Leflunomide immunosuppression

I have some questions about immunosuppression, particularly relating to leflunomide, that I hope someone can help me with.

I'm 50, male and was diagnosed with psoriatic arthritis about 7 years ago. I also have hemochromatosis and high blood pressure. The former is well managed with monthly venesections, the latter with daily candesartan.

Currently I'm on 3g of sulfasalazine a day, fortnightly adalimumab injections.

I was also put on 10mg of leflunomide a day about 6 months ago but it affected my platelet count and was reduced to 10mg every other day a couple of months ago. The other drugs I'm on aren't immunosuppressive and so I won't list them here.

I've had 4 Pfizer jabs, each about 3 months apart with the last one at the end of December.

I can't find much information about leflunomide and it's effect on the immune system online other than the fact it reduces B and T blood cells. I believe these are both of great importance in fighting infections such as covid. I have found information about the other drugs I'm on in relation to covid and the vaccine but no data about leflunomide.

I'm still very worried about covid, especially because of my lack of knowledge with leflunomide. Should I be?

I hope someone is able to help answer my question.

Thank you.


  • Hi Moonunit,

    Thank you for posting on the Helpline forum. I am sorry to hear you have psoriatic arthritis and you are dependent on immune-suppressant medication to help control your symptoms and the disease process. It is good that you have now had 4 Covid-19 vaccines. You can be re-assured that this will certainly give you some protection against the Covid-19 virus. However, as you are aware your level of protection and immunity will be less than if you were not taking this medication.

    Important research on the level of protection for those with compromised immunity is being carried out. You may have heard of the Octave Study. I have given a link to more information about this below which I hope will be of some help.

    Unfortunately, we are unable to answer all your specific questions about Leflunomide etc. but we can re-assure you that further research is being done.

    It sounds as if it would be good to talk things through with your rheumatology nurse who is aware of your individual clinical situation.

    If at any point you would like to talk things through informally and in confidence about your arthritis, you are welcome to call our Free Helpline on 0800 520 0520 weekdays 9am – 6pm. 

    Best wishes,

    Fiona, Helpline Advisor 

  • Moonunit
    Moonunit Member Posts: 8

    Thank you for your reply, I'll try the nurses.