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Biomedical subjects

V Friman

Publications and source records attributed to V Friman.

16 recordsLinked to original sources
PubMed2006

Infectious complications after multivisceral transplantation in adults.

UNLABELLED: It is thought that multivisceral transplantation requires high levels of immunosuppression and therefore, patients run an increased risk of infection. We retrospectively reviewed our center's experience with clinically relevant infectious complications. PATIENTS: Between 2000 and 2005, 10 adult patients underwent multivisceral transplantation. Two immunosuppression protocols were used: between 2000 and 2003, a high immunosupression protocol (six patients; daclizumab induction, tacrolimus trough levels >20 ng/mL and steroids) and an immunomodulatory, low imunosuppression scheme from 2003 onward (four patients; ATG induction, tacrolimus levels 5 to 10 ng/mL, no steroids). Standard antimicrobial prophylaxis consisted of vancomycin, meropenem, and amphotericin B. Cytomegalovirus (CMV) prophylaxis was used in all but first two cases. Donor and recipient CMV status were D+/R+ (n = 7), D+/R- (n = 2), D-/R+ (n = 1). RESULTS: The median follow-up period was 627 days (range, 19 to 2207 days). A total of 47 infectious episodes were recorded in all patients (range 1 to 14 per patient). The etiology was bacterial in 32 (69%), viral in 8 (17%), and fungal in 7 (14%) cases. The most frequent were catheter related (n = 13) followed by respiratory (n = 7), intraabdominal (n = 6), and wound infections (n = 5). Symptomatic viral infection of the graft (CMV gastritis or enteritis, adenoviral enteritis) was also encountered. Epstein-Barr virus was transiently detected in the serum of nine patients, one of whom later developed posttransplant lymphoproliferative disorder (PTLD). Three deaths all among patients receiving high immunosuppression were owing to infectious complications: pulmonary PTLD at 4 months posttransplantation, ruptured mycotic aneurysm after 8 weeks, and sepsis after 3 weeks. CONCLUSIONS: Infections accounted for a high morbidity after multivisceral transplantation, representing the leading cause of mortality. Exhaustive monitoring, early antimicrobial intervention, and lower immunosuppression may improve the outcome.

Adult↗
PubMed2004

Antibody response to the Haemophilus influenzae type b-tetanus toxoid conjugate vaccine in healthy and infection-prone individuals with IgG3 subclass deficiency.

Searching for a possible explanation for the phenotypic heterogeneity in IgG3 deficiency, we studied the antibody response to a polysaccharide and a protein antigen in IgG3-deficient (IgG3d) adults after vaccination with Haemophilus influenzae type b capsular polysaccharide (Hib CP) conjugated to tetanus toxoid. Distribution of isotypes, idiotypes, clonotypes, and Gm allotypes were compared. All the vaccinated individuals, irrespective of the level of IgG3 and proneness to infections, developed protective levels of anti-Hib CP. Significantly lower prevaccination levels of IgG2 (p < 0.05) and IgG4 anti-Hib CP (p < 0.04 and p < 0.03) were noted among the infection-prone compared to the healthy IgG3d individuals and/or controls. Seventy percent of the IgG3d patients and none of the controls had the low responding Gm(ga-n/ga-n) genotype, while the majority of the controls had the alternative Gm(bfn/bfn) genotype. The conjugate ACT-HIB vaccine efficiently overcomes the IgG3 subclass deficiency state and the genetic predisposition for lower responsiveness, providing protection against Hib and tetanus infections. The proneness to infection in some IgG3d individuals may relate to their low prevaccination antibody levels.

Enzyme-Linked Immunosorbent Assay↗
PubMed2004

Aberrant IgG2 antibody response to Neisseria meningitidis polysaccharide A after vaccination in frequently infected compared to healthy IgA-deficient individuals.

In search for a possible explanation of the phenotypic heterogeneity in selective immunoglobulin (Ig)A deficiency, we studied the IgG2 antibody response to meningococcal polysaccharide A (PSA) in IgA-deficient (IgAd) individuals after vaccination with meningococcal A + C polysaccharide vaccine. Two groups of IgAd individuals, one frequently infected and one clinically apparently healthy, as well as healthy controls, were studied. In response to meningococcal A + C polysaccharide vaccine, a significant titre increase of specific IgG2 anti-PSA was found in 71% of the control individuals, in 50% of the healthy and in 42% of the infection-prone IgAd individuals. The specific IgG2 response against meningococcal PSA was significantly lower in the infection-prone IgAd individuals compared to the controls (P < 0.05). Among the IgAd individuals who responded with a significant IgG2 antibody increase, the IgG2 antibody response was significantly lower in the infection-prone than in the healthy IgAd individuals (P < 0.05). Thus, a limited capacity to mount a specific IgG2 response may suggest a more profound antibody maturation defect in infection-prone IgAd patients compared to healthy IgAd individuals.

