A comparison of electrochemiluminescence and flow cytometry for the detection of natural latex-specific human immunoglobulin E

In vitro correlates of type 1 hypersensitivity to natural latex (NL) proteins continue to be limited by both sensitivity and specificity. Methods which have detection limits in the picogram range, namely, radioallergosorbent assays (RAST) and enzyme-linked immunosorbent assays (ELISA), are inadequate for the identification of NL hypersensitivity in certain at-risk groups, such as health care workers. A flow cytometry assay (FCA), previously shown to be comparable to RAST and ELISA in the identification of NL-sensitized pediatric patients with spina bifida, was compared with electrochemiluminescence (ECL) in the evaluation of pediatric patients with spina bifida and NL-sensitized adult health care workers. As with RAST and ELISA, ECL is capable of detecting picogram amounts of specific analyte. The ECL assay detected NL-specific immunoglobulin E (NL-IgE) in three of six health care workers with strong histories of NL hypersensitivity. All six patients were negative by FCA. Further, 2 of 11 spina bifida patients found to be NL-IgE negative by FCA were NL-IgE positive by ECL. These findings suggest that in sensitivity the ECL assay is an improvement over the FCA for the identification of NL-sensitive individuals.

Latex hypersensitivity in children: clinical presentation and detection of latex-specific immunoglobulin E

OBJECTIVE

To better understand the clinical characteristics, diagnosis, and possible prevention of immediate hypersensitivity reactions to latex in a hospitalized, pediatric patient population.

METHODS

We performed a retrospective case analysis of the first 35 patients with latex allergy evaluated by our service over a 2-year period at our institution. Characteristics of patients and clinical reactions were analyzed and the presence of latex-specific immunoglobulin E was assessed using in vitro methods. In a limited group of patients, the success of strict environmental control and premedication with steroids and antihistamines was evaluated for the prevention of latex allergic reactions.

RESULTS

The majority of our patients had life-threatening reactions. In previous reports, most pediatric patients underwent reactions in the perioperative period and belonged to two well-recognized "high-risk" patient groups (spina bifida and genitourinary malformations). In our series, 21 patients (60%) had reactions outside of the operating room setting, and 14 patients (40%) had primary diagnoses outside of the previously recognized "high-risk" groups. Many patients had a history of multiple surgical procedures, and a history of a surgical procedure in the first year of life was very common. A pre-existing clinical history of latex allergy was present in only 18 of the 35 patients, and a severe or life-threatening allergic reaction was the presenting feature of latex allergy in 11 of the 35 patients. Using in vitro assays, we were able to detect latex-specific immunoglobulin E in the sera of all but two of our patients. Latex gloves and latex-containing intravenous sets were common triggers for reactions. When exposure to latex occurs systemically, as through an intravenous line, premedication with steroids and antihistamines may fail to protect against anaphylaxis.

CONCLUSIONS

Our experience indicates that the incidence of latex hypersensitivity in children is increasing, that the circumstances (patient profile, hospital location, route of exposure) in which life-threatening reactions may occur are more broad than previously reported, and that a better understanding of both environmental sources of latex antigens and host responses to latex exposure are needed for improved prevention of serious reactions.

Candidacidal mechanisms in the human neonate. Impaired IFN-gamma activation of macrophages in newborn infants

We studied the interaction between Candida albicans and mononuclear phagocytes derived from cord blood. In the presence of normal serum, the extent of phagocytosis and killing of candida by monocyte-derived macrophages was equivalent for newborns and adults. In the absence of serum both phagocytosis and killing by macrophages were reduced by half, but cord and adult cells were still equivalent. Mannosylated BSA and mannan inhibited ingestion of unopsonized candida by macrophages, suggesting a role for the mannose receptor. Exposure of cord and adult macrophages to IFN-gamma (10-500 U/ml) gave quantitatively different results in Candida killing, as well as in release of superoxide anion (O2-). Maximal increase in these functions with adult macrophages was achieved with 100 U/ml IFN-gamma. No enhancement with cord macrophages could be detected after treatment with 100 U/ml, and at 500 U/ml there was still significantly lower killing and O2- release compared with adult cells. Defective up-regulation of O2- release was also present in cord monocytes exposed to IFN-gamma on day 0. Studies of the surface expression of IFN-gamma receptors using a "nonblocking" mAb against the IFN-gamma receptor revealed a comparable number of receptors on cord and adult monocytes. When blocking Abs were used, however, there was a three times higher number of positive cells in cord monocytes. Specific binding of 125I-IFN-gamma to cord monocytes and macrophages was also higher compared with adult cells. These data suggest that neonatal macrophages have a normal capacity to ingest and kill both opsonized and unopsonized Candida but cannot be fully activated by IFN-gamma, a finding that could not be attributed to lower expression of IFN-gamma receptors on the neonatal cells.

