Questionnaire survey of proliferative enteropathy on British pig farms

Risk factors for proliferative enteropathy were investigated by means of a postal questionnaire survey of randomly selected British pig farms. Replies were received from 319 (56 per cent) of the 569 questionnaires posted, representing 1.5 per cent of the total number of pig farms in Britain. Thirty-one per cent of the farms had experienced at least one episode of proliferative enteropathy within the previous three years, usually confirmed by their veterinary surgeon. There was a strong association for the occurrence of proliferative enteropathy in herds of over 500 sows (P < 0.005) and in herds with enzootic pneumonia (P < 0.01). Outbreaks had occurred in five of the six nucleus herds surveyed, the other had only 80 sows. Outbreaks occurred in 32 of 69 herds that had obtained their replacement boars from nucleus herds (P < 0.05), suggesting that infected boars may carry the disease into distant herds. The use of either fully slatted (P < 0.05) or fully meshed floors (P < 0.01) above sunken pits in buildings used to house pigs immediately after weaning, and the use of partially (P < 0.05) or fully slatted floors (P < 0.05) in buildings used to house pigs two to six months old, were risk factors for outbreaks of proliferative enteropathy, compared with the use of straw bedding or solid floors. The destocking of entire buildings containing pigs two to four months old before the introduction of fresh pigs, was associated with a reduced risk (P < 0.05), but the destocking of selected pens rather than the whole building had no such association. The type of diet, or feeding or watering system and the types of buildings used were not identified as risk factors.

Development of persistent intestinal infection and excretion of Lawsonia intracellularis by piglets

Challenge experiments using Lawsonia intracellularis as oral inocula have established its aetiological role in porcine proliferative enteropathy. Thirty piglets, in four groups, were weaned at 21 days of age and inoculated orally at 24 days. Six piglets were challenged with 1.0 x 10(8) L intracellularis strain 916/91 (NCTC 12657) passaged 12 times in vitro, six with 5.0 x 10(8) of the same strain, seven with 3.0 x 10(8) L intracellularis strain LR 189/5/83, passaged nine times, and 11 controls were dosed with sucrose-potassium glutamate buffer. An immunofluorescence assay for L intracellularis was applied to faecal smears and a polymerase chain reaction (PCR) incorporating L intracellularis-specific primers was applied to extracts of bacterial DNA derived from the faeces samples. Up to five pigs in each challenge group excreted detectable L intracellularis in faeces, in samples taken between two and 10 weeks after challenge. Some of the pigs had up to 7 x 10(8) L intracellularis g-1 faeces. The average weight gains of the higher dose challenge groups were moderately below those of the control pigs between three and nine weeks after challenge; diarrhoea was also observed in six pigs, two to four weeks after challenge. Numerous L intracellularis were detected in the intestines of all the pigs challenged with strain LR 189/5/83 and two of the pigs challenged with 916/91, but not in other tissues.

Treatment and prevention of porcine proliferative enteropathy with oral tiamulin

The effect of an oral treatment or prevention programme, incorporating the antibiotic tiamulin, on the development of proliferative enteropathy in experimentally challenged pigs was studied. Twenty weaner pigs were challenged orally with a virulent inoculum of Lawsonia intracellularis strain LR189/5/83, a British isolate of the causative agent of porcine proliferative enteropathy, and seven control pigs were dosed with a buffer solution. Seven of the 20 challenged pigs were left untreated; they gained less weight than the controls and three of them developed mild to moderate diarrhoea two weeks after the challenge. All seven developed lesions, six visible grossly, of proliferative enteropathy, and numerous intracellular L intracellularis were detected in sections of the intestines examined three weeks after the challenge. To test a 'prevention' dosing strategy for tiamulin, six of the challenged pigs were dosed orally with 50 ppm tiamulin, incorporated in a 2 per cent stabilised premix, given from two days before the challenge until they were euthanased. To test a 'treatment' strategy, the remaining group of seven challenged pigs were dosed orally with 150 ppm tiamulin given in the premix from seven days after challenge until they were euthanased. All the control pigs and the 13 pigs treated with tiamulin, either before or after challenge, remained clinically normal and had no specific lesions of proliferative enteropathy in sections of the intestines examined post mortem.

