Baseline TGF-β correlates with protection after immunization with Plasmodium falciparum sporozoites in the Controlled Human Malaria Infection model

BACKGROUND

Here we assessed a possible relationship between baseline TGF-β concentrations and acquisition of sterile immunity after Plasmodium falciparum sporozoite immunization.

METHODS

TGF-β concentrations were determined in samples of 65 malaria-naive volunteers in 4 studies either prior to and after challenge infection, or prior to and after first immunizing infection under chemoprophylaxis with P. falciparum sporozoites.

RESULTS

High baseline TGF-β concentrations were associated with rapid acquisition of sterile protection (p=0.028).

CONCLUSION

Baseline TGF-β concentrations predict the efficiency of acquisition of sterile immunity following sporozoite immunisation and may represent a steady-state regulatory mechanism to keep in check immune systems with a low threshold for activation.

Non-invasive ventilation with bubble CPAP is feasible and improves respiratory physiology in hospitalised Malawian children with acute respiratory failure

BACKGROUND

In low-income countries and those with a high prevalence of HIV, respiratory failure is a common cause of death in children. However, the role of non-invasive ventilation with bubble continuous positive airway pressure (bCPAP) in these patients is not well established.

METHODS

A prospective observational study of bCPAP was undertaken between July and September 2012 in 77 Malawian children aged 1 week to 14 years with progressive acute respiratory failure despite oxygen and antimicrobial therapy.

RESULTS

Forty-one (53%) patients survived following bCPAP treatment, and an HIV-uninfected single-organ disease subgroup demonstrated bCPAP success in 14 of 17 (82%). Compared with children aged ≧60 months, infants of 0-2 months had a 93% lower odds of bCPAP failure (odds ratio 0·07, 95% confidence interval 0·004-1·02, P  =  0·05). Following commencement of bCPAP, respiratory physiology improved, the average respiratory rate decreased from 61 to 49 breaths/minute (P  =  0·0006), and mean oxygen saturation increased from 92·1% to 96·1% (P  =  0·02).

CONCLUSIONS

bCPAP was well accepted by caregivers and patients and can be feasibly implemented into a tertiary African hospital with high-risk patients and limited resources.

Observation of edge instability limiting the pedestal growth in tokamak plasmas

With fusion device performance hinging on the edge pedestal pressure, it is imperative to experimentally understand the physical mechanism dictating the pedestal characteristics and to validate and improve pedestal predictive models. This Letter reports direct evidence of density and magnetic fluctuations showing the stiff onset of an edge instability leading to the saturation of the pedestal on the Alcator C-Mod tokamak. Edge stability analyses indicate that the pedestal is unstable to both ballooning mode and kinetic ballooning mode in agreement with observations.

Inhibitory receptor expression on neonatal immune cells

Neonates are born with quantitative and qualitative defects in both adaptive and innate immune responses. The immune system is regulated by several mechanisms, including the signalling of inhibitory receptors. Increased expression of inhibitory receptors may result in a higher threshold for activation and suppressed function of neonatal cells. The aim of this study was to determine whether the expression of seven inhibitory receptors is increased on neonatal immune cells compared to adult immune cells. In a healthy birth cohort, we examined the expression of seven inhibitory immune receptors on neonatal neutrophils, monocytes, natural killer (NK) cells, CD4(+) and CD8(+)T cells. The expression of leucocyte-associated immunoglobulin (Ig)-like receptor-1 (LAIR-1), signal inhibitory receptor on leucocytes-1 (SIRL-1), CD31, signal-regulatory protein alpha (SIRPα), Siglec-9, CD200R, immune receptor expressed on myeloid cells-1 (IREM-1) and the membrane-bound ligand CD200 was studied by flow cytometry on leucocytes in cord blood (n = 14), neonatal venous blood (n = 24) and adult venous blood (n = 22). Expression of LAIR-1, CD31 and CD200 was increased consistently across all neonatal T cell subsets. Neonatal monocytes exhibited decreased expression of LAIR-1 and IREM-1 compared to adults. Furthermore, cord blood and neonatal venous blood samples contained a distinct LAIR-1-positive neutrophil population, which was not detected in adult blood. We demonstrated distinct expression of inhibitory receptors on neonatal peripheral blood immune cells in a healthy birth cohort. This is the first evidence that inhibitory receptors play a role in regulation of the neonatal immune system. Consistently increased inhibitory receptor expression on T cells may be an important mechanism in preventing the development of allergy and autoimmunity.