Although intravesical instillation of Bacille-Calmette-Guerin (BCG) immunotherapy was approved many decades ago as a first line therapy for intermediate to high-risk non-muscle invasive bladder cancer, its long-term efficacy is still arguable as a proportion of up to 30-40% of patients will develop recurrence or progression of their disease. Based on currently available data on the clinical application of checkpoint inhibitors in solid tumors, the mucosa-associated lymphoid tissue seems to be a main target for anti-CTLA-4 antibodies. In this manuscript we hypothesize that the combination of anti-CTLA-4 therapy with BCG might enhance the immune activity in the bladder submucosal tissue, and subsequently, improve oncological outcomes of NMIBC.
Melatonin is not only synthesized by the pineal gland but also in many other organs and tissues of the body, particularly by lymphoid organs such as the bone marrow, thymus and lymphocytes. Melatonin participates in various functions of the body, among which its immunomodulatory role has assumed considerable significance in recent years. Melatonin has been shown to be involved in the regulation of both cellular and humoral immunity. Melatonin not only stimulates the production of natural killer cells, monocytes and leukocytes, but also alters the balance of T helper (Th)-1 and Th-2 cells mainly towards Th-1 responses and increases the production of relevant cytokines such as interleukin (IL)-2, IL-6, IL-12 and interferon-gamma. The regulatory function of melatonin on immune mechanisms is seasonally dependent. This fact may in part account for the cyclic pattern of symptom expression shown by certain infectious diseases, which become more pronounced at particular times of the year. Moreover, melatonin-induced seasonal changes in immune function have also been implicated in the pathogenesis of seasonal affective disorder and rheumatoid arthritis. The clinical significance of the seasonally changing immunomodulatory role of melatonin is discussed in this review.