Change of annexin binding of monocytes as an expression of cellular response to Candida albicans: down-regulation in severe sepsis.

To study the differences of monocyte activation by albicans and non-albicans species of Candida and its change in sepsis, peripheral blood mononuclear cells were isolated from 17 healthy volunteers and 26 patients with severe sepsis/shock, and incubated in the absence/presence of heat-killed (HK) isolates of four different Candida species and purified ß-D-glucan from C.albicans. Experiments were repeated in the presence and absence of inhibitors of intracellular activation pathways. Expression of annexin V on cells membranes of monocytes and lymphocytes, cytoplasmic activity of caspase-3, and DNA fragmentation of monocytes were studied. Membrane expression of annexin V on viable monocytes of healthy volunteers decreased significantly after incubation with C.albicans but not with non-albicans species. The decrease was dose-dependent from the Candida inoculum and by the concentration of ß-D-glucan. A relationship with inhibition of apoptosis was found as the activity of caspase-3 activity, and the level of DNA fragmentation were also decreased. Incubation in the absence/presence of inhibitors showed that the decrease by annexin V expression resulted by activation of the dectin-1 pathway and Raf-1 by ß-D glucan. The decrease of annexin V(+)/PI(-) expression was not shown on monocytes of patients with severe sepsis/shock, where no effect of inhibitors was found. Decrease of annexin V binding on monocytes can be viewed as a selective response to C.albicans partly effected through activation of dectin-1. This response is down-regulated after a septic insult.

Time-kill effect of levofloxacin on multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii: synergism with imipenem and colistin.

In the present study, we challenged the concept that levofloxacin should not be used for the management of ventilator-associated pneumonia (VAP) when minimum inhibitory concentrations (MICs) exceed 2 µg/ml. Multidrug-resistant (MDR) and genetically distinct isolates of Pseudomonas aeruginosa (n = 49) and Acinetobacter baumannii (n = 29) from patients with VAP were exposed over time to levofloxacin, imipenem, colistin and their combinations. Synergy between levofloxacin and imipenem was found in 55.3 % and between levofloxacin and colistin in 90.9 % of isolates of P. aeruginosa within the first 4 h of growth. Synergy with imipenem but not with colistin was dependent of the MIC. Synergy between levofloxacin and imipenem was found in 58.6 % of isolates of A. baumannii after 24 h of growth. Considerable synergy was found between levofloxacin and colistin, reaching 84.8 % of isolates of A.baumannii after 6 h of growth. Synergy was independent from the MIC. These results create hopes that levofloxacin can be used as combination therapy for infections by MDR bacteria.

Single nucleotide polymorphisms of toll-like receptor-4 protect against acne conglobata.

BACKGROUND: Former studies have shown that Propionibacterium acnes may stimulate expression of toll-like receptor 4 (TLR4) in keratinocytes of patients with acne vulgaris. OBJECTIVE: To investigate the impact of single nucleotide polumorphisms (SNPs) of the TLR4 gene in acne vulgaris. METHODS: Genomic DNA was isolated from 191 patients with acne vulgaris and 75 healthy controls. Asp299Gly and Thr399Ile SNPs were defined after cutting of the PCR products by restriction enzymes. Sebum of lesions was cultured for P. acnes. RESULTS: No differences in SNP allele frequencies were found between patients and healthy controls. 46.5% of carriers of wild-type alleles were suffering from acne conglobata compared with 28.6% of carriers of SNP alleles (P=0.040). After adjusting for gender, family history of acnes, intake of any therapy and skin isolation of P. acnes, carriage of TLR4 gene SNPs was the only independent variable linked with a protective role against acne conglobata (OR=0.269, P=0.014). No differences were found in the amount of pro-inflammatory cytokines released by peripheral blood mononuclear cells isolated from patients with acne conglobata carrying only wild-type alleles and SNP alleles. CONCLUSIONS: Carriage of gene SNPs is protective against the development of acne conglobata even in the presence of P. acnes.

Indication for a role of regulatory T cells for the advent of influenza A (H1N1)-related pneumonia.

Regulatory T cells (T(regs) ) have an anti-inflammatory role. A former study in a limited number of patients found that absolute counts of T(regs) increase when infection by the new influenza H1N1 virus is complicated with pneumonia. These results generate the question if H1N1-related pneumonia is associated with a state of hypo-inflammation. A total of 135 patients were enrolled with blood sampling within less than 24 h from diagnosis; 23 with flu-like syndrome; 69 with uncomplicated H1N1-infection; seven with bacterial pneumonia; and 36 with H1N1-related pneumonia. T(regs) and CD14/HLA-DR co-expression were estimated by flow cytometry; concentrations of tumour necrosis factor-alpha (TNF-α), of interleukin (IL)-6 and of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) by an enzyme immunoassay; those of procalcitonin (PCT) by immuno-time-resolved amplified cryptate technology assay. Expression of human leucocyte antigen D-related (HLA-DR) on monocytes was similar between groups; absolute T(reg) counts were greater among patients with H1N1-related pneumonia than flu-like syndrome or H1N1-uncomplicated infection. Serum TNF-α of patients with bacterial pneumonia was greater than those of other groups, but IL-10 was similar between groups. Serum PCT was greater among patients with H1N1-related pneumonia and sTREM-1 among those with H1N1-related pneumonia. Regression analysis revealed that the most important factors related with the advent of pneumonia were the existence of underlying illnesses (P = 0·006) and of T(regs) equal to or above 16 mm(3) (P = 0·013). It is concluded that the advent of H1N1-related pneumonia is related to an early increase of the absolute T(reg) counts. This increase is probably not part of a hypo-inflammatory state of the host.