High procalcitonin in Gram-negative urosepsis: indicator of immune modulation rather than poor outcome

Within a defined concentration range, PCT down-regulates IL-1β secretion and is associated with reduced markers of disease severity in Gram-negative urosepsis, compared to other sepsis entities. These findings suggest that pronounced PCT elevations in this setting may represent a protective host response rather than a worse prognosis, pointing to a novel immunomodulatory role of PCT in urosepsis that warrants further investigation. DRKS00037950, retrospectively registered on 22 September 2025.