PCNA and ulcerative colitis: Monitoring of relevant specific criteria in individual forms of ulcerative colitis in our study included pathological anatomical findings, evaluation of DAI and HAI scores, haematological parameters supported by morphometric parameters, marker of cellular proliferation PCNA, anti-apoptotic marker Bcl-xL, inflammatory markers iNOS and COX2, mRNA transcript levels of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α, as well as regulatory cytokines IL-10 and TGF-β, and viability of microorganisms.