CD40 cross-linking inhibits specific antibody production by human B cells

Ligation of CD40 on B cells is a co-stimulatory signal for proliferation, antibody secretion, heavy chain switching and rescue from apoptosis after somatic mutation in the germinal centre. The importance of these manifold responses to CD40 activation for humoral immunity is exemplified by the inability of boys with X-linked hyper IgM syndrome to make IgG, IgE or IgA due to a mutation in in the gene coding for CD40 ligand (CD40L). In the present study, we have investigated the effect of CD40 ligation on specific antibody production by human B cells to influenza virus. The antibody response was T cell dependent and specific for the strain of influenza virus used as antigen. Addition of either CD40 mAb or recombinant trimeric CD40L profoundly inhibited specific antibody production. Antibody production by unseparated tonsillar mononuclear cells and by T-depleted B cells stimulated with antigen in the presence of T cell replacing factor were equally inhibited with CD40 antibody showing that the effect was due to ligation of CD40 on B cells rather than blocking of T cell help. The specific antibody detected in these experiments was mostly IgG with little or no IgM and was obtained from surface IgM B cells consistent with activation of a secondary (memory) response. Co-stimulation of tonsillar B cells with CD40 antibody and anti-IgG induced proliferation of IgG+ B cells. These results suggest that CD40 ligation can inhibit specific antibody responses and stimulate proliferation in the same IgG+ (memory) B cell subpopulation. Addition of CD40 antibody during the first 24-48 h of the response was required for inhibition, suggesting that the effect was on early B cell activation and/or proliferation required for antibody production. There was no correlation, however, between the ability of CD40 mAb to stimulate proliferation and inhibit antibody production. We suggest that early activation of CD40 in the specific antibody response inhibits the formation of plasma cells and promotes instead the generation of memory cells.

CD40 ligand (CD40L) expression and B cell function in agammaglobulinemia with normal or elevated levels of IgM (HIM). Comparison of X-linked, autosomal recessive, and non-X-linked forms of the disease, and obligate carriers

Hyper-IgM syndrome is a rare immunodeficiency characterized by low or absent IgG, IgA, and IgE with normal or elevated levels of IgM. It can occur as an acquired or familial disorder with either X-linked or autosomal modes of inheritance. The X-linked form (HIGM1) is a result of mutations in the CD40 ligand (CD40L) gene, but the defect in non-X-linked forms of the disease (HIM) has not been determined. We show here that CD40L expression on activated T cells from non-X-linked patients can be detected by CD40Fc, 5c8 Mab, and anti-TRAP, whereas activated T cells from HIGM1 patients either had no detectable CD40L (Type I), or stained with anti-TRAP but not CD40Fc or 5c8 (Type II). Activated T cells from obligate carriers varied from low to normal expression of CD40L. B cells from HIGM1 and non-X-linked HIM patients proliferated in response to CD40L. Costimulation of B cells from HIGM1, from sporadic HIM, or from non-X-linked HIM patients with CD40L plus IL-2 resulted in some IgM production, but no significant IgG or IgA. Costimulation with CD40L plus IL-10 resulted in significant IgG and/or IgA secretion by B cells from some HIGM1 patients, but consistently failed to stimulate IgG or IgA secretion by B cells from non-X-linked patients. In addition, costimulation with CD40L and IL-4 failed to induce IgE secretion by B cells from one non-X-linked HIM patient, and induced a weak response in another. These results suggest that patients with non-X-linked forms of HIM may have an intrinsic B cell defect preventing heavy chain switching, which is not related to expression of CD40L.

CD40 ligand (CD40L) expression and B cell function in agammaglobulinemia with normal or elevated levels of IgM (HIM). Comparison of X-linked, autosomal recessive, and non-X-linked forms of the disease, and obligate carriers

Hyper-IgM syndrome is a rare immunodeficiency characterized by low or absent IgG, IgA, and IgE with normal or elevated levels of IgM. It can occur as an acquired or familial disorder with either X-linked or autosomal modes of inheritance. The X-linked form (HIGM1) is a result of mutations in the CD40 ligand (CD40L) gene, but the defect in non-X-linked forms of the disease (HIM) has not been determined. We show here that CD40L expression on activated T cells from non-X-linked patients can be detected by CD40Fc, 5c8 Mab, and anti-TRAP, whereas activated T cells from HIGM1 patients either had no detectable CD40L (Type I), or stained with anti-TRAP but not CD40Fc or 5c8 (Type II). Activated T cells from obligate carriers varied from low to normal expression of CD40L. B cells from HIGM1 and non-X-linked HIM patients proliferated in response to CD40L. Costimulation of B cells from HIGM1, from sporadic HIM, or from non-X-linked HIM patients with CD40L plus IL-2 resulted in some IgM production, but no significant IgG or IgA. Costimulation with CD40L plus IL-10 resulted in significant IgG and/or IgA secretion by B cells from some HIGM1 patients, but consistently failed to stimulate IgG or IgA secretion by B cells from non-X-linked patients. In addition, costimulation with CD40L and IL-4 failed to induce IgE secretion by B cells from one non-X-linked HIM patient, and induced a weak response in another. These results suggest that patients with non-X-linked forms of HIM may have an intrinsic B cell defect preventing heavy chain switching, which is not related to expression of CD40L.

