Secondary organizing pneumonia associated with protracted COVID: A case series

OBJECTIVES

Immunocompromised B-cell-depleted patients are at risk of developing protracted COVID-19, a clinical syndrome characterized by prolonged viral shedding and respiratory symptoms that can lead to hypoxemic pneumonia. Our aim is to describe this unusual condition and its treatment.

PATIENTS AND METHODS

This monocentric retrospective study reports six cases of severe organizing pneumonia that developed during the clinical course of protracted COVID-19.

RESULTS

All patients developed organizing pneumonia (OP) in the setting of protracted COVID. Clinical improvement was obtained after several treatment lines including specific antiviral agents and occurred simultaneously with control of the viral load.

CONCLUSION

As it was the most frequent presentation of protracted COVID-19 in our survey, we believe that this specific form of organizing pneumonia warrants increased awareness. Furthermore, specific antiviral therapy seems to control this condition.

Validation and shortcomings of the most common mouse model of chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis (CRS) is a highly prevalent airway disease worldwide. Whereas eosinophilic CRS with nasal polyps (eCRSwNP) represents its most severe phenotype, pathogenic mechanisms remain poorly understood despite a wide spectrum of in vitro and in vivo experimental models. A mouse model of experimental ovalbumin (OVA)-induced airway allergy with coadministration of Staphylococcus aureus enterotoxin B (SEB) has been widely used to study eosinophilic eCRSwNP. This study revisits the features of this model and its suitability for studying eCRS.

METHODOLOGY

We implemented the most used eCRSwNP mouse model based on OVA+SEB intranasal challenges. Readouts including inflammatory features by (immuno)histology of the sinonasal epithelium (NP formation, eosinophils, epithelial and basement membrane thickness, fibrosis, goblet cells, Charcot-Leyden crystals (CLC)-like, tight junctions) and IgE production by enzyme-linked immunosorbent assay (ELISA), were compared to features of the corresponding human disease.

RESULTS

The OVA+SEB model induced eosinophilic inflammation of upper and lower airways, with epithelial and basement membrane thickening, goblet cell hyperplasia and subepithelial fibrosis in the sinuses, along increased IgE production. Except local IgE in nasal lavage (NL), which was only increased in OVA+SEB group, all other features did not differ between OVA and OVA+SEB groups. Macro- or microscopic NP were not detected.

CONCLUSIONS

With the notable exception of local IgE production, the addition of SEB did not induce additional inflammatory or structural change in the sinuses from mice exposed to and challenged with OVA. This model might represent a model for severe upper airway allergy rather than a specific model of human eCRSwNP.

Cost-Effectiveness Analysis of Nintedanib Versus Pirfenidone in Idiopathic Pulmonary Fibrosis in Belgium

BACKGROUND

Nintedanib (Ofev^®) and pirfenidone (Esbriet^®) are recommended by international guidelines as treatment options for idiopathic pulmonary fibrosis (IPF).

OBJECTIVES

To compare the cost-effectiveness of nintedanib with that of pirfenidone for the treatment of IPF from a Belgian healthcare payer perspective.

METHODS

The economic analysis used a Markov model that calculated outcomes over patient lifetime. Overall survival was assumed to be the same for the two comparators. Data from a network meta-analysis were used for loss of lung function, acute exacerbation events, safety and treatment discontinuation (for any reason). The health-state utility estimates in the model were calculated from EQ-5D scores collected in nintedanib studies. The assumed resource use for background care was also based on patient-level data that were categorised to fit the health states in the model and synthesised with costs and tariffs from Belgian national databases.

RESULTS

Treatment with nintedanib resulted in an estimated total cost of €102,315, which was less than the total cost of treatment with pirfenidone (€113,313). Given the similarities in the survival and progression outcomes obtained with nintedanib and pirfenidone, the model predicted near equivalence in total QALYs (3.353 QALYs for the nintedanib arm and 3.318 for the pirfenidone arm). Results were largely driven by model assumptions underlying mortality, acute exacerbations and treatment discontinuation.

