When we don't measure important stuff.
A thread about the immune response to #SARSCoV2
1. Since serology/IgG can be readily measured, this is what is conventionally used to assess an individual's response
That's a very incomplete picture
https://www.cell.com/trends/pharmacological-sciences/pdf/S0165-6147(20)30130-9.pdf?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0165614720301309%3Fshowall%3Dtrue

2. Just because T cell repertoire isn't measured, except for research purposes, doesn't mean it's not important. Very important. Like in this recent @SciImmunology paper that showed the #SARSCoV2-specific T cell response in patients with ARDS
https://immunology.sciencemag.org/content/5/48/eabd2071

3. So many studies have reported IgG, IgM but provide no insight on T-cell mediated immunity, no less serially assess this over time. A good example is this excellent recent paper @NatureMedicine in asymptomatic patients https://www.nature.com/articles/s41591-020-0965-6

4. Yet posts like this appeared yesterday, reverberate widely (not even a link to the study), and are impossible to interpret

5. One of the best studies to show the importance of T-cell immunity was published in @CellCellPress https://www.cell.com/cell/fulltext/S0092-8674(20)30610-3
In some people there was a pre-existing T-cell response to #SARSCoV2, cross-reactive from other coronaviruses; only rough correlated w/ the Ab response

6. Today this got even a bit more complicated. It's not just T cells that respond to a virus.
https://media.nature.com/original/magazine-assets/d41586-020-01916-2/d41586-020-01916-2.pdf @NatureNV
https://www.nature.com/articles/s41586-020-2424-4 @nature

7. So when you interpret seroprevalence, serology, antibody only data, please keep the incomplete nature of that assessment in terms of the broader cellular immune response to #SARSCoV2.
There's a lot more to learn about the stuff we don't measure.

8. Exemplar: A new study that in 7 families that shows multiple individuals were negative for antibodies (and virus, antigen) but demonstrated #SARSCoV2 specific T cell responses
https://www.medrxiv.org/content/10.1101/2020.06.21.20132449v1 (h/t @Dereklowe)