SAS, a gene amplified in human sarcomas, encodes a new member of the transmembrane 4 superfamily of proteins

Amplification of 12q13-14 occurs in a subset of human sarcomas including malignant fibrous histiocytoma and liposarcoma. This chromosomal region has previously been found to include a number of growth-related genes including the GLI proto-oncogene and the p53-associated protein, MDM2. We now report the characterization of SAS (sarcoma amplified sequence), a novel transcript found in this region. Sequence analysis demonstrates that SAS is a novel member of a transmembrane protein family (transmembrane 4 superfamily or TM4SF) thought to be involved in growth-related cellular processes. This observation adds a TM4SF protein to the cluster of genes at 12q13-14 frequently amplified in human sarcomas.

The surface structure of Leptotrichia buccalis

Leptotrichia buccalis shows a mosaic of surface structure on its outer membrane consisting of curved ridges 35 mm high and 22 nm apart, and erect on that surface. Fimbriae (common pili) are not present and nor is an S layer. The flap-like ridges consist of strings of macromolecules radiating from the cell surface. This ridge structure is not soluble in any of the usual chaotropes and can only be released when the outer membrane has been damaged or dispersed by extracting envelope preparations with 0.5% SDS at room temperature. The ridge is then found to be attached firmly to the peptidoglycan sacculus, which may be the point of origin of the structure. When so prepared the macromolecules forming the ridge can be removed from the sacculus by treatment with 6 M guanidine HCl, and SDS-PAGE analysis of the extract reveals a 210-kDa polypeptide as a major component and a 15-kDa minor component. The latter is probably a peptidoglycan-associated protein and much of it remains with the sacculus. Each string forming the ridge is of a volume consistent with being made of three elongated 210-kDa molecules, which are united in series by strong hydrophobic association and laterally with neighboring strings by slightly weaker forces. We confirm that L. buccalis causes haemagglutination and the bacteria are known to attach to various tissue cells. Human group A red blood corpuscles remove both of the proteins from solution, which supports the hypothesis that the ridges are adhesin structures. It is likely but not proven that the 210-kDa molecule is the adhesin.

Uremic pericarditis in chronic renal failure: nursing implications

Cardiovascular complications are the leading cause of death in patients with chronic renal failure. Pericardial disease is among the first recognized manifestations of uremia. This article explores the pathophysiology of uremic pericarditis, assessment of chronic renal failure patients at risk for developing pericarditis, and major complications of pericarditis. Current treatment modalities and nursing care for the patient with uremic pericarditis are included.

Interleukin 6 is not required for antigen-specific antibody responses by human B cells

Interleukin-6 (IL-6) is a late-acting differentiation factor for human B cells activated by polyclonal mitogens such as pokeweed mitogen (PWM) and Staphylococcus aureus Cowan strain I, but its role in specific antibody responses has not been established. We show here that IL-6 has no consistent effect on specific antibody responses by tonsillar mononuclear cells (TMC) stimulated with influenza virus. A blocking IL-6 antibody also had no effect on antibody production, suggesting that endogenous IL-6 production was not required. In control experiments, this antibody inhibited PWM-stimulated immunoglobulin secretion and proliferation of the IL-6-dependent B cell line B9. A requirement for IL-6 in responses of unfractionated TMC may have been disguised by the presence of T cells. To overcome this problem, we investigated the effect of IL-6 on specific antibody production by T-depleted B cells stimulated with antigen in the presence of IL-2, which is a T cell replacing factor (TRF) for human B cells. Specific antibody production was restored by IL-2, but not IL-6. Neither IL-6 nor anti-IL-6 antibody had any consistent effect on specific antibody production by purified B cells stimulated with antigen and TRF. These experiments show that IL-6 does not have a significant role in antigen (influenza virus)-specific antibody responses by human B lymphocytes.

