Neutrophils, NETs, NETosis and their paradoxical roles in COVID-19

The pandemic of COVID-19 has adversely affected the world in many aspects. The health and economic sectors suffer most of the repercussions of this disease. The search for a cure for this rapidly spreading virus which is causing massive life losses worldwide requires clear understanding of the immunopathogenesis of this virus so as to develop pinpointed targeted therapies rather than relying mainly on supportive care measures and drug repurposing to fight this life-threatening virus infection. Neutrophils, neutrophil extracellular traps (NETs), and NETosis are not well studied not only in COVID-19, but also in coroviruses in general. The review will shed lights on the functions of neutrophils, NETs, and NETosis in various infectious complications as well as in sepsis and acute lung conditions in an attempt to understand their actual roles and in order to help in designing targeted therapies in the near future

Natural killer cells in patients with hematologic malignancies, solid tumors and in recipients of hematopoietic stem cell transplantation

Natural killer cells represent the first line of defense against infections and tumors and can be derived from various sources including: bone marrow, peripheral blood, specific types of human stem cells, and certain cell lines. The functions of natural killer cells are influenced by: several cytokines, activating and inhibitory receptors, as well as other immune cells such as dendritic cells and mesenchymal stem cells. Natural killer cells are attractive candidates for adoptive cellular therapy in patients with hematologic malignancies and solid tumors in addition to recipients of various forms of hematopoietic stem cell transplantation as they enhance antitumor effects without causing graft versus host disease. Several clinical trials have shown safety and efficacy of natural killer cell products obtained from autologous as well as allogeneic sources and used in conjunction with cytotoxic chemotherapy, monoclonal antibodies and novel agents. The following review, which includes extensive literature review on several aspects of natural killer cells, will give particular attention to: the rising role of natural killer cell therapies in patients with malignant hematological disorders, solid tumors and in recipients of stem cell therapies; preparation and manufacture of natural killer cell products; challenges facing the utilization of this form of cellular therapy including evolution of resistance; and maneuvers that can be employed to enhance the efficacy of natural killer cell therapies as well as suggested solutions to resolve the remaining challenges

The beneficial effects of varicella zoster virus

Varicella zoster virus behaves differently from other herpes viruses as it differs from them in many aspects. Recently, there has been growing evidence on the beneficial effects of the virus in immune compromised hosts and these effects are translated into prolongation of survival. The reported beneficial effects of the virus include: (1) stimulation of bone marrow activity in patients with hematologic malignancies and bone marrow failure syndromes, (2) antitumor effects in various hematologic malignancies and solid tumors, and (3) association with graft versus host disease which has anticancer effects. Additionally, there are several reports on the safety of the live-attenuated even in severely immune suppressed individuals and on the emerging role of the virus in cancer immunotherapy. In this review, the following aspects of the virus will be thoroughly discussed: (1) new data on the genetic background, pathogenesis, vaccination, and new therapeutic modalities; (2) bone marrow microenvironment and hematopoiesis; (3) cells involved in the pathogenesis of the virus such as: mesenchymal stem cells, dendritic cells, natural killer cells, T-cells and mononuclear cells; (4) cellular proteins such as open reading frames, glycoproteins, promyelocytic leukemia protein, chaperons, and SUMOs; (5) extracellular vesicles, exosomes, and micro-RNAs; and (6) signaling pathways, cytokines, and interferons