It has been reported that patients with "chronic Lyme disease" have decreased number of natural killer cells, as defined by the CD57 marker.
We performed immunophenotyping in 9 individuals with post-Lyme disease syndrome, 12 who recovered from Lyme disease and 9 healthy volunteers.
The number of natural killer cells was not significantly different between the groups.
Source: Clinical and Vaccine Immunology, Jun 10, 2009. PMID: 19515868, by Marques A, Brown MR, Fleisher TA. Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD; Immunology Service, Department of Laboratory Medicine, Clinical Center, NIH, Bethesda, MD. [E-mail: firstname.lastname@example.org]