The S-layer of Caulobacter crescentus: three-dimensional image reconstruction and structure analysis by electron microscopy

The regular surface protein structure (S-layer) of Caulobacter crescentus was analyzed by electron microscopy and three-dimensional image reconstruction to a resolution of 2 nm. Projections showed that the S-layer is an array of ring structures, each composed of six subunits that are arranged on a lattice with p6 symmetry. Three-dimensional reconstructions showed that the ring subunits were approximately rod-shaped structures and were perpendicular to the plane of the array, with a linker arm emanating from approximately the middle of the rod, accounting for the connections between the rings. The calculated subunit mass was ca. 100 kDa, very close to the size of RsaA (the protein known to be at least the predominant species in the S-layer) predicted from the DNA sequence of the rsaA gene. The core region of the rings creates an open pore 2.5 to 3.5 nm in diameter. The size of the gaps between the neighboring unit cells is in the same range, suggesting a uniform porosity predicted to exclude molecules larger than ca. 17 kDa. Attempts to remove membrane material from S-layer preparations with detergents revealed that the structure spontaneously rearranged into a mirror-image double layer. Negative-stain and thin-section electron microscopy examination of colonies of C. crescentus strains with a mutation in a surface molecule involved in the attachment of the S-layer showed that shed RsaA protein organized into large sheets. The sheets in turn organized into stacks that tended to accumulate near the upper surface of the colony. Image reconstruction indicated that these sheets were also precise mirror-image double layers, and thickness measurements obtained from thin sections were consistent with this finding. The sheets were absent when these mutant strains were grown without calcium, supporting other data that calcium is involved in attachment of the S-layer to a surface molecule and perhaps in subunit-subunit interactions. We propose that when the membrane is removed from S-layer fragments by detergents or the attachment-related surface molecule is absent, the attachment sites of the S-layer align precisely to form a double layer via a calcium interaction.

Wearable air supply for pneumatic artificial hearts and ventricular assist devices

An experimental wearable air supply for pneumatic artificial hearts and ventricular assist devices has been built and tested. The unit eliminates the need for tethering to a large, stationery driver. The miniaturized air supply is designed for ambulatory patients with implanted pulsatile pneumatic total artificial hearts (TAH) or pneumatic left-ventricular assist devices (LVAD), to permit mobility in clinical and home settings. The device has major short-term utility as a supply for pneumatic TAH or VAD bridges in patients awaiting heart transplants. The system design for the wearable driver includes a novel, fast rotary compressor, driven by a brushless direct current (DC) motor to supply air to the ventricle through an electromagnetically actuated directional valve, all controlled by a microcomputer. Stroke volume from 0 to 200 cc; pulse rate from 60 to 160 bpm, and duty cycle from 33% to 50% are selected on a keyboard, and the selected or measured parameters can be shown on a liquid crystal display. For control of delivery from a single ventricular assist device, stroke volume is controlled by variation of compressor speed. In the wearable air supply for a TAH, a single compressor drives both ventricles alternately through a double-acting directional valve. Air volume delivered to the left ventricle is adjusted by variation of compressor speed, and air volume to the right ventricle by variation of ejection time. The effect on blood flow rate of the lower impedance to the right ventricle is compensated by provision of a two-stage compressor, in which a single stage drives the right ventricle, and both stages connected in parallel drive the left ventricle. The overall dimensions of the prototype air supply for driving either a TAH or LVAD are 4.5 by 7.8 by 4.5 inches, including an emergency battery with a duration of 15 to 30 min depending on load. The weight is presently 5.5 lb, but this will be reduced in a production design and for a dedicated LVAD air supply. The size and weight of a separately worn, rechargeable battery pack depend on the load and desired duration of operation.

SAS amplification in soft tissue sarcomas

Gene amplification is an important mechanism of increased gene expression in a number of human solid tumors. We have recently identified and cloned sequences from a novel DNA amplification unit in malignant fibrous histiocytoma. The amplified sequences are derived from chromosome 12q13-14 and encode a gene designated SAS (sarcoma amplified sequence). In the present study, a series of soft tissue sarcomas was studied to characterize further the phenomenon of SAS amplification. Seven of 22 (32%) malignant fibrous histiocytomas and three liposarcomas contained SAS amplification. Strikingly, all of the tumors with SAS amplification occurred in central sites (i.e., in the abdominal or inguinal regions) rather than in the extremities (i.e., in the arms of legs). These observations demonstrate that SAS amplification occurs with a significant frequency in mesenchymal tumors and is particularly associated with abdominal disease.

