Activation of CD8+ T Cells in Chronic Obstructive Pulmonary Disease Lung

Rationale: Despite the importance of inflammation in chronic obstructive pulmonary disease (COPD), the immune cell landscape in the lung tissue of patients with mild-moderate disease has not been well characterized at the single-cell and molecular level. Objectives: To define the immune cell landscape in lung tissue from patients with mild-moderate COPD at single-cell resolution. Methods: We performed single-cell transcriptomic, proteomic, and T-cell receptor repertoire analyses on lung tissue from patients with mild-moderate COPD (n = 5, Global Initiative for Chronic Obstructive Lung Disease I or II), emphysema without airflow obstruction (n = 5), end-stage COPD (n = 2), control (n = 6), or donors (n = 4). We validated in an independent patient cohort (N = 929) and integrated with the Hhip+/- murine model of COPD. Measurements and Main Results: Mild-moderate COPD lungs have increased abundance of two CD8+ T cell subpopulations: cytotoxic KLRG1+TIGIT+CX3CR1+ TEMRA (T effector memory CD45RA+) cells, and DNAM-1+CCR5+ T resident memory (TRM) cells. These CD8+ T cells interact with myeloid and alveolar type II cells via IFNG and have hyperexpanded T-cell receptor clonotypes. In an independent cohort, the CD8+KLRG1+ TEMRA cells are increased in mild-moderate COPD lung compared with control or end-stage COPD lung. Human CD8+KLRG1+ TEMRA cells are similar to CD8+ T cells driving inflammation in an aging-related murine model of COPD. Conclusions: CD8+ TEMRA cells are increased in mild-moderate COPD lung and may contribute to inflammation that precedes severe disease. Further study of these CD8+ T cells may have therapeutic implications for preventing severe COPD.

Single-cell transcriptomics reveal a hyperacute cytokine and immune checkpoint axis after cardiac arrest in patients with poor neurological outcome

BACKGROUND

Most patients hospitalized after cardiac arrest (CA) die because of neurological injury. The systemic inflammatory response after CA is associated with neurological injury and mortality but remains poorly defined.

METHODS

We determine the innate immune network induced by clinical CA at single-cell resolution.

FINDINGS

Immune cell states diverge as early as 6 h post-CA between patients with good or poor neurological outcomes 30 days after CA. Nectin-2+ monocyte and Tim-3+ natural killer (NK) cell subpopulations are associated with poor outcomes, and interactome analysis highlights their crosstalk via cytokines and immune checkpoints. Ex vivo studies of peripheral blood cells from CA patients demonstrate that immune checkpoints are a compensatory mechanism against inflammation after CA. Interferon γ (IFNγ)/interleukin-10 (IL-10) induced Nectin-2 on monocytes; in a negative feedback loop, Nectin-2 suppresses IFNγ production by NK cells.

CONCLUSIONS

The initial hours after CA may represent a window for therapeutic intervention in the resolution of inflammation via immune checkpoints.

FUNDING

This work was supported by funding from the American Heart Association, Brigham and Women's Hospital Department of Medicine, the Evergreen Innovation Fund, and the National Institutes of Health.

"Allergic bronchopulmonary aspergillosis misdiagnosed as smear negative pulmonary tuberculosis; a retrospective study from Pakistan"

Background

Undiagnosed allergic bronchopulmonary aspergillosis (ABPA) can lead to chronic persistent symptoms. In country like Pakistan where tuberculosis (TB) is endemic, a significant proportion of ABPA patients are misdiagnosed as smear negative TB before reaching a diagnosis of ABPA due to chronicity of symptoms.This lead to empiric use of ATT(Anti-tuberculous therapy) and delay in primary diagnosis. The aim of the study is to determine such proportion of ABPA patients.

Material and methods

This retrospective study was conducted at the outpatient pulmonology clinic of a tertiary care hospital in Karachi, Pakistan from January 2017 to December 2018. Xpert MTB/Rif, TB smear and culture were performed in all patients to rule out active TB.

