PCR and other non-culture methods for diagnosis of invasive Candida infections in allogeneic bone marrow and solid organ transplant recipients

In this prospective study 197 serum and 152 urine samples were collected from 40 bone marrow and solid organ transplant recipients with clinically suspected invasive fungal infection before, during and after empirical treatment with lipid formulation of amphotericin B or fluconazole. Serum was analysed by Candida polymerase chain reaction (PCR) and urine by measurement of D/L-arabinitol ratio. One serum from each patient was also tested for concentration of (1-->3)-beta-glucan and two commercial Candida antigens. Invasive fungal infection was diagnosed in four candidosis and one aspergillosis patients (13%). Positive PCR, elevated D/L-arabinitol ratio, (1-->3)-beta-glucan concentration and antigens were detected in nine, 15, 17, and seven patients, respectively. The agreement between PCR and D/L-arabinitol assays was poor. However, 56% agreement was observed between positive PCR and beta-glucan and/or antigen assays, and 60% agreement between positive D/L-arabinitol and beta-glucan and/or antigen assays. Combination of several non-culture assays is needed to diagnose invasive fungal infection in high-risk transplant recipients. No single test was sufficient for diagnosis.

Interferon gamma (IFN-gamma) deficiency in generalized Epstein-Barr virus infection with interstitial lymphoid and granulomatous pneumonia, focal cerebral lesions, and genital ulcers: remission following IFN-gamma substitution therapy

A 26-year-old previously healthy woman developed granulomatous pneumonitis, encephalitis, and genital ulceration during primary Epstein-Barr virus (EBV) infection. EBV DNA was demonstrated by polymerase chain reaction analysis of serum, lung tissue, and genital ulcer specimens. Serology verified primary EBV infection. The patient lacked lymphocytes cytotoxic to autologous EBV-transformed B lymphocytes. No spontaneous or in vitro EBV-induced interferon gamma (IFN-gamma) production was evident in peripheral blood. The cells had normal IFN-gamma production when stimulated with Staphylococcus aureus exotoxin A. In the bone marrow and peripheral blood, the number of large granular CD56+ lymphocytes (natural killer cells) increased 39%-55%, but no CD4 or CD8 cell lymphocytosis was initially found. A partial clinical response was achieved with treatment with acyclovir, corticosteroids, and intravenous gamma-globulin. Because of persistent granulomatous central nervous system and lung involvement, subcutaneous IFN-gamma therapy was started but was discontinued after 3 months because of development of fever, pancytopenia, and hepatitis. This therapy initiated a complete clinical recovery, which occurred parallel to development of EBV-specific cytotoxic CD8+ T lymphocytes and normalization of natural killer cell lymphocytosis. These findings provide evidence for an EBV-induced lymphoproliferative disorder due to a T lymphocyte dysfunction associated with a selective lack of IFN-gamma synthesis.

A controlled comparison of two different clinical grade devices for CD34+ cell selection of autologous blood stem cell grafts

Six patients who were to undergo autologous PBSC transplantation with positively selected CD34+ cells were included in this study to compare the efficiency of two devices for clinical grade stem cell selection, the Isolex 300i (Baxter, Munich, Germany) and CEPRATE SC (CellPro, Bothell, WA). PBSC were mobilized by chemotherapy and G-CSF and were collected by leukapheresis on a CS3000 cell separator on 2 consecutive days. The two apheresis products were pooled for CD34 selection. The pooled apheresis products from each patient were divided into two equal portions to be separated on each of the two devices. Cell selection was performed according to the manufacturers' instructions. Enumeration of CD34+ cells was performed by flow cytometry using the HPCA-2 MAb. Purity and yield were significantly better with Isolex than with CEPRATE. Median purity was 93.0% (range 80%-98%) for Isolex and 61.5% (range 27%-72%) for CEPRATE (p = 0.03); median yields for Isolex and for CEPRATE were 48.0% (range 18%-73%) and 23.0% (range 17%-29%), respectively (p = 0.03). The number of CD34+ cells/kg body weight was also significantly higher with Isolex (median 3.8x10(6), range 1.7-5.2) compared with CEPRATE (median 2.35x10(6), range 0.7-4.3) (p = 0.03). Thus, the Isolex 300i device gave products of higher purity and recovered a higher proportion of the CD34+ cells in the harvest before separation. The yield was still poor with both devices, however, and further optimization of the technique for clinical grade stem cell selection is warranted.