Candidacidal mechanisms in the human neonate. Impaired IFN-gamma activation of macrophages in newborn infants

We studied the interaction between Candida albicans and mononuclear phagocytes derived from cord blood. In the presence of normal serum, the extent of phagocytosis and killing of candida by monocyte-derived macrophages was equivalent for newborns and adults. In the absence of serum both phagocytosis and killing by macrophages were reduced by half, but cord and adult cells were still equivalent. Mannosylated BSA and mannan inhibited ingestion of unopsonized candida by macrophages, suggesting a role for the mannose receptor. Exposure of cord and adult macrophages to IFN-gamma (10-500 U/ml) gave quantitatively different results in Candida killing, as well as in release of superoxide anion (O2-). Maximal increase in these functions with adult macrophages was achieved with 100 U/ml IFN-gamma. No enhancement with cord macrophages could be detected after treatment with 100 U/ml, and at 500 U/ml there was still significantly lower killing and O2- release compared with adult cells. Defective up-regulation of O2- release was also present in cord monocytes exposed to IFN-gamma on day 0. Studies of the surface expression of IFN-gamma receptors using a "nonblocking" mAb against the IFN-gamma receptor revealed a comparable number of receptors on cord and adult monocytes. When blocking Abs were used, however, there was a three times higher number of positive cells in cord monocytes. Specific binding of 125I-IFN-gamma to cord monocytes and macrophages was also higher compared with adult cells. These data suggest that neonatal macrophages have a normal capacity to ingest and kill both opsonized and unopsonized Candida but cannot be fully activated by IFN-gamma, a finding that could not be attributed to lower expression of IFN-gamma receptors on the neonatal cells.

Effect of hematopoietic growth factors on human blood monocytes/macrophages in in vitro culture

The production of mature monocytes/macrophages is regulated by a group of hematopoietic growth factors, or colony-stimulating factors (CSF). We investigated the in vitro effect of human hematopoietic growth factors on human blood monocyte/macrophage differentiation and proliferation in short- and long-term in vitro cultures. The addition of macrophage CSF, granulocyte-macrophage CSF, and granulocyte CSF and interleukin-6 and interleukin-3 growth factors to monocyte/macrophage cultures induced morphological changes in cultured cells, including enhancement of cell growth and the formation of multinucleated giant cells, spindle-like cells, and fibroblast-like cells. In addition, CD4 and HLA-DR antigen expression was down regulated by the addition of growth factors without a change in the expression of other surface antigens, including CD3, CD11B, CD14, CD15, NK H1, and B1. The proliferating cell nuclear antigen was not detected in growth factor-treated nonadherent monocytes/macrophages in long-term cultures. Bromodeoxyuridine was incorporated in the adherent monocytes/macrophages, and intense staining in the small rounded cells which occur above the adherent cells in these cultures was observed after a 72-h pulse, indicating that monocytes/macrophages are slowly dividing cells.

Leukocytosis and natural killer cell function parallel neurobehavioral fatigue induced by 64 hours of sleep deprivation

The hypothesis that sleep deprivation depresses immune function was tested in 20 adults, selected on the basis of their normal blood chemistry, monitored in a laboratory for 7 d, and kept awake for 64 h. At 2200 h each day measurements were taken of total leukocytes (WBC), monocytes, granulocytes, lymphocytes, eosinophils, erythrocytes (RBC), B and T lymphocyte subsets, activated T cells, and natural killer (NK) subpopulations (CD56/CD8 dual-positive cells, CD16-positive cells, CD57-positive cells). Functional tests included NK cytotoxicity, lymphocyte stimulation with mitogens, and DNA analysis of cell cycle. Sleep loss was associated with leukocytosis and increased NK cell activity. At the maximum sleep deprivation, increases were observed in counts of WBC, granulocytes, monocytes, NK activity, and the proportion of lymphocytes in the S phase of the cell cycle. Changes in monocyte counts correlated with changes in other immune parameters. Counts of CD4, CD16, CD56, and CD57 lymphocytes declined after one night without sleep, whereas CD56 and CD57 counts increased after two nights. No changes were observed in other lymphocyte counts, in proliferative responses to mitogens, or in plasma levels of cortisol or adrenocorticotropin hormone. The physiologic leukocytosis and NK activity increases during deprivation were eliminated by recovery sleep in a manner parallel to neurobehavioral function, suggesting that the immune alterations may be associated with biological pressure for sleep.

