Iron metabolism disorders of patients with chronic paracoccidioidomycosis

Abstract

Paracoccidioidomycosis (PCM) is caused by Paracoccidioides spp.; during infection, some host mechanisms limit the availability of iron, thereby reducing its reproduction. However, Paracoccidioides spp. can evade the immune defense and, even under limited iron conditions, use this mineral for growth and dissemination. This study evaluated the iron metabolism of 39 patients who were diagnosed with chronic PCM between 2013 and 2021. The forms of iron before treatment and at the time of clinical cure were evaluated based on the following: serum ferritin levels (storage iron); total iron-binding capacity (TIBC) and transferrin saturation (TSAT) level (transport iron); red blood cell (RBC), hemoglobin (Hb), hematocrit (HCT), and soluble transferrin receptor (sTfR) levels; and sTfR/log ferritin ratio (functional iron). The mean age of the patients was 54.5 years (±6.7 years). Most patients were men (97.4%), rural workers (92.1%), and smokers (84.6%); most had moderate disease severity (66.7%). Before treatment, the median values of all evaluated parameters were within or just slightly outside the normal range of values. However, it is possible to infer that PCM interferes with functional and storage iron because improvements in these parameters after treatment as well as associations with disease severity were observed. Furthermore, moderate correlations were observed between C-reactive protein and the Hb (r=-0.500; p=0.002), RBC (r=-0.461; p=0.005), HCT (r=-0.514; p=0.001), and iron levels (r=-0.491; p=0.002). PCM interferes with iron metabolism by transforming functional iron to storage iron, as revealed by anemia, low iron levels with normal TSAT levels, normal TIBC, normal sTfR levels, normal sTfR/log ferritin ratios, and normal or slightly increased ferritin levels. PCM can lead to anemia of inflammation, which can be differentiated from iron deficiency anemia by a careful investigation of the iron form parameters.