Signalling of Bruton's tyrosine kinase, Btk

Bruton's tyrosine kinase, which is encoded by the BTK gene, is a cytoplasmic protein tyrosine kinase (PTK) crucial for B-cell development and differentiation. It belongs to the Tec family of PTKs containing several domains that are characteristic of signalling molecules. In humans, mutations that disrupt the function of this gene lead to the classical XLA syndrome (X-linked agammaglobulinaemia), a primary immunodeficiency mainly characterized by lack of mature B cells as well as low levels of immunoglobulins. In contrast, animal models of this disease such as the xid mice display profoundly milder XLA phenotype. BTK phosphorylation and activation in response to engagement of the B-cell receptor (BCR) by antigen is a dynamic process whereby a variety of proteins interact with each other and recruit signalling molecules resulting in a physiological response such as B-cell proliferation and antibody production. The main players, however, that participate in the intracellular downstream cascade have not yet been identified and are therefore under intense scrutiny in several laboratories. This review discusses certain aspects of BTK activation following receptor stimulation by agonists and how this event is translated into the biochemical signals within the cell that eventually lead to nuclear responses.

Epidemiologic and molecular investigation of outbreaks of hepatitis C virus infection on a pediatric oncology service

BACKGROUND

Despite screening of blood donors, hepatitis C virus (HCV) infection can occur in patients who receive multiple transfusions.

OBJECTIVE

To clarify mechanisms of nosocomial transmission of HCV.

DESIGN

Epidemiologic and molecular analyses of hepatitis C outbreaks.

SETTING

Pediatric oncology ward.

PATIENTS

Children with cancer.

MEASUREMENTS

Epidemiologic analysis, HCV RNA detection, genotyping, and hypervariable region 1 (HVR1) sequencing.

RESULTS

Ten cases of infection with acute HCV genotype 3a occurred between 1990 and 1993. Sequencing of HVR1 revealed three related strains. Despite an overhaul of hygiene procedures, a patient infected with genotype 1b generated nine subsequent infected patients in 1994. Several patients had high virus titers and strongly delayed anti-HCV antibody responses. All had permanent intravenous catheters. Multidose vials used for flushing or treatment had probably been contaminated during periods of overlapping treatment.

CONCLUSIONS

Contamination of multidose vials was the most likely mode of HCV transmission; therefore, use of such vials should be restricted. Rigorous adherence to hygiene routines remains essential to preventing transmission of bloodborne infections.

MHC class I mosaic mice reveal insights into control of Ly49C inhibitory receptor expression in NK cells

We have analyzed lymphocyte development in natural MHC class I chimeric mice, generated through a transgenic approach in beta2-microglobulin (beta2m)-/- mice. In these mice, MHC class I+ cells coexist with an equal proportion of MHC class I-deficient cells. These MHC class I mosaic mice had normal numbers of CD8+ T cells, which had a target cell specificity similar to that of wild-type mice. Consequently, the mice did not develop any signs of autoimmunity. They also had normal numbers of NK cells. This allowed an examination of the MHC class I influence on the expression of the Ly49C inhibitory receptor on NK cells. This receptor binds to H-2Kb. It is expressed at low levels on NK cells in wild-type mice of the H-2b haplotype, but at markedly higher levels on NK cells in beta2m-/- mice and other strains of mice lacking expression of H-2Kb. Relatively little is known about how MHC class I molecules affect expression of the Ly49 receptors. Through the analysis of the present MHC class I mosaic mice, we demonstrate that the expression levels of Ly49C on NK cells is a consequence not only of MHC class I expression in the environment, but also of the expression of MHC class I molecules by the NK cells themselves. These findings are discussed in relation to the biological role of the calibration of the Ly49 inhibitory receptor expression in relation to self-MHC class I.

