Positional cloning of the gene for Nijmegen breakage syndrome.

Nijmegen breakage syndrome (NBS), also known as ataxia-telangiectasia (AT) variant, is an autosomal recessive disorder characterized by microcephaly, growth retardation, severe combined immunodeficiency and a high incidence of lymphoid cancers. Cells from NBS patients display chromosome instability, hypersensitivity to ionizing radiation and abnormal cell-cycle regulation after irradiation, all of which are characteristics shared with AT. Recently, the NBS locus was mapped at 8q21 by two independent approaches, complementation studies and linkage analysis. Here, we report the positional cloning of the NBS gene, NBS1, from an 800-kb candidate region. The gene comprises 50 kb and encodes a protein of 754 amino acids. The amino-terminal region of the protein shows weak homology to the yeast XRS2, MEK1, CDS1 and SPK1 proteins. The gene is expressed at high levels in the testes, suggesting that it might be involved in meiotic recombination. We detected the same 5-bp deletion in 13 individuals, and conclude that it is likely to be a founder mutation.

Anti-viral antibodies in HIV (HTLV-III) infection possess auto-antibody activity against a CH1 domain determinant in human IgG: possible immunological consequences.

Two regions of the envelope glycoprotein gp120 of the human immunodeficiency virus were shown to have a significant degree of homology to human immunoglobulin-gamma heavy-chain constant domains. We have now synthesized three short linear peptides, the first representing a sequence within the CH1 domain, the second an analogue of it, and the third representative of a region within the viral gp120. Polyclonal antibodies against these peptides were raised in rabbits and used to demonstrate that they all reacted well with human native IgG. Vice-versa, we observed the reaction of these antisera to the virus in an ELISA system. The proportion of sera reacting with the human gamma-chain peptide was significantly higher in HIV-positive individuals than in HIV-negative individuals, suggesting production of anti-viral antibodies in AIDS patients with auto-antibody activity against a CH1 domain determinant in human IgG.

HIV and HIV-infected cells differentially activate the human complement system independent of antibody.

The human retroviruses HTLV-I and HIV-I have previously been shown not to be lysed by human serum. An interaction between HIV and the complement system, however, has not been investigated in any detail. In this report we show that purified HIV as well as HIV-infected cells activate the complement system. In the case of virus-infected cells this activation is mediated by the alternative pathway of complement, whereas the classical pathway seems to be in operation for the triggering of the complement system by purified virus and recombinant envelope glycoprotein (gp 160). We demonstrate that this leads to the deposition of C3b and/or C3bi on the surface of infected cells. But the HIV-infected cells are not lysed by human complement. C3 fragments deposited on the surface of HIV-infected cells are capable of mediating immune adherence to complement receptor-bearing cells, such as human erythrocytes and phagocytes. Whether this might have an influence on infectivity of HIV for certain cells bearing complement receptors has yet to be shown.

Comparison of two antiretroviral triple combinations including the protease inhibitor indinavir in children infected with human immunodeficiency virus.

OBJECTIVE: The effects of two antiretroviral triple combinations including the protease inhibitor indinavir on the surrogate markers, viral load and CD4 cells were evaluated. METHODS: Fifteen patients with high viral load or disease progression under their prior antiretroviral therapy were switched to zidovudine/lamivudine/indinavir (Group A, n = 10) or stavudine/lamivudine/indinavir (Group B, n = 5). Serial determinations of viral load and CD4 cells were performed. RESULTS: The median reduction of the viral load was 0.6 log after 3 months and 0.8 log after 6 months in Group A and 2.5 and 2.4 log after 3 and 6 months in Group B, respectively. After 3 and 6 months 3 of 10 patients in Group A and 3 of 5 patients in Group B had viral load reductions below the detection limit of the assay. Patients with an additional switch of nucleoside analogues at start of indinavir therapy (regardless of the specific reverse transcriptase inhibitor used) had significantly better reductions of the viral load than patients without such a switch (median 2.3 log vs. 0.2 log after 6 months, P < 0.05). In Group A the median of the relative increase of CD4 cells was 37% after 3 months and 57% after 6 months (P = 0.002); in Group B the medians of the relative increase of CD4 cells were 145 and 163% (not significant), respectively. Two patients from Group A and 1 from Group B developed renal calculi, which resolved after adequate hydration. One patient was withdrawn because of intractable vomiting attributed to indinavir. CONCLUSION: In a small cohort of HIV-infected pediatric patients with extensive prior antiretroviral treatment, triple therapy including indinavir had a sustained effect on the decrease of the viral load and the increase of CD4 cells similar to results obtained in antiretrovirally experienced adults. This effect was significantly better in patients with an additional switch of a nucleoside analogue at start of triple therapy with indinavir than in patients without such a change.

