The role of individual cytokines and polymorphisms in pneumonia has been described, but the relationship between different cytokines and polymorphisms in relation to causative microorganisms, antibiotics, corticosteroids and clinical course has not. This study questions the relationship between cytokines, polymorphisms and clinical characteristics of pneumonia. Patients diagnosed with pneumonia were included in the study. Serum cytokine levels were measured during hospital stay, genotyping was performed, causative microorganisms were identified and patients were monitored throughout the hospital stay. In 201 patients with pneumonia interleukin (IL)-1 receptor antagonist (IL-1RA), IL-6, IL-8 and IL-10 acted as acute phase proteins. After admission, the levels of these cytokines decreased rapidly. Single nucleotide polymorphisms did not influence cytokine production and were not associated with clinical outcome. Cytokine serum levels were significantly higher in patients with pneumococcal pneumonia. The decrease in levels of cytokines was independently influenced by the start of corticosteroid therapy. IL-1RA, IL-6, IL-8 and IL-10 are acute phase proteins, independent of genotype. Their levels are influenced by the nature of the causative microorganism and the start of corticosteroids therapy.