Peter Kragsbjerg

Dynamics of blood cytokine concentrations in patients with bacteremic infections

Cytokines play a major role in the pathophysiology of sepsis and septic shock. Using enzyme immunoassays the acute serum levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), granulocyte-colony stimulating factor (G-CSF), interleukin-8 (IL-8), and leukemia inhibitory factor (LIF) were investigated in 90 patients with positive blood cultures and clinical signs of infection. In 27 patients samples were obtained on admission, after 1, 4, 12, 18, and 24 h, and then daily. The acute serum levels of IL-6, TNF-alpha, G-CSF, and IL-8 were significantly higher among patients with severe sepsis. Patients with Gram-negative infection had significantly higher levels of TNF-alpha on admission than did patients with Gram-positive infections (p = 0.0008). The levels of IL-6, G-CSF and, to some extent, TNF-alpha decreased rapidly in survivors within the first 24 h of admission to hospital and institution of treatment. LIF was detected in 8/90 in both survivors and nonsurvivors.

Cytokine responses in patients with pneumonia caused by Chlamydia or Mycoplasma

The serum concentrations of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) were measured by enzyme immunoassays in 44 patients with Chlamydia (n = 13) or Mycoplasma (n = 14) pneumonia or influenza A infection (n = 17) and in 20 control subjects. The levels of IFN-γ were raised in 29/44 patients. The concentrations of IL-6 were raised in 32/44 patients. Raised levels of TNF-α were seen in 26/44 but there was no significant difference between the levels of the different groups of patients. All three cytokines indicated clinical recovery when acute and convalescent samples from 10 patients with Chlamydia pneumonia were analyzed. IFN-γ, IL6 and TNF-α are present in the circulation in the majority of patients with Chlamydia and Mycoplasma pneumonia and in influenza A infection. We suggest that repeated measurement of cytokines, such as IL-6, IFN-γ and TNF-α, may be useful in the management of lower respiratory tract infections but further studies are needed to define the value of cytokine measurements in acute pneumonia.

Chronic Active Mononucleosis

A 16-year-old girl with 3 clinical episodes of mononucleosis during a period of more than 2 year is presented. The patient had persistently elevated VCA-IgM antibodies during follow-up for 15 months until she became EBNA-positive. This is a case of prolonged primary EBV infection and late seroconversion as clinical restitution and development of EBNA antibodies occurred 2 year after the onset of clinical illness.

Recurrent Pneumococcal Bacteraemia and Meningitis in an Asplenic Adult with Possible Unusual Focus

An unusual case of a dental infection leading to osteitis of the mandible and possibly to 4 episodes of invasive pneumococcal disease in an asplenic adult is presented. The patient had 2 episodes of pneumococcal meningitis with bacteraemia and 2 episodes of bacteraemia without meningitis during a 1-y period. Investigations using bone and leukocyte scintigraphy revealed only a focal uptake in the right mandibular bone. The pneumococcal strains isolated during the 4 episodes were all serotype 23F, and fully susceptible to penicillin.

Cytokine Responses in Patients with Pneumonia

The importance of proinflammatory cytokines was first appreciated in studies of patients with sepsis or septic shock, but during the 1990s, the research expanded to include a wide range of infectious and other inflammatory conditions. The first investigations of the role of cytokines in lower-respiratory-tract infections were published in 1992. Since then, clinical studies have been performed on different aspects of inflammation in pneumonia. One group of studies focuses on the pathogenesis of bacterial pneumonia. A second group studies the relation between the microbial etiology of pneumonia and the ensuing inflammatory response. A third group relates the cytokine response in bacterial pneumonia to severity [i.e., SIRS (1), APACHE II (2), or other clinical scoring systems]. A fourth group of studies investigates the role of age in relation to the inflammatory response caused by an acute bacterial pneumonia. Finally, in a few studies, the impact of immunomodulating therapy has been investigated.