title: Lymphocyte and monocyte flow cytometry immunophenotyping as a diagnostic tool in uncharacteristic inflammatory disorders.
abstract: BACKGROUND
  Patients with uncharacteristic inflammatory symptoms such as long-standing fatigue or pain, or a prolonged fever, constitute a diagnostic and therapeutic challenge. The aim of the present study was to determine if an extended immunophenotyping of lymphocytes and monocytes including activation markers can define disease-specific patterns, and thus provide valuable diagnostic information for these patients.
  
  
  METHODS
  Whole blood from patients with gram-negative bacteraemia, neuroborreliosis, tuberculosis, acute mononucleosis, influenza or a mixed connective tissue disorders, as diagnosed by routine culture and serology techniques was analysed for lymphocyte and monocyte cell surface markers using a no-wash, no-lyse protocol for multi-colour flow cytometry method. The immunophenotyping included the activation markers HLA-DR and CD40. Plasma levels of soluble TNF alpha receptors were analysed by ELISA.
  
  
  RESULTS
  An informative pattern was obtained by combining two of the analysed parameters: (i), the fractions of HLA-DR-expressing CD4+ T cells and CD8+ T cells, respectively, and (ii), the level of CD40 on CD14+ CD16- monocytes. Patients infected with gram-negative bacteria or EBV showed a marked increase in monocyte CD40, while this effect was less pronounced for tuberculosis, borrelia and influenza. The bacterial agents could be distinguished from the viral agents by the T cell result; CD4+ T cells reacting in bacterial infection, and the CD8+ T cells dominating for the viruses. Patients with mixed connective tissue disorders also showed increased activation, but with similar engagement of CD4+ and CD8+ T cells. Analysis of soluble TNF alpha receptors was less informative due to a large inter-individual variation.
  
  
  CONCLUSIONS
  Immunophenotyping including the combination of the fractions of HLA-DR expressing T cell subpopulations with the level of CD40 on monocytes produces an informative pattern, differentiating between infections of bacterial and viral origin. Furthermore, a quantitative analysis of these parameters revealed the novel finding of characteristic patterns indicating a subacute bacterial infection, such as borreliosis or tuberculosis, or a mixed connective tissue disorder. The employed flow cytometric method is suitable for clinical diagnostic laboratories, and may help in the assessment of patients with uncharacteristic inflammatory symptoms.
authors.affiliation: Department of Infectious Diseases, Skane University Hospital, Lund University, 20502 Malmo, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Janols
authors.forename: Anders
authors.initials: A
authors.lastname: Bredberg
authors.forename: Irene
authors.initials: I
authors.lastname: Thuvesson
authors.forename: Sabina
authors.initials: S
authors.lastname: Janciauskiene
authors.forename: Olof
authors.initials: O
authors.lastname: Grip
authors.forename: Marlene
authors.initials: M
authors.lastname: Wullt
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D003141:Communicable Diseases / Q000175:diagnosis / Q000209:etiology; D003937:Diagnosis, Differential; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D016130:Immunophenotyping / Q000379:methods*; D007249:Inflammation / Q000175:diagnosis* / Q000276:immunology*; D008214:Lymphocytes / Q000737:chemistry / Q000145:classification*; D008297:Male; D009000:Monocytes / Q000737:chemistry / Q000145:classification*; D018124:Receptors, Tumor Necrosis Factor / Q000097:blood
chemical_list: D015703:Antigens, CD; D006684:HLA-DR Antigens; D018124:Receptors, Tumor Necrosis Factor