Although bacterial infections predominate in patients with hypogammaglobulinemia, patients who do not produce normal amounts of immunoglobulin also have an increased incidence of viral infections. This is particularly true of infections with enteroviruses. Echovirus encephalitis has been a major problem for patients with hypogammaglobulinemia. Neurologic damage, frequently resulting in death, has been common in such patients. Because there is an obligatory extracellular phase in the cell to cell spread of enteroviruses, therapy with immunoglobulin has been attempted. In certain patients intravenous and intrathecal gammaglobulin has temporarily halted progression of the disease, but no patients have been cured by this approach. In this report we detail treatment of three children with X-linked hypogammaglobulinemia who had encephalitis caused by echovirus infections. Despite doses of intravenous immunoglobulin that maintained the patients' IgG levels within the normal range, their condition deteriorated in all cases. Treatment with intraventricular immunoglobulin was then tried. In all three cases cerebrospinal fluid protein levels and cell counts returned to normal after this treatment and the echoviruses can no longer be isolated from the cerebrospinal fluid. Follow-up time has ranged from 18 months to 4 years. Ommaya reservoirs were placed into the lateral ventricle of each patient and concentrated (6%) immunoglobulin (Sandoglobulin) was injected into the reservoir on a daily basis. On Days 1 through 7 of the regimen patients were given 120, 300, 450, 510, 540 and 600 mg of IgG, respectively. Patients then received 300 mg daily for periods ranging from 1 week to 1 month. Cultures of cerebrospinal fluid removed from the reservoir were repeatedly analyzed to determine the need for further treatment. Clinically the patients improved markedly.(ABSTRACT TRUNCATED AT 250 WORDS)