a specific RT-PCR product in CD13 positive cases.

Polybacterial immunomodulator Respivax restores the inductive function of innate immunity in patients with recurrent respiratory infections.

Respivax (BulBio-NCIPD Ltd.) is an oral polybacterial immunomodulator intended for treatment and prevention of non-specific respiratory tract infections. We studied for the first time its effects on the inductive mechanisms of innate immunity, in the course of 3-month immunoprophylaxis of 25 patients with recurrent and chronic respiratory infections.

Selective silencing of disease-associated B-lymphocytes by chimeric molecules targeting their Fc gamma IIb receptor.

The presently used approaches to silence autoreactive disease-associated B cells act indiscriminately and more specific therapies are obviously needed. In the present study, we analyze the ability of a chimeric antibody to suppress selectively pathological autoreactive B-lymphocytes in lupus-prone mice by cross-linking their surface Ig receptors with the inhibitory IgG Fc gamma RIIb receptors. The chimera was constructed by coupling an immunodominant mouse Histone 1 peptide to a rat monoclonal anti-mouse CD32 (Fc gamma RIIb) antibody.

Chronic Epstein-Barr virus-related hepatitis in immunocompetent patients.

Aim: To investigate reactivated Epstein-Barr virus (EBV) infection as a cause for chronic hepatitis.

Methods: Patients with occasionally established elevated serum aminotransferases were studied. HIV, HBV and HCV-infections were excluded as well as any other immunosuppressive factors, metabolic or toxic disorders.

Comparision of two-flow cytometry methods for basophil degranulation in patients sensitized to grass pollen.

Background: Two-flow cytometry methods for quantification of degranulated basophil after allergen-specific activation were discussed. The methods are discerned by used membrane receptors--FcepsilonRI or IL-3Ralpha Our goal was to evaluate the diagnostic potential of the methods and to correlate them to allergen-specific IgE detection and skin prick test (SPT).

Methods: Patient's and control's groups were studied with Bulgarian grass pollen allergen B1 simultaneously by flow cytometry kits: Basotest and BD FastImmune test.

Cellular and humoral systemic and mucosal immune responses stimulated in volunteers by an oral polybacterial immunomodulator "Dentavax".

The oral polybacterial immunomodulator Dentavax (D), composed of killed cells from Klebsiella pneumoniae, Streptococcus pyogenes, Staphylococcus aureus, Candida albicans and Lactobacillus acidophilus and their lysates was created for immunoprophylaxis and therapy of oral mucosa and parodont inflammations. The stimulating effect of the preparation was evaluated in twelve volunteers immunized for 10 consecutive days. On days 7, 14, 21, 28 and 49 after the last immunization peripheral blood (PB) lymphocyte subsets, T lymphocyte activation and PB phagocytic activity, were studied by flow cytometry.

The CD160+ CD8high cytotoxic T cell subset correlates with response to HAART in HIV-1+ patients.

We investigated the circulating cytotoxic CD160+ CD8(high) subset in correlation to antiviral immunity and response to highly active antiretroviral therapy (HAART) in HIV+ subjects. The study included 45 treatment-naive patients receiving HAART for 18 months, retrospectively defined as good (n=29) and transient (n=16) responders. HIV-specific CD8 T lymphocyte levels were measured by IFNgamma production in response to p17 Gag, in the presence of immobilized anti-CD160 mAb.

SC3 monoclonal antibody defines a novel specific human B-cell surface antigen differentially expressed on B-cell leukaemias and lymphomas and involved in the proliferation of normal and malignant B lymphocytes.

The monoclonal antibody SC3 was raised against the NK leukaemia cell line YTindi. It detected a 98-kDa surface antigen with weak expression on a restricted number of leukaemia cell lines under reducing conditions. SC3 mAb labelled 5-10% of normal peripheral blood lymphocytes corresponding almost exclusively to B lymphocytes, and 60-70% of tonsillar B cells.

Uncoupling of unwinding from DNA synthesis implies regulation of MCM helicase by Tof1/Mrc1/Csm3 checkpoint complex.

The replicative DNA helicases can unwind DNA in the absence of polymerase activity in vitro. In contrast, replicative unwinding is coupled with DNA synthesis in vivo. The temperature-sensitive yeast polymerase alpha/primase mutants cdc17-1, pri2-1 and pri1-m4, which fail to execute the early step of DNA replication, have been used to investigate the interaction between replicative unwinding and DNA synthesis in vivo.

Novel molecular mechanisms of dendritic cell-induced T cell activation.

In this study we have re-examined the molecular mechanisms involved in activation of T cells by dendritic cells (DC). Human peripheral blood DC (PBDC) were derived by 2 h adhesion followed by 7 day culture in a combination of granulocyte macrophage colony stimulating factor and IL-4, and depletion of residual T and B cells. These PBDC were used to induce autologous T cell proliferation in a CD3-dependent response, and antibodies against CD11a/18 and CD86 were used as control inhibitors of accessory function.