Lack of T-lymphocytosis and poor interferon gamma production in BAL fluid from HIV-negative immunocompetent patients with pulmonary non-tuberculous mycobacteriosis

Very little is known about the pathogenesis of pulmonary non-tuberculous mycobacteriosis in immunocompetent individuals. Local inflammatory response was assessed by examining bronchoalveolar lavage fluid from 13 HIV-negative patients (12 F) without known cell-mediated immunosuppression, aged 48-72 y (median age 60 y), with non-tuberculous lung mycobacteriosis. Macrophages, lymphocytes, polymorphonuclear neutrophils and eosinophils in bronchoalveolar lavage fluid were analysed morphologically, and the subsets of T-lymphocytes (CD3+, CD4+, CD8+), HLA-DR+, B-lymphocytes (CD19+) and CD16+/CD56+ cells (natural killer, NK cells) were analysed by flow cytometry. Interleukin-1 beta (IL-1beta), IL-2, IL-4, IL-6, IL-8, IL-10 and interferon-gamma (IFN-gamma) levels were assessed by ELISA. The total number of cells/ml was significantly higher in BAL fluid from the patients (median value=880 x 10(3)/ml) compared to six healthy controls (200 x 10(3)/ml). The polymorphonuclear neutrophil population was significantly increased in the patients both proportionally and in the count/ml. The proportion of macrophages was significantly reduced in the patients but not the count/ml. The count of lymphocytes/ml was significantly higher in the patients but the proportion of lymphocytes was unchanged. No significant difference was seen in the relative proportion of NK cells, B- or T-lymphocytes and HLA-DR+ compared to the healthy controls. The IL-1beta and IL-8 levels were significantly increased in the patients. No differences were seen between the patients and controls in the leukocyte or lymphocyte subsets in peripheral blood. The local inflammatory response in BAL fluid from the studied patients was characterized by granulocytosis, and increase in the IL-1beta and IL-8 levels. There was no specific T-cell response.

Immunopathology of metastases in patients of colorectal carcinoma treated with monoclonal antibody 17-1A and granulocyte macrophage colony-stimulating factor

Twenty patients with metastatic colorectal carcinoma were treated with a single infusion (400 mg) of a mouse monoclonal antibody (IgG2a) against the tumor-associated antigen CO 17-1A and with a daily injection of granulocyte macrophage colony-stimulating factor (GM-CSF) for 10 days. The cycle was repeated every month. Metastases from 5 of the 20 patients biopsied on days 1 and 10 of the first two treatment cycles were studied by immunohistochemistry. During treatment, neutrophils, monocytes, and T lymphocytes increased concordantly in the tumor as in the blood of the individual patient. Macrophages (CD68) and CD8+ T cells infiltrated the tumor glands and displayed TIA-1-reactive cytotoxic granules. Neutrophils were seen mainly in areas of necrosis. Activated (HLA-DR+) CD4+ T cells were usually abundant in the stroma. During treatment, few natural killer cells were found in the tumor, contrary to the marked increase seen in blood. Our observations indicate that GM-CSF markedly recruited activated, tumor-infiltrating leukocytes, possibly representing antibody-dependent cellular cytotoxicity and cytotoxic T effector cells. The notion that combined antibody and GM-CSF therapy may also promote a T-cell antitumor response is further supported and advocated by our findings. The study lends further support to combining GM-CSF with monoclonal antibody-based therapy.

[Advances in the diagnosis of mycoses. New tests detect Candida infections]

New techniques for the detection of deep fungal infections are reviewed with a focus on Candida albicans, the species most frequently isolated. The introduction provides an outline of the similarities and differences between bacteria and fungi on one hand and animal cells on the other, which are important to bear in mind in the detection and treatment of deep fungal infections. In addition to cultures of biopsy material, blood, and mucous membranes (colonisation), serum tests for such fungal constituents as antigens or beta-glucan, the PCR technique for the detection of fungal DNA, and a test for the D-/L-arabinitol ratio in urine, are all valuable approaches. As yet, no single laboratory test is available that reliably detects disseminated candidosis. Rapid, sensitive, and specific methods for mycological diagnosis need to be developed to minimize the necessity of resorting to empirical therapy when deep mycosis is suspected.

