Cell-mediated and humoral immunity in West syndrome

Putative neurotransmitter abnormalities in infantile spasms: cerebrospinal fluid neurochemistry and drug effects

The neuropharmacologic basis of infantile spasms and the mechanism by which adrenocorticotropic hormone (ACTH) exerts its therapeutic effects are unknown. This is a critical review of cerebrospinal fluid neurotransmitters or their metabolites in infantile spasms before and during treatment with ACTH, and of clinical drug trials with drugs acting on neurotransmission. Cerebrospinal fluid studies have shown lower gamma-aminobutyric acid (GABA), ACTH, and 5-hydroxyindoleacetic acid concentrations in patients with infantile spasms compared to controls, elevated lysine and glutamate, variable or no differences in homovanillic acid, 3-methoxy-4-hydroxyphenylglycol, norepinephrine, corticotropin-releasing hormone, and beta-endorphin. Chronic treatment with ACTH in infantile spasms reduces cerebrospinal fluid GABA, beta-endorphin, and somatostatin, increases norepinephrine and tyrosine, and has variable or no effect on homovanillic acid, 3-methoxy-4-hydroxyphenylglycol, 5-hydroxyindoleacetic acid, histamine, and tryptophan. Small therapeutic trials with drugs that act through different neurotransmitters such as methysergide, alpha-methylparatyrosine, various benzodiazepine agonists, and vigabatrin lend some support to a role for GABA and monoamines in infantile spasms. These data, though promising, provide only a hint of potential neurotransmitter disturbances, and more basic and clinical data are needed.

Infantile spasms

Infantile spasms constitute a relatively rare disorder of infancy and early childhood; their onset is usually within the first 6 to 8 months of life. A large percentage of patients with this disorder (85-90 per cent) show various degrees of retardation. Infantile spasms typically occur in clusters immediately on arousal, or soon thereafter, but rarely occur while the infant is actually asleep. The usual interictal EEG pattern associated with infantile spasms is hypsarrhythmia, but infantile spasms may occur in the absence of this EEG pattern. The pathophysiology of infantile spasms is not known, but recent evidence suggests that certain regions in the brain stem that are associated with sleep cycling may be responsible for the clinical and EEG manifestations of this disorder. At present, the only known effective treatment for infantile spasms is ACTH or corticosteroids. The therapeutic efficacy of these two agents is relatively equal, and one drug may be effective if the other drug fails. The effectiveness of certain traditional anticonvulsants (valproic acid and the benzodiazepines) and pyridoxine in the treatment of infantile spasms has not been adequately assessed. The long-term mental and developmental outcome of patients with infantile spasms is poor. The only factor that appears to be important in terms of long-term outcome is whether the patient is initially classified as cryptogenic or symptomatic, with the cryptogenic patients having the better outcomes. Approximately half of the infantile spasm patients will continue to have other types of seizures after their spasms stop.

Intrathecal immunoglobulin production and minor motor seizures

Five infants with idiopathic infantile minor motor seizures had an elevated immunoglobulin G (IgG) index ((cerebrospinal fluid IgG/serum IgG):(cerebrospinal fluid albumin/serum albumin)). The infants had prolonged prodromal symptoms, and bad prognosis. It is suggested that immunological mechanisms may contribute to the pathophysiology in certain cases of infantile spasms.

Immunological disturbance in West and Lennox-Gastaut syndromes

Cell-mediated and humoral immunity were investigated in 18 patients with West syndrome, 12 with Lennox-Gastaut syndrome and 19 healthy controls. The study included determination of T and B peripheral blood lymphocytes, serum levels of IgG, IgA and IgM, skin sensibilization with DNCB, intracutaneous PHA, leucocyte migration inhibition test and lymphocyte blastic transformation in the presence of PHA. Cell-mediated deficiency was detected in 28 children whereas low levels of immunoglobulins were observed only in 6 children. Immunological disturbances were more prominent in children with West syndrome.