What has happened in the last 50 years in immunology

Fifty years ago, in 1964, our understanding of the immune system was very rudimentary. Gell and Coombs had just described classes of hypersensitivity reactions, and Bruton had described and commenced immunoglobulin replacement in agammaglobulinaemia. The distinction between T and B cells was not identified and characterised until the 1960s and 1970s. This was followed by increasing recognition of T and B cell collaboration in immune responses and identification of significant immunodeficiencies. CD4 and CD8 T cells were only recognised in the 1970s and 1980s. We now know of five CD4 subsets; dysfunction of each is associated with different disorders. By 2014, advances in technology have enabled identification of the genetic basis of over 240 primary immunodeficiencies. Research into the gut microbiome and vitamin D holds promise for the understanding, treatment and prevention of autoimmune and allergic diseases. Immunoglobulin preparations for the treatment of antibody deficiencies improved with the development of preparations for intravenous then subcutaneous administration, giving patients choice and the ability for home‐based treatment, especially if experiencing infusion associated adverse effects. Newborn screening for severe combined immunodeficiency is a reality. Improvements in haemopoietic stem cell transplantation and now gene therapy, albeit still only available in the research setting, are improving long‐term survival in primary immunodeficiencies. Biologic therapeutic agents are improving the control of autoimmune disease but potentially leading to secondary immunodeficiency, increasing the risk of opportunistic infection and malignancy. It is an exciting time.     

Catheter ablation of the atrioventricular node using radiofrequency energy

Background: Catheter ablation of the atrioventricular (AV) junction using stored direct current (DC) energy from a standard DC Cardioverter defibrillator was first reported in 1982. Since then many patients have been treated using this procedure for refractory supraventricular arrhythmias, usually atrial fibrillation and flutter. Undesirable thermal effects such as barotrauma and arcing are largely responsible for complications associated with the use of DC energy. This report details our experience of catheter ablation of the AV junction using radiofrequency (RF) energy in a series of 30 consecutive patients. Methods: RF ablations were performed using steerable Mansfield (Webster Laboratories) 4 mm tipped electrodes and locally assembled RF energy delivery system. Results: The procedure was successful in 27/30 (90%) patients using RF energy, while three patients required DC energy to achieve successful AV junction ablation. General anaesthesia was required in nine patients, six of whom required this for cardioversion to sinus rhythm so that an adequate His Bundle spike could be recorded and three for DC ablation. Dual chamber permanent pacemakers with automatic mode switching were implanted in four patients who had paroxysmal atrial fibrillation or flutter and the remainder had ventricular rate responsive pacemakers. Conclusions: In patients with drug refractory paroxysmal atrial fibrillation and flutter and in patients with established atrial fibrillation where control of the ventricular rate is difficult, catheter ablation of the AV junction using RF energy is a safe and effective procedure with a high success rate.     

l‐Methionine anti‐biofilm activity against Pseudomonas aeruginosa is enhanced by the cystic fibrosis transmembrane conductance regulator potentiator,ivacaftor

Background

Biofilms may contribute to refractory chronic rhinosinusitis (CRS), as they lead to antibiotic resistance and failure of effective clinical treatment. l ‐Methionine is an amino acid with reported biofilm‐inhibiting properties. Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator with mild antimicrobial activity via inhibition of bacterial DNA gyrase and topoisomerase IV. The objective of this study was to evaluate whether co‐treatment with ivacaftor and l ‐methionine can reduce the formation of Pseudomonas aeruginosa biofilms.

Methods

P aeruginosa (PAO‐1 strain) biofilms were studied in the presence of l ‐methionine and/or ivacaftor. For static biofilm assays, PAO‐1 was cultured in a 48‐well plate for 72 hours with stepwise combinations of these agents. Relative biofilm inhibitions were measured according to optical density of crystal violet stain at 590 nm. Live/dead assays (BacTiter‐Glo? assay, Promega) were imaged with laser scanning confocal microscopy. An agar diffusion test was used to confirm antibacterial effects of the drugs.

Results

l ‐Methionine (0.5 μM) significantly reduced PAO‐1 biofilm mass (32.4 ± 18.0%; n = 4; p < 0.001) compared with controls. Low doses of ivacaftor alone (4, 8, and 12 μg/mL) had no effect on biofilm formation. When combined with ivacaftor (4 μg/mL), a synergistic anti‐biofilm effect was noted at 0.05 μM and 0.5 μM of l ‐methionine (two‐way analysis of variane, p = 0.0415) compared with corresponding concentrations of l ‐methionine alone.

Conclusion

Ivacaftor enhanced the anti‐biofilm activity of l ‐methionine against the PAO‐1 strain of P aeruginosa. Further studies evaluating the efficacy of ivacaftor/l ‐methionine combinations for P aeruginosa sinusitis are planned.

     

Protective immunity induced by daily bites from irradiated mosquitoes infected with Plasmodium yoelii

Individuals in malaria endemic regions do not develop fully protective immune responses against Plasmodium liver stage infections. In high transmission areas, individuals can be exposed to more than two infective mosquito bites daily. Their exposure to Plasmodium sporozoites, therefore, is in the form of small and frequent doses. This is very different from individuals studied in controlled immunization trials where the delivery of large numbers of radiation-attenuated sporozoites in a limited number of doses can induce sterile protective immunity. Using irradiated mosquitoes infected with Plasmodium yoelii 17XNL, we tested whether daily bites from a few mosquitoes can induce a protective immune response in mice. This immunization strategy successfully induced a protective response, preventing the development of liver stages when mice were challenged with nonirradiated sporozoites. These results provide further support for the development of liver stage vaccines. They are also a call for further study into why fully protective responses against the liver stage are not seen in individuals from endemic regions.     

