Identification and quantification of innate immune system mediators in human breast milk.

Breast-feeding decreases the risk of breast cancer in mothers and infection, allergy, and autoimmunity in infants. The presence of mediators of the innate immune system in human milk, including soluble defensins, cathelicidins, and toll-like receptors (TLRs), has not been researched thoroughly. The whey fractions of colostrum and transitional and mature milk (n = 40) from normal mothers (n = 18) and from mothers with autoimmune or allergic diseases (n = 22) were analyzed for defensins by competitive enzyme-linked immunosorbent assay, and expression of messenger RNA (mRNA) for defensins, TLRs, and cathelicidin-derived antimicrobial peptide (LL-37) by cells in breast milk was determined by semiquantitative reverse-transcription-polymerase chain reaction. In whey, human neutrophil-derived a-defensin 1 (HNP-1) and human beta-defensin 2 (HBD-2) were present in the highest concentrations (median, 33.0 and 31.3 microg/mL, respectively), human alpha-defensin 6 (HD-6) was present in moderate amounts (3.1 microg/mL), and HD-5 and HBD-1 were present in the lowest concentrations (2.4 and 1.7 microg/mL, respectively). There was great variability of defensin levels between subjects, but there was no relation to autoimmune or allergic diagnosis. HNP-1, HD-5, and HD-6 were present in significantly higher levels in colostrum than in mature milk. Regarding defensin mRNA expression in the breast milk cells, 95% of the samples (n = 41) were positive for HBD-1, 68% were positive for HD-5, 22% were positive for HBD-3, 15% were positive for HBD-2, 5% were positive for HBD-4, and 2% were positive for HD-6; 88% (14/16) were positive for HNP-1. Breast milk cells also expressed mRNA for TLR1, TLR2, TLR3, TLR4, TLR5, TLR6, TLR7, TLR9, CD14, and LL-37. Human breast milk contains high concentrations of multiple defensin proteins and cells in breast milk express mRNA for these defensins, multiple TLRs, and LL-37. The innate immune system in breast milk is complex and likely provides protection for maternal breast tissue and the developing digestive tract of newborns.

A prospective observational study of the effect of penicillin skin testing on antibiotic use in the intensive care unit.

BACKGROUND: Patients with penicillin allergy admitted to the intensive care unit (ICU) frequently receive non-beta-lactam antimicrobials for the treatment of infection. The use of these antimicrobials, more commonly vancomycin and fluoroquinolones, is associated with the emergence of multidrug-resistant infections. The penicillin skin test (PST) can help detect patients at risk of developing an immediate allergic reaction to penicillin and those patients with a negative PST may be able to use a penicillin antibiotic safely. METHODS: We determined the incidence of true penicillin allergy, the percentage of patients changed to a beta-lactam antimicrobial when the test was negative, the safety of the test, and the safety of administration of beta-lactam antimicrobials in patients with a negative test. Skin testing was performed using standard methodology. RESULTS: One hundred patients admitted to 4 ICUs were prospectively studied; 58 of them were male. The mean age was 63 years. Ninety-six patients had the PST: one was positive (1.04%), 10 (10.4%) were nondiagnostic, and 85 (88.5%) were negative. Of the 38 patients who received antimicrobials for therapeutic reasons, 31(81.5%) had the antibiotic changed to a beta-lactam antimicrobial after a negative reading versus 7 patients of the 57 (12%) who had received a prophylactic antimicrobial (P < .001). No adverse effects were reported after the PST or after antimicrobial administration. CONCLUSIONS: The PST is a safe, reliable, and effective strategy to reduce the use of non-beta-lactam antimicrobials in patients who are labeled as penicillin allergic and admitted to the ICU.

Nitric oxide blocks inflammatory cytokine secretion triggered by CD23 in monocytes from allergic, asthmatic patients and healthy controls.

BACKGROUND: In allergic asthma, monocytes/macrophages may be activated to produce inflammatory cytokines through triggering of the low-affinity IgE receptor (CD23). Elevated airway levels of nitric oxide (NO) are associated with asthmatic exacerbations. Our previous work suggested that NO may function in an anti-inflammatory capacity by downregulating endotoxin-stimulated cytokine production by alveolar macrophages and matured monocytes. OBJECTIVE: The purpose of this study was to determine the effect of NO on CD23-triggered cytokine production by monocytes from asthmatic patients and healthy controls. METHODS: Monocytes were obtained from normal volunteers (n = 13) and asthmatic patients with atopy (n = 8). Monocyte cultures were treated with interleukin-4 (IL-4) and granulocyte macrophage colony-stimulating factor (GM-CSF) for 24 hours to upregulate CD23 expression. Cultures were stimulated by anti-CD23 and treated with DETA NONOate [2,2-(hydroxynitrosohydrazonon)-bis-ethanamine] releases NO in culture with t(1/2) of 20 hours at 37 degrees C for 24 hours. Cell free culture supernatants were collected and assayed by enzyme-linked immunoadsorbent assay for macrophage inflammatory protein-1-alpha (MIP-1) and IL-6. RESULTS: NO inhibits MIP-1 secretion triggered by CD23 activation of IL-4- and GM-CSF-matured monocytes (percentage of MIP-1 suppression = 52 +/- 11 of monocytes from asthmatic patients; percentage = 55 +/- 8 healthy controls). The inhibitory effect of NO was not cytokine-specific, as similar results were obtained with IL-6 (50 +/- 9% IL-6 suppression, asthmatic patients; 66 +/- 20%, healthy controls). CONCLUSIONS: The results demonstrate for the first time an inhibitory effect of NO on cytokine production stimulated by CD23 receptor activation. We suggest that NO may be upregulated as a potent anti-inflammatory agent in the asthmatic lung.