Hi guys,
I recently learned about pentoxifylline because it was prescribed to a friend of mine with ME/CFS by an immunologist, who said that 50% of his ME/CFS patients improved on it.
She was reassured that it was mainly an immune-modulator agent, so she had nothing to worry about.
She is doing amazingly well on this drug after about 2 months on it, to the point where she is feeling almost normal.
I have been doing a thorough research on the drug (because I was considering trying it, as I am bedridden, so is my mom and my partner!). And I found that it actually is a powerful immunesupresive agent. Most available studies are done in vitro, and they show that it strongly decreases NK cells cytotoxicity, inhibits fagocytic activity of the PBMCs, inhibits T and B cell activation, inhibits expression of adhesion molecules on the surface of CD4+ and CD8+ lymphocytes, lowers total count of leukocytes, decreases neutrophil functions, reactivates CMV, and a long etc. (links to the studies below). It's been also shown that pentoxifylline is as immune supressive as dexamethasone.
I have only found 2 studies in vivo where immune system status was assessed. In this respect, one study in humans confirmed what the studies in vitro had found repeatedly: after 1 year or more on pentoxifylline, patients showed a 38% and a 41% reduction in NK cytotoxicity compared with patients or with healthy controls, respectively.
The second study I found in humans showed an 11% reduction in leukocyte count after just one month on the treatment, when given to diabetic patients.
I can understand how this drug can work amazingly for some patients. It lowers TNF-alpha, which is a key cytokine in the feeling of fatigue. It also inhibits the T and B polyclonal proliferation, and also quenches autoimmune processes that might play a role in the pathogenesis of the disease. Moreover, it inhibits the translation of the inflammatory complex NF-kappa B, which we know is also key in ME/CFS pathophysiology. It even increases reduced glutathione (what is to be expected when lowering inflammation) and improves microcirculation.
Now, all this might come at a price, and it is my intention to figure out what exactly this price may be.
A 40% reduction in vivo of NK cell function is just a lot. The relationship between low NKs and cancer is certain. For example, there was a 23.6% higher survival rate of gastric cancer patients in 5 years follow-up, if NK functionality was more conserved:
https://pubmed.ncbi.nlm.nih.gov/11232710
In this regard I've done some research on the cancer-induced rate of immune suppressive drugs when taken as a single treatment for autoimmune conditions. Thus, a review on the subject explains how, for example, for multiple sclerosis patients taking azathioprine, there's a 30% increase of cancer in less than 5 years, a 100% increase in 5-10 years and a 440% increase in more than 10 years. Similarly, a mean of 8 years follow-up of patients with Wegener’s granulomatosis taking cyclophosphamide showed a 2.4-fold overall increase in malignancies per year. In the same vein, patients with psoriasis treated with cyclophosphamide had a 2.1-fold increase of cancer in a 5 years follow-up.
A drug that could be compared to some extent to pentoxifylline is the anti TNF-alpha Infliximab, given that pentoxifylline is known for its capacity to lower TNF-alpha levels. In this case there are mixed results. For example, some studies do not show more cancer rates in Crohn’s disease patients taking Infliximab, but other trials demonstrated a 2-3 fold increase in the risk of non-Hodgkin lymphomas, in patients with reumathoid arthritis taking Infliximab (although to be fair, this comparison is not completely adequate given that Infliximab is a single targeted drug, versus pentoxifylline which shows immunesupresive properties in numerous branches of the immune system):
https://pubmed.ncbi.nlm.nih.gov/12581698
https://pubmed.ncbi.nlm.nih.gov/1739240/
In summary, what I'm asking is not whether it would be worth taking the risk to take immune suppressants in ME/CFS, as, of course, the answer is: it depends! .
What I'd like is for you to help me figure out the real risks in terms of future cancer that might entail the chronic use of pentoxifylline. Unfortunately this is a pretty cheap drug which have not been properly studied.
Thank you so much in advance for your insights and opinions,
Best!