Levels of expression of CAF7 (CD98) have prognostic significance in adult acute leukemia.

The levels of CD98 antigen expression were studied in 62 consecutive cases of adult acute leukemia including 24 acute lymphoblastic leukemia (ALL) and 38 acute myeloid leukemia (AML) using the monoclonal antibody CAF7 and flow cytometry. The mean follow-up was 13.5 months.

CD4+ acute undifferentiated leukaemia, probably early monoblastic type, developing in a patient with myelodysplastic syndrome and bone marrow fibrosis.

We report here a patient who presented with pancytopenia, hypercellular bone marrow and three-lineage dysplasia associated with an increase of reticulin fibres. After a 5-month period, anaemia and thrombocytopenia progressed very rapidly and the white blood count increased showing 45% blasts with monocytoid morphology, but cytochemically undifferentiated in nature. The immunophenotype revealed an unusual expression of CD4, CD36 and HLA-DR in the absence of any other myeloid or lymphoid lineage-associated markers.

Humoral and cellular immune response to elastin in patients with systemic sclerosis.

The humoral immune response against elastin and collagen was studied in parallel with the delayed type hypersensitivity (DTH) reaction to elastin and the percentage of lymphocyte subpopulations in peripheral blood in 20 patients with systemic sclerosis (SSc). An increase of anti-elastin antibodies of all subclasses was found with a significant prevalence of IgE and IgA antibodies. The profile of anti-collagen type I and type IV antibodies showed an increase of IgE isotypes.

ABH blood group antigen significance as markers of endothelial differentiation of mesenchymal cells.

The expression pattern of A, B and H blood group antigens was evaluated by staining frozen sections with specific monoclonal antibodies developed by us and using the indirect immunoperoxidase method. The expression of blood group antigens was ubiquitously upregulated in the endothelial cells of fetal organs. In the process of their differentiation to endothelial naive embryonic mesenchymal cells expressed cytoplasmic ABH antigens.

Levels of CAF7 (CD98) expression correlate with the complete remission duration in childhood acute leukemia.

The levels of expression of the activation antigen CD98 were studied by mAB CAF7 in 51 newly diagnosed consecutive cases of childhood acute lymphoblastic leukemia aged from 1 to 13 years. The mean follow-up was 8 months. A wide range of CAF7 expression was observed, the highest mean fluorescence intensity exceeding the lowest by 20 times.

Immunological subtypes of childhood acute lymphoblastic leukemia in Bulgaria.

With regards to the geographical variation in acute lymphoblastic leukemia (ALL) distribution, we present data from the immunophenotyping of 171 newly diagnosed cases of childhood ALL in Bulgaria during a 4 year period (1990-1994). On the basis of 17 phenotypic markers the distribution of immunological subtypes was as follows: AUL 4%; Pro-B ALL 13%; common ALL 42%; Pre-B ALL 11%; B-ALL 1%; T-ALL 28% and unclassified 2%. Most of the cases were between 2 and 5 years of age.

Detection of antibodies toward epididymal sperm antigens--an obligatory step in evaluation of human immunologic infertility?

Problem: To test the relative impact of epididymal versus ejaculated sperm in immunologic infertility.

Method: Human antibody binding to epididymal and ejaculated spermatozoa was compared by flow cytometry (FCM) since it allows quantitative analysis of viable sperm while ignoring nonsperm cells. To select sera for FCM, GAT, TAT, and ELISA were applied on 145 sera from fertile men, idiopathically infertile and varicocele patients.

Expression of 1D8--a novel non-sialylated B-cell-associated carbohydrate epitope in lymphoproliferative disorders.

The expression of a novel B-cell-associated carbohydrate epitope (1D8) was studied by means of flow cytometry in 153 well defined cases of leukemias and lymphomas and 19 cases of lymphadenopathy used as controls. The 1D8 epitope was detected preferentially in proliferations of mature B-lymphocytes (11/15 CD20+ acute lymphoblastic leukemia (ALL), 14/16 chronic lymphocytic leukemia (CLL), 4/7 mantle cell non-Hodgkins lymphoma (NHL), 3/8 follicle cell NHL. However its expression did not appear lineage- or differentiation stage-restricted.

Monoclonal antibody 1D8 detects an activation-related molecule on human B lymphocytes and on a minor T-lymphocyte subpopulation.

A novel murine monoclonal antibody (MAb) 1D8 was produced after immunization with the nylon wool-adherent fraction of human peripheral blood mononuclear cells (PBMNC). Its reactivity pattern was studied on a panel of hemopoetic normal cells, cell lines and malignancies. Mab 1D8 detects a lymphocyte-specific surface antigen expressed on a major subpopulation of mature B lymphocytes as well as on a minor T-cell subset.