Affiliations: Department of Pediatrics, Faculty of Medicine, Ain
Shams University, Cairo, Egypt | Department of Clinical Pathology, Faculty of Medicine,
Ain Shams University, Cairo, Egypt
Note: [] Correspondence: Dr. Gehan A. Mostafa, 9 Ahmed El-Samman Street
off Makram Ebaid, Nasr City, Cairo, Egypt. Tel.: +20 2 227 13 217; +20 10 35
128 77; E-mail: hafezg@softhome.net
Abstract: One of the most consistent biological findings in autism is elevated
blood serotonin levels. Immune abnormalities, including allergy, are also
commonly observed in this disorder. Allergy may play a role in pathogenesis of
autism wherein immune responses to allergens may induce the production of brain
autoantibodies found in many autistic children. Hyperserotonemia may be the
reason behind the increased frequency of allergic manifestations in autistic
children through reduction of T-helper 1-type cytokines. Thus, we investigated
the possible connection between hyperserotonemia and the increased frequency of
allergic manifestations in 40 autistic and 40 healthy matched children.
Autistic children had significantly higher serum serotonin levels than controls
[125 (250.75) vs. 41.5 (41.5) ng/mL, P < 0.001]. Fifty five percent
(22/40) of autistic children had elevated serum serotonin. Allergic
manifestations (bronchial asthma, atopic dermatitis and allergic rhinitis) were
elicited in 45% of autistic patients which were significantly higher than
controls (10%, P < 0.001). Moreover, autistic patients with allergic
manifestations had significantly higher serum serotonin levels than those
without (P < 0.001). Furthermore, there was a significant positive
correlation between serum serotonin and total immunoglobulin E levels in
autistic patients (r = 0.8, P < 0.001). In conclusion, hyperserotonemia
may be a contributing factor to the increased frequency of allergic
manifestations in some autistic children. Inclusion of serum serotonin levels
as a correlate may be useful in future immune studies in autism to help unravel
the long-standing mystery of hyperserotonemia and its possible role in the
pathophysiology of this disorder. In addition, the effect of blood serotonin
lowering drugs in hyperserotonemic autistic children, on amelioration of
allergic manifestations and immune abnormalities, should be studied.