Sergio
******
Bibliography:
- Pentoxifylline given to patients for more than a year showed a 38% and a 41% less cytotoxicity compared to patients and controls, respectively:
https://link.springer.com/article/10.1007/PL00005346
- Pentoxifylline strongly suppressed NK cell function in vitro:
https://pubmed.ncbi.nlm.nih.gov/1593221/
- Pentoxifylline inhibits granzyme B and perforin expression following T-lymphocyte activation by anti-CD3 antibody, in mice:
https://www.sciencedirect.com/science/article/abs/pii/S0192056196000690
- Pentoxifylline reduces pro-inflammatory cytokines and inhibits adhesion between leukocytes and endothelial or epithelial cells. There may also be inhibitory effects on neutrophil, T and B lymphocytes and NK cell activity:
https://www.sciencedirect.com/science/article/pii/B9780702028588500142
- Pentoxyfilline may inhibit HIV expression indirectly by diminishing TNF production and directly, by decreasing activity of NF-kappa B:
https://pubmed.ncbi.nlm.nih.gov/8699854/
- Pentoxifylline decreases neutrophil function, decreases leukocyte response and proliferation, inhibits B and T cells and decreases Th1 cytokines and increases Th2 cytokines:
https://onlinelibrary.wiley.com/doi/full/10.1002/vms3.204
- Pentoxifylline, after one month given to type-2 diabetes patients: decreases 11.1% of total leukocyte count, decreases CRP and ESR, and increases reduced glutathione:
https://pubmed.ncbi.nlm.nih.gov/17613279
- Pentoxifylline inhibits binder and killer cell generation, cytotoxicity, proliferation, regulation of surface antigen expression, and induction of cell surface receptors:
https://link.springer.com/article/10.1007/BF01541173
- Pentoxifylline increases fibroblast collagenases and decreases collagen, fibronectin and glycosaminoglycan production (...) Pentoxifylline is an inhibitor of production of IL-1 and IL-6, an inhibitor of T and B cell activation, and a suppressor of neutrophil degranulation:
https://escholarship.org/uc/item/6270c6vm
- Pentoxifylline Promotes Replication of Human Cytomegalovirus In Vivo and In Vitro:
https://ashpublications.org/blood/a.../Pentoxifylline-Promotes-Replication-of-Human
- Pentoxifylline inhibits natural cytotoxicity as effectively as dexamethasone:
https://www.researchgate.net/public...forin-dependent_natural_cytotoxicity_in_vitro
- Pentoxifylline strongly reduces total number of monocytes capable of fagocytizing latex particles in vitro:
https://pubmed.ncbi.nlm.nih.gov/3023514/
- Pentoxifylline suppressed expression of adhesion molecules LFA-1 and VLA-4, in CD4+ and CD8+ lymphocytes:
https://www.jni-journal.com/article/S0165-5728(96)00198-1/fulltext
I recently learned about pentoxifylline because it was prescribed to a friend of mine with ME/CFS by an immunologist, who said that 50% of his ME/CFS patients improved on it.
She was reassured that it was mainly an immune-modulator agent, so she had nothing to worry about.
She is doing amazingly well on this drug after about 2 months on it, to the point where she is feeling almost normal.
I have been doing a thorough research on the drug (because I was considering trying it, as I am bedridden, so is my mom and my partner!). And I found that it actually is a powerful immunesupresive agent. Most available studies are done in vitro, and they show that it strongly decreases NK cells cytotoxicity, inhibits fagocytic activity of the PBMCs, inhibits T and B cell activation, inhibits expression of adhesion molecules on the surface of CD4+ and CD8+ lymphocytes, lowers total count of leukocytes, decreases neutrophil functions, reactivates CMV, and a long etc. (links to the studies below). It's been also shown that pentoxifylline is as immune supressive as dexamethasone.
I have only found 2 studies in vivo where immune system status was assessed. In this respect, one study in humans confirmed what the studies in vitro had found repeatedly: after 1 year or more on pentoxifylline, patients showed a 38% and a 41% reduction in NK cytotoxicity compared with patients or with healthy controls, respectively.
The second study I found in humans showed an 11% reduction in leukocyte count after just one month on the treatment, when given to diabetic patients.
I can understand how this drug can work amazingly for some patients. It lowers TNF-alpha, which is a key cytokine in the feeling of fatigue. It also inhibits the T and B polyclonal proliferation, and also quenches autoimmune processes that might play a role in the pathogenesis of the disease. Moreover, it inhibits the translation of the inflammatory complex NF-kappa B, which we know is also key in ME/CFS pathophysiology. It even increases reduced glutathione (what is to be expected when lowering inflammation) and improves microcirculation.
Now, all this might come at a price, and it is my intention to figure out what exactly this price may be.
