RNA-containing cytoplasmic inclusion bodies in ciliated bronchial epithelium months to years after acute Kawasaki disease

Background

Kawasaki Disease (KD) is the most common cause of acquired heart disease in children in developed nations. The KD etiologic agent is unknown but likely to be a ubiquitous microbe that usually causes asymptomatic childhood infection, resulting in KD only in genetically susceptible individuals. KD synthetic antibodies made from prevalent IgA gene sequences in KD arterial tissue detect intracytoplasmic inclusion bodies (ICI) resembling viral ICI in acute KD but not control infant ciliated bronchial epithelium. The prevalence of ICI in late-stage KD fatalities and in older individuals with non-KD illness should be low, unless persistent infection is common.

Methods and Principal Findings

Lung tissue from late-stage KD fatalities and non-infant controls was examined by light microscopy for the presence of ICI. Nucleic acid stains and transmission electron microscopy (TEM) were performed on tissues that were strongly positive for ICI. ICI were present in ciliated bronchial epithelium in 6/7 (86%) late-stage KD fatalities and 7/27 (26%) controls ages 9–84 years (p = 0.01). Nucleic acid stains revealed RNA but not DNA within the ICI. ICI were also identified in lung macrophages in some KD cases. TEM of bronchial epithelium and macrophages from KD cases revealed finely granular homogeneous ICI.

Significance

These findings are consistent with a previously unidentified, ubiquitous RNA virus that forms ICI and can result in persistent infection in bronchial epithelium and macrophages as the etiologic agent of KD.     

Thf complete amino acid sequence of C-I (apoLp-Ser), an apolipoprotein from human very low density lipoproteins.

C-I was prepared from very low density lipoproteins of patients with familial type V hyperliporproteinemia. Peptides from tryptic digests of unmodified and succinylated C-I, chymotryptic peptides, and the products of cayanogen bromide cleavage were isolated and characterized. Sequence analysis of tryptic peptides was performed by the dansyl (5-dimethylaminonaphthalene-1-sulfonyl) technique and hydrolytic regeneration of the amino acid residues from the phenylthiocarbamyl derivatives. Alignment of the tryptic fragments within the cyanogen bromide and succinyl-tryptic peptides was confirmed by the overlap chymotryptic peptides. The complete amino acid sequence of C-I, 57 residues in length, does not reveal any obvious basis for its lipophilic properties.     

IL-6 receptors and sensitivity to growth inhibition by IL-6 in clones of human breast carcinoma cells.

Pure recombinant human IL-6 inhibits growth of T47D, MCF-7 and SK-BR-3 human breast carcinoma and OVCAR-3 ovarian carcinoma cells in cultures. Subcloning of the breast ductal carcinoma T47D cells yields clones with high and low sensitivity to the growth inhibitory effect of IL-6. The subclones vary 40 fold in their sensitivity for inhibition of colony formation in sparse cultures and 200 fold for inhibition of thymidine incorporation in subconfluent cultures. Binding studies with 125I-rIL6 show that T47D cells and their subclones, as well as SK-BR-3 and MCF-7 cells, express high-affinity receptors for IL-6. The number and affinity constant of these receptors are comparable to those on lymphocytic and myeloid cells, and show no correlation with the high or low sensitivity phenotype. Proliferation of the breast cancer cells is inhibited by IL-6 in a cell density dependent manner, and is not due to a cytotoxic effect. In addition, IL-6 induces a morphological change with loss of epithelial characteristics and of cell-cell adhesion. Sensitivity to growth inhibition by IL-6 is independent from that of IFN-beta 1, IFN-gamma or TNF.     

A V region mutation in a phosphocholine-binding monoclonal antibody results in loss of antigen binding

A V region mutant producing an antibody that had lost the ability to bind phosphocholine was isolated from a hybridoma producing a germline encoded T15 antibody. The mutation resulted in a single aspartic acid to asparagine substitution at residue 95 of the H chain V region. This confirms that the aspartic acid at residue 95 plays a major role in Ag binding. The results also suggest that somatic cell genetic techniques can be used to generate mAb with useful changes in Ag binding.     

Novel peptides derived from a region of local homology between uteroglobin and lipocortin-1 inhibit platelet aggregation and secretion

The active site for uteroglobin inhibition of phospholipase A2 has been localized to a nonapeptide (P1) which is partially homologous to a nonapeptide (P2) in lipocortin, which also inhibits phospholipase A2. P1 and P2 share an identical tetrapeptide (P4) which is required for inhibition, although P4 alone does not inhibit this enzyme. We found the mechanism of inhibition of platelet aggregation and secretion by the nonapeptides and P4 varied depending on whether platelets were thrombin- or ADP-activated. All three peptides decrease thrombin esterolytic activity and thereby inhibit thrombin-induced platelet activation. P1 decreases ADP-induced aggregation and serotonin secretion by inhibiting phospholipase A2 whereas P4 decreases only aggregation by blocking fibrinogen binding to activated platelets. The P4 sequence in P1 may affect the interaction of P1 with platelets since the presence of P4 potentiates P1 inhibition of platelet activation.     

In-Use Contamination of Intravenous Infusion Fluid

During the 1970 to 1971 nationwide epidemic of septicemias caused by Enterobacter cloacae and Enterobacter agglomerans traced to intrinsic contamination of Abbott intravenous infusion products, 94 infusion systems manufactured by Baxter Laboratories were studied microbiologically and epidemiologically during hospital use. Intravenous fluid from 10 systems (11%) contained microorganisms, usually Staphylococcus or Bacillus species; one infusion was heavily contaminated with Klebsiella pneumoniae. No national epidemic organisms, E. cloacae or E. agglomerans (formerly Erwinia), were recovered, suggesting that during this period frequent contamination with these organisms was unique to Abbott's infusion products. Contamination in this study appeared to be extrinsic in origin (introduced during clinical use) and related to the duration of continuous intravenous therapy. Nine of 61 systems (15%) that had been used longer than 48 h were contaminated, whereas only 1 of 33 used less than 48 h (3%) contained microorganisms. This study and the recent national outbreak indicate that contamination of infusion fluid, both from intrinsic and extrinsic sources, must be recognized as an additional risk of intravenous therapy; however, a once-daily replacement of the delivery apparatus can significantly diminish this hazard.