Regioselectivity of the insertion reactions of some aromatic diazo compound complexes with cyclomaltoheptaose

Pyrolysis of solid complexes of aromatic diazo compounds with cyclomaltoheptaose (beta-cyclodextrin) yields either derivatives via insertion of carbene into hydroxyl groups. The distribution of the 2-, 3-, and 6-O-isomers indicates that the regioselectivity is moderate. The guest geometry is not as important as its size in determining the ratios of regioisomers. The origins of the regioselectivity are discussed.

CD19 regulation of human B cell responses. B cell proliferation and antibody secretion are inhibited or enhanced by ligation of the CD19 surface glycoprotein depending on the stimulating signal used

The regulation of human B cell proliferation and differentiation by the CD19 surface glycoprotein was investigated. As expected, proliferation induced by costimulation with anti-IgM plus IL-4 or IL-2, or with G28.8 antibody plus IL-4 was inhibited by antibody ligation of CD19. In contrast, proliferation of tonsillar B cells to mitogenic doses of PMA (5 ng/ml) or to EBV were enhanced, and proliferation of B cell lines to BCGF(low) was unaffected. Similarly, specific antibody responses by tonsillar B cells to influenza virus, and Ig secretion by the CESS lymphoblastoid cell line in response to IL-6 were inhibited, whereas polyclonal Ig production in response to EBV was enhanced. These results show that human B cell responses may be inhibited or enhanced by CD19 depending on the stimulating signal used. The difference in response to CD19 ligation did not depend on whether proliferation or differentiation was being measured, or whether stimulation was by surface Ig. In experiments using PMA as a T cell independent mitogen, it was found that ligation of CD19 inhibited proliferation of B cells costimulated with low doses of PMA plus G28.5 (CD40) antibody, but enhanced the response to higher (mitogenic) doses with or without costimulation with G28.5. The change from inhibition to enhancement occurred over a very small increase in PMA dose (0.5-1.0 ng/ml) that corresponded exactly to the lowest dose required for mitogenic activity. Finally, we showed that CD19 ligation inhibited the increase in surface expression of CD23, but not IgM, induced by IL-4, showing that CD19 ligation can have opposed effects on different responses to the same signal. Together our results suggest that CD19 activation of human B cells interacts with other signaling events to enhance or inhibit the subsequent response.

CD19 regulation of human B cell responses. B cell proliferation and antibody secretion are inhibited or enhanced by ligation of the CD19 surface glycoprotein depending on the stimulating signal used

The regulation of human B cell proliferation and differentiation by the CD19 surface glycoprotein was investigated. As expected, proliferation induced by costimulation with anti-IgM plus IL-4 or IL-2, or with G28.8 antibody plus IL-4 was inhibited by antibody ligation of CD19. In contrast, proliferation of tonsillar B cells to mitogenic doses of PMA (5 ng/ml) or to EBV were enhanced, and proliferation of B cell lines to BCGF(low) was unaffected. Similarly, specific antibody responses by tonsillar B cells to influenza virus, and Ig secretion by the CESS lymphoblastoid cell line in response to IL-6 were inhibited, whereas polyclonal Ig production in response to EBV was enhanced. These results show that human B cell responses may be inhibited or enhanced by CD19 depending on the stimulating signal used. The difference in response to CD19 ligation did not depend on whether proliferation or differentiation was being measured, or whether stimulation was by surface Ig. In experiments using PMA as a T cell independent mitogen, it was found that ligation of CD19 inhibited proliferation of B cells costimulated with low doses of PMA plus G28.5 (CD40) antibody, but enhanced the response to higher (mitogenic) doses with or without costimulation with G28.5. The change from inhibition to enhancement occurred over a very small increase in PMA dose (0.5-1.0 ng/ml) that corresponded exactly to the lowest dose required for mitogenic activity. Finally, we showed that CD19 ligation inhibited the increase in surface expression of CD23, but not IgM, induced by IL-4, showing that CD19 ligation can have opposed effects on different responses to the same signal. Together our results suggest that CD19 activation of human B cells interacts with other signaling events to enhance or inhibit the subsequent response.

