BACKGROUND Primary immunodeficiency diseases (PIDs) are considered rare but are generally assumed to be more common in Middle Eastern countries. The prevalence and characteristics of PIDs are unknown in Oman. METHODS Sultan Qaboos University Hospital is the national referral center for PID in Oman during the study period. Patients were diagnosed and classified according to the clinical and la...

Group A Streptococcus (GAS) is a Gram-positive bacterium associated with a variety of mucosal and invasive human infections. GAS systemic disease reflects the diverse abilities of this pathogen to avoid eradication by phagocytic defenses of the innate immune system. Here we review how GAS can avoid phagocyte engagement, inhibit complement and antibody functions required for opsonization, impair...

Biological cellular systems are groups of cells sharing a set of characteristics, mainly key function and origin. Phagocytes are crucial in the host defense against microbial infection. The previously proposed phagocyte cell systems including the most recent and presently prevailing one, the mononuclear phagocyte system (MPS), grouped mononuclear cells but excluded neutrophils, creating an unac...

The serotonin transporter (5-HTT) is most well known as the site of action of the serotonin reuptake inhibitors, which were initially developed as antidepressants, but now are the most widely used agents in the treatment of many additional neuropsychiatric and related disorders. The discovery that the gene that expresses the 5-HTT possesses a functional promoter-region polymorphism, which is as...

UNLABELLED An important first line of defense against Candida albicans infections is the killing of fungal cells by professional phagocytes of the innate immune system, such as polymorphonuclear cells (PMNs) and macrophages. In this study, we employed live-cell video microscopy coupled with dynamic image analysis tools to provide insights into the complexity of C. albicans phagocytosis when mac...

Chronic granulomatous disease (CGD) encompasses a group of rare inherited disorders characterized by defects in a phagocyte-specific NADPH-oxidase complex that forms the superoxide radical during the respiratory burst. In this chapter, the protein components and cellular biochemistry of the oxidase are reviewed in light of recent genetic and biochemical studies of CGD. The classification and mo...

BACKGROUND Deficient production of reactive oxygen species (ROS) by the phagocyte nicotinamide adenine dinucleotide (NADPH) oxidase in patients with chronic granulomatous disease (CGD) results in susceptibility to certain pathogens secondary to impaired oxidative killing and mobilization of other phagocyte defenses. Peroxisome proliferator-activated receptor (PPAR) γ agonists, including pioglit...

In previous reports there have been scattered references to possible disorders in function of macrophages in malignant disease. For example, a decrease in macrophage numbers was reported in skin window exudates of patients with Hodgkin's granuloma,' while the foreign body inflammatory response within a variety of transplantable tumours in subcutaneous sites in rodents was found to be minimal.2 ...

Bacteria of the genus Legionella are intracellular parasites and major human pathogens. They bind to surface receptors, penetrate eukaryotic cells and initiate complex disorders during phagocytosis. These disorders include inhibition of oxidative burst, a decrease in phagosome acidification, the blocking of phagosome maturation and changes in organelle trafficking. As a result, the microorganis...