Immune activation in human rabies

Serum cytokines were compared by enzyme-linked immunosorbent assay among (i) 28 patients with rabies, (ii) 13 patients with non-fatal encephalitis due to other viruses, (iii) 16 patients with immune-mediated neurological diseases, and (iv) 15 patients with non-viral central nervous system infections and non-HTLV-I progressive spastic paraparesis. Levels of soluble interleukin 2 receptor (S-IL2R) were comparable in groups (i)-(iii). Fewer paralytic (1/6) than encephalitic (12/22) rabies patients had elevated S-IL2R. Only one patient with rabies and one with non-fatal viral encephalitis (group ii) had elevated S-CD8. Interleukin 6 (IL-6) was elevated in 5/22 rabies patients with encephalitis and in 0/6 paralytic rabies patients. Four individuals in groups (ii) and (iii) had elevated IL-6. Patterns of cytokine responses in group (iv) were similar to those in groups (i)-(iii). The results suggest defects in immune responsiveness in paralytic rabies.