Production and characterization of a monoclonal antibody against neopterin.

We have produced and characterized the first monoclonal antibody against neopterin (D-erythro-6-(1,2,3,-trihydroxypropyl)pterin). The antibody specifically recognizes neopterin in a modified RIA. The binding capacity in this assay is 34%, the sensitivity limit of inhibition is 0.9 nmol/l. Cross-reactivity exists with monapterin (L-threo(1,2,3,trihydroxypropyl)pterin) in 30%, with other pteridines cross-reactivity has been found in less than 5%.

Dyskeratosis congenita: multisystemic disorder with special consideration of immunologic aspects. A review of the literature.

Dyskeratosis congenita (DC) is a rare, predominantly X-linked multisystemic disorder. It demonstrates a wide spectrum of clinical manifestations and typically presents with dermatologic symptoms during the first decade of life. This review of the literature points out the importance of hematologic and immunologic alterations in defining the course and prognosis of the disease process. Pancytopenia as well as the humoral and cellular disturbances in immunologic functions associated with this disease complex may lead to severe infections that represent the main cause of death. The pathogenesis of DC is still unclear and a curative therapy is presently lacking. Recent reports suggest that a beneficial effect may be observed in the administration of hematopoietic growth factors (G-CSF, GM-CSF) for patients with DC and neutropenia.

[Enterohemorrhagic Escherichia coli and hemolytic-uremic syndrome]. / Enterohämorrhagische Escherichia coli und hämolytisch-urämisches Syndrom.

Enterohemorrhagic Escherichia coli (EHEC) are increasingly identified as the cause of diarrhea and hemorrhagic colitis in countries with highly developed livestock. In 5-10% of patients, full-blown hemolytic uremic syndrome (HUS) occurs as a postinfectious life-threatening complication. Up to 1996, 5 out of 39 patients (12.8%) with EHEC O157 infections in Austria developed HUS. Acute complications of HUS such as brain edema may also lead to death; one fatal outcome has been observed so far in Austrian patients. Aside from the cytotoxic Shiga toxins, other different pathogenic factors are often found in clinical EHEC isolates. These include a cytolysin termed EHEC-hemolysin and a low molecular heat-stabile enterotoxin. Furthermore, most EHEC strains express an important surface protein, intimin, which is important for adherence to intestinal epithelial cells. EHEC are heterogeneous in their antigenic structure (O-, H-antigens). In Austria O157:H7 and O157:H- are the dominating serogroups; in 1997 the first Austrian case of HUS due to EHEC O26:H11 was documented. Because there are no known reliable phenotypical markers for EHEC, diagnostic strategies should focus on the demonstration of Shiga toxins or Shiga toxin genes. For epidemiological purposes it is also important to attempt to isolate the causative agent. Cows and other ruminants are reservoirs for EHEC. In the Tyrol 3% of unpasteurised milk samples, up to 10% of minced beef samples, and 6% of calves yield EHEC O157. Aside from transmission via contaminated food, direct transmission from person to person also plays a major role in the chain of EHEC infection. In contrast to Italy and Bavaria, Austria has not experienced a major outbreak due to this organism so far. A nationwide surveillance system of HUS has shown an incidence of 0.37 HUS cases per 100,000 residents in the age group 0-14 years for 1995 (Italy: 0.2 cases per 100,000; Bavaria: approx. 1.5 cases per 100,000).

