We elucidated the causes for compromised levels of GSH, by demonstrating by Western blot analysis that the levels of GCLC (catalytic subunit of the enzyme responsible for catalyzing the fist-step reaction involved in the GSH synthesis) were significantly compromised in AD and HIV-1 positive individuals with low levels of CD4 + T-cells compared to the healthy group (Fig. 2A,B). Here, GCLC is linked to Alzheimer disease.