CONCLUSIONS

After performing a synthesis of the most recently published evidence for IPF patients and assuming a Belgian healthcare payer perspective, we found nintedanib to be more cost-saving than pirfenidone.

The role of allergen components for the diagnosis of latex-induced occupational asthma

BACKGROUND

Recombinant Hevea brasiliensis (rHev b) natural rubber latex (NRL) allergen components have been developed to assess the patients' allergen sensitization profile and to improve the diagnosis of NRL allergy.

OBJECTIVE

To examine whether the determination of specific IgE (sIgE) reactivity to a panel of recombinant allergen components would be helpful for diagnosing NRL-induced occupational asthma (OA) in predicting the outcome of a specific inhalation test.

METHODS

sIgE levels to NRL extract and 12 recombinant NRL allergen components were assessed in 82 subjects with OA ascertained by a positive specific inhalation challenge (SIC) with NRL gloves and in 25 symptomatic subjects with a negative challenge.

RESULTS

The sensitivity, specificity, positive predictive value, and negative predictive value of a NRL-sIgE level ≥0.35 kUA /l as compared to the result of SICs were 94%, 48%, 86%, and 71%, respectively. The positive predictive value increased above 95% when increasing the cutoff value to 5.41 kUA /l. Subjects with a positive SIC showed a significantly higher rate of sIgE reactivity to rHev b 5, 6.01, 6.02, and 11 than those with a negative SIC. A sIgE sum score against rHev b 5 plus 6.01/6.02 ≥ 1.46 kUA /l provided a positive predictive value >95% with a higher sensitivity (79%) and diagnostic efficiency (Youden index: 0.67) as compared with a NRL-sIgE ≥5.41 kUA /l (49% and 0.41, respectively).

CONCLUSION

In suspected OA, high levels of sIgE against rHev b 5 combined with rHev b 6.01 or 6.02 are the most efficient predictors of a bronchial response to NRL.

When polymerase chain reaction does not help: cytomegalovirus pneumonitis associated with very low or undetectable viral load in both blood and bronchoalveolar lavage samples after lung transplantation

Cytomegalovirus (CMV) pneumonitis occurs frequently among solid organ transplant recipients and is classically associated with significant viral replication in both blood and bronchoalveolar lavage (BAL) samples. We present a case of a 64‐year‐old lung transplant recipient who presented with CMV pneumonitis that was diagnosed based on the association of viral inclusion in the BAL sample, rapid response to ganciclovir, and absence of other infectious etiology. Surprisingly, we observed very low or undetectable viral load both in blood and BAL samples. Diagnosis of CMV pneumonitis should rely on the association of clinical, pathological, radiological, and microbiological signs, while quantitative nucleic acid amplification testing should be interpreted with caution.

Dendritic cells revisited in human allergic rhinitis and asthma

The role of dendritic cells (DCs) in airway allergy has been studied for 15 years; recent data has highlighted the cross talk with airway epithelial cells and environmental factors (allergens, virus) during the inception and exacerbation of allergic asthma. Although murine models have provided key information, it remains uncertain to what extent these basic mechanisms take place in human allergic disease, notably with regard to different clinical phenotypes. In the present review, we discuss new evidence regarding mechanisms of DC regulation in the mouse which could be important in human asthma. Finally, after discussing the effects of current therapies on DC biology, we focus on pathways that could represent targets for future therapies.

Impaired ICOSL in human myeloid dendritic cells promotes Th2 responses in patients with allergic rhinitis and asthma

BACKGROUND

Myeloid dendritic cells (mDCs) and costimulatory molecules such as ICOSL/B7H2 play a pivotal role in murine experimental asthma, while little is known in human allergic disease. The aim of this study was to characterize the phenotype and ICOSL expression of mDCs from allergic rhinitis patients (AR) and their functional correlates on mDC regulation of T cell responses.

