Tumor necrosis factor (TNF)alpha and its soluble receptor (sTNFR) p75 during acute human parvovirus B19 infection in children.

Human parvovirus B19 (HPV) has been shown to be involved in the pathogenesis of various connective tissue and autoimmune diseases. In order to gain more information on HPV possible role in these diseases, we have investigated some immune responses in patients with acute HPV infection, mainly the secretion of the proinflammatory cytokine tumor necrosis factor (TNF)alpha and it's antagonist--the soluble TNF receptor (sTNFR) p75. Thirteen children with acute HPV infection and 13 healthy volunteers were investigated for the presence of autoantibodies, lymphocyte subpopulation counts, levels of total immunoglobulins, IgG subclasses and complement. The levels of TNFalpha and sTNFR p75 were determined in serum and conditioned medium (CM) from unstimulated and LPS stimulated peripheral blood mononuclear cell (PBMC) cultures. There was no difference between patients and controls regarding autoantibodies, lymphocytes, immunoglobulins, IgG subclasses and complement. A significant imbalance between TNFalpha and sTNFR p75 was found in the patients group. TNFalpha concentrations were significantly higher both in sera and in CM from the patients as compared with the controls. The levels of sTNFR concentrations were either similar (in sera) or significantly lower (in CM) in the patients compared with the controls. The TNF index, representing the biologically available TNFalpha, was significantly higher in patient's sera and CMs. In view of these results, it is conceivable that infection with human HPV in otherwise healthy children may lead to a proinflammatory state. The presence of high levels of biologically available TNFalpha, in susceptible individuals, may in turn play a role in the pathogenesis of systemic autoimmune diseases in HPV infected individuals.