CD11b immunophenotyping identifies inflammatory profiles in the mouse and human lungs

The development of easily accessible tools for human immunophenotyping to classify patients into discrete disease endotypes is advancing personalized therapy. However, no systematic approach has been developed for the study of inflammatory lung diseases with often complex and highly heterogeneous disease etiologies. We have devised an internally standardized flow cytometry approach that can identify parallel inflammatory alveolar macrophage phenotypes in both the mouse and human lungs. In mice, lung innate immune cell alterations during endotoxin challenge, influenza virus infection, and in two genetic models of chronic obstructive lung disease could be segregated based on the presence or absence of CD11b alveolar macrophage upregulation and lung eosinophilia. Additionally, heightened alveolar macrophage CD11b expression was a novel feature of acute lung exacerbations in the SHIP-1(-/-) model of chronic obstructive lung disease, and anti-CD11b antibody administration selectively blocked inflammatory CD11b(pos) but not homeostatic CD11b(neg) alveolar macrophages in vivo. The identification of analogous profiles in respiratory disease patients highlights this approach as a translational avenue for lung disease endotyping and suggests that heterogeneous innate immune cell phenotypes are an underappreciated component of the human lung disease microenvironment.

Proliferation is not increased in airway myofibroblasts isolated from asthmatics

Airway mesenchymal cells, such as myofibroblasts and airway smooth muscle cells, contribute to inflammation, airway remodelling and hyperresponsiveness in asthma by excessive proliferation and inflammatory mediator production. Using endobronchial biopsies obtained from both nonasthmatic and asthmatic subjects, in situ proliferation was assessed by immunostaining for cyclin D1. The number of immunoreactive cells increased with asthma severity and was restricted to the epithelium and subepithelial connective tissue. Despite increases in smooth muscle area, cyclin D1 was not detected in cells in intact muscle bundles. Biopsy-derived cell cultures were characterised as predominantly myofibroblasts, and were assessed to determine whether proliferation and cytokine production varied with asthma status. Cell enumeration showed that basal proliferation was similar in cells from nonasthmatics and asthmatics, and mitogenic responses to fibroblast growth factor-2, thrombin or serum were either reduced or unchanged in cells from asthmatics. Interleukin (IL)-1-dependent granulocyte-macrophage colony-stimulating factor and IL-8 release was increased in cell supernatants from asthmatics. Thus, increased rates of cellular proliferation identified in situ in the asthmatic airway occurred outside the expanded smooth muscle compartment. Although reduced proliferative responses were observed in cultured myofibroblasts from asthmatics, the increased cytokine production by these cells suggests that this contributes to and may perpetuate ongoing inflammation in asthma.

Hutchinson-Gilford progeria syndrome: clinical findings in three patients carrying the G608G mutation in LMNA and review of the literature

BACKGROUND

Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature ageing disorder that belongs to a group of conditions called laminopathies which affect nuclear lamins. Classical and atypical forms of HGPS have been reported and there are clinical overlaps with mandibulo-acral dysplasia and restrictive dermopathy. To date, mutations in two genes, LMNA and ZMPSTE24, have been found in patients with HGPS. The p.G608G LMNA mutation is the most commonly reported mutation. Correlations between genotype and phenotype in children with progeroid syndromes are beginning to emerge.

OBJECTIVES

To establish whether the LMNA p.G608G mutation is associated with a particular phenotype of HGPS.

METHODS

We reviewed the clinical features and skin histology of three children with HGPS associated with the p.G608G LMNA mutation, and compared our findings with those reported in the literature.

RESULTS

Our patients shared a very similar presentation and clinical course. Skin changes were the earliest finding in all three. Skin histology showed nonspecific changes only.

CONCLUSIONS

The LMNA p.G608G mutation results in a uniform phenotype through early to mid-childhood, in keeping with that described in classical HGPS. Skin changes are the earliest distinctive clinical finding and should prompt careful physical and radiological examination for other features of HGPS. Skin biopsy for histology is not a useful investigation when a diagnosis of HGPS is suspected.

An epidemiologic study of fatigue with relevance for the chronic fatigue syndrome

We surveyed households in four rural Michigan communities to confirm a reported cluster of cases resembling chronic fatigue syndrome (CFS) and to study the epidemiology of fatigue in a rural area. Data were collected from 1698 households. We did not confirm the reported cluster. The prevalence of households containing at least one fatigued person was similar between communities thought to harbor the cluster and communities selected for comparison. Symptoms and features of generic forms of fatigue were very similar to those often attributed to CFS.