METHODS

Human blood myeloid, CD1c(+) DCs were isolated from AR or healthy controls. Expression of costimulatory molecules inducible costimulatory ligand (ICOSL) and programmed death ligand 1 (PD-L1) was analysed in blood mDCs by flow cytometry and in nasal tissue biopsies by dual immunostaining. Blood mDCs were cocultured with (allogeneic) CD4(+) T cells before immunoassays for cytokine responses.

RESULTS

mDCs from AR patients expressed a lower level of ICOSL, in both blood and nasal tissue. mDCs from AR were constitutively primed to induce Th2 cytokines and TNF in allogeneic CD4(+) T cells, while no difference was observed for IFN-γ or IL-10. Production of IL-10 and IL-12 did not differ between AR and control mDCs. Blockade of ICOSL in control DCs up-regulated IL-13 but not IFN-γ in cocultures with T cells, while PD-L1 blockade up-regulated both IL-13 and IFN-γ.

CONCLUSIONS

Our data show that mDCs from patients with AR display impaired expression of ICOSL, and this defect licenses mDCs to promote aberrant IL-13- and IL-5-producing Th2 cell responses.

Myeloid dendritic cells are primed in allergic asthma for thymic stromal lymphopoietin-mediated induction of Th2 and Th9 responses

BACKGROUND

Type 1 myeloid dendritic cells (mDCs) contribute to inception of allergic asthma (AA) and are regulated by epithelial-derived cytokines.

OBJECTIVES

To evaluate whether mDCs from AA patients are primed for thymic stromal lymphopoietin (TSLP)-driven responses.

METHODS

mDCs from 18 AA patients and 15 controls were purified using immunomagnetic sorting. Cells were pulsed with TSLP or Dermatophagoides pteronyssinus (Der p) allergen, before FACS phenotyping and co-culture with allogeneic CD4+ T cells. Bronchial biopsies from 15 AA patients and four controls were immunostained for CD1c and TSLP receptor (TSLPR).

RESULTS

Allergic asthma patients had a higher proportion of TSLPR+ mDCs, in blood and bronchial mucosa. When compared to mDCs from controls, both TSLP- and Der p-pulsed blood mDCs from AA patients induced increased polarization of CD4+ T cells into Th2 cells (IL-5, IL-13, and GATA3+), while only TSLP-mDCs promoted Th9 cells (IL-9 and PU.1+ /IRF4+). In addition, OX40L was induced upon TSLP stimulation and was required for the induction of Th2, but not Th9, cells. In contrast, development of Th9 cells in this model depended on TGF-β1.

CONCLUSIONS

Our data indicate overlapping but partially distinct effects of TSLP and Der p allergen pathways, showing that DCs are primed in human asthma for TSLP-driven induction of both Th2 and Th9 cells. This novel TSLP/mDC/Th9 axis operates through a distinct, OX40L-independent pathway. These data further highlight the TSLP pathway as a relevant target in human asthma.

Multisystemic sarcoidosis associated with a second therapy for chronic hepatitis C

Hepatitis C virus (HCV) infection is a very common chronic infectious disease. Combined antiviral therapy including pegylated interferon and ribavirine is presently the standard treatment, with sustained viral response rate over 50%. Interferon induces the development of several autoimmune diseases. Some cases of induced sarcoidosis have been described (affecting mostly lungs, skin and eyes), both with standard and pegylated interferon. We report the case of an African woman, heterozygote for sickle cell anaemia mutation and for glucose-6-phosphate-deshydrogenase (G6PD) deficiency, who developed a multisystemic sarcoidosis (skin, lungs, liver, salivary and lachrymal glands, peripheral nerves), confirmed by biopsies, in the course of a second treatment with pegylated interferon and ribavirine for hepatitis C. The antiviral treatment was discontinued and all symptoms regressed spontaneously within some weeks.