Flow cytometric measurement of immunoglobulin E to natural latex proteins

Immediate hypersensitivity to natural latex (NL) occurs in sensitized individuals after repeated exposure to products or devices containing NL components. Since allergic reactions to NL proteins are quite frequent and may be quite serious, diagnostic assays are needed to identify individuals at risk. A number of latex proteins have been considered the major antigens, but they have been incompletely characterized. There is no standard material available for skin testing. In vitro diagnostic tests, such as the radioallergosorbent test (RAST), are time consuming and their sensitivity and specificity remain to be proven. We have developed a rapid microsphere-based, fluorescence-activated flow cytometry assay for the measurement of NL protein-specific human immunoglobulin E and have compared it with both the enzyme-linked immunosorbent assay and radioallergosorbent test methods. By using the total purified NL protein fraction isolated from raw ammoniated NL sap as the antigen, the flow cytometry assay was both sensitive and specific for the detection of NL protein-specific human immunoglobulin E in the sera of sensitized pediatric patients.

In vitro and in vivo effects of granulocyte colony-stimulating factor on neutrophils in glycogen storage disease type 1B: granulocyte colony-stimulating factor therapy corrects the neutropenia and the defects in respiratory burst activity and Ca2+ mobilization

Children with glycogen storage disease (GSD) type 1b are susceptible to recurrent bacterial infections and have chronic neutropenia accompanied by phagocytic cell dysfunction including decreased superoxide anion (O2-) generation, calcium (Ca2+) mobilization, and chemotactic activity. Granulocyte colony-stimulating factor (G-CSF), a cytokine that corrects neutropenia in other diseases, in vitro enhances f-Met-Leu-Phe-triggered neutrophil O2- generation. Short-term pretreatment (15 min) of GSD 1b neutrophils with G-CSF increased the rate of O2- production (p < 0.01); however, this rate was still significantly below the rate of O2- production in control neutrophils. Recombinant human G-CSF (5 micrograms/kg/d) was administered s.c. to a GSD 1b patient. Before treatment, absolute neutrophil counts were < 500/mm3. Two d after G-CSF administration, the absolute neutrophil counts increased to 1333 and remained in the normal range during a 12-mo follow-up period. In vivo, G-CSF therapy increased f-Met-Leu-Phe-stimulated O2- production to 52% of control after 1 mo, and by mo 4, O2- production reached control levels. Our previous studies (J Clin Invest 56:196-202, 1990) demonstrated that decreased O2- production in neutrophils was associated with impaired Ca2+ mobilization. In vivo administration of G-CSF increased f-Met-Leu-Phe-triggered Ca2+ mobilization by neutrophils to 43% of control by mo 1 of G-CSF therapy and to 93% of control by mo 4, thus paralleling the improvements in O2- generation. In contrast, G-CSF therapy had no effect on the defective neutrophil chemotaxis. In summary, G-CSF therapy produced a rapid increase in circulating neutrophils and a gradual correction of O2- production.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytofluorographic analysis of effects of interferons on expression of human cytomegalovirus proteins

The appearance of cytomegalovirus (CMV) proteins in infected fibroblasts was determined by flow cytometry. The sequential production of immediate early (IE), early (E), and late (L) proteins reacting with respective monoclonal antibodies (mAbs) E13, 58/5, and 24/4 was determined in fibroblasts infected with the AD-169 strain of CMV. The percentage of cells expressing CMV proteins and the intensity of fluorescence within cells were determined from day 1 to day 7 post-infection. The effect of interferons (IFNs) alpha, beta, gamma on expression of CMV proteins was analyzed using flow cytometry. IFNs inhibited E and L protein production at days 3 and 6 post-infection in a dose-dependent manner. This inhibitory effect on protein expression was associated with a reduction in release of infectious CMV into culture media. The method described here for detection of CMV proteins using flow cytometry may be useful for basic studies of gene expression and for diagnostic purposes.

