Subacute sclerosing panencephalitis is a rare progressive inflammatory disease of the central nervous system caused by a persistent aberrant measles virus infection. Cytokines are polypeptides that regulate immune responses and inflammatory reactions. Interleukin-1 beta has been implicated as a central mediator of tissue damage and destruction in a number of central nervous system diseases. Interleukin-1 receptor antagonist could function as an important anti-inflammatory cytokine. We studied interleukin-1 beta and interleukin-1 receptor antagonist levels in the cerebrospinal fluids of patients with subacute sclerosing panencephalitis and evaluated the effects of different treatment protocols on these cytokines. Interleukin-1 beta and interleukin-1 receptor antagonist levels were measured in 15 patients who had a recent diagnosis of subacute sclerosing panencephalitis (group 1), 6 patients who had been treated with isoprinosine (group 2), 5 patients with intraventricular interferon-alpha (group 3), and 6 patients with interferon-beta (group 4). The results were compared within the groups and also with the results of 10 patients with other neurologic disease (group 5). The interleukin-1 beta concentrations in cerebrospinal fluid and sera were all below the detection limits (3.9 pg/mL). Interleukin-1 receptor antagonist levels were not statistically different, except for the group treated with intraventricular interferon-a. Interleukin-1 receptor antagonist levels were 170 +/- 52, 175 +/- 58, 1605 +/- 518, 77.5 +/- 24, and 108 +/- 18 pg/mL in groups 1 to 5, respectively. Interleukin-1 receptor antagonist levels and cerebrospinal fluid serum ratios were significantly increased during interferon-alpha treatment. In conclusion, interleukin-1 and interleukin-1 receptor antagonist levels were not elevated in the patients with subacute sclerosing panencephalitis. The only treatment protocol that affects interleukin-1 receptor antagonist levels in cerebrospinal fluid was intraventricular interferon-alpha. Further studies on higher numbers of patients may better document the immunologic status of patients with subacute sclerosing panencephalitis and the effects of different treatment modes.