Persistent activation of the tumor necrosis factor system in a subgroup of patients with common variable immunodeficiency--possible immunologic and clinical consequences

In patients with common variable immunodeficiency (CVI), we have previously defined a subgroup of patients (CVIHyper) characterized by decreased numbers of CD4+ lymphocytes in peripheral blood, splenomegaly, and persistent immune activation in vivo, particularly of monocytes/macrophages. To further characterize this hyperactivity, parameters of activation of the tumor necrosis factor (TNF) system (TNF alpha and soluble TNF receptors [sTNFRs]) were measured in 24 patients with CVI and 20 healthy controls. Patients with CVI had significantly higher serum levels of TNF alpha and both types of sTNFRs, with the highest levels in the CVIHyper subgroup. In vitro, peripheral blood mononuclear cells (PBMC) and purified monocytes from CVIHyper patients spontaneously released significantly higher levels, and, after lipopolysaccharide (LPS) stimulation, significantly lower levels of TNF alpha and soluble p75-TNFR than cells from both other CVI patients and healthy controls. CVIHyper patients also had significantly higher TNF alpha:sTNFRs ratios in both serum and in unstimulated PMBC supernatants. The present study demonstrates persistent in vivo activation of the TNF system in CVI, particularly in the CVIHyper subgroup. This activation may contribute to the pathogenesis of both clinical and immunologic manifestations in CVI.