A 40% reduction in vivo of NK cell function is just a lot. The relationship between low NKs and cancer is certain. For example, there was a 23.6% higher survival rate of gastric cancer patients in 5 years follow-up, if NK functionality was more conserved:
https://pubmed.ncbi.nlm.nih.gov/11232710
In this regard I've done some research on the cancer-induced rate of immune suppressive drugs when taken as a single treatment for autoimmune conditions. Thus, a review on the subject explains how, for example, for multiple sclerosis patients taking azathioprine, there's a 30% increase of cancer in less than 5 years, a 100% increase in 5-10 years and a 440% increase in more than 10 years. Similarly, a mean of 8 years follow-up of patients with Wegener’s granulomatosis taking cyclophosphamide showed a 2.4-fold overall increase in malignancies per year. In the same vein, patients with psoriasis treated with cyclophosphamide had a 2.1-fold increase of cancer in a 5 years follow-up.
A drug that could be compared to some extent to pentoxifylline is the anti TNF-alpha Infliximab, given that pentoxifylline is known for its capacity to lower TNF-alpha levels. In this case there are mixed results. For example, some studies do not show more cancer rates in Crohn’s disease patients taking Infliximab, but other trials demonstrated a 2-3 fold increase in the risk of non-Hodgkin lymphomas, in patients with reumathoid arthritis taking Infliximab (although to be fair, this comparison is not completely adequate given that Infliximab is a single targeted drug, versus pentoxifylline which shows immunesupresive properties in numerous branches of the immune system):
https://pubmed.ncbi.nlm.nih.gov/12581698
https://pubmed.ncbi.nlm.nih.gov/1739240/
In summary, what I'm asking is not whether it would be worth taking the risk to take immune suppressants in ME/CFS, as, of course, the answer is: it depends! .
What I'd like is for you to help me figure out the real risks in terms of future cancer that might entail the chronic use of pentoxifylline. Unfortunately this is a pretty cheap drug which have not been properly studied.
Thank you so much in advance for your insights and opinions,
Best!
Sergio
******
Bibliography:
- Pentoxifylline given to patients for more than a year showed a 38% and a 41% less cytotoxicity compared to patients and controls, respectively:
https://link.springer.com/article/10.1007/PL00005346
- Pentoxifylline strongly suppressed NK cell function in vitro:
https://pubmed.ncbi.nlm.nih.gov/1593221/
- Pentoxifylline inhibits granzyme B and perforin expression following T-lymphocyte activation by anti-CD3 antibody, in mice:
https://www.sciencedirect.com/science/article/abs/pii/S0192056196000690
- Pentoxifylline reduces pro-inflammatory cytokines and inhibits adhesion between leukocytes and endothelial or epithelial cells. There may also be inhibitory effects on neutrophil, T and B lymphocytes and NK cell activity:
https://www.sciencedirect.com/science/article/pii/B9780702028588500142
- Pentoxyfilline may inhibit HIV expression indirectly by diminishing TNF production and directly, by decreasing activity of NF-kappa B:
https://pubmed.ncbi.nlm.nih.gov/8699854/
- Pentoxifylline decreases neutrophil function, decreases leukocyte response and proliferation, inhibits B and T cells and decreases Th1 cytokines and increases Th2 cytokines:
https://onlinelibrary.wiley.com/doi/full/10.1002/vms3.204
- Pentoxifylline, after one month given to type-2 diabetes patients: decreases 11.1% of total leukocyte count, decreases CRP and ESR, and increases reduced glutathione:
https://pubmed.ncbi.nlm.nih.gov/17613279
- Pentoxifylline inhibits binder and killer cell generation, cytotoxicity, proliferation, regulation of surface antigen expression, and induction of cell surface receptors:
https://link.springer.com/article/10.1007/BF01541173
- Pentoxifylline increases fibroblast collagenases and decreases collagen, fibronectin and glycosaminoglycan production (...) Pentoxifylline is an inhibitor of production of IL-1 and IL-6, an inhibitor of T and B cell activation, and a suppressor of neutrophil degranulation:
https://escholarship.org/uc/item/6270c6vm
- Pentoxifylline Promotes Replication of Human Cytomegalovirus In Vivo and In Vitro:
https://ashpublications.org/blood/a.../Pentoxifylline-Promotes-Replication-of-Human
- Pentoxifylline inhibits natural cytotoxicity as effectively as dexamethasone:
https://www.researchgate.net/public...forin-dependent_natural_cytotoxicity_in_vitro
- Pentoxifylline strongly reduces total number of monocytes capable of fagocytizing latex particles in vitro:
https://pubmed.ncbi.nlm.nih.gov/3023514/
- Pentoxifylline suppressed expression of adhesion molecules LFA-1 and VLA-4, in CD4+ and CD8+ lymphocytes:
https://www.jni-journal.com/article/S0165-5728(96)00198-1/fulltext