Enhancement of antigen-specific T-cell reactivity on the affected side in stroke patients.

We have analyzed the impact of stroke with subsequent hemiparesis and sensory loss on in vivo mediated immune functions. The delayed-type hypersensitivity (DTH) reaction to purified protein derivate (PPD, tuberculin) was used as a measure of antigen-specific T-cell reactivity, and subcutaneous immunization with influenza vaccine was employed to evaluate T-cell-dependent B-cell function. Thirty-two of the 50 stroke patients tested displayed positive DTH reaction to PPD. All but two showed equal or stronger DTH reaction on the paretic arm compared to the contralateral side (p less than 0.0001). This stroke-induced enhancement of DTH reactivity was evident in patients with combined motor and sensory deficit as well as in subjects with hemiparesis alone. In contrast, immunization of stroke patients with influenza vaccine, a T-cell-dependent B-cell antigen, raised equal antigen-specific serum IgG, IgA and IgM antibody responses irrespective of side (paretic or not paretic). We conclude that stroke enhances antigen-specific T-cell reactivity on the affected side of the body, and that motor but not sensory deficit seems to be required for this enhancement. Antigen-specific B-cell reactivity was not significantly influenced by the hemiparesis.