ICAM G241A polymorphism and soluble ICAM-1 serum levels: Evidence for an active immune process in schizophrenia

Objectives: We have previously reported reduced serum levels of
soluble intercellular adhesion molecule-1 (sICAM-1) in
schizophrenic patients. A single-nucleotide polymorphism ( SNP) of
the ICAM-1 gene was described at position 241. The G --> A SNP
results in a nonsynonymous amino acid exchange of the ICAM-1
protein, and the A allele was shown to be also associated with
several immunological disorders like rheumatoid arthritis. Methods:
We investigated 70 schizophrenic patients and 128 unrelated healthy
control persons regarding the relationship between the serum levels
of sICAM-1 and the ICAM-1 G214A polymorphism. Results: We were able
to replicate our previous finding of reduced sICAM-1 levels in
schizophrenia. Healthy control persons carrying the polymorphic A
allele showed markedly lower sICAM-1 serum levels than carriers of
the homozygous GG wild type ( p < 0.004). In contrast, no
significant difference in the sICAM-1 serum levels were seen
regarding the G241A genotype distribution in schizophrenic
patients. Conclusion: We hypothesize that the biochemical effect of
the G241A SNP is masked in schizophrenic patients, indicating a
disease-related mechanism leading to reduced levels of sICAM-1 in
schizophrenia. Copyright (C) 2005 S. Karger AG, Basel.