Expression of collagen-binding protein and types 5 and 8 capsular polysaccharide in clinical isolates of Staphylococcus aureus

In vitro collagen binding of 216 Staphylococcus aureus isolates from patients with various diagnoses was studied. Polymerase chain reaction was used to examine these isolates regarding the existence of the corresponding cna gene. Distribution of capsular polysaccharide (CP) types was examined. Fifty-six (57%) of 99 S. aureus isolates from patients with endocarditis or bacteremic bone or joint infection were cna-positive compared with 65 (56%) of 117 isolates from bacteremic patients without signs of bone or joint infection (P = .99). There was a good correlation between in vitro collagen binding and presence of the cna gene. These data suggest that collagen binding is not a prerequisite for the development of endocarditis, osteomyelitis, or septic arthritis. There was no significant difference in the distribution of CP types among various patient groups, although there was a strong association between CP type 8 and the existence of the cna gene.

Higher proportion of CD8+ T cells in the blood in healthy adults from Ethiopia and Bangladesh compared with Sweden

The phenotypic composition of peripheral blood lymphocytes in 45 healthy adults (15 each from Bangladesh, Ethiopia and Sweden) was analysed as an indicator of the influence of environment and/or ethnic background on the human immune response. The possible interference of technical factors was minimized by highly standardized handling of samples and by use of a similar simultaneous 3-colour flow cytometry analysis technique for all samples. The percentage of CD4+ cells was lower, and the percentage of CD8+ cells was higher, in Bangladeshi and Ethiopian subjects than in those from Sweden. A higher percentage of CD57+/CD8+ T cells was also found in these 2 groups than in Swedish subjects. The percentage of gamma delta T cells was higher in Bangladeshi subjects and a difference in T cell receptor V beta expression was also noted between Bangladeshi and Swedish subjects. The data suggest that environmental or genetic factors are important bias factors to be considered in immunophenotyping studies. Possibly differences in the pattern or level of microbial challenge, as well as nutritional factors, may lead to different adaptive changes in the immune response. The potential influence of such immune adaptation on the response to vaccination or pharmaceutical therapy may be important in the development of new strategies of medical intervention in different geographical regions or ethnic groups.

Quantitative assessment of IgG and IgA subclass producing cells in rectal mucosa during shigellosis

AIMS

To assess quantitatively both the morphological changes in the rectal mucosa and the changes in the relative frequency of IgA and IgG subclass producing cells found in the rectal mucosa during the acute phase of shigellosis and at convalescence.

METHODS

Rectal biopsies from 25 Shigella dysenteriae 1 infected patients, 10 Shigella flexneri infected patients, and 40 uninfected controls were studied. Morphological changes in the mucosa were graded. The frequency of IgA and IgG subclass producing cells was assessed. In addition, immunostaining for secretory component in epithelial cells was analysed.

RESULTS

Using morphological grading, 20% of the 35 patients studied had advanced inflammation (grade 3) in the acute phase of the disease. At convalescence, grade 1 inflammation was seen in 37% of the patients and in 10% of the controls. In the acute phase, as well as at convalescence, the number of IgA1, IgA2, and IgG2 positive cells was significantly higher than in the controls. The results were related to the histopathological degree of inflammation.

CONCLUSIONS

In shigellosis, there is evidence for a prolonged humoral response residing in the mucosa long after the clinical symptoms have resolved, suggesting that shigellosis induces persisting mucosal humoral immune and inflammatory responses, remaining at least until 30 days after the infection.

Preventive effect of IgG from EBV-seropositive donors on the development of human lympho-proliferative disease in SCID mice

