Immune monitoring of pediatric patients co-infected with Rickettsia rickettsii and Ehrlichia canis

In 2021, 273 Rocky Mountain Spotted Fever cases have been reported nationwide. In Chihuahua City, fourteen samples were obtained from children suspected of rickettsial infection. The analysis of samples collected from January to December 2021 showed a prevalence of 28.5%, 43% and 28.5% for Rickettsia rickettsii, Ehrlichia canis, and both pathogens in coinfection, respectively. The analysis of clinical hematological and biochemistry analytes showed alterations such as 100% of the children coursed with elevated liver enzymes and coagulation times, 64% showed leukocytosis due to neutrophilia, 55% of them had thrombocytopenia, lymphopenia and hypoalbuminemia, and 45% showed normocytic normochromic anemia. Statistically significant differences were obtained in the chemokines IL-8, RANTES, CXCL9/MIG, and CXCL10/IP-10 across the coinfected and control groups; the differences in IP-10 were significant for patients infected by R. rickettsii compared to the control group. Also, significant differences were observed for IL-1{beta}, IL-6, IL-17, IFN{gamma}, and TNF among the R. rickettsii positive group compared to the control group; on the other hand; the coinfected group exhibited modified levels of IL-6, IL-8, and IL-10 compared with the control group. Finally, significant differences were obtained for CD8 + T lymphocytes subpopulations between positive individuals for R. rickettsii and E. canis.