Lymphopenia as a determinant factor of sepsis severity, as an exact diagnostic criterion, and as an object of therapy

Attempts to optimize the diagnosis of sepsis and its complications have led to the development of Sepsis-3 concept which contradicts the basic provisions of therapy for this threatening condition, namely, the earliest possible onset of the treatment. In turn, the introduction of new methods for monitoring and substitution of organ functions in multiple organ failure did not cause a noticeable improvement in the results of sepsis therapy. The high incidence of antibiotic-resistant strains also requires the search of the new approaches in the diagnosis and therapy of sepsis. The present review is intended to focus on such a typical sepsis phenomenon as absolute lymphopenia. Numerous studies show that it is lymphopenia that determines the severity of sepsis. Composite biomarkers (the neutrophil-lymphocyte count ratio, NLCR) or lymphocyte index (the lymphocyte/peripheral blood granulocytes ratio)) are the most reliable criteria in sepsis diagnosis. In addition, the presented data suggest that lymphopenia correction significantly improves prognosis in sepsis. It seems clear that the acknowledgment of the absolute lymphopenia’s key role in pathogenesis, diagnosis and therapy of sepsis will serve as an impulse for further development of sepsis concept.