Natural bioburden levels detected on rigid lumened medical devices before and after cleaning

Controversy exists concerning the degree of microbial contamination associated with the us of rigid lumened medical devices, the efficacy of standard cleaning techniques used to remove pathogenic microorganisms from lumen channels, and whether patients are placed at risk of cross infection because of microbial contamination. In this study the level and types of microorganisms found on rigid lumened medical devices before and after cleaning in a hospital environment were investigated. The bioburden level after clinical use was found to be relatively low, ranging from 10¹ to 10⁴ colony forming units (CFU) per device. After the instruments were cleaned, none of the devices studied contained bioburden levels greater than 10⁴ CFU and 83% had bioburden levels less than or equal to 10² CFU. The bioburden present before cleaning was comprised of organisms derived from the handling of the device, from the hospital environment, and from the patient. The bioburden present after cleaning was comprised of organisms typically derived from the handling of the device and from the hospital environment. The level of bioburden per device was also related to the anatomic site where the device was used, with lower numbers of organisms found on devices exposed to sterile body sites and the respiratory tract.     

Characteristics of dysphagia in children with cerebral palsy

Videofluoroscopic modified barium swallow (VMBS) examinations may provide clinically relevant information regarding deglutition in children with cerebral palsy and dysphagia. A retrospective review of clinical evaluations and VMBS studies on 90 consecutive children with cerebral palsy and dysphagia was completed. Most children were referred because of concerns regarding airway protection during oral feedings. Most children had multiple disabilities and 93% were nonambulatory. The majority of children were totally dependent for oral feedings (80%). Oral and pharyngeal phase abnormalities were present in almost all patients. Abnormalities of deglutition were observed only while swallowing specific food textures in the majority of patients. Aspiration of specific food textures was significantly more common than aspiration of all food textures (p<0.0001). Finally, aspiration was silent in 97% of the patients. VMBS studies can provide clinicians with valuable information regarding the most appropriate food textures and rates of oral feeding for children with cerebral palsy and dysphagia.     

Sleep problems in early childhood and early onset of alcohol and other drug use in adolescence

BACKGROUND: No prospective studies exist on the relationship between sleep problems early in life and subsequent alcohol use. Stimulated by the adult literature linking sleep problems to the subsequent onset of alcohol use disorders in some adults, we examined whether sleep problems in early childhood predicted the onset of alcohol and other drug use in adolescence and whether such a relationship was mediated by other known predictors of this relationship, namely, attention problems, anxiety/depression, and aggression in late childhood. METHODS: This study is part of an ongoing longitudinal study of the development of risk for alcohol and other substance use disorders. Study participants were 257 boys from a community-recruited sample of high-risk families. RESULTS: Mothers' ratings of their children's sleep problems at ages 3 to 5 years significantly predicted an early onset of any use of alcohol, marijuana, and illicit drugs, as well as an early onset of occasional or regular use of cigarettes by age 12 to 14. Additionally, although sleep problems in early childhood also predicted attention problems and anxiety/depression in later childhood, these problems did not mediate the relationship between sleep problems and onset of alcohol and other drug use. CONCLUSIONS: This is, to our knowledge, the first study that prospectively examines the relationship between sleep problems and early onset of alcohol use, a marker of increased risk for later alcohol problems and alcohol use disorders. Moreover, early childhood sleep problems seem to be a robust marker for use of drugs other than alcohol. Implications for the prevention of early alcohol and other drug use are discussed.     

Cardiac Genetic Predisposition in Sudden Infant Death Syndrome

Background

Sudden infant death syndrome (SIDS) is a leading cause of postneonatal mortality. Genetic heart diseases (GHDs) underlie some cases of SIDS.

Pediatric patients who receive antibiotics for fever and neutropenia in less than 60 min have decreased intensive care needs

Background

Antibiotic delivery to patients with fever and neutropenia (F&N) in <60 min is an increasingly important quality measure for oncology centers, but several published reports indicate that a time to antibiotic delivery (TTA) of <60 min is quite difficult to achieve. Here we report a quality improvement (QI) effort that sought to decrease TTA and assess associated clinical outcomes in pediatric patients with cancer and F&N.

Procedure

We used Lean‐Methodology and a Plan‐Do‐Study‐Act approach to direct QI efforts and prospectively tracked TTA measures and associated clinical outcomes (length of stay, duration of fever, use of imaging studies to search for occult infection, bacteremia, intensive care unit (ICU) consultation or admission, and mortality). We then performed statistical analysis to determine the impact of our QI interventions on total TTA, sub‐process times, and clinical outcomes.

Results

Our QI interventions significantly improved TTA such that we are now able to deliver antibiotics in <60 min nearly 100% of the time. All TTA sub‐process times also improved. Moreover, achieving TTA <60 min significantly reduced the need for ICU consultation or admission (P = 0.003) in this population.

Conclusion

Here we describe our QI effort along with a detailed assessment of several associated clinical outcomes. These data indicate that decreasing TTA to <60 min is achievable and associated with improved outcomes in pediatric patients with cancer and F&N. Pediatr Blood Cancer 2015;62:807–815. © 2015 The Authors. Pediatric Blood & Cancer, published by Wiley Periodicals, Inc.