The effect of weekly treatments with various gammaglobulin preparations on the development of human B-cell tumors was studied in severe combined immunodeficient (SCID) mice. SCID mice were injected i.p. with human peripheral blood mononuclear cells (PBMCs) from an Epstein-Barr virus (EBV)-seropositive healthy blood donor. Repopulated SCID mice were divided into 7 treatment groups receiving either PBS, 2 commercial gammaglobulin preparations, purified IgG prepared from pooled plasma from EBV-seronegative or -seropositive blood donors, a rabbit anti-serum against EBV envelope glycoprotein gp340 or interferon (IFN)-alpha. All treatments started 1 day after injection of PBMC and continued for 8 weeks. In the PBS-treated control group, 85% of mice developed tumors in the abdominal cavity, mostly with liver metastasis within 150 days. Tumor formation was prevented by treatment with the 2 commercial gammaglobulin preparations as well as by purified IgG from EBV-seropositive donors. In contrast, purified IgG from EBV-seronegative donors, rabbit anti-gp340 anti-serum or IFN-alpha had no effect. Our results indicate that the effect of gammaglobulin is due to the presence of specific antibodies against EBV antigens. Further experiments showed that both the time of onset and the duration of treatment, as well as the dose of Ig, are important factors for prevention of tumor formation. Studies aiming at identification of target antigens for antibodies which prevent lymphoma development may be clinically relevant for prevention and possibly treatment of lympho-proliferative disease in severely immuno-compromised patients.

Gap junctions promote the bystander effect of herpes simplex virus thymidine kinase in vivo

Transfer of the herpes simplex thymidine kinase gene (HSVtk) into tumor cells followed by the administration of ganciclovir (GCV) provides a potential strategy for the treatment of some malignancies. During GCV treatment, not only the cells that express the HSVtk gene are killed but also frequently neighboring tumor cells that are not genetically altered. This has been called the "bystander effect." Although the mechanism of the bystander effect in vivo remains elusive, our results suggest that gap junction formation between neighboring cells is an important contributing factor. The C6 rat glioma cell line, which exhibits a low level of intercellular communication by gap junctions and connexin43 (Cx43)-transfected clones of this cell line forming gap junctions from a moderate level (Cx43-12 and Cx43-14) to a high level (Cx43-13), were transduced with HSVtk. Transduced and nontransduced cells were mixed in various concentrations and then cultured in vitro or injected s.c. into C.B-17/SCID-beige mice followed by i.p. injections of GCV. Cx43-transfected clones showed a significant increase of the bystander effect compared with the less coupled C6 parental cell line. In 11 of 12 mice injected with cells of Cx43-transfected clones, no tumors were seen at the inoculation site when a mixture of 50% HSVtk-negative and HSVtk-positive cells was used. Moreover, in mice injected with cells of clone Cx43-13, which exhibits the highest intercellular communication, tumors were frequently undetectable at the inoculation site when using mixtures of 75% HSVtk-negative and 25% HSVtk-positive cells, and even mixtures containing 5% HSVtk-positive cells of Cx43-transfected clones showed tumor size reduction. All animals in control groups (n = 26) developed large tumors at every injection site. These results demonstrate that gap junctions are an important component in mediating the bystander effect in vivo.

Lymphocyte activation and subset redistribution in the peripheral blood in acute malaria illness: distinct gammadelta+ T cell patterns in Plasmodium falciparum and P. vivax infections

Lymphocyte subset distributions and activation in the peripheral blood were studied in 39 patients with acute malaria and 16 healthy controls from Addis Ababa and Nazareth, Ethiopia. As confirmed by polymerase chain reaction (PCR), 15 patients were infected with Plasmodium falciparum (Pf), 17 with P. vivax (Pv) and seven were double-infected (Di) with both Pf and Pv. Three-colour flow cytometry was used for phenotyping. Total leucocyte and lymphocyte counts were lower in malaria patients than in controls. The T cell count was reduced in Pf patients, while in the Pv and Di patients there was a reduction in the natural killer (NK) cell count. The CD4/CD8 ratio remained unchanged. gammadelta+ T cells were significantly elevated in Pf and Di patients, but not in Pv patients. The increase in gammadelta+ T cells was mostly due to an increase in Vdelta1+ cells. Analyses of cellular activation indicated by the expressions of CD25 and HLA-DR revealed significantly higher numbers of activated CD3+ cells, including gammadelta+ T cells, in all patient groups compared with controls. Our results thus indicate that in acute malaria illness there is a complex pattern of change in lymphocyte subset distribution and activation, including gammadelta+ T cells. These patterns in Pf infection seem to be distinct from those in Pv infection.