Immunogenicity of inactivated influenza vaccine in residential homes for elderly people

One hundred and seventy residents of 11 Leicester City Council homes for the elderly, with a total of 515 beds, were studied during a 30-week period from September 1988 to March 1989 to determine the use of influenza vaccine, the levels of influenza antibody, the incidence of influenza, and the protection afforded by vaccination. The study group of 133 women and 37 men had a mean age of 85 years and 59% had one or more chronic medical conditions. The immunization rates by home for the 170 symptomatic residents ranged from 8% to 90% (mean 45%). Seventy-one sera, 36 from vaccinated and 35 from non-vaccinated residents were collected between 1 December 1988 and 24 March 1989 and were assayed for antibody to A/Taiwan/1/86 (H1N1), A Sichuan/2/87 (H3N2) and B/Beijing/1/87. Analysis revealed no statistically significant differences between the antibody profiles of vaccinated and unvaccinated subjects. Six influenza A and 6 influenza B infections were confirmed among the 170 subjects with upper respiratory tract infections. Influenza vaccination was not associated with significant levels of protection against influenza A or B. Studies of the haemagglutinins of the vaccine strains and influenza isolates during 1988/89 showed that they were closely related.

Isolation and comparison of the paracrystalline surface layer proteins of freshwater caulobacters

Several methods for isolation of the paracrystalline surface (S) layer protein (RsaA) of Caulobacter crescentus CB15A were evaluated. Treatment of cells with HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) buffer at pH 2 was the most effective means of selectively removing RsaA from cells, and after neutralization, the protein was capable of reassembling into a paracrystalline structure. Ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid treatment could also be used to extract RsaA and yielded protein capable of reassembly. The success of the methods was likely related to disruption of calcium-mediated bonding; calcium was required for recrystallization, while magnesium and strontium ions were ineffective. Antibody was raised against purified RsaA and, along with the S-layer extraction techniques, was used to evaluate 42 strains of caulobacters isolated from a variety of aquatic and wastewater treatment locations. A single characteristic protein could be isolated from the 35 strains that produced an S layer; with one exception, no proteins were extracted from strains that had no S layer. The presumed S-layer proteins ranged in size from 100 to 193 kDa. All of these proteins specifically reacted with anti-RsaA serum by Western immunoblot analysis. In strain CB15A, a specific S-layer-associated oligosaccharide has been proposed to be involved in a calcium-mediated attachment of the S layer to the cell surface. This molecule was detected by Western immunoblotting with a specific antiserum and on polyacrylamide gels stained for polysaccharides. A comparable band was found in all S-layer-producing strains and for most, S-layer-associated oligosaccharide-specific antibody reacted with them in Western analysis. Overall, in freshwater caulobacters at least portions of their S-layer structures appear to be strongly conserved entities, as well as the means of attachment to the cell surface.

Activation of human B cells through the CD19 surface antigen results in homotypic adhesion by LFA-1-dependent and -independent mechanisms

Addition of CD19 monoclonal antibodies (mAb) to highly purified tonsillar B cells resulted in homotypic adhesion and the formation of cell clusters. This response was completely blocked by antibody to LFA-1, indicating an LFA-1-dependent adhesion mechanism. In contrast, aggregate formation by B cells activated with phorbol myristate acetate (PMA) was only partially inhibited by anti-LFA-1 antibody, and those formed in response to PMA plus CD19 antibody were not inhibited at all, suggesting aggregation of activated B cells stimulated with CD19 antibody was LFA-1 independent. This was confirmed with B-cell lines. The pre-B-cell line Nalm-6 formed aggregates in response to CD19 antibody which were not inhibited with anti-LFA-1. In addition, CD19 antibody induced aggregate formation by an Epstein-Barr virus (EBV)-transformed B-cell line derived from an LFA-1-deficient donor. These results suggest that different adhesion molecules may operate at different stages of B-cell activation, and that CD19 may be important in cell-cell interactions involved in regulation of antibody responses.

Agglutination of blood cardioplegia by cold-reacting autoantibodies

Cold-reacting autoantibodies occasionally occur in patients requiring cardiac operations. This report describes the clinical course of 1 patient with cold-reacting autoantibodies and intracoronary agglutination of the blood cardioplegia solution. Observations made in vivo and in vitro are considered in discussing recommendations for the management of extracorporeal circulation and cardioplegic arrest in patients with clinically silent cold-reacting autoantibodies.