Adult↗
PubMed2002

Increased frequency of intestinal Escherichia coli carrying genes for S fimbriae and haemolysin in IgA-deficient individuals.

Persons with selective IgA deficiency carry an increased risk of coeliac disease, inflammatory bowel disease and perhaps also gastrointestinal malignancies. Inflammatory bowel disease is associated with an increased carriage of adherent and haemolytic Escherichia coli in the intestinal microflora. This study was designed to investigate whether IgA-deficient individuals carry E. coli with virulence-associated properties in their gut flora. The last free-lying colony of E. coli isolates obtained from rectal flora of 25 IgA-deficient and 20 age-matched control individuals was assayed by multiplex PCR for genes for the following adhesins or virulence determinants: P, type 1 and S fimbriae, Dr haemagglutinin, haemolysin, aerobactin and the capsular types K1 and K5. E. coli strains from the intestinal microflora of IgA-deficient individuals more often had the gene for S fimbriae (36% of the strains compared with 0% in control subjects, P=0.003) as well as for haemolysin (40 vs 10% of the strains, P=0.040). IgA-deficient individuals had instead lower frequencies of E. coli carrying genes for type 1 fimbriae in their microflora (68 vs 90%, P=0.14). The results suggest that IgA-deficient individuals carry an increased frequency of E. coli with potentially inflammatogenic properties in their microflora, which may contribute to the development of gastrointestinal disorders such as inflammatory bowel diseases.

Adolescent↗
PubMed1997

Variable increases of IgG and IgM antibodies in milk of IgA deficient women.

Serum, milk and saliva from seven IgA deficient mothers were studied for the presence of IgA, IgG and IgM antibodies to Escherichia coli and poliovirus antigens. Different variable patterns were obtained. One mother had very much increased IgM and IgG antibodies in milk and saliva against both antigens; the milk IgG antibodies were 11-14 times higher than the reference milk pool. Another mother showed also striking increases of both IgM and IgG antibodies in milk, as well as in saliva where the increases were much higher for the poliovirus than the E. coli antibodies. Yet another mother showed a certain increase of IgM but not of IgG antibodies in the milk. The uneven appearance of IgG and IgM antibodies in serum and secretions suggests local production. So do the differences of antibody avidities, the variations in IgG subclass distribution of antibodies and different patterns after isoelectric focusing (IEF)/immunoblotting analysis of antibody spectrotypes in secretions and serum. The study illustrates the variable patterns of compensatory increases of IgG and IgM antibodies which may occur in IgA deficiency. It also shows that the milk from IgA deficient mothers can still be rich in antibodies, in spite of the lack of secretory IgA.

Antibodies, Bacterial↗
PubMed1996

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.

Adult↗
PubMed1996

Decreased expression of mannose-specific adhesins by Escherichia coli in the colonic microflora of immunoglobulin A-deficient individuals.

Most Escherichia coli isolates can express type 1 fimbriae with mannose-specific adhesins. These adhesins bind to the oligosaccharide chains of secretory immunoglobulin A (IgA). Thus, in addition to specific antibody activity, secretory IgA possesses a broad reactivity with bacteria expressing type 1 fimbriae. The absence of secretory IgA in colonic secretions, as seen in IgA deficiency, might therefore alter the ability of type 1-fimbriated E. coli to colonize the large intestines of these individuals. In the present study, 10 E. coli isolates from each of 17 IgA-deficient and 17 age-matched control individuals were assessed for the carriage of the fim gene cluster by DNA-DNA hybridization and for the expression of type 1 fimbriae by hemagglutination of guinea pig erythrocytes. The contribution of type 1-fimbria-mediated adherence to HT-29 colonic cells was also analyzed. The proportion of fim+ E. coli isolates was lower in IgA-deficient than in control individuals (74 versus 94%, P < 0.05), as was the proportion of isolates expressing type 1 fimbriae in vitro (69% versus 85%, P < 0.05). The median mannose-sensitive adherence to HT-29 cells was lower for isolates from IgA-deficient individuals than from the controls (9 versus 26 bacteria per cell, P < 0.05). Isolates expressing type 1 fimbriae showed lower adherence to HT-29 cells when they were derived from IgA-deficient individuals than when they were derived from control individuals (15 versus 27 bacteria per cell, P < 0.05). The results suggest that the interaction of type 1 fimbriae with secretory IgA contributes to the large intestinal colonization by these bacteria.

Adhesins, Bacterial↗
PubMed1994

Intestinal and circulating antibody-forming cells in IgA-deficient individuals after oral cholera vaccination.

