Increased frequency of T cells expressing IL-10 in Alzheimer disease but not in late-onset depression patients

• Higher % of T cells expressing IL-10 in AD patients compared to controls
• IL-10 polymorphism was not associated among LOD or AD patients or controls.
• Relation of IL-10 polymorphisms and serum levels in AD remains to be studied.

Higher risk of dementia is expected for patients with late onset depression (LOD) history. The IL-10 polymorphisms are associated with Alzheimer disease (AD). On the other hand, there is no study associating IL-10 polymorphisms to LOD. This study aimed to investigate the − 1082G/A polymorphism association in LOD, AD patients and controls and also the peripheral expression of IL-10 in CD4 + T cells. It was done in a case–control study comparing immune system phenotype and genetic polymorphism association among control individuals, LOD and AD patients. Participants were 569 subjects composed the genetics sample (249 AD, 222 LOD and 98 controls) from a tertiary medical center based on Belo Horizonte, Brazil. Flow cytometry analysis was performed in 55 people (22 AD patients, 11 LOD patients and 22 controls). A real time PCR for IL-10 SNP (rs 1800896) through genotyping analysis and flow cytometry evaluation of CD4 + T cells expressing IL-10 was done. An increased CD4 + T cells expressing IL-10 were detected only in the AD group. There was no difference detected in allele or genotype analysis for IL-10 polymorphism among LOD, AD patients or controls. IL-10 might have a role in the modulation of immune response in AD patients, however it is not presented in LOD population.