Rabies is considered a fatal disease once clinical symptoms have developed. The aim of this study was to evaluate epidemiological aspects and immune response in patients attacked by domestic and wild animals and subjected to post-exposure rabies treatment with equine serum and associated vaccine. Thirty-three patients were evaluated; they were between 13 and 65 years old, 75.8% were male and 24.2% female, and from the Botucatu neighborhood. Twenty healthy control individuals with the same age range were also studied. Specific antibodies to equine immunoglobulins and IFN-gamma, IL-2, IL-4, and IL-10 production were evaluated by ELISA. IgM, IgE, IgG and subclasses, and rabies virus antibodies serum levels were determined by nephelometry and seroneutralization methods, respectively. No anaphylactic or serum sickness allergic reactions were observed in patients after treatment. Anti-equine IgG levels were significantly higher than those of IgM after 14 and 28 days of treatment. Protective antibodies to rabies virus > 0.5 UI/ml were detected in 84.6% and 75% of patients at days 14 and 28, respectively. IFN-gamma, IL-2 and IL-10 levels in patients before and 48h after treatment were significantly higher than in controls suggesting that both Th1 and Th2 cells were activated in the patients. Serum IgM levels were higher at day 14, and IgG2 and IgE levels were higher at day 28 of treatment. These results suggest that post-exposure rabies treatment in humans induces significant alterations in patient immune response characterized by increased levels of cytokines, serum levels of specific rabies virus antibodies, and the equine serum components employed in the treatment.

This review deals with heterologous sera produced and used in Brazil. The authors studied 64 patients. Of these, 35 had been attacked by domestic and wild animals and received antirabies serum; 20 had been bitten by venomous animals (snakes and scorpions) and were treated with specific antivenoms; and 9 had traumas and received antitetanic serum All these patients were submitted to the intradermal sensitivity test before, and 30 days after reveiving heterologous serotherapy. The following results obtained by the authors agree with those in literature: - The intradermal test using undiluted heterologous serum produced a more acute reaction than that using heterologous serum diluted 1:10; - The larger the volume of serum, the larger was the wheal directly after inoculation; - The antigenic concentration influenced the final local reaction; - The reading 30 minutes after inoculation was always higher than that 15 min after; - No systemic reaction was observed during the tests; - The use of promethazine as a prophylactic medication did not protect against the early reactions; - Tests performed 30 days after serotherapy showed a higher reactivity, probably due to sensitization; - The intradermal sensitivity test did not allow the authors to predict early reactions. After these observations, the authors do not recommend the intradermal sensitivity test for patients submitted to heterologous serotherapy. They, however, strongly recommend a careful observation during the infusion and clinical follow up in the first 24 hours.