Significantly increased frequency of the apolipoprotein E epsilon 4 allele in elderly non-demented leprosy patients

A pleiotropic effect of the APOE gene: association of APOE polymorphisms with multibacillary leprosy in Han Chinese from Southwest China

BACKGROUND

Patients with leprosy have a very low risk of Alzheimer disease (AD) and β-amyloid (Aβ) deposition is significantly lower in the brain tissue of elderly patients with leprosy compared with age-matched controls. Apolipoprotein E (ApoE) plays a critical role in lipid metabolic pathways and in the brain, facilitating the proteolytic clearance of Aβ. We hypothesized that APOE confers risk of leprosy as lipid metabolism is involved in Mycobacterium leprae infection.

OBJECTIVES

To investigate the potential genetic associations between APOE and leprosy in two independent Chinese case-control cohorts from the Yuxi and Wenshan prefectures, Yunnan Province of Southwest China.

METHODS

Five APOE single-nucleotide polymorphisms (SNPs) were analysed in 1110 individuals (527 patients and 583 controls) from the Yuxi prefecture using a SNaPshot assay. Genetic variations in the entire APOE exons were screened in 1788 individuals (798 patients and 990 controls) from the Wenshan prefecture using next-generation sequencing technology.

RESULTS

The AD-associated SNPs rs405509 and rs439401 increased the risk of leprosy per se and multibacillary leprosy (P < 0·005), but the APOE-ε4 allele did not. The SNPs rs405509 and rs439401 were cis expression quantitative trait loci (eQTL) for APOE expression in human skin. Differential APOE mRNA expression was observed in skin lesions of patients with type I reaction leprosy and those with multibacillary leprosy. APOE and related lipid genes are involved in an interaction network with leprosy susceptibility genes.

CONCLUSIONS

The APOE gene is associated with leprosy, most likely by regulating lipid-metabolism-related genes.

Improved cognitive and memory abilities in a patient with Alzheimer's disease treated with activated immune cells: Immune cell therapy may benefit more AD patients

So far, the pathogenesis of Alzheimer's disease (AD) has not been clarified, nor has patient therapy been satisfactory. Although inheritance dominates the less frequent early-onset AD in young and middle-aged individuals, environmental and immunogenetic factors have been identified in the most frequently occurring late-onset AD of higher-aged individuals, comprising 90% of AD patients. Thorough investigations have detected a prevalence of certain microbes which are known to affect brain activities in the brains of AD patients. This microbial prevalence suggests failing immune responses by immune gene variants against specific microbes. In fact, some immune gene variants have been detected significantly more often in AD patients. Failing immune responses can be corrected by activating immune cells outside the body ("in vitro") for the subsequent therapeutical injections. Activated immune cells digest and present microbial peptides better and differentiate naïve/resting immune cells to powerful effector cells, which can be used for therapy. The patient's activated immune cells can pass the blood-brain barrier and overcome chronic infections in the brain. Furthermore, activated immune cells can secrete a series of neurotrophins for the restoration of neuronal circuits. Based on the encouraging results of immunotherapy in a patient with late-onset AD, we hypothesize that therapy with the patient's activated immune cells would safely benefit many AD patients.

No effect of anti-leprosy drugs in the prevention of Alzheimer's disease and beta-amyloid neurotoxicity

There is continuing controversy as to whether or not anti-leprosy drugs prevent Alzheimer's disease (AD). Therefore, we examined the effect of anti-leprosy drugs on the prevalence of AD in leprosy patients, and also investigated the effect of anti-leprosy drugs on amyloid beta-protein (Abeta)-induced neurotoxicity in vitro. The present study suggests that anti-leprosy treatments do not prevent the onset of AD. None of our data found anti-leprosy drugs (dapsone, rifampicin, clofazimine, minomycin or ofloxacin) had any effect on Abeta neurotoxicity. It is now important to examine the infection of Mycobacterium leprae in the central nervous system to clarify the reason for the low prevalence of senile dementia, and low frequency of Abeta deposition in leprosy patients.

Alpha-1-antichymotrypsin is not associated with the increased frequency of apolipoprotein-E-epsilon-4 allele in elderly non-demented leprosy patients

In our previous study, elderly leprosy patients showed a low prevalence of senile dementia of the Alzheimer type, but the frequency of apolipoprotein E (APO-E) epsilon 4 was elevated in non-demented elderly leprosy patients. Recent study has shown that Alzheimer's disease risk associated with APO-E epsilon 4 is significantly increased by the alpha 1-antichymotrypsin (ACT) genotype AA. Therefore we examined an association between ACT polymorphism and the APO-E epsilon 4 allele in 350 leprosy patients. None of our data showed an association of ACT genotype and APO-E epsilon 4 allele in leprosy patients. The allelic frequencies of the ACT gene did not differ even between demented patients with leprosy and age-matched controls. Our present data suggest that ACT polymorphism is not associated with the increased frequency of APO-E epsilon 4 in leprosy patients.

Sequence analysis of presenilin-1 gene mutation in Japanese Alzheimer's disease patients

The mutations of presenilins (PSs) gene and their clinicopathological correlations to Alzheimer's disease (AD) have lately attracted considerable attention. In this report we analyzed fifteen Japanese familial Alzheimer's disease (FAD) including 12 early-onset FAD and 13 sporadic AD patients for the mutation of PS-1 gene by direct sequence analysis. We found the mutations, G384A, E280A in two FAD and H163R in one sporadic AD patient, and no N1411 or M239V mutation in PS-2 gene, and no mutation in exons 16 and 17 in amyloid precursor protein (APP) gene. Families in which we failed to find the mutation by this screening may have mutations elsewhere in PSs or in APP gene, or yet unidentified other AD loci may exist. This is the first report to find a sporadic AD patient having PS-1 mutation.