Airway remodelling rather than cellular infiltration characterizes both type2 cytokine biomarker-high and -low severe asthma

BACKGROUND

The most recognizable phenotype of severe asthma comprises people who are blood eosinophil and FeNO-high, driven by type 2 (T2) cytokine biology, which responds to targeted biological therapies. However, in many people with severe asthma, these T2 biomarkers are suppressed but poorly controlled asthma persists. The mechanisms driving asthma in the absence of T2 biology are poorly understood.

OBJECTIVES

To explore airway pathology in T2 biomarker-high and -low severe asthma.

METHODS

T2 biomarker-high severe asthma (T2-high, n = 17) was compared with biomarker-intermediate (T2-intermediate, n = 21) and biomarker-low (T2-low, n = 20) severe asthma and healthy controls (n = 28). Bronchoscopy samples were processed for immunohistochemistry, and sputum for cytokines, PGD2 and LTE4 measurements.

RESULTS

Tissue eosinophil, neutrophil and mast cell counts were similar across severe asthma phenotypes and not increased when compared to healthy controls. In contrast, the remodelling features of airway smooth muscle mass and MUC5AC expression were increased in all asthma groups compared with health, but similar across asthma subgroups. Submucosal glands were increased in T2-intermediate and T2-low asthma. In spite of similar tissue cellular inflammation, sputum IL-4, IL-5 and CCL26 were increased in T2-high versus T2-low asthma, and several further T2-associated cytokines, PGD2 and LTE4 , were increased in T2-high and T2-intermediate asthma compared with healthy controls.

CONCLUSIONS

Eosinophilic tissue inflammation within proximal airways is suppressed in T2 biomarker-high and T2-low severe asthma, but inflammatory and structural cell activation is present, with sputum T2-associated cytokines highest in T2 biomarker-high patients. Airway remodelling persists and may be important for residual disease expression beyond eosinophilic exacerbations. Registered at ClincialTrials.gov: NCT02883530.

Hemophilic pseudotumor of the chest

We report the progressive imaging findings of a case of hemophilic pseudotumor of the chest, not previously described. The pseudotumor, although originally extrapleural, has gradually enlarged and eroded into a bronchus, producing a bronchopleural fistula.

Polymorphonuclear leukocytes L-selectin expression decreases as they age in circulation

We recently reported that L-selectin expression increases on circulating polymorphonuclear leukocytes (PMN) during active bone marrow release, which suggests that older cells in the circulation have lower levels of L-selectin than those recently released from the bone marrow. The present study was designed to test the hypothesis that L-selectin expression reduces on PMN as they age in the circulation. In vitro studies using flow cytometry showed that PMN L-selectin decreased to 14.6 +/- 2.3% of baseline during a 24-h incubation at 37 degrees C. To test this hypothesis in vivo, rabbit PMN, labeled in vivo with 5'-bromo-2-deoxyuridine (PMN-brdU) in donor animals, were infused into recipient rabbits as whole blood (n = 5) and followed over 24 h in the circulation with a double immunolabeling technique. These results showed that the fraction of the L-selectin-negative PMN-BrdU in the circulation increased with time (P < 0.001), and nearly all of the PMNBrdU in the circulation were L-selectin negative after 24 h. Removal of L-selectin from the surface of PMN-BrdU with chymotrypsin before infusion did not change their rate of removal from the circulation (half-life or t 1/2 262 vs. 296 min, P = NS). We conclude that there is a continuous loss of L-selectin from PMN during their life span in the circulation, which supports the hypothesis that L-selectin expression decreases on PMN as they age.

A non-radioisotopic method for tracing neutrophils in vivo using 5'-bromo-2'-deoxyuridine

Polymorphonuclear leukocytes (PMN) labeled in vivo with 5'-bromo-2'-deoxyuridine (BrdU) in donor animals were transferred to recipients to determine the rate of clearance of labeled PMN from the circulation, their margination within the vascular space, and migration into Streptococcus pneumoniae-induced inflammatory sites. The donor animals received intravenous infusions at 25 mg/kg/day of BrdU for 7 days when cytospins of leukocyte-rich plasma (LRP) showed that 80 +/- 2.3% PMN were labeled. The BrdU labeled cells were then transfused to serum-compatible recipients as either whole blood, leukocyte-rich plasma, or PMN purified from an equal volume of whole blood. Twenty-four hours after transfer, the distribution of BrdU-labeled PMN in the lung, liver, spleen, bone marrow, and gut was determined morphometrically and by Southern blot analysis of DNA extracted from these organs. BrdU-labeled PMN transfused as either LRP or purified PMN provided no advantage over transfusing whole blood. The half-life of BrdU-labeled PMN in the recipient circulation after transfusing whole blood was 270.4 min (95% confidence intervals, 248.5 to 296.4 min). The majority of the BrdU-labeled DNA was found in the spleen, where DNA analysis showed that the white blood cells underwent programmed cell death by apoptosis. Four hours after infection with S. pneumoniae and 1 h after transfusion of labeled whole blood, BrdU-labeled PMN had migrated into the infected sites. We conclude that transfer of BrdU PMN in whole blood provides a simple, effective method of tracing labeled PMN in vivo.

High dose epirubicin chemotherapy in untreated poorer prognosis small cell lung cancer

A single agent chemotherapy regimen, comprising epirubicin 120 mg m-2 iv at 21-day intervals for a maximum of six cycles was administered to 26 patients with intermediate or poor prognosis small cell lung cancer. Staging consisted of both conventional disease extent and prognostic guidelines based on laboratory parameters. The overall response rate was 57% which predominantly occurred among the intermediate prognosis group (14 of 17 patients), compared with only 1 of 9 patients in the poor prognosis category. Seven patients survived for at least 12 months, including one 3-year survivor (remains disease free). Chemotherapy toxicity was easily managed and chemoresponse was generally accompanied by an improvement in perceived performance rating. The study confirms the activity of epirubicin against small cell lung cancer and emphasizes the importance of patient selection within the spectrum of small cell lung cancer.