AUTHOR=Lindgren Helena , Eklund Johan , Eneslätt Kjell , Sjöstedt Anders 

TITLE=Kinetics of the serological response up to one year after tularemia

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=12

YEAR=2023

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.1072703

DOI=10.3389/fcimb.2022.1072703

ISSN=2235-2988

ABSTRACT=<p>Serological analysis is the predominant method used to diagnose tularemia, a zoonotic disease caused by the highly virulent bacterium <italic>F. tularensis</italic>. We determined <italic>F. tularensis</italic>-specific IgM and IgG antibody titers by an LPS-based ELISA assay on five occasions one to twelve months after onset of ulceroglandular tularemia in 19 individuals. Peak IgM antibody titers were observed at the one-month time point and peak IgG antibody titers at the two-month time point. Both IgG and IgM antibody levels declined linearly thereafter with rather similar kinetics. Compared to the average one-month antibody titers, average IgG titers were not significantly lower before the 12-month time point and IgM titers before the 4-month time point. All, but one average titer, were significantly increased compared to the cut-off of the assay. Average IgG and IgM titers were significantly lower for the group = 69 years old compared to the group &lt; 69 years. Collectively, the data demonstrate a persistence of <italic>F. tularensis</italic>-specific IgM and IgG antibody titers for at least 12 months after ulceroglandular tularemia. Thus, low, but significantly elevated <italic>F. tularensis</italic>-specific antibody titers are of limited diagnostic value since they are not indicative of ongoing tularemia.</p>