Results

A total 167 of ABPA patients were included. Mean age of the patients was 41.9 ± 13.0 years, 91(54.5%) were female and 71 (42.5%) patients had received ATT in past. Out of these 71 patients, 63 (88.7%) patients were diagnosed as smear negative TB and received empiric ATT. Among 63 patients, 52 (82.5%) patient had received ATT once, 8 (12.6%) twice and 3 (4.7%) patients had received empiric ATT thrice. Of these 27 (16.16%) patients had already developed long term complications at the time of diagnosis of ABPA and 17 (62.96%) patients were in empiric TB treatment group.

Conclusion

Patient with ABPA frequently received empiric ATT as smear negative TB in high TB burden country. This results in over diagnosis of TB and unnecessary use of global resource. When Gene Xpert negative alternate diagnosis should be considered.

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Allergic bronchopulmonary aspergillosis (ABPA) can lead to chronic persistent symptoms.

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In country like Pakistan where tuberculosis (TB) is endemic, a significant proportion of ABPA patients are misdiagnosed as smear negative TB before reaching a diagnosis of ABPA due to chronicity of symptoms which leads to empiric use of ATT.

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So the aim of the study is to determine such proportion of ABPA patients in country where TB is endemic.

Idiopathic pulmonary hemosiderosis - A rare cause of chronic anemia

Idiopathic pulmonary hemosiderosis (IPH) is a rare disease marked by alveolar bleeding and accumulation of hemosiderin in the lungs. Here we present three cases of IPH. The first case is of a 26-year-old male with anemia, hemoptysis and dyspnea. Bronchoscopy confirmed diffuse alveolar hemorrhage (DAH). A diagnosis of IPH was made after ruling out other causes of DAH and observing good response to steroids. The patient's condition improved with prednisolone and azathioprine. The second case is of 26-year-old female with severe anemia. Imaging suggested IPH and lung biopsy confirmed it. She died shortly afterwards. The third case is of a 7-year-old male with chronic anemia. CT was suggestive of IPH and lung biopsy confirmed the diagnosis. Later, patient developed posterior reversible encephalopathy syndrome (PRES). This patient is stable on azathioprine and prednisolone. We aim to emphasize the importance of considering IPH as a differential in patients with DAH or chronic anemia.

Comparison of Xpert MTB/RIF with AFB smear and AFB culture in suspected cases of paediatric tuberculosis in a tertiary care hospital, Karachi

OBJECTIVE

To evaluate the sensitivity, specificity, positive predictive and negative predictive values of Xpert mycobacterium tuberculosis and resistance to rifampicin by comparing it with acid-fast bacilli smear and culture in suspected tuberculosis patients.

METHODS

The retrospective study was conducted at the Aga Khan University Hospital, Karachi, and comprised patient data from January 2013 to December 2016. Data related to children with clinical suspicion of pulmonary and extra-pulmonary tuberculosis based on Modified Kenneth Jones criteria, aged 1 month to 18 years whose samples (respiratory or non-respiratory) were sent for Xpert mycobacterium tuberculosis and resistance to rifampicin and acid-fast bacilli smear and culture con currently. Analysis was carried out by STATA 12 and Med Calc softwares .

RESULTS

Of the 91 cases, 50(54.9%) related to females. The overall median age of the patients was 12.5 years (interquartile range: 8 years). Overall, 42(46.2%) cases had extra-pulmonary tuberculosis. The Xpert test had 66.7% sensitivity compared to smear microscopy 47.6%. Overall sensitivity, specificity, positive predictive value and negative predictive value were 95.7%, 72%, 51.2% and 98.3% respectively when the two tests were compared.

CONCLUSIONS

Xpert mycobacterium tuberculosis was found to be more sensitive than acid-fast bacilli smear and culture in both pulmonary and extra-pulmonar y tuberculosis in children.

Autosomal Recessive Agammaglobulinemia - first case with a novel TCF3 mutation from Pakistan

Autosomal Recessive Agammaglobulinemia (ARA) is an uncommon type of primary immunodeficiency characterized by mutations in genes responsible for early B cell differentiation and function. One such gene is the TCF3 gene, which encodes a transcription factor important for immunoglobulin gene expression. We present the case of a 9 year old girl with history of diarrhea and recurrent pneumonias. Laboratory investigation showed significantly reduced levels of immunoglobulins along with a significant fall in the number of CD19+ cells. Genetic analysis identified a TCF3 gene base deletion covering exons 5-11.