In search for a possible explanation for the different susceptibility to mucosal infections in IgA-deficient (IgAd) individuals, the frequency of total immunoglobulin-secreting cells (ISC) and vaccine-specific antibody-secreting cells (ASC) in intestinal mucosa and peripheral blood was determined by the enzyme-linked immunospot (ELISPOT) assay before and after peroral vaccination with a B subunit-whole cell cholera vaccine. Two groups of IgAd individuals, frequently infected and non-infected respectively, and normal controls were studied. Before cholera vaccination there were significantly higher frequencies of total IgM and IgG ISC in the gut, but not in the blood, in the IgAd individuals than in the controls. However, there were no significant differences between healthy and infection-prone IgAd individuals in this respect. In response to oral cholera vaccination, intestinal cholera toxin (CT)-specific IgG and IgM ASC were significantly more abundant among the IgAd individuals with a history of frequent infections than among the healthy IgAd individuals and controls. A similar difference in IgG and IgM ASC, although not significant, was also noted in blood. In IgAd individuals with frequent infections the vaccine induced variable anti-CT IgM ASC responses in the gut, ranging from no increase to a few strikingly high responses. In the controls, the CT-specific responses were dominated by IgA ASC. The data show that oral cholera vaccination evoked strong CT-specific IgG ASC responses, and in some cases also strong IgM ASC responses in the intestinal mucosa of IgAd patients with a history of frequent infections. The healthy IgAd individuals unexpectedly responded with lower numbers of CT-specific IgG ASC and did not show any increase of CT-specific IgM ASC in the intestinal mucosa. Thus, inability to mount a mucosal immune response to an oral antigen cannot in itself explain recurrent infections among many IgAd individuals.

Administration, Oral↗
PubMed1993

B-cell activation in duodenal mucosa after oral cholera vaccination in IgA deficient subjects with or without IgG subclass deficiency.

Alterations in duodenal Ig-producing cells induced by two oral cholera vaccinations were studied by two-colour immunofluorescence in mucosal tissue sections from adults with selective IgA deficiency (IgAD), either with (n = 7) or without (n = 9) frequent infections, infection-prone patients with combined IgAD and IgG subclass deficiency (IgGSD) (n = 7), and normal control subjects (n = 11). The proportion of IgG-producing cells prior to immunization tended to be lower in the symptomatic IgAD subjects than in the clinically healthy ones. In the first subgroup the absolute number of IgG cells per intestinal length unit was significantly increased after immunization (P < 0.04), and this tendency was also observed in the healthy IgAD subjects (6/9) and in those with combined deficiency (5/7). Very few IgAD subjects responded with an increase of IgM-producing cells. The normal controls responded variably in all major immunocyte classes, in the order IgA > IgG > IgM. Compared with these controls, the patients with combined IgAD and IgGSD showed significantly increased IgG1 (P < 0.01) and reduced IgG2 (P < 0.006) proportions, which was in accordance with their serum subclass levels. Our study showed that oral cholera vaccination preferentially activates intestinal IgG-producing cells in IgAD subjects. This result agreed with data recently obtained by ELISPOT in the same patients with regard to antibody-forming cells specific for cholera toxin. Both methods suggested that IgG rather than IgM antibodies are elicited as compensation for a lacking IgA response. However, our overall results showed that intestinal B-cell activation is quite variable after oral cholera vaccination. Although such vaccination might be of importance for enhancing mucosal immunity also in IgAD patients, a concurrent gut disease could possibly be aggravated by IgG-mediated mucosal immunopathology in the absence of anti-inflammatory IgA antibodies.

Adult↗
PubMed1993

Similar proportions of immunoglobulin A1 (IgA1) protease-producing streptococci in initial dental plaque of selectively IgA-deficient and normal individuals.

By comparing the initial colonization of cleaned teeth in immunoglobulin A (IgA)-deficient, IgM-compensating individuals with that in normal individuals, no significant difference in the proportion of IgA1 protease-producing streptococci was found. Thus, as one of several bacterial means of immune evasion, the ability to cleave secretory IgA1 does not appear essential to the successful adherence of oral streptococci.

Adolescent↗
PubMed1992

Aberrations in titre and avidity of serum IgM and IgG antibodies to microbial and food antigens in IgA deficiency.

The antibody levels and relative avidity of serum IgM and IgG antibodies against E. coli O antigens, poliovirus type 1 and beta-lactoglobulin were determined with enzyme-linked immunosorbent techniques in IgA deficient (IgAd) patients with frequent respiratory tract infections and healthy IgAd individuals. Healthy individuals with normal immunoglobulin levels served as controls. The IgM antibody levels against the bacterial, viral and food antigens and the IgG antibody levels against the bacterial antigens were significantly higher in the IgAd group with recurrent infections than in the group of healthy IgAd individuals. The symptomatic IgAd group had significantly higher levels of the IgG antibodies against the bacterial antigen, also when compared with controls. In contrast the healthy IgAd individuals had the highest avidities of IgM antibodies to the viral and food antigens. The high avidities of antibodies could be a compensatory host defence mechanism in IgAd. These aberrations may appear as a consequence of increased mucosal exposure in IgAd to antigens such as E. coli or beta-lactoglobulin, but presumably not to poliovirus which is only exceptionally present in the milieux. They could also be a result of the previously suggested dysregulation of antibody responses in IgAd.

Antibody Affinity↗