[Antiretroviral therapy in children]. / Antiretrovirale Therapie bei Kindern.

Former antiretroviral treatment strategies in pediatric HIV-infection were based on the occurrence of clinical symptoms or loss of CD4-cells. Because of toxicity and dosing concerns HIV-infected children have often been denied new drugs routinely prescribed to HIV-infected adults. Over the last few years new insights into the pathogenesis of HIV disease, the availability of quantitative viral load measurements and the development of new antiretroviral agents have brought dramatic changes in our understanding of the disease and the role of antiretroviral treatment. Similar to adults it was also shown in children that potent combination regimens applied early in the course of HIV-infection can achieve long-term control of viral replication and thus preservation of immune function and reduction of disease progression. However, there are only poor clinical data regarding dosing, pharmacokinetics, and antiretroviral activity of new combination therapies in infants and young children, pediatric studies are urgently needed. Consensus has been growing that children must not be denied modern therapy because of the lack of pediatric clinical data, and recently treatment guidelines were developed by specialists in pediatric HIV-care which recommend early combination antiretroviral therapies in infants and young children. It is likely that recommendations will change as more data become available about the effects of different treatment regimens.

Surgical treatment of bacillus Calmette Guérin lymphadenitis.

Although its protective effect is contested and the risk of contracting tuberculosis is rather low nowadays, BCG vaccination is frequently performed. Changes of strain repeatedly led to an increased complication rate. In Austria between 1990 and 1991, of 3386 newborn babies (Strain Pasteur) 116 developed lymphadenitis 3 to 28 weeks after vaccination. The affected children received four types of treatment: nothing specific, isoniazid, or surgery with and without isoniazid. Surgical treatment was found to be necessary in 96 cases. Bacilli were successfully grown in culture in 46% of cases up to week 20 after vaccination; but later than 20 weeks no culture became positive. All cultured bacteria were isoniazid-sensitive. From our data we drew the following conclusions: isoniazid therapy did not prove successful when inflamed lymph nodes exceeded a certain size. Suppurative lymphadenitis in lymph nodes exceeding 1.0 to 1.5 cm usually led to infiltration or even perforation of the skin. Surgery prevents these complications and significantly reduces healing time. Adjuvant isoniazid therapy cannot be recommended, except for generalized BCG tuberculosis.

[Dyskeratosis congenita. Genetic hematologic-immunologic systemic disease with pancytopenia]. / Dyskeratosis congenita. Genetische hämatologisch-immunologische Systemerkrankung mit Panzytopenie.

Dyskeratosis congenita (DC) is a rare, predominantly X-linked multisystemic disorder. It shows a wide spectrum of clinical manifestations and typically presents with dermatological symptoms within the first decade. This review of the literature points out the importance of haematological and immunological changes defining course and prognosis of disease. Pancytopenia, humoral and cellular disorders of immune function may lead to severe infections, which present the main cause of death. The pathogenesis of DC is still unclear, no causative therapy is available. Recent reports suggest a beneficial effect of haemato-poietic growth factors (G-CSF, GM-CSF) in patients with DC and neutropenia.

Persistent rubella infection after erroneous vaccination in an immunocompromised patient with acute lymphoblastic leukemia in remission.

A 16-year-old male patient with acute lymphoblastic leukemia in complete remission and on maintenance treatment with weekly oral methotrexate and daily oral 6-mercaptopurine for 3 months was immunized in error with the WI-RA 27/3-HDC live attenuated rubella vaccine. Increasing rubella HAI antibodies were noted from 3 to 7 months post-vaccination as well as high levels of IgM antibody up to 8 months in three different tests. High HAI antibody titers persisted for 12-18 months after vaