Participants taking methotrexate for an immune disorder did not show an increase in CD8 T cells.
A recent study conducted by investigators from NYU Langone Health, in collaboration with the NYU Grossman School of Medicine, has discovered that individuals who take methotrexate, a common therapy for immune system disorders, mount a weaker immune response to COVID-19 vaccines.
Results from the study were published in the journal Annals of the Rheumatic Diseases.
"It is most important to state that patients should not be concerned about our study findings as the majority of patients with immune system disorders are responding well to the mRNA vaccines," Rebecca Haberman a co-first author on the study said. "It is also possible that methotrexate is delaying, rather than preventing, an adequate immune response against COVID-19."
For the study, the team of investigators gave 2 doses of the Pfizer-BioNTech COVID-19 vaccine to healthy patients and those being treated for immune-mediated disorders, including rheumatoid arthritis, psoriatic arthritis and psoriasis.
They then analyzed blood samples from the participants to determine the amount of antibodies that the patients produced, including key cells such as CD8 T cells.
Findings from the study demonstrated that 90% of the healthy participants and those not taking methotrexate mounted a strong antibody response. However, only 62% of those who were taking the therapy mounted an adequate immune response.
Additionally, the participants taking methotrexate showed no increase in CD8 T cells, while those not taking it produced them.
"More research is needed to understand why such a significant proportion of people with common immune disorders who take methotrexate have deficiencies in mounting an antibody and cellular response," Jose U. Scher, a co-first author on the study said. "This may not necessarily mean that the vaccine is not efficacious, but that alternate vaccine strategies need to be investigated."