Isolation and flow cytometric characterization of newborn mouse brain-derived microglia maintained in vitro

Microglia have been identified in the white matter of developing and adult mouse brain using different murine macrophage markers. While several techniques for the isolation of murine microglia have been described, the small cell yields and partial purification have limited the progress of these studies. We now describe the isolation of murine microglia using a modification of McCarthy and de Vellis method. Brain tissues from 1-2 day old newborn mice were mechanically and chemically dissociated and maintained in in vitro culture for 3 weeks. In primary dissociated brain cultures, microglia are observed after 10 days migrating from small colonies. After 16-20 days, brain-derived microglia were isolated with high cell yields by continuous shaking of the cultures for 16 hr. In contrast to resident murine peritoneal macrophages, microglia express less Class II (Ia) antigen and a small percentage express L3T4 (CD4) antigen by flow cytometry.

Isolation and characterization of human fetal brain-derived microglia in in vitro culture

Human brain microglia may play a central role in immunopathogenesis of CNS diseases including HIV infection, multiple sclerosis and Alzheimer's disease. In order to investigate the possible relationship between microglia and the mononuclear phagocyte system, human brain microglia were isolated from 14-18-week-old fetal brains, and maintained in in vitro culture. Enriched fetal brain microglia were stained for different monocyte/macrophage and glial cell markers. Fresh dissociated brain cells lacked macrophage surface markers. Isolated microglial cells stained positive for complement receptor C3bi, Class II [human leukocyte antigen-DR (HLA-DR)] antigen and with the lectin Ricinus communis. Microglia also share several functional properties with monocyte/macrophages, which include generation of superoxide anion and histochemically demonstrable intracellular acid phosphatase and non-specific esterase. Primary human dissociated brain cultures were maintained in culture for at least 28 weeks. Although microglia were not observed above the astrocyte cell layer after 5 weeks in culture, microglia-like cells appear below the astrocyte layer after 12 weeks in culture. These cells stained positive for non-specific esterase and displayed oxidative burst activity upon activation with phorbol myristate acetate. Thus, we have successfully isolated an enriched population of microglia from human fetal brain and have demonstrated that these cells possess markers and properties which are characteristics of mononuclear phagocytes.

Interaction between human peripheral blood monocytes and tumor promoters: effect on growth differentiation and function in vitro

Studies on the differentiation and activation of human monocytes in tissue cultures have usually been limited by the deterioration of human monocytes and macrophages in long-term cultures. In this study, we attempted to establish long-term human monocyte/macrophage cultures using the phorbol ester 12-0 tetradecanoyl-phorbol-13-acetate (TPA), and we studied the morphology, function, and biochemical properties of such treated human blood monocytes. Enriched suspensions of monocytes were obtained using Ficoll-Hypaque gradient and cultured in the absence or presence of various concentrations of TPA. Samples were removed at different times and processed for scanning electron microscopy. Parallel samples were examined for numbers of adherent cells, phagocytosis, oxidative burst, beta-galactosidase assays, and lectin-mediated erythrolysis. TPA-treated monocytes survived in larger numbers in culture for up to 7 weeks and were more pleomorphic and exhibited higher beta-galactosidase activities after 14 days in culture than untreated monocytes. TPA-treated cells and untreated cells in long-term cultures showed a decrease in their oxidative burst activity while their phagocytic activity was not affected, and the TPA treatment augmented the lysis of wheat germ agglutinin-opsonized erythrocytes by the cultured monocytes. TPA treatment of adherent human monocytes resulted in cell cultures with increased numbers of viable and functionally adherent cells for extended periods of time and does not seem to interfere with the differentiation and maturation of the cells in culture.

Expression of the complement receptors CR1 and CR3 and the type III Fc gamma receptor on neutrophils from newborn infants and from fetuses with Rh disease

Developmental defects in neutrophil function, including diminished expression of plasma membrane receptors, may play an important role in the susceptibility of the newborn infant to infection. We used monoclonal antibodies and flow cytometry to study the expression of complement receptor type one (CR1), complement receptor type three (CR3), and Fc gamma receptor type three (FcRIII) on neutrophils from six fetuses with Rh disease, 10 preterm infants, nine term infants, and nine adults. Expression of the complement receptors on unstimulated cells was similar for all groups, but significant differences in complement receptor expression were observed after stimulation with N-formyl-methionyl-leucyl-phenylalanine (FMLP). Fetal, preterm, and term infant neutrophils expressed less CR3 than FMLP-stimulated neutrophils of adults [61 +/- 2, 48 +/- 4, and 66 +/- 4% (mean +/- SEM) of the mean for adults, p less than 0.05]. FMLP-stimulated CR1 expression for these groups was 61 +/- 6, 73 +/- 6, and 91 +/- 9% of the adult mean (p less than 0.05, fetal versus term infant and adult). Expression of both CR3 and CR1 increased with postconceptional age in the infants (r2 = 0.49, p less than 0.001 for CR3; r2 = 0.23, p less than 0.05 for CR1). Neutrophils of the preterm and term infants expressed less FcRIII than adult neutrophils (68 +/- 10 and 77 +/- 7% of the adult mean, p less than 0.05, for FMLP-stimulated cells), whereas fetal neutrophil FcRIII expression did not differ from that of the adult.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoembryonic antigen enhances metastatic potential of human colorectal carcinoma

