In Vitro Cytokine Production by HLA-B8, DR3 Positive Subjects

Abstract

It is well known that healthy subjects carrying the HLA-B8, DR3 haplotype may show an impairment of immune system, the T cells being the most affected. To gain insight into the mechanism(s) of the impairment displayed by these subjects, efforts have been centered on the study of in vitro cytokine production because of the pivotal role played by these mediators in the activation and control of several immune functions. The available results indicate that the ability to produce interleukin-1 (IL-1), IL-2 and the soluble form of its receptor (sIL-2R) is impaired in HLA-B8, DR3 positive healthy subjects. To better characterize the cytokine production capacity of HLA-B8, DR3 positive subjects, we have investigated the pattern of in vitro production of IL-2, sIL-2R, IL-4, IL-6 and γ-interferon (γ-IFN) by mononuclear cells from HLA-B8, DR3 positive subjects after phytohaemoagglutinin stimulation. A significant decrease of IL-2, sIL-2R and γ-IFN production by HLA-B8, DR3 positive subjects was observed. No significant difference was instead found between the HLA-B8, DR3 positive subjects and the negative ones as regards IL-4 and IL-6 production. We suggest that this imbalanced cytokine production may well account for the pattern of immune response that may be observed in HLA-B8, DR3 positive subjects, i.e. a normal or increased humoral response in face of a low T cell immue responsiveness.