Effect of clarithromycin in inflammatory markers of patients with ventilator-associated pneumonia and sepsis caused by Gram-negative bacteria: results from a randomized clinical study

Abstract

One recent, double-blind, randomized clinical trial with 200 patients showed that clarithromycin administered intravenously for 3 days in patients with ventilator-associated pneumonia (VAP) accelerated the resolution of pneumonia and decreased the risk of death from septic shock and multiple organ dysfunctions (MODS). The present study focused on the effect of clarithromycin on markers of inflammation in these patients. Blood was drawn immediately before the administration of the allocated treatment and on six consecutive days after the start of treatment. The concentrations of circulating markers were measured. Monocytes and neutrophils were isolated for immunophenotyping analysis and for cytokine stimulation. The ratio of serum interleukin-10 (IL-10) to serum tumor necrosis factor alpha (TNF-α) was decreased in the clarithromycin group compared with the results in the placebo group. Apoptosis of monocytes was significantly increased on day 4 in the clarithromycin group compared with the rate of apoptosis in the placebo group. On the same day, the expression of CD86 was increased and the ratio of soluble CD40 ligand (sCD40L) to CD86 in serum was unchanged. The release of TNF-α, IL-6, and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) by circulating monocytes after stimulation was greater in the clarithromycin group than in the placebo group. The expression of TREM-1 on monocytes was also increased in the former group. These effects were pronounced in patients with septic shock and MODS. These results suggest that the administration of clarithromycin restored the balance between proinflammatory versus anti-inflammatory mediators in patients with sepsis; this was accompanied by more efficient antigen presentation and increased apoptosis. These effects render new perspectives for the immunotherapy of sepsis.

Fig 1

Ratios of serum interleukin-10 (IL-10) to serum tumor necrosis factor-alpha (TNF-α) on day 4 after allocation to treatment. P values refer to indicated comparisons between placebo and clarithromycin. The asterisk denotes a significant difference for the comparison between placebo-treated patients without septic shock and MODS and placebo-treated patients with septic shock and MODS (P = 0.007). A similar difference was not found within the clarithromycin group. IL-10/TNF-α ratios of day 0 are also shown.

Fig 2

Apoptosis of monocytes of placebo-treated patients and of clarithromycin-treated patients on day 4 after allocation to treatment. P values refer to indicated comparisons between placebo and clarithromycin groups. The respective values from day 0 are also shown.

Fig 3

Biomarkers of antigen presentation of placebo-treated patients and of clarithromycin-treated patients on day 4 after allocation to treatment. Data on the surface antigen CD86 are given both as percentage of isolated monocytes (A) and as mean fluorescence intensity (B). Concentrations of soluble CD40 ligand (sCD40L) are shown (C). P values refer to indicated comparisons between placebo and clarithromycin. The asterisk denotes a significant difference for the comparison between placebo-treated patients without septic shock and MODS and placebo-treated patients with septic shock and MODS (P = 0.028).

Fig 4

Production of tumor necrosis factor-alpha (ΤΝF-α) and of interleukin-6 (IL-6) by LPS-stimulated monocytes of placebo-treated patients and clarithromycin-treated patients on day 4 after allocation to treatment. P values denote statistically significant differences between the two groups at the indicated time intervals. Asterisks denote significant differences for comparisons between placebo-treated patients without septic shock and MODS and placebo-treated patients with septic shock and MODS (*, P = 0.002; **, P = 0.015).

Fig 5

Release of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) from LPS-stimulated monocytes of placebo-treated patients and clarithromycin-treated patients on day 4 after allocation to treatment. P values denote statistically significant differences between the two groups.

Fig 6

Release of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) from LPS-stimulated neutrophils of placebo-treated patients and clarithromycin-treated patients on day 4 after allocation to treatment.

Fig 7

Main effects of treatment with clarithromycin found in serum cytokines and in freshly isolated monocytes. Abbreviations: ShMODS, septic shock and multiple organ dysfunctions; mCD86, membrane CD86 measured by flow cytometry; mTREM-1, membrane TREM-1 measured by flow cytometry; TNF-α, tumor necrosis factor alpha; IL, interleukin; ↓, decrease; ↑, increase; Rx, administration of blind treatment.