Intracellular cytokine profile of cord blood T-, and NK- cells and monocytes

Background and Objectives. Many functional peculiarities of cord blood (CB) lymphocytes and antigen presenting cells, including cytokine production, a re associated with low intensity of innate and acquired (cellular and humor al) responses. These peculiarities may have implications both for immunolog ic maturation in post-natal life and for immune functions after CB transpla ntation [e.g. the lower incidence of graft-versus-host disease (GvHD) in co mparison with after bone marrow transplantation (BMT)]. The aim of our stud y was to compare the intracellular production of cytokines invoked both in phagocyte-dependent immunity/inflammation and in humoral immune responses i n CB and adult peripheral blood (PB). Design and Methods. Intracellular single cell analysis by now cytometry was used to detect, following aspecific in vitro stimulation, the production o f interferon (IFN)-gamma, interleukin (IL)-2, IL-1 alpha, IL-1 beta, IL-8, tumor necrosis factor (TNF)-alpha and -beta, IL-4, IL-5, IL-6, IL-10 and IL -13 by T-cell subsets, NK-cells and monocytes obtained from 10 CB and 10 PB samples. The cytokine production was expressed as the percentage of positi ve cells. Results. Significantly lower numbers of CD4+ T-cells producing IFN-gamma (p <0.001), TNF-alpha (p=0.012) and TNF-beta (p=0.03) and of CD8+ T-cells prod ucing IFN-gamma (p<0.001), IL-2 (p=0.005) and TNF-alpha (p<0.001) were foun d in CB as compared to PB. In CB we also found a lower number of NK cells a nd monocytes producing TNF-alpha (p<0.001 and p=0.001, respectively). In co ntrast, the number of IL-1 alpha(+) monocytes was higher in CB than in PB ( p=0.03). Interpretation and Conclusions. Our data confirm that the cytokines which n ormally sustain the phagocytic-dependent T helper/cytotoxic 1-type immune r esponses (IFN-gamma, IL-2 and TNF-alpha) and the NK-cell/monocyte-dependent aspecific responses (TNF-alpha) are reduced in CB. Since these cytokines a re also involved in acute GvHD pathogenesis, these results are in keeping w ith the evidence of a low incidence of acute GVHD after CB transplantation. (C)2000, Ferrata Storti Foundation.