Alpha2 macroglobulin elevation without an acute phase response in depressed adults with Down's syndrome: implications

Area of Science:

• Neuroimmunology
• Psychiatry
• Genetics

Background:

• Depression in individuals without intellectual disability (ID) is associated with elevated alpha2 macroglobulin (alpha2M) and an acute phase protein (APP) response.
• Individuals with Down's syndrome (DS) may possess inherent genetic immune system abnormalities.
• Understanding immune markers in DS depression is crucial for accurate diagnosis and treatment.

Purpose of the Study:

• To investigate the acute phase protein (APP) response and alpha2M changes in depressed versus non-depressed adults with Down's syndrome (DS).
• To explore potential immune system differences related to depression in the DS population.

Main Methods:

• Serum levels of alpha2 macroglobulin (alpha2M) and several acute phase proteins (APPs) were measured in 38 adults with DS (19 depressed, 19 non-depressed) using ELISA.
• Diagnoses of depression were based on DSM-IV criteria.
• Medical and neurological examinations excluded confounding medical conditions.

Main Results:

• Significantly higher alpha2 macroglobulin (alpha2M) levels were observed in the depressed DS group compared to the non-depressed group.
• C-reactive protein (CRP) levels were lower in the depressed DS group, particularly in those not on psychotropic medications, deviating from the expected APP response.
• The observed alpha2M elevation in depressed adults with DS appears independent of the typical APP response.

Conclusions:

• Alpha2 macroglobulin (alpha2M) elevation in depressed adults with Down's syndrome (DS) is likely independent of the acute phase protein (APP) response.
• An alternative hypothesis links elevated alpha2M to a dormancy/hibernation process associated with core depression symptoms.
• Further research is warranted to confirm alpha2M as a specific diagnostic marker for depression in individuals with intellectual disability (ID).