Correction to: Heparin resistance in COVID‑19 patients in the intensive care unit

Journal of Thrombosis and Thrombolysis - In the original publication of this article, one of the co-author name "D. de Monteverde-Robb" was inadvertently mentioned as "R. de...     

IL-10-driven immunoglobulin production by B lymphocytes from IgA-deficient individuals correlates to infection proneness

In search for a possible explanation of the phenotypic heterogeneity in IgA deficiency, we studied the function of B cells from IgA-deficient (IgAd) individuals. Two groups of IgAd individuals, one frequently infected and one clinically apparently healthy, as well as normal controls, were studied. Peripheral blood mononuclear cells (PBMC) and B cells from IgAd individuals and controls were cultured with Staphylococcus aureus Cowan I strain and with anti-CD40 MoAb presented on the CD32-transfected fibroblast cell line in the presence of IL-10. In this experimental system PBMC and B cells from the infection-prone IgAd individuals produced only minute amounts of IgA. In contrast, PBMC and B cells from healthy IgAd subjects secreted significantly more IgA1 and IgA2 in comparison with infection-prone IgAd patients (P < 0.05). These data suggest that the abnormalities of B cell differentiation in IgAd could be of heterogeneous origin. Thus, whereas in healthy IgAd subjects IgA production may be efficiently up-regulated in vitro by addition of IL-10 to CD40-activated B cell culture, the corresponding B cell differentiation does not occur in infection-prone IgAd patients. These observations provide a conceptual framework for phenotypic heterogeneity in IgAd subjects.     

Serum TABM produced during anterior chamber-associated immune deviation passively transfers suppression of delayed-type hypersensitivity to primed mice

Injection of soluble protein antigen into the anterior chamber of the eye of primed mice induces anterior chamber-associated immune deviation (ACAID) which is manifested by suppression of delayed-type hypersensitivity (DTH) to the antigen. Recently, we found that ACAID induced in primed mice also results in a rapid rise in serum of soluble T lymphocyte-derived proteins specific for nominal antigen (TABM). Here, we demonstrate that serum TABM induced in primed mice during ACAID will transfer the suppression of DTH to mice primed to the same antigen. Sera from TNP-BSA-primed mice that received an anterior chamber injection of TNP-BSA, but not BSA alone, suppressed the DTH response to TNP when injected into other TNP-BSA-primed mice. Sera absorbed with Sepharose beads conjugated with either anti-TCR C(alpha), anti-TCR C(beta), anti-TABM or TNP-BSA did not contain TNP-specific TABM and did not transfer suppression of DTH. These results suggest that the antigen-specific, TCR C(alphabeta)+ TABM that appear in serum during ACAID are able to confer on or amplify the capacity of sensitized T cells to suppress DTH. We believe this to be the first demonstration of an in vivo immunologic function that is specifically associated with TABM produced in vivo.      

Improved Identification of Epidemiologically Related Strains of Salmonella enterica by use of a Fusion Algorithm Based on Pulsed-Field Gel Electrophoresis and Multiple-Locus Variable-Number Tandem-Repeat Analysis

Pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem-repeat analysis (MLVA) are used to assess genetic similarity between bacterial strains. There are cases, however, when neither of these methods quantifies genetic variation at a level of resolution that is well suited for studying the molecular epidemiology of bacterial pathogens. To improve estimates based on these methods, we propose a fusion algorithm that combines the information obtained from both PFGE and MLVA assays to assess epidemiological relationships. This involves generating distance matrices for PFGE data (Dice coefficients) and MLVA data (single-step stepwise-mutation model) and modifying the relative distances using the two different data types. We applied the algorithm to a set of Salmonella enterica serovar Typhimurium isolates collected from a wide range of sampling dates, locations, and host species. All three classification methods (PFGE only, MLVA only, and fusion) produced a similar pattern of clustering relative to groupings of common phage types, with the fusion results being slightly better. We then examined a group of serovar Newport isolates collected over a limited geographic and temporal scale and showed that the fusion of PFGE and MLVA data produced the best discrimination of isolates relative to a collection site (farm). Our analysis shows that the fusion of PFGE and MLVA data provides an improved ability to discriminate epidemiologically related isolates but provides only minor improvement in the discrimination of less related isolates.Salmonellosis is one of the most common food-borne diseases in the United States (5). Consequently, it is important to understand how Salmonella strains disseminate within and between reservoirs and environments. Many molecular typing tools have been used for this purpose (11). Of these methods, pulsed-field gel electrophoresis (PFGE) is considered by many to be the gold standard for strain typing, and variable-number tandem-repeat (VNTR) assays are powerful alternative or complementary typing tools (3, 22). Both methods offer a high degree of genetic resolution for strain typing, depending on several factors.PFGE involves separating chromosomal DNA macro-restriction fragments by size, and strains are discriminated based on the resulting band pattern observed after electrophoresis has been completed. It is one of the most reproducible and highly discriminatory typing techniques and has been widely and successfully used for a variety of Salmonella enterica serovars (12, 15); for many situations, PFGE is capable of discriminating between closely related strains. In addition, the use of the assay to analyze different serovars does not require a great deal of modification, as might be required with procedures that are dependent on PCR. Difficulties arise when strains are very closely related (i.e., poor discrimination [18, 27]) or when bands comigrate in the gel or identically sized bands represent completely different fragments of chromosomal DNA and thereby produce spurious matches (6). These complications are more pronounced when a large number of bands are generated by the restriction digest (4). In addition, while band patterns convey a crude degree of genetic relatedness, a large number of independent restriction digests would be needed to infer an accurate phylogenetic relationship (6).Multiple-locus variable-number tandem-repeat analysis (MLVA) is a PCR-based technique that relies on the amplification of chromosomal or plasmid DNA that encompasses short tandem repeats of a DNA sequence. The tandem repeats are prone to higher-than-background mutation rates due to DNA strand slippage during replication (23), and thus, the amplified fragments will vary in length depending on the number of repeats harbored at a given locus. Different fragment lengths are tallied either as the total length (base pairs) or the estimated number of repeat units, and each discretely sized fragment is considered a unique “allele” for the locus under investigation. Because of the relatively high mutation rate, strains can accumulate distinctive allele patterns within a relatively short period of time (5). Furthermore, the technique can be multiplexed and automated and is conducive to rapid and relatively high-throughput strain typing. MLVA assays are relatively robust (5, 15-17) and, while not perfect, they can provide phylogenetic information even with a limited number of loci (13, 18). While access to a sequenced genome dramatically speeds the ability to establish new assays (3), it is not a requisite to assay development. The primary limitations of the technique include the potential need for a new set of loci for every species or serovar under investigation and the fact that some loci are very “unstable” and can “disappear” from some strains or lineages; this produces the equivalent of an uninformative “null” allele. Mutation rates can also vary between loci (5, 24, 25); if ignored, this factor can introduce bias into comparative analyses.Clearly, PFGE and MLVA offer different technical and interpretive advantages and disadvantages, but it is important to emphasize that the nature of the methodological and interpretive errors is independent between the techniques. For example, errors due to comigration of bands for PFGE are independent of band size estimation errors for MLVA because differences in MLVA band size are not detectable using PFGE and macro-restriction fragments are generally independent of tandem-repeat sequences. Provided that most of the experimental variation from these two methods is uncorrelated (i.e., independent), it is possible to combine results from the two methods to produce improved estimates (8), and this premise underlies the current study.Our objective was to determine whether combining the information obtained from both PFGE and MLVA assays produces more rigorous and discriminatory analyses of bacterial pathogens, such as Salmonella. Two sets of Salmonella enterica isolates were used in this study; one set included serovar Typhimurium isolates from a wide range of sampling dates, locations, and host species while the other set included a group of serovar Newport isolates collected over a limited geographic and temporal scale for a single host species. The results of the different typing methods were assessed by comparison with those of phage-typing assays (serovar Typhimurium) and with known epidemiological relationships (serovar Newport). To interpret the MLVA data, we employed a metric that incorporates a stepwise-mutation model, and to interpret the PFGE data, we employed Dice coefficients to construct distance matrices. Our analysis shows that the fusion of the two typing methods provides an improved ability to discriminate between isolates when PFGE and MLVA separately provide partial but incomplete discrimination between strains with a high degree of probable genetic similarity.     

A clinical study assessing the tolerability and biological effects of infliximab, a TNF-alpha inhibitor, in patients with advanced cancer

BACKGROUND: Tumour necrosis factor-alpha (TNF-alpha) is an important regulator of the chronic inflammation contributing to tumour progression. Infliximab, an anti-TNF-alpha monoclonal antibody was investigated in this trial of patients with advanced cancer. The primary objectives were to determine the safety profile and biological response of infliximab in a cancer population. Clinical response was a secondary objective. PATIENTS AND METHODS: Forty-one patients received infliximab at 5 mg/kg (n = 21) or 10 mg/kg (n = 20) i.v. at 0 and 2 weeks and then every 4 weeks. Post-treatment samples were measured for changes in plasma and serum TNF-alpha, CCL2, IL-6 and C-reactive protein (CRP). RESULTS: Infliximab was well tolerated with no dose-limiting toxic effects. At both doses of infliximab, neutralisation of serum TNF-alpha was observed after 1 h while plasma CCL2, IL-6 and serum CRP were decreased 24 and 48 h following infliximab administration. Seven patients experienced disease stablisation (range 10-50+ weeks). There was no evidence of disease acceleration in any patient. CONCLUSIONS: Infliximab treatment was safe and well tolerated in patients with advanced cancer. There was evidence of biological activity with baseline TNF-alpha and CCL2 being correlated with infliximab response.     

Feeding during acute diarrhea as a risk factor for persistent diarrhea

Dietary intake during diarrhea in children less than three years of age was estimated from information recorded on illustrated dietary forms used by children's caretakers during the first week of illness in a prospective community-based study of diarrheal diseases in Lima, Peru. The frequency of consumption and the amount consumed of food groups and selected commonly consumed foods were analyzed by the final duration of the diarrheal episode. Cereals were less frequently consumed during the acute phase of diarrheal episodes that ultimately became persistent (>14 days'duration), apparently shortening the duration of the episode by one day (median duration of four days in children not consuming vs three days in children consuming cereals during diarrhea, p <0.02 Kaplan-Meier logrank test). Only roots and tubers (mainly potatoes) were consumed in greater quantity during episodes that became persistent. There was no evidence that consumption of breast milk or non-maternal milk was associated with an alteration in diarrheal duration. This study provides further evidence of the beneficial effects of continuing feeding during diarrhea using foods available at the home level, especially cereals, which are commonly used in the diet of young children.