Lisa writes:

Happy New Year to the Immuniverse All Stars!

I am listening to a “This Podcast Will Kill You” podcast on poison ivy.  I was happy to learn that urushiol compounds like those in poison ivy are used to glaze Japanese pottery, which makes sense as it is a phenolic resin.  Also, benedryl doesn’t work so well against the poison ivy symptoms in humans because the delayed poison ivy symptoms are due to a T cell response, which seems to be almost exclusive to humans.  This was news to me, and I thought y’all might like to discuss this immune response that so many of us have experienced.  Also, I have always observed that poison ivy made me crazy at the same times every day.  What do we know about the effect of circadian rhythms and T cell activity in the body?  

I am grateful to you all and the sibling Microbe shows.  Thank you Vincent for the hard work of trying to evolve a more educated public.  


Duke   BS Chemistry
UVA     MS Materials Science 

Now farming in beautiful Sperryville, Va and studying Virology and Immunology on You Tube with Vincent and Brianne.  Thank you.  

Andrew writes:

Kia ora from Pongaroa,

Online I have discovered several people who have Dissociative Identity Disorder (previously Multiple Personality Disorder) they very interesting stories to tell. One or two report that different alters (persons), in the same body, have different reactions to allergens depending on who is in control of the body.

My first thought was that this is psychosomatic but I looked in Google Scholar and I can see that variations in allergic reactions, in these people, is a recognized and real thing along with other physiological changes like  differences in visual acuity, medication responses, plasma glucose levels in diabetic patients, and more. Sadly I am shut out of reading more by paywalls.

So my question is: as allergies are mostly an immune response – what is going on here? Is there a known mechanism where this can be explained?


Ayala writes:

Dear Prof. Vincent Racaniello and all other “Immune” hosts. 

Firstly, I love your podcasts! I listen to every episode you post in this show and on TWIV, and I’m very excited to finally have a good reason to contact you in person. 

I’m writing because my lovely 4-year-old niece asked my brother a really good question, just before she went to sleep (when all of her philosophical-life concerning questions appears). 

She wanted to know whether all animals have nasal-mucus as we humans have? 

Small literature research taught me that all mammalian, birds and some fish do have it, however, it was hard to understand if they are referring to a more general mucosal-first line of defense mechanism (in other body parts such as the lungs and gut for example) or if all of these animals do secrete mucus out of their nose (or gills) as a defense mechanism to prevent bacterial or viral infection (or to get rid of dust and other unwelcome particles)? 

She specifically asked about: horses, cows, dolphins, spiders, snails, butterflies, turtles, alligators… 

I hope this question is not too random, given that most of the world’s interest today is around COVID-19.

Thank you for your time, I appreciate everything all of you do, 

Ayala (from Israel) 

Tim writes:


I take a non-prescription H1 receptor antagonist – cetirizine for pollen allergy (I think it’s tree pollen, but I don’t know which species, and usually end up taking cetirizine daily from April and June).

I’ve recently had my first dose of Moderna SARS-Cov-2 vaccine, and was curious to know if there might be any impact on vaccine efficacy (improvement or otherwise!) of pausing the antihistamines around the time of the jab?

I read a few papers and articles on the role of histamine in the immune system, but the only conclusion I reached was that (as I suspected) I was stupendously out of my depth.

If pausing antihistamines around the time of vaccination could be beneficial, what sort of time period might be a good bet?

If the pollen gets too much I could don an FFP3 (~N99) mask instead whilst sitting at my desk.

My home office faces a busy foot path, so I risk passers by and neighbours assuming that I have extreme COVID paranoia, but I think I can put up with that.