Patients with human colorectal carcinoma have a poor prognosis when serum carcinoembryonic antigen level exceeds 5 ng/mL. The hypothesis that carcinoembryonic antigen enhances metastasis by promoting the attachment of tumor cells to Kupffer cells and hepatocytes was tested in an experimental metastasis model in which colorectal carcinoma cells were injected into the spleens of BALB/c athymic nude mice and liver colonies counted 5 weeks later. Pretreatment with systemic injections of carcinoembryonic antigen significantly increased the metastatic potential of a poorly metastatic colorectal carcinoma cell line KM-12c, but did not induce the nonmetastatic colorectal carcinoma cell line HC 2998 to produce metastases, nor did carcinoembryonic antigen make the highly metastatic colorectal carcinoma cell line mHC 1410 more metastatic. Carcinoembryonic antigen did not stimulate proliferation of colorectal carcinoma but appeared to be a cofactor for metastasis possibly as an adhesion factor.

Natural killer cell-mediated lysis of T cell lines chronically infected with HIV-1

The susceptibility of HIV-1-infected CD4+ T cell lines to natural killer (NK) cell-mediated lysis was examined. Non-adherent peripheral blood mononuclear cells (PBMC) of healthy adults lysed HUT cells chronically infected with the IIIB or WMJ1 strains of HIV-1 to a significantly greater extent than uninfected HUT cells. In contrast, Sup-T1 cells chronically infected with these two strains of HIV-1 were not lysed to a greater extent than uninfected Sup-T1 cells. Clone A1.25-infected Sup-T1 (A1.25/Sup-T1), derived from IIIB-infected Sup-T1 cells (IIIB/Sup-T1), were susceptible to non-adherent PBMC-mediated lysis, as were A1.25-infected HUT cells (A1.25/HUT). When non-adherent PBMC were depleted of CD16 (Leu-11b)+ NK cells by treatment with anti-Leu-11b plus C, lysis of HIV-1-infected HUT or Sup-T1 cells was reduced to low levels, indicating that the lysis was mediated by NK cells. Expression of HIV antigens on these target cells did not correlate with their susceptibility to NK cell-mediated lysis. Depletion of interferon-alpha (IFN-alpha) producing HLA-DR+ cells from non-adherent PBMC had no effect on the magnitude of NK cell-mediated lysis of IIIB or WMJ1-infected HUT cells. In contrast, lysis of A1.25/Sup-T1 or A1.25/HUT cells required the presence of HLA-DR+ cells. IFN-alpha production appeared to be required for NK cell-mediated lysis of A1.25/Sup-T1 or A1.25/HUT cells, while lysis of HUT cells infected with the WMJ1 or IIIB strains of HIV-1 was IFN-alpha independent. These results indicate considerable variability in the susceptibility of different HIV-1 infected T cell lines to NK cell-mediated lysis and suggest the existence of alternative mechanisms of activation of NK cells for lysis of HIV-1-infected T cell lines.

Synthetic peptide homologous to the envelope proteins of retroviruses shares a cross-reacting epitope with the CD4 receptor

A synthetic peptide (CKS-17) homologous to a highly conserved region of the retroviral transmembrane protein p15E was tested for its effect on receptor expression on monocytes. The CKS-17 amino acid sequence is present in several retroviruses including human T-cell lymphotropic virus types I and II and human immunodeficiency virus. The CKS-17 peptide has been previously shown to inhibit monocyte superoxide production, natural killer cell activity, polyclonal B-cell activation, and monocyte-mediated killing by inactivation of interleukin-1. In this study, we demonstrated that the anti-CD4 monoclonal antibody OKT4 binds strongly in vitro to CKS-17-treated human blood monocytes, whereas other antibodies tested were not reactive. This observed binding was the result of direct interaction of OKT4 antibody with the CKS-17 peptide. Moreover, a partial homology was found in amino acid sequence analysis of the CD4 epitope and the CKS-17 peptide.

