Cystic fibrosis is a congenital disorder of the salt and water balance of all glands, which is triggered by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Chronic infections of the airways with viruses, bacteria and fungi determine the quality of life and the life expectancy of cystic fibrosis patients. In 1980, CF patients in Germany still only lived on average to nine years old. Since 2020, most CF patients can be treated with CFTR modulators, which directly attack the basic defect of the impaired salt and water transport. During therapy, the symptoms weaken so much that, for the future generation of CF patients, a normal life expectancy is predicted. 

The DNWG has set itself the task to develop and validate methods for the diagnosis of cystic fibrosis and CFTR-related diseases (CFTR-RD) and for progress monitoring of the treatment with CFTR modulators.  With these CFTR biomarkers, the CF-specific disorders of the CFTR function in the sweat gland, airways and intestine can be examined directly on humans, cell or tissue samples. The hosts of the meeting presented in theory and practice a sweat secretion test developed at the University of Göttingen and the MHH, with which one can, for the first time, measure the CFTR activity in humans in real time.¹ 

This year’s DNWG Meeting was focussed primarily on CFTR disorders on the fringe between healthy and CF: When screening newborns for CF, besides identifying infants who had fallen ill with CF, other infants were also identified who were suspected of having CF, but in whom the suspicion of CF was neither clearly confirmed nor denied when using further CFTR biomarkers. At the meeting, suggestions were discussed regarding the management of these children, who as a rule are spared CFTR disorders, but sometimes develop a CF or CFTR-RD later in life. 

Amongst those patients who, during their lifetime, suffer bronchiectasis in their lung or fall ill with inflammation of the pancreas, in a small number there is a malfunction of the CFTR function (CFTR-related disorder, CFTR-RD) that is responsible for the condition. At the meeting, position papers on the definition, diagnostics, therapy and management of the CFTR-RD were presented, which members of the DNWG had developed over the last five years on behalf of the ECFS. 

The meeting was rounded off with presentations by the Hannover hosts, who reported on their research on genetics, diagnostics, imaging and microbiology of cystic fibrosis, and with presentations on rare or unusual diseases, which led to lively discussions amongst the experts attending from the DNWG, as to how the cases should be explained and dealt with.

Text: Burkhard Tümmler, MHH
Photo: Burkhard Tümmler, MHH

¹ Publication on the sweat secretion test in real time:
Pallenberg ST, Junge S, Ringshausen FC, Sauer-Heilborn A, Hansen G, Dittrich AM, Tümmler B, Nietert M. CFTR modulation with elexacaftor-tezacaftor-ivacaftor in people with cystic fibrosis assessed by the β-adrenergic sweat rate assay. J Cyst Fibros. 2022;21:442-447. doi: 10.1016/j.jcf.2021.10.005.