Diagnosis of invasive candidiasis in neutropenic children with cancer by determination of D-arabinitol/L-arabinitol ratios in urine

Determination of D-arabinitol/L-arabinitol ratios (referred to as D/L-arabinitol ratios) in urine as a tool for the diagnosis of invasive candidiasis was investigated in a prospective study comprising 100 children with cancer. The analyses were made by gas chromatography. Positive D/L-arabinitol ratios were found for 10 of 10 children with confirmed invasive candidiasis, 12 of 23 patients undergoing empiric antifungal chemotherapy, and 4 of 67 children not receiving antifungal treatment. D/L-Arabinitol ratios were positive 3 to 31 days (median, 12 days) before the first culture-positive blood sample was drawn or empiric therapy was initiated. The regular monitoring of D/L-arabinitol ratios in urine holds great promise as a sensitive method for diagnosing invasive candidiasis in immunocompromised children with cancer. Moreover, it may be possible to use an early rise in D/L-arabinitol ratios as a basis for the institution of antifungal chemotherapy and as a means of avoiding unnecessary treatment with potentially toxic antifungal agents.

In situ characterization of inflammatory responses in the rectal mucosae of patients with shigellosis

Shigella species cause bacillary dysentery in humans by invading epithelial cells of the colonic mucosa leading to colonic epithelial cell destruction and inflammation. For further analysis of local gut inflammation, morphological changes and the potential involvement of mediators in regulatory mechanisms of cell activation and cell proliferation were studied immunohistochemically in rectal mucosal biopsies taken from patients during the acute phase of shigellosis and at convalescence. Rectal biopsies from 25 Shigella dysenteriae-1 and 10 Shigella flexneri-infected patients and from 40 controls were studied. The frequencies of proliferative cells (Ki67-positive cells), p53-immunostaining cells, and cells coexpressing Ki67 with CD3 or with p53 were analyzed. Immunostaining for the inducible nitric oxide synthase (iNOS) and the endothelial NOS was assessed. In addition, the frequencies of apoptotic cells and CD68+ cells that engulf apoptotic cells were assessed. By morphological grading, 20% of the patients had advanced inflammation (grade 3) in the acute phase; mild inflammation (grade 1) was seen in 37% of the patients at convalescence as well as in 10% of the controls. The findings in the present study suggest that in the acute phase of shigellosis inflammation is characterized by increased cell turnover in the lamina propria (LP) and the epithelium, increased iNOS expression in the surface epithelium, and apoptosis, which seems to be associated with LP macrophages. The findings also suggest that neither p53 nor iNOS are important factors for the induction of apoptosis in shigellosis. Expression of p53 may be related to early cell activation in crypt epithelium. Moreover, there is an indication of an active, low-level inflammatory process at convalescence. The results thus indicate that Shigella-induced inflammation is associated with a complex series of cellular reactions in the rectal gut mucosa which persist long after clinical symptoms have resolved.

Preliminary data on hard metal workers exposure to tungsten oxide fibres

The first personal exposure data for tungsten oxide fibres, in two hard metal manufacturing industries is presented. Occupational exposure was studied by static and personal measurements during tungsten metal production. Three different initial materials were used, ammonium-paratungstate (APT), blue oxide and tungsten trioxide. In both factories, airborne tungsten oxide fibres were detected both in static and personal samples. Fibre exposure varies for different activities. Charging of raw material, changing the hammer, cleaning-work on the cyclone and the micro-filter were found to be among the most high dusty operations. However, as workers use respirators during cleaning operations, these filters could not be related to personal exposure. The calcination of APT to the blue oxide generates fibrous dust. The raw material imported as blue oxide is also fibrous material and both charging it into the calcination furnace and re-charging it into the reduction furnace generates unnecessarily additional dusty periods. A single reduction-stage is, therefore, preferable. Furthermore, the tungsten trioxide raw material is non-fibrous, therefore, calcination of APT to tungsten trioxide and its reduction to tungsten metal is preferable with respect to minimising workers exposure to tungsten oxide fibres.

