Recent advances in microbiome research have uncovered a dynamic and complex connection between the gut and lungs, known as the gut–lung axis. This bidirectional communication network plays a critical role in modulating immune responses and maintaining respiratory health. Mediated by immune interactions, metabolic byproducts, and microbial communities in both organs, this axis demonstrates how gut-derived signals, such as metabolites and immune modulators, can reach the lung tissue via systemic circulation, influencing respiratory function and disease susceptibility. To explore the implications of this connection, we conducted a systematic review of studies published between 2001 and 2024 (with as much as nearly 60% covering the period 2020–2024), using keywords such as “gut–lung axis”, “microbiome”, “respiratory disease”, and “immune signaling”. Studies were selected based on their relevance to gut–lung communication mechanisms, the impact of dysbiosis, and the role of the gut microbiota in respiratory diseases. This review provides a comprehensive overview of the gut–lung microbiome axis, emphasizing its importance in regulating inflammatory and immune responses linked to respiratory health. Understanding this intricate pathway opens new avenues for microbiota-targeted therapeutic strategies, which could offer promising interventions for respiratory diseases like asthma, chronic obstructive pulmonary disease, and even infections. The insights gained through this research underscore the potential of the gut–lung axis as a novel target for preventative and therapeutic approaches in respiratory medicine, with implications for enhancing both gut and lung health.

Cytokine receptors are critical regulators of the antimycobacterial immune response, playing a key role in initiating and coordinating the recruitment and activation of immune cells during infection. They recognize and bind specific cytokines and are involved in inducing intracellular signal transduction pathways that regulate a diverse range of biological functions, including proliferation, differentiation, metabolism and cell growth. Due to mutations in cytokine receptor genes, defective signaling may contribute to increased susceptibility to mycobacteria, allowing the pathogens to avoid killing and immune surveillance. This paper provides an overview of cytokine receptors important for the innate and adaptive immune responses against mycobacteria and discusses the implications of receptor gene defects for the course of mycobacterial infection.

Although the therapeutic effect of mycobacteria as antitumor agents has been known for decades, recent epidemiological and experimental studies have revealed that mycobacterium-related chronic inflammation may be a possible mechanism of cancer pathogenesis. Mycobacterium tuberculosis and non-tuberculous Mycobacterium avium complex infections have been implicated as potentially contributing to the etiology of lung cancer, whereas Mycobacterium ulcerans has been correlated with skin carcinogenesis. The risk of tumor development with chronic mycobacterial infections is thought to be a result of many host effector mechanisms acting at different stages of oncogenesis. In this paper, we focus on the nature of the relationship between mycobacteria and cancer, describing the clinical significance of mycobacteria-based cancer therapy as well as epidemiological evidence on the contribution of chronic mycobacterial infections to the increased lung cancer risk.

Over the past decade, a group of lymphocyte-like cells called innate lymphoid cells (ILCs) has gained considerable attention due to their crucial role in regulating immunity and tissue homeostasis. ILCs, lacking antigen-specific receptors, are a group of functionally differentiated effector cells that act as tissue-resident sentinels against infections. Numerous studies have elucidated the characteristics of ILC subgroups, but the mechanisms controlling protective or pathological responses to pathogens still need to be better understood. This review summarizes the functions of ILCs in the immunology of infections caused by different intracellular and extracellular pathogens and discusses their possible therapeutic potential.

Despite controversy over the protective effect of the BCG (Bacille Calmette-Guérin) vaccine in preventing pulmonary tuberculosis (TB) in adults, it has been used worldwide since 1921. Although the first reports in the 1930s had noted a remarkable decrease in child mortality after BCG immunization, this could not be explained solely by a decrease in mortality from TB. These observations gave rise to the suggestion of nonspecific beneficial effects of BCG vaccination, beyond the desired protection against M. tuberculosis. The existence of an innate immunity-training mechanism based on epigenetic changes was demonstrated several years ago. The emergence of the pandemic caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2) in 2019 revived the debate about whether the BCG vaccine can affect the immune response against the virus or other unrelated pathogens. Due to the mortality of the coronavirus disease (COVID-19), it is important to verify each factor that may have a potential protective value against the severe course of COVID-19, complications, and death. This paper reviews the results of numerous retrospective studies and prospective trials which shed light on the potential of a century-old vaccine to mitigate the pandemic impact of the new virus. It should be noted, however, that although there are numerous studies intending to verify the hypothesis that the BCG vaccine may have a beneficial effect on COVID-19, there is no definitive evidence on the efficacy of the BCG vaccine against SARS-CoV-2.

This review addresses the urgent need for alternative strategies to combat drug-resistant mycobacterial infections, including multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis, as well as non-tuberculous mycobacterial (NTM) diseases. Traditional antibiotics are increasingly limited by resistance, toxicity, and poor efficacy, particularly in immunocompromised patients. A comprehensive literature search was conducted using PubMed, Scopus, and Google Scholar, covering publications primarily from 2000 to 2025. Only articles published in English were included to ensure consistency in data interpretation. Search terms included “mycobacteriophages,” “phage therapy,” “drug-resistant mycobacteria, “diagnostic phages,” and “phage engineering.” The review examines the therapeutic and diagnostic potential of mycobacteriophages—viruses that specifically infect mycobacteria—focusing on their molecular biology, engineering advances, delivery systems, and clinical applications. Evidence suggests that mycobacteriophages offer high specificity, potent bactericidal activity, and adaptability, positioning them as promising candidates for targeted therapy. Although significant obstacles remain—including immune interactions, limited host range, and regulatory challenges—rapid progress in synthetic biology and delivery platforms continues to expand their clinical potential. As research advances and clinical frameworks evolve, mycobacteriophages are poised to become a valuable asset in the fight against drug-resistant mycobacterial diseases, offering new precision-based solutions where conventional therapies fail.