Monocyte disorder causing cellular immunodeficiency: a family study

Tolerating CD47

Cluster of differentiation 47 (CD47) occupies the outer membrane of human cells, where it binds to soluble and cell surface receptors on the same and other cells, sculpting their topography and resulting in a pleiotropic receptor-multiligand interaction network. It is a focus of drug development to temper and accentuate CD47-driven immune cell liaisons, although consideration of on-target CD47 effects remain neglected. And yet, a late clinical trial of a CD47-blocking antibody was discontinued, existent trials were restrained, and development of CD47-targeting agents halted by some pharmaceutical companies. At this point, if CD47 can be exploited for clinical advantage remains to be determined. Herein an airing is made of the seemingly conflicting actions of CD47 that reflect its position as a junction connecting receptors and signalling pathways that impact numerous human cell types. Prospects of CD47 boosting and blocking are considered along with potential therapeutic implications for autoimmune diseases and cancer.

Investigating the susceptibility of mice to a bacterial challenge after intravenous exposure to durable nanoparticles

AIM

The goal of this study was to determine whether bacterial clearance in a rodent model would be impaired upon exposure to gold, silver or silica nanoparticles (NPs).

MATERIALS & METHODS

Mice received weekly injections of NPs followed by a challenge of Listeria monocytogenes (LM). On days 3 and 10 after LM injections, the animals were sacrificed and their tissues were collected for elemental analysis, electron microscopy and LM count determination.

RESULTS

The untreated and NP-treated animals cleared LM at the same rate suggesting that bioaccumulation of NPs did not increase the animals' susceptibility to bacterial infection.

CONCLUSION

The data from this study indicate that the bioaccumulation of NPs does not significantly affect the ability to react to a bacterial challenge.

Effect of silica and gold nanoparticles on macrophage proliferation, activation markers, cytokine production, and phagocytosis in vitro

The accumulation of durable nanoparticles (NPs) in macrophages following systemic administration is well described. The ultimate biological impact of this accumulation on macrophage function, however, is not fully understood. In this study, nontoxic doses of two durable NPs, SiO₂ and Au, at particle sizes of ~10 nm and 300 nm were used to evaluate the effect of bioaccumulation on macrophage function in vitro using RAW 264.7 mouse macrophage-like cells as a model system. Cell proliferation, cell cycle, cytokine production, surface marker activation, and phagocytosis responses were evaluated through a panel of assays using flow cytometry and confocal microscopy. The most dramatic change in RAW 264.7 cell function was a reduction in phagocytosis as monitored by the uptake of Escherichia coli. Cells exposed to both 10 nm Au NPs and 10 nm SiO₂ NPs showed ~50% decrease in phagocytosis, while the larger NPs caused a less dramatic reduction. In addition to modifying phagocytosis profiles, 10 nm SiO₂ NPs caused changes in proliferation, cell cycle, and cell morphology. Au NPs had no effect on cell cycle, cytokine production, or surface markers and caused interference in phagocytosis in the form of quenching when the assay was performed via flow cytometry. Confocal microscopy analysis was used to minimize this interference and demonstrated that both sizes of Au NPs decreased the phagocytosis of E. coli. Overall, our results demonstrate that Au and SiO₂ NP uptake by macrophages can influence macrophage phagocytosis in vitro without altering surface markers and cytokine production in vitro. While the biological impact of these findings remains unclear, our results indicate that bioaccumulation of durable NPs within the macrophages may lead to a suppression of bacterial uptake and possibly impair bactericidal activity.

Evaluation of the child with suspected primary immunodeficiency

Infections are one of the major causes for visits to paediatricians. Most children recover without sequelae, untreated or if treated properly, and develop specific immunity towards the challenging microorganisms (mostly viruses). There is a small proportion of children however, with unusual frequent, severe, chronic, recurrent or opportunistic infections in whom an underlying immunodeficiency must be suspected. Based on current knowledge about the major types of congenital immunodeficiencies this review suggests a diagnostic approach to these children. Early evaluation will allow early identification of affected children and, subsequently, lead to proper treatment before devastating infections cause irreversible organ damage.

High-dose intravenous immunoglobulin in non-ABO transfusion incompatibility

The administration of intravenous immunoglobulin (IVIG) in immune and autoimmune diseases led us to use this agent to ameliorate or prevent the consequences of non-ABO incompatible transfusions in patients who need this form of therapy. IVIG (400 mg/kg/day) was infused within 24 h of transfusion in 5 patients with: (1) intestinal angiodysplasia, gastrointestinal bleeding, and anti-Kpb; (2) paroxysmal nocturnal hemoglobinuria, anti-c, anti E, anti Fyb, anti-K and autoantibodies; (3) lymphoma and autoimmune hemolytic anemia (AIHA); (4) systemic lupus erythematosus (SLE), AIHA, and anti-D, and (5) SLE and AHIA. A sustained increase in hematocrit was noted and no transfusion reaction developed in any of the cases. A single dose of pretransfusion IVIG may therefore be a useful therapeutic alternative in patients for whom no compatible blood is available. Patients with severe anemia, allo- and autoantibodies, either showing hemolysis in their pathophysiology or not, cause a serious problem in any transfusion center, especially when dealing with emergencies. In order to reduce the risks of incompatible transfusions, different modalities have previously been attempted, all with poor results. In 1989 we reported the successful use of pretransfusional high-dose intravenous immunoglobulin (IVIG) in a patient with gastrointestinal bleeding and anti-Kpb. The transfusion of incompatible red blood cells improved the anemia and allowed the exploratory laparotomy to take place. A protocol was then developed based on this case administering pretransfusion IVIG in high doses for patients for whom no compatible blood (non-ABO) is available.