TNF and common variable immunodeficiency: CVID patients have an underlying B-cell defect, but many patients also display T-cell dysfunction and evidence of systemic immune activation with elevated levels of inflammatory cytokines such as tumor necrosis factor (TNF) and interleukin (IL)-6, and soluble markers of monocyte/macrophage- (e.g., soluble [s]CD14) and T cell activation (i.e., sCD25)11.