Humoral immune responses in the hantavirus cardiopulmonary syndrome

The immunologic responses that mediate viral clearance of and recovery from hantavirus cardiopulmonary syndrome (HCPS) due to Sin Nombre (SN) virus ar e unknown. Serial serum samples from 26 patients with acute SN virus infect ion were tested for Igc, IgA, and IgM reactivity to recombinant viral nucle ocapsid (N) and glycoprotein G1 antigens by a novel strip immunoblot assay, The titers of antibodies capable of neutralizing SN virus in vitro also we re determined for each sample. At admission, patients with severe disease h ad lower titers of Ige antibodies to SN virus N antigen (P < .033) and lowe r neutralizing antibody titers (P < 3.4 x 10(-5)), compared with patients w ith mild disease. These data suggest that a strong neutralizing antibody re sponse may be a predictor of effective clearance of and recovery from SN vi rus infection and raise the possibility that passive immunotherapy may be u seful in HCPS.