Suicide gene therapy for plasma cell tumors

Suicide gene therapy for plasma cell tumors was attempted in severe combined immunodeficient (SCID) mice injected with human myeloma cell lines. Initially, a ganciclovir-induced bystander effect was observed in vitro using myeloma cells transduced with a herpes simplex thymidine kinase (HSVtk) gene. Transduced cells injected subcutaneously (SC) into SCID mice could be eradicated by the administration of ganciclovir (GCV). Furthermore, an in vivo bystander effect was noticed when mice received mixtures of HSVtk-positive and nontransduced cells. Unexpectedly, a "distant bystander" effect was observed as tumors in regions inoculated with only nontransduced cells were significantly smaller and had increased frequency of apoptotic figures and decreased mitotic frequency in GCV-treated mice transplanted with HSVtk-positive cells at a different region compared with control mice.

Persistence of nontypeable Haemophilus influenzae in adenoid macrophages: a putative colonization mechanism

That nontypeable H. influenzae (NTHI) can reside intracellularly in human adenoid tissue has been suggested by use of in situ hybridization of a fluorescein labelled 16S rRNA-targeted oligonucleotide probe (FISH). Adenoid tissues from 43 children operated on in a clinically infection-free interval were investigated. FISH revealed H. influenzae in macrophage-like cells, located subepithelially in the crypts in all 43 adenoids. Furthermore, H. influenzae was detected in 22/22 adenoids using immunohistochemistry with the monoclonal antibody MAHI-3 recognizing a conserved H. influenzae LPS inner-core region. FISH and staining with monoclonal antibodies against immunophenotypic markers were performed simultaneously in order to characterize the cellular interrelations in this microenvironment. The findings of widespread presence of H. influenzae in cells of which some strongly expressed the CD14 marker of the monocyte/macrophage lineage may correspond to an important aspect of the colonization mechanisms whereby NTHI persists in the nasopharynx of children.

Absolute identification of muramic acid, at trace levels, in human septic synovial fluids in vivo and absence in aseptic fluids

This is the first report of a study employing the state-of-the-art technique of gas chromatography-tandem mass spectrometry for absolute identification of muramic acid (a marker for peptidoglycan) at trace levels in a human or animal body fluid or tissue. Daughter mass spectra of synovial fluid muramic acid peaks (> or = 30 ng/ml) were identical to those of pure muramic acid. Absolute chemical identification at this level represents a 1,000-fold increase in sensitivity over previous gas chromatography-mass spectrometry identifications. Muramic acid was positively identified in synovial fluids during infection and was eliminated over time but was absent from aseptic fluids.

Reduction in serum levels of antimitochondrial (M2) antibodies following immunoglobulin therapy in severe combined immunodeficient (SCID) mice reconstituted with lymphocytes from patients with primary biliary cirrhosis (PBC)

The effect of gammaglobulin treatment on autoantibody production was investigated in SCID mice reconstituted with human peripheral blood mononuclear cells (PBMC) obtained from patients with PBC. All reconstituted mice displayed the presence of human antimitochondrial antibodies (alpha M2Ab) of both IgG and IgM types before treatment with human immunoglobulin. Two weeks after i.p. injection of 20 x 10(6) PBMC into SCID mice, i.p. treatment with various preparations of human immunoglobulin was initiated. In control animals treated with saline, serum levels of human alpha M2Ab of the IgG type increased with time, peaking around 4 weeks after reconstitution. In contrast, human IgG autoantibodies rapidly decreased in all animals treated with human IgG. Treatment with a human IgM preparation had no effect on serum levels of alpha M2Ab of the IgG type. The results may suggest that the pronounced reduction of specific IgG autoantibodies was due to an increased catabolism of human IgG, including the autoantibodies, in the gammaglobulin-treated mice. Although the production of human alpha M2Ab in reconstituted mice could be easily shown, PBC-specific liver lesions or bile duct destruction were not observed, irrespective of treatment protocol.

