Clinico-biological characteristics and treatment of type I monoclonal cryoglobulinaemia: a study of 64 cases.

This retrospective analysis was conducted in 64 patients diagnosed with type I cryoglobulinaemia (CG) followed at two French centres. Median follow-up was 6·75 years. CG was IgG in 60% and IgM in 40% of all cases and was asymptomatic in 16 patients (25%). Cold-triggered ischaemic skin manifestations were observed in 33 patients (51%). Neurological manifestations were observed in 15 patients and renal manifestations in 13. Most of the patients with necrotic purpura (14/16, P = 0·009) and renal manifestations (11/13, P = 0·057) had IgG CG. IgG CG was associated with monoclonal gammopathy of undetermined significance (MGUS), myeloma, chronic lymphocytic leukaemia and lymphoplasmocytic lymphoma in 18, 13, 5 and 2 patients, respectively. IgM CG was associated with MGUS and Waldenström macroglobulinaemia in 8 and 18 cases, respectively. One third of patients did not receive any specific treatment. Various treatments, including rituximab, were administered to 25/31 patients with IgG CG and 6/25 patients with IgM CG due to CG-related symptoms. Rituximab was ineffective in all cases associated with a predominantly plasmacytic proliferation. To conclude, type I CG has specific clinico-biological characteristics compared to type II CG. Furthermore, there are differences in terms of related manifestations between type I IgG and type I IgM CG.

Primary bovine colonic cells: a model to study strain-specific responses to Escherichia coli.

The parasitic or commensal lifestyle of bacteria in different hosts depends on specific molecular interactions with the respective host species. In vitro models to study intestinal bacteria-host interactions in cattle are not available. Bovine primary colonocyte (PC) cultures were generated from colon crypt explants. Up to day 4 of culture, the vast majority of cells were of epithelial phenotype (i.e., expressed cytokeratin but not vimentin). PCs harboured mRNA specific for Toll-like receptors (TLR) 1, TLR3, TLR4 and TLR6 but not for TLR2, TLR5, TLR7, TLR8, TLR9 and TLR10. Six hours after inoculation of PC cultures with Escherichia coli (E. coli) prototype strains representing different pathovars (enterohaemorrhagic E. coli [EHEC], enteropathogenic E. coli [EPEC], enterotoxic E. coli [ETEC]), bacteria were found attached to the cells. EPEC adhesion was accompanied by intracellular actin accumulation. An attenuated laboratory strain (E. coli K12 C600) and a bovine commensal E. coli strain (P391) both did not adhere. Bacterial or LPS challenge of PC cultures resulted in specific increases in mRNA transcripts for IL-8, GRO-alpha, MCP-1, RANTES, and IL-10. The level of mRNA transcripts for TGF-beta stayed constant, while IL-12 mRNA was not detectable. Short-term cultures of PCs, maintaining epithelial cell properties, interacted with commensal and pathogenic bacteria in a strain-specific manner and have proven to be a useful in vitro model to study the interaction of bacteria with the bovine intestinal mucosa.

Epithelial and mesenchymal cells in the bovine colonic mucosa differ in their responsiveness to Escherichia coli Shiga toxin 1.

Bovine colonic crypt cells express CD77 molecules that potentially act as receptors for Shiga toxins (Stx). The implication of this finding for the intestinal colonization of cattle by human pathogenic Stx-producing Escherichia coli (STEC) remains undefined. We used flow cytometric and real-time PCR analyses of primary cultures of colonic crypt cells to evaluate cell viability, CD77 expression, and gene transcription in the presence and absence of purified Stx1. A subset of cultured epithelial cells had Stx receptors which were located mainly intracellularly, with a perinuclear distribution, and were resistant to Stx1-induced apoptosis and Stx1 effects on chemokine expression patterns. In contrast, a population of vimentin-positive cells, i.e., mesenchymal/nonepithelial cells that had high numbers of Stx receptors on their surface, was depleted from the cultures by Stx1. In situ, CD77(+) cells were located in the lamina propria of the bovine colon by using immunofluorescence staining. A newly established vimentin-positive crypt cell line with high CD77 expression resisted the cytolethal effect of Stx1 but responded to Stx1 with a significant increase in interleukin-8 (IL-8), GRO-alpha, MCP-1, and RANTES mRNA. Combined stimulation with lipopolysaccharide and Stx1 increased IL-10 mRNA. Our results show that bovine colonic crypt cells of epithelial origin are resistant to both the cytotoxic and modulatory effects of Stx1. In contrast, some mucosal mesenchymal cells, preliminarily characterized as mucosal macrophages, are Stx1-responsive cells that may participate in the interaction of STEC with the bovine intestinal mucosa.