COVID-19 and Pneumocystis jirovecii pneumonia: Back to the basics

International audienc

Epithelial chimerism in lung tissue after allogeneic hematopoietic stem cell transplantation

International audienc

Altered pIgR/IgA mucosal immunity in bronchiolitis obliterans syndrome

Aims: Long-term survival after lung transplantation (LT) is hampered by the occurrence of chronic lung allograft dysfunction (CLAD), manifesting as bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS). CLAD is triggered by several factors, e.g. recurrent infections. As immunoglobulin (Ig) A is crucial to ensure mucosal immunity and limit airway microbial load, we explored whether IgA and its epithelial receptor, the polymeric Ig receptor (pIgR) are impaired in BOS. Methods: Bronchoalveolar lavages (BAL, n=120) from LT recipients included in the Cohort for Lung Transplantation were collected at pre-defined timepoints prior to the diagnosis of functional stability (BOS-free, n=30) or BOS (pre-BOS, n=30), and assessed for secretory (S)-IgA. Bronchiolar epithelium pIgR expression was quantified in transbronchial biopsies from BOS-free (n=20), pre-BOS (n=19) and BOS LT recipients (n=12), as well as in end-stage BOS explants (n=15). Results: S-IgA levels were reduced in BAL from pre-BOS LT recipients versus BOS-free (16.1 vs 33.4 µg/ml, p<0.01). pIgR bronchiolar expression was reduced in transbronchial biopsies from BOS (p<0.05 vs BOS-free and pre-BOS), with further decrease in end-stage BOS explants (p<0.0001 vs BOS-free and pre-BOS). Conclusions: BAL S-IgA and pIgR decreased levels suggest that the pIgR/IgA system is impaired in BOS. This could play a pathogenic role by increasing susceptibility to local infections

Telomerase activity in connective tissue diseases: elevated in rheumatoid arthritis, but markedly decreased in systemic sclerosis

WOS: 000254206100012PubMed ID: 17938929Telomerase is a reverse transcriptase enzyme contributing to the maintenance of the telomeric structure by adding telomere repeat sequences to chromosomal ends, thus compensating for its shortening. Telomerase activity which is common in cancers and human germ line tissue, may also be increased, although to a lesser extent, in systemic autoimmune diseases. We aimed to evaluate telomerase activity in a group of Turkish patients with various connective tissue diseases. In this cross sectional study, 19 patients with systemic sclerosis (SSc), 15 with systemic lupus erythematosus (SLE), 10 with rheumatoid arthritis (RA) and 14 with primary Sjogren's syndrome (pSjS) were studied. As the control group, 29 healthy subjects were also included. Human telomerase-specific reverse transcriptase (hTERT) was measured in peripheral blood lymphocytes, using online real-time reverse-transcriptase polymerase chain reaction (PCR). We also investigated if hTERT values in each patient group were correlated with clinical parameters and disease activity. Highest hTERT values were observed in RA group (21.24 +/- 28.54), followed by SLE (13.38 +/- 26.05) and pSjS (11.73 +/- 10.59) groups. Only hTERT values in RA group was significantly higher than the healthy control group (7.62 +/- 4.21) (p < 0.05). Interestingly, hTERT values in SSc were very low (2.09 +/- 3.18), even less than the healthy control group. In consistent with previous studies, telomerase activity was increased in SLE and RA. Very low telomerase activity in SSc group was rather surprising. Since existing telomerase data in SSc was limited and telomere shortening was previously reported in SSc, our finding of low telomerase activity in SSc group deserves relevant discussion and further studies