"Patients with PTLD are no longer infectious," explains Rachow. "But they suffer considerable consequential damage, both medically and socially." Tuberculosis can leave scars in the lungs, leading to reduced lung volume and increasing the risk of respiratory problems. Post-tuberculosis can also manifest as a persistent cough, sputum production and shortness of breath. Many people are no longer able to work and participate in social life to the same extent as before their illness due to such symptoms. Children of parents with post-tuberculosis show a decline in their previous school performance; their educational opportunities dwindle. These are the key findings of the "TB Sequel I" (Tuberculosis Sequelae) study.
But how can those affected be helped? This is precisely where the TB Sequel I and TB Sequel II projects come in, which are being carried out by Rachow and colleagues together with the Aurum Institute in South Africa and six other research institutions in Germany and sub-Saharan Africa.
"When we started planning the first study, there wasn't even a standardized term for post-tuberculosis symptoms," recalls Rachow. "We wanted to understand the long-term pulmonary consequences of the disease." Other questions are: What complications, such as superinfections, are there? Do patients with this disease require more frequent medical treatment? Do some of them die in connection with PTLD?
A total of 1,500 participants were included in the cohort at the time of TB diagnosis. "We are now observing them for the fifth to seventh year," reports Rachow. The team was able to confirm that even several years after the acute illness, up to 25 percent of the study participants have moderate to severe restrictions in lung function. "In addition, we collect blood or sputum samples to determine immunological parameters and understand which inflammatory processes are involved in the disease process, especially in a chronic course."
In this context, the researchers are investigating whether N-acetylcysteine (NAC), a substance that is approved as a cough suppressant, could also be of benefit in PTLD. A small pilot study has provided corresponding indications. N-acetylcysteine has anti-inflammatory effects and scavenges harmful oxygen radicals. Rachow: "We hope that NAC therapy will result in less tissue damage and the resulting functional limitations in the lungs during the course of TB disease."
In addition to medical aspects, TB Sequel II also aims to gain a better understanding of economic effects, such as the increase in severe poverty among patients and families affected by TB and PTLD. Sociological consequences, such as the marginalization of patients with PTLD, are also being investigated. Last but not least, the costs associated with PTLD for healthcare systems will also be examined.