Ontogeny of the antibody response to cow milk proteins

Twenty-nine infants were followed prospectively for the development of immunoglobulin G (IgG) and IgE antibodies to the cow milk proteins (CMPs) alpha-lactalbumin, alpha-casein, and beta-lactoglobulin. Thirteen infants were fed formula, eight were exclusively breast fed, and eight were breast fed with formula supplementation. By 4 months of life, infants fed formula or breast milk with formula supplementation had elevated IgE and IgG antibody levels to CMPs, when compared with values before 1 month of age. Further, breast-fed infants demonstrated significantly lower levels of IgE and IgG antibodies to CMPs than infants who received formula or breast milk with formula supplementation. Clinical symptoms of cow milk allergy were more common in infants fed formula or breast fed with supplementation, but were not significantly related to the presence of specific antibody. Our data suggest that the formation of CMP antibodies may reflect a normal humoral response following exposure to CMP antigens in this age group.

Organ distribution of experimental metastases of a human colorectal carcinoma injected in nude mice

The metastatic behavior of the HT-29 human colorectal carcinoma cell line was studied following injection into nude mice by different routes. After intrasplenic injection, experimental metastases formed in the livers of most mice. Variant lines were established in culture from the liver lesions and from tumors growing at the site of injection, the spleen. Cells of the HT-29 LMM line exhibited slightly enhanced ability to form liver metastases compared with cells of the non-selected parent line. When injected i.v., the HT-29 cells produced only a few small experimental metastases in the lungs, but in most of the mice macroscopic tumors were found in various lymph nodes and the interscapular fat. Analyses of the distribution of IdUrd-labeled cells did not reveal a preferential localization of the HT-29 cells in sites where metastases subsequently formed. This suggested that the growth of the human colon carcinoma cells in those sites might be the result of a stimulatory interaction between the tumor and host cells as opposed to growth in sites such as the lungs, where numerous cells arrested after i.v. injection but only a few, small metastases were seen 60 days later.

Rickets of prematurity: controversies in causation and prevention

Metabolic bone disease in the growing premature infant is an important disorder owing to inadequate intake of calcium or phosphorus over an extended period of time. Prevention of serious bone disease is an important goal in the care of the VLBW infant. Attempts to reproduce intrauterine bone accretion rates in intrauterine life may be unnecessary and may result in potential complications.

Phorbol myristate acetate induced oxidation of 2',7'-dichlorofluorescin by neutrophils from patients with chronic granulomatous disease

The oxidative metabolic burst of stimulated human polymorphonuclear leukocytes (PMNs) has been evaluated by the measurement of oxygen consumption, chemiluminescence, and oxygen radicals (O2-, H2O2, OH-) derived from activation of the hexose monophosphate shunt (HMPS). PMNs from patients with chronic granulomatous disease (CGD) are shown to lack functional NADPH oxidase and undetectable oxygen radical generation. However, using single cell analysis by flow cytometry and 2',7'-dichlorofluorescin (DCFH) oxidation by H2O2, significant DCFH oxidation by the PMA stimulated CGD PMNs was observed. Furthermore, 1mM potassium cyanide enhanced DCFH oxidation by control and CGD PMNs. DCFH oxidation by cells from an obligate heterozygous mother of an X-linked CGD patient was intermediate. These observations suggest that a PMA induced oxidase enzyme is present in CGD cells.

Pharmacology of olsalazine

In the treatment of inflammatory bowel disease the main anti-inflammatory component of sulphasalazine is 5-ASA. Based on the same azo-splitting principle in the colon as sulphasalazine, the new drug olsalazine was developed. Olsalazine consists of two 5-ASA molecules joined by an azo bridge. Pharmacokinetic studies have shown that on oral administration there is little systemic absorption of olsalazine. Almost the whole dose passes into the colon, where the olsalazine is completely split into 5-ASA and subsequently excreted in faeces and urine. It can be concluded that from all toxicological and pharmacological aspects, olsalazine is a safe drug. Olsalazine will present the colonic mucosa with twice the amount of 5-ASA/unit compared with sulphasalazine (the present drug of choice) without concomitant delivery of sulphapyridine, which is believed to carry most of the drug's side-effects. Thus, olsalazine seems to be a suitable drug for long-term treatment of ulcerative colitis in man.