J Bone Jt Infect 2020; 5(4):205-211. doi:10.7150/jbji.46187
Plasma Cell Infiltration on Histopathological Samples of Chronic Bone and Joint Infections due to Cutibacterium acnes: A series of 21 Cases
1. Hospices Civils de Lyon, Institut de pathologie multisites des Hospices Civils de Lyon, Site Est et plateforme de pathologie moléculaire, Bron, France.
2. Université Claude Bernard Lyon 1, Lyon, France.
3. Hospices Civils de Lyon, Hôpital de la Croix-Rousse, Service de Maladies Infectieuses et Tropicales, Lyon, France.
4. Centre de Référence des Infections Ostéo- Articulaires Complexes de Lyon, Lyon, France.
5. Centre International de Recherche en Infectiologie, CIRI, Inserm U1111, CNRS UMR5308, ENS de Lyon, UCBL1, Lyon, France.
6. Hospices Civils de Lyon, Hôpital Croix-Rousse, Institut des Agents Infectieux, Laboratoire de Bactériologie, Lyon, France.
Trecourt A, Brevet M, Champagnac A, Conrad A, Josse J, Dupieux-Chabert C, Valour F, Ferry T. Plasma Cell Infiltration on Histopathological Samples of Chronic Bone and Joint Infections due to Cutibacterium acnes: A series of 21 Cases. J Bone Jt Infect 2020; 5(4):205-211. doi:10.7150/jbji.46187. Available from http://www.jbji.net/v05p0205.htm
Introduction: Histopathological definition of bone and joint infection (BJI) is based on Mirra's criterion (≥ 5 polymorphonuclears (PMNs) per field in 5 high power fields (HPFs)). However, this definition does not seem appropriate for chronic BJIs caused by slow-growing germs such as Cutibacterium acnes (C. acnes). The aim of this study was to confirm that Mirra's criterion is not adequate for diagnosis of BJIs due to C. acnes. The second objective was to determine if plasma cell infiltration could be useful for the diagnosis of chronic BJIs due to C. acnes.
Methods: We retrospectively selected 25 consecutive patients from 2009 to 2013 with chronic BJIs due to C. acnes. Histological analysis was performed on the 21 cases with at least two C. acnes positive cultures. In addition of Mirra's criterion, the number of plasma cells (≥5 plasma cells/5 HPFs, defined as “CRIOAc Lyon's criterion”) was implemented in the histopathological analysis. Patients were defined as infected, if at least one of the two criteria were present.
Results: According to Mirra's and CRIOAc Lyon's criteria, positive histopathology was observed in 12 (57.1%) and 15 (71.4%) cases respectively. Considering the 9 cases with negative Mirra's criterion, high plasma cell infiltration (≥5 plasma cells per field/5 HPFs) was observed in 5 cases (55.6%), and low plasma cells infiltration (2-5 plasma cells per field/5 HPFs) was observed in 4 other cases (44.4%).
Conclusions: Adding CRIOAc Lyon's criterion to Mirra's criterion might restore some histopathological diagnosis of chronic BJIs due to C. acnes when a chronic BJI is clinically suspected.
Keywords: Cutibacterium acnes, Bone and joint infection, Plasma cells, Plasma cells infiltration, CRIOAc Lyon's criterion