Introduction: Angiostrongylus cantonensis meningoencephalitis is an emergent zoonotic disease in the Caribbean basin, characterized by the presence of eosinophils and third stage larva of the helmint. Objective: To analyze the IgG subclasses and IgE intrathecal synthesis patterns obtained by reibergrams in pediatric patients suffering from eosinophilic meningoencephalitis due to A. cantonensis. Patients and methods: 20 pediatric patients with the disease were studied. During the first diagnostic lumbar puncture an eosinophilic pleocytosis was found. Simultaneously a serum sample was taken. Eight days later, a second lumbar and venous puncture was performed. IgA, IgM, IgG, albumin in serum and cerebrospinal fluid samples were quantified by immunodiffusion in addition to a differential cell count in cerebrospinal fluid. IgG subclasses were quantified in 10 patients by immunodiffusion and IgE in four patients by nephelometry. Results: During the first diagnostic lumbar puncture, all the cases had a blood-cerebrospinal fluid barrier dysfunction with absence of immunoglobulins intrathecal synthesis, a mean of 450 cells/mu l and an average of 48% of eosinophils. In the second lumbar puncture 40% of the patients had a dysfunction of the blood-cerebrospinal fluid barrier and an intrathecal synthesis pattern of IgA+IgM+IgG in 50% of the patients. Eight patients had an intrathecal lgA + lgG class response. The synthesis pattern of lgG subclasses was lgG(1) + lgG(2) in six patients, IgG(1) + lgG(2) + IgG(3) in one patient, IgG(1) + IgG(2) + IgG(4) in one more patient. Two patients from the second lumbar puncture remained without intrathecal synthesis. IgE intrathecal synthesis was observed in the four analyzed patients in the first diagnostic lumbar puncture. Conclusions: The IgG(1) + IgG(2) and IgE intrathecal synthesis pattern demonstrated the complexity of the antigenic mosaic of the helmint and it can contribute to diagnosis of eosinophilic meningoencephalitis due to A. cantonensis. (c) 2005 Elsevier B.V All rights reserved.