Neurocysticercosis, IgG immunoglobulins, and nitric oxide.

This study evaluated the role of parasite load and nitric oxide on IgG levels in neurocysticercosis. Total serum IgG, IgG antibodies specific for cysticercus antigens, and nitric oxide were compared between 85 neurocysticercosis patients, 65 with solitary cysts and 20 with multiple cysts, and 13 normal healthy controls. Sixty-six percent of patients were seropositive for cysticercus IgG antibodies. Among seropositive patients, IgG levels did not differ between those infected with multiple or solitary cysts whose serum nitric oxide levels were low (<40 nmol/ml). Among seropositive solitary cyst infected patients, IgG levels were significantly higher in those whose serum nitric oxide was low compared to those with high nitric oxide levels (p < 0.001). IgG levels were significantly higher in patients with multiple compared to single cyst infections among those negative for cysticercus antibodies (p < 0.001). Parasite load and nitric oxide modulated IgG production in neurocysticercosis. IgG levels were not determined by the number of infecting cysts in seropositive patients who did not mount a nitric oxide response. IgG production correlated to parasite load in patients negative for cysticercus antibodies.