Advances in basic and clinical immunology in 2010

Targeting immune pathways for therapy in asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent chronic inflammatory diseases of the airways, with differences in etiology, pathogenesis, immunologic mechanisms, clinical presentation, comorbidities, prognosis, and response to treatment. In mild to moderate early-onset allergic asthma, the Th2-driven eosinophilic airway inflammation and the ensuing disease can be well controlled with maintenance treatment with inhaled corticosteroids (ICS). In real-life settings, asthma control can be improved by facilitating adherence to ICS treatment and by optimizing inhaler technique. In patients with uncontrolled severe asthma, old and novel therapies targeting specific immunologic pathways should be added according to the underlying endotype/phenotype. In COPD, there is a high unmet need for safe and effective antiinflammatory treatments that not only prevent exacerbations but also have a beneficial impact on the course of the disease and improve survival. Although several new approaches aim to target the chronic neutrophilic pulmonary inflammation per se in patients with COPD, strategies that target the underlying causes of the pulmonary neutrophilia (e.g., smoking, chronic infection, and oxidative stress) might be more successful. In both chronic airway diseases (especially in more difficult, complex cases), the choice of the optimal treatment should be based not only on arbitrary clinical labels but also on the underlying immunopathology.

Compound heterozygous CORO1A mutations in siblings with a mucocutaneous-immunodeficiency syndrome of epidermodysplasia verruciformis-HPV, molluscum contagiosum and granulomatous tuberculoid leprosy

PURPOSE

Coronin-1A deficiency is a recently recognized autosomal recessive primary immunodeficiency caused by mutations in CORO1A (OMIM 605000) that results in T-cell lymphopenia and is classified as T(-)B(+)NK(+)severe combined immunodeficiency (SCID). Only two other CORO1A-kindred are known to date, thus the defining characteristics are not well delineated. We identified a unique CORO1A-kindred.

METHODS

We captured a 10-year analysis of the immune-clinical phenotypes in two affected siblings from disease debut of age 7 years. Target-specific genetic studies were pursued but unrevealing. Telomere lengths were also assessed. Whole exome sequencing (WES) uncovered the molecular diagnosis and Western blot validated findings.

RESULTS

We found the compound heterozygous CORO1A variants: c.248_249delCT (p.P83RfsX10) and a novel mutation c.1077delC (p.Q360RfsX44) (NM_007074.3) in two affected non-consanguineous siblings that manifested as absent CD4CD45RA(+) (naïve) T and memory B cells, low NK cells and abnormally increased double-negative (DN) ϒδ T-cells. Distinguishing characteristics were late clinical debut with an unusual mucocutaneous syndrome of epidermodysplasia verruciformis-human papilloma virus (EV-HPV), molluscum contagiosum and oral-cutaneous herpetic ulcers; the older female sibling also had a disfiguring granulomatous tuberculoid leprosy. Both had bilateral bronchiectasis and the female died of EBV+ lymphomas at age 16 years. The younger surviving male, without malignancy, had reproducibly very short telomere lengths, not before appreciated in CORO1A mutations.

CONCLUSION

We reveal the third CORO1A-mutated kindred, with the immune phenotype of abnormal naïve CD4 and DN T-cells and newfound characteristics of a late/hypomorphic-like SCID of an EV-HPV mucocutaneous syndrome with also B and NK defects and shortened telomeres. Our findings contribute to the elucidation of the CORO1A-SCID-CID spectrum.

The vagus nerve and the inflammatory reflex: wandering on a new treatment paradigm for systemic inflammation and sepsis

BACKGROUND

The immune system protects the host against dangerous pathogens and toxins. The central nervous system is charged with monitoring and coordinating appropriate responses to internal and external stimuli. The inflammatory reflex sits at the crossroads of these crucial homeostatic systems. This review highlights how the vagus nerve-mediated inflammatory reflex facilitates rapid and specific exchange of information between the nervous and immune systems to prevent tissue injury and infection.

METHODS

Review of the pertinent English-language literature. Nearly two decades of research has elucidated some of the essential anatomic, physiologic, and molecular connections of the inflammatory reflex. The original descriptions of how these key components contribute to afferent and efferent anti-inflammatory vagus nerve signaling are summarized.

RESULTS

The central nervous system recognizes peripheral inflammation via afferent vagus nerve signaling. The brain can attenuate peripheral innate immune responses, including pro-inflammatory cytokine production, leukocyte recruitment, and nuclear factor kappa β activation via α7-nicotinic acetylcholine receptor subunit-dependent, T-lymphocyte-dependent, vagus nerve signaling to spleen. This efferent arm of the inflammatory reflex is referred to as the "cholinergic anti-inflammatory pathway." Activation of this pathway via vagus nerve stimulation or pharmacologic α7 agonists prevents tissue injury in multiple models of systemic inflammation, shock, and sepsis.

CONCLUSIONS

The vagus nerve-mediated inflammatory reflex is a powerful ally in the fight against lethal tissue damage after injury and infection. Further studies will help translate the beneficial effects of this pathway into clinical use for our surgical patients.

Past and Present Scenario of Imaging Infection and Inflammation: A Nuclear Medicine Perspective

Nuclear medicine techniques provide potential non-invasive tools for imaging infections and inflammations in the body in a precise way. These techniques are further exploited by the use of radiopharmaceuticals in conjunction with imaging tests such as scintigraphy and positron emission tomography. Improved agents for targeting infection exploit the specific accumulation of radiolabeled compounds to understand the pathophysiologic changes involved in the inflammatory process and correlate them with other chronic illnesses. In the recent past, a wide variety of radiopharmaceuticals have been developed, broadly classified as specific radiopharmaceuticals and nonspecific radiopharmaceuticals. New developments in positron emission (leveraging 18F and 18fluorodeoxyglucose) and heterocyclic/peptide chemistry and radiochemistry are resulting in unique agents with high specific activity. Various approaches to visualizing infection and inflammation are presented in this review, in an integral manner, that give a clear view of the existing radiopharmaceuticals in clinical practice and those under development.

Rituximab in immunologic glomerular diseases

Experimental data suggest that the B-cell antigen CD20 may play a significant role in the pathogenesis of many diseases including glomerular diseases. These and other findings underpin the central concept of B-cell-depleting therapies that target CD20 antigen as treatments for lupus nephritis, idiopathic membranous nephropathy, focal segmental glomerulosclerosis, cryglobulinemic glomerulonephritis, antibody mediated renal allograft rejection and recurrent glomerulonephritis in renal allograft. Use of rituximab as a B-cell depleting therapy has been associated with clinical improvement and has emerged as a possible adjunct or alternative treatment option in this field of nephrology.

MST1 mutations in autosomal recessive primary immunodeficiency characterized by defective naive T-cell survival

The molecular mechanisms that underlie T-cell quiescence are poorly understood. In the present study, we report a primary immunodeficiency phenotype associated with MST1 deficiency and primarily characterized by a progressive loss of naive T cells. The in vivo consequences include recurrent bacterial and viral infections and autoimmune manifestations. MST1-deficient T cells poorly expressed the transcription factor FOXO1, the IL-7 receptor, and BCL2. Conversely, FAS expression and the FAS-mediating apoptotic pathway were up-regulated. These abnormalities suggest that increased cell death of naive and proliferating T cells is the main mechanism underlying this novel immunodeficiency. Our results characterize a new mechanism in primary T-cell immunodeficiencies and highlight a role of the MST1/FOXO1 pathway in controlling the death of human naive T cells.