Semiquantitative estimation of Shigella antigen-specific antibodies: correlation with disease severity during shigellosis

Systemic and mucosal antibody responses during shigellosis were analysed and correlated with clinical severity. Patients infected with Shigella dysenteriae type 1 (SDIP), and S. flexneri (SFIP) were grouped according to disease severity. The disease was more severe in SDIP than in SFIP. Higher levels of Shigella antigen-specific serum antibodies were associated with severe disease. In contrast, decreased serum levels of IgG, IgM and total protein were associated with severe disease. Faecal levels of total IgA, secretory IgA, albumin, and LPS specific s-IgA were increased in severe disease. The results of the study indicate that the level of humoral immune response correlates with the disease severity in shigellosis and that the local immune system in the mucosa is directly engaged in the response. This is also reflected at the systemic level by increased serum levels of specific antibodies and non-specific inflammatory parameters.

Flow cytometric quantitation of serum anti-D in pregnancy

BACKGROUND

The major cause of fetal hemolytic disease is maternal immunization to D in D-incompatible pregnancies. To prevent complications, D-incompatible pregnancies are monitored for the level of maternal anti-D. At present, the monitoring of anti-D levels is performed by the indirect antiglobulin test complemented by quantitation by the technique used in an automated antibody detection and quantitation instrument.

STUDY DESIGN AND METHODS

Flow cytometry was used to quantitatively determine the level of anti-D in serum and to analyze the IgG subclass distribution and the presence of IgM anti-D in these samples. The results were compared to the indirect antiglobulin test titer and to the results obtained by the technique used in an automated antibody detection and quantitation instrument.

RESULTS

Flow cytometry allowed sensitive and accurate determinations of anti-D levels with low interassay and intra-assay variability, both for serum samples and standard curves.

CONCLUSION

Flow cytometry is a simple, rapid, and reliable method for determining the serum levels of D antibodies and their Ig subclass distribution. It is therefore well suited for the monitoring of women during D-incompatible pregnancies.

Changes in the peripheral blood T-Cell receptor V beta repertoire in vivo and in vitro during shigellosis

A sequential activation of T cells in peripheral blood during shigello sis has been observer (D. Islam, P.K. Bradham, A. A. Lindberg, and B. Christensson, Infect. Immun 63:2941-2949, 1995). To further investigate the cellular response during the course of Shigella infection, changes in the T-cell receptor (TCR) repertoire in the subsets in blood in patients during shigellosis was that Shigella antigens may modulate the function of T cells carrying TCRs capable of recognizing Shigella-specific epitopes or superantigens. Such a selective preference for T cells expressing certain TCR Vbeta types could lead to the expansion or deletion of these T cells. In the present study of 27 adult male Bangladeshi patients with dysentery (14 cases caused by Shigella Dysenteriae 1 and 13 cases caused by Shigella flexneri), the changes in the TCR Vbeta repertoire of peripheral blood CD4+ and CD8+ T-cell subsets have been analyzed with a panel of nine anti-Vbeta monoclonal antibodies by flow cytometry. Twenty healthy males from Bangladesh and 20 healthy males from Sweden served as controls. Compared with the Bangladeshi controls, the patients had an increased frequency of CD4+T cells expression Vbeta2, Vbeta3, and Vbeta17, with a maximum at day 7 after the onset of disease. The frequency of CD4+T cells expressing Vbeta5.1 was increased only in patients with S. flexneri infection. Peripheral blood T cells from Shigella-infected patients also responded to in vitro stimulation in a TCR Vbeta-specific manner. Stimulation with heat-killed S. dysenteriae 1 and Shiga toxin enhanced the frequency of cells expressing Vbeta2, Vbeta3, Vbeta5.1, Vbeta13.6, and Vbeta17, especially in samples obtained at day 7. The enhanced frequency of cells expressing Vbeta2, Vbeta3, Vbeta5.1, and Vbeta17 found both in in vivo and in vitro could suggest that in shigellosis antigens or superantigens are presented to the immune system and preferentially activate certain TCR Vbeta types in T-cell subsets. The kinetics of the change in the TCR Vbeta repertoire in blood during shigellosis may indicate that following local activation, the antigen activated T cells can be retrieved in the blood and restimulated in vitro. If confirmed by parallel analysis of T cells in the gut and blood by TCR sequence analysis, the possibility suggested by our findings would facilitate further analysis of the role of cell-mediated immune responses in the pathogenesis of and protection against Shigella infection.