***Make no changes to the treatment of a CF patient without the permission and supervision of that person's medical professional!
 

Given the theory that CF persons not only suffer from an extracellular deficit of GSH, but that their immune system cells are chronically depleted of GSH, it would seem appropriate not only to recity the extracellular deficit by providing additional GSH, but also to boost the capability of the immune system cells to produce their own GSH.
 

Question: Can One Augment Cellular Production of GSH?
 

Yes, provision of a cysteine donor such as NAC (n-acetyl cysteine) has been shown to increase such production. Given that cysteine is the rate-limiting amino acid for GSH production, provision of additional cysteine, usually through oral ingestion of a cysteine donor, allows the cells to produce more GSH [1, 2, 3]. This is a well-established therapy, with adult dosage rates for GSH deficiency diseases (such as AIDS) ranging from 2-8 grams of orally ingested NAC. For CF patients on GSH augmentation therapy, it may only be necessary to use NAC or another cysteine donor in the morning, after a night of returning to baseline levels in CF. After that initial dose of NAC, the augmentation of the extracellular GSH level by GSH itself may be sufficient to maintain redox equilibrium of GSH in the MRP-expressing cells (e.g., the immune system cells) [4]. It is important not to use too much cysteine, as it can be toxic to the liver in high doses. Check with your medical professional about appropriate levels of NAC. Make no changes to your medical treatment without prior consultation with your medical professional.

References
 

[1] Droge W et al., "Modulation of Lymphocyte Functions and Immune Responses by Cysteine and Cysteine Derivatives," The American Journal of Medicine 91(3C): 140-143, 1991 September 30.
 

[2] Droge W, "Cysteine and glutathione deficiency in AIDS patients: a rationale for the treatment with N-acetyl-cysteine," Pharmacol. 46(2): 61-65, 1993.
 

[3] Mihm S et al., "Inhibition of HIV-1 replication and NF-kappa B activity by cysteine and cysteine donors," AIDS 5(5): 497-503, 1991 May.
 

[4] We are indebted to Keith Crawford, Ph.D. for this information.