A close interaction between the virus SARS-CoV-2 and the
immune system of an individual results in a diverse clinical
manifestation of the COVID-19 disease. While adaptive immune
responses are essential for SARS-CoV-2 virus clearance, the
innate immune cells, such as macrophages, may contribute, in
some cases, to the disease progression. Macrophages have
shown a significant production of IL-6, suggesting they may
contribute to the excessive inflammation in COVID-19 disease.
Macrophage Activation Syndrome may further explain the high
serum levels of CRP, which are normally lacking in viral
infections. In adaptive immune responses, it has been revealed
that cytotoxic CD8+ T cells exhibit functional exhaustion patterns,
such as the expression of NKG2A, PD-1, and TIM-3. Since SARSCoV-2 restrains antigen presentation by downregulating
MHC class I and II molecules and, therefore, inhibits the T cellmediated immune responses, humoral immune responses also
play a substantial role. Specific IgA response appears to be
stronger and more persistent than the IgM response. Moreover,
IgM and IgG antibodies show similar dynamics in COVID-19
disease.
Babesiosis is a tick-borne disease that may exhibit a broad range of clinical manifestations. According to the Food and Drug Administration (FDA), Babesia species belong to the most common transfusion-transmitted pathogens (FDA, May 2019), but the awareness of the disease caused by these parasitic protists is still low. In immunocompromised patients, the clinical course of babesiosis may be of extreme severity and may require hospital admission. We demonstrate a case of a young male who experienced severe polytrauma requiring repetitive blood transfusions. Six months later, the patient developed a classic triad of arthritis, conjunctivitis and non-specific urethritis. These symptoms largely mimicked Reiter's syndrome. The patient was later extensively examined by an immunologist, rheumatologist, urologist, and ophthalmologist with no additional medical findings. In the search for the cause of his symptoms, a wide laboratory testing for multiple human pathogens was performed and revealed a babesiosis infection. This was the first case of human babesiosis mimicking Reiter's syndrome. Following proper antimicrobial therapy, the patient fully recovered in four weeks. We aim to highlight that a search for Babesia species should be considered in patients with non-specific symptomatology and a history of blood transfusion or a possible tick exposure in pertinent endemic areas.