Introduction: Antinuclear antibody (ANA) tests are widely used for the diagnosis of autoimmune diseases, but ANAs are also commonly found in patients with various infections. This retrospective study aimed to investigate the relationship between infections and ANA status. Methods: Patients that visited the Department of Infectious Diseases at Inha University Hospital between January 2007 and July 2018 were investigated. We analysed their ANA test results and reviewed rheumatic and infectious diagnoses of patients with positive ANA findings. Results: Of the 9,320 patients during the study period, 1,111 underwent ANA testing and 110 tested positive. Seven of the 110 patients were previously diagnosed with ANA-positive disease, and 21 were diagnosed with autoimmune disease during the present study. Of the remaining 82 patients, 43 were confirmed with infectious disease. The most common pathogen was Mycobacterium tuberculosis (n = 10), followed by Treponema pallidum (n = 5), Orientia tsutsugamushi (n = 5), Escherichia coli (n = 5), Bartonella henselae (n = 3), and human immunodeficiency virus (n = 3). Of the 39 patients without a confirmed pathogen, 7 were seropositive for O. tsutsugamushi, B. henselae, or Rickettsia spp. Patients were observed at an average of 24 weeks in our hospital. One patient developed systemic lupus erythematosus after being diagnosed with Epstein–Barr virus-induced infectious mononucleosis, and another patient developed adult-onset Still’s disease after being diagnosed with scrub typhus. Conclusion: This study showed that various relationships exist between infections and rheumatic diseases. In particular, several patients with a positive ANA test result were found to have intracellular infections such as mycobacterial infections, syphilis, or scrub typhus.

Seo MR, et al. J Korean Med Sci. 2014 Aug;29(8):1178-1181. https://doi.org/10.3346/jkms.2014.29.8.1178

Although severe malaria by Plasmodium vivax has been increasingly reported, there are marked variations in the type and rate of the complications by geographic area. This is possibly because of the presence of concurrent falciparum malaria or bacteraemia, and of differences in underlying immune status among the infected subjects. Furthermore, published studies on P. vivax in temperate regions are limited. The present study investigated severe vivax malaria in Korea, where only vivax malaria occurs. Hence, other compounding factors are rare. Additionally, most of the patients are possibly non-immune to this malarial disease. Adults with vivax malaria observed in one 860-bed university hospital from January 2006 to December 2012 were retrospectively evaluated. Seventeen patients who had travelled overseas within 6 months before the presentation of malaria were excluded. Severe vivax malaria was diagnosed according to World Health Organization criteria. Other complications were also investigated. Two-hundred and ten patients were enrolled, of which 88 (41.9%) were treated as inpatients and the remainder as outpatients. Eleven patients were treated in an intensive care unit; among them, five patients received mechanical ventilation, and one needed extracorporeal membrane oxygenation therapy (ECMO) additionally. Severe vivax malaria was identified in 44 patients (21.0%), and the most common severe complication was pulmonary manifestation (40/188, 21.9%), which was followed by cerebral malaria (5/210, 2.4%), shock (4/210, 1.9%), spontaneous bleeding (3/210, 1.4%), metabolic acidosis (3/210, 3.5%) and acute kidney injury (2/210, 1.0%). Unusual complications, such as splenic infarction (ten patients) and retinal haemorrhage (two patients) were sometimes observed. There were no deaths, but the case involving ECMO was potentially fatal. Plasmodium vivax infection can be severe to be fatal and is frequently associated with various complications in non-immune adults. The frequency of each complication seems to differ from other countries. Hence, further investigation is needed to elucidate the causes and mechanisms responsible for these differences.

Tsutsugamushi disease or scrub typhus in Korea was first officially reported in foreign soldiers in 1951 and in indigenous persons in 1986. However, the history is further prolonged. The book Dong Ui Bo Gam, published in 1613, described "Soo Dok" (water poisoning), which is similar to tsutsugamushi disease. Further, the term was mentioned in the book Hyang Yak Gu Geup Bang, first published in 1232-1251. During the Japanese colonial rule (1910-1945), Trombicula akamushi was identified in Suwon, Korea, in 1917. Although cases of tsutsugamushi disease in Korea with a murine typhus-like illness and OXK-positivity were reported in 1935, such atypical presentation was not recognized as tsutsugamushi disease. During the Korean War, in 1951, tsutsugamushi disease developed in two British soldiers stationed in the Imjin River, who presented typical features and positive OXK reactions. Indigenous cases have re-emerged since 1986. Thereafter, there were many studies on various aspects of tsutsugamushi disease: epidemiology, vector, small mammals, clinical features and complications, diagnosis, and treatment. Persistence of Orientia tsutsugamushi and its possible recrudescence with pneumonia were reported in 2012 and 2014, respectively.

Kim MS, et al. Infect Chemother. 2013 Dec;45(4):431-434. http://dx.doi.org/10.3947/ic.2013.45.4.431

Kim B, et al. Infect Chemother. 2020 Jun;52(2):194-203. https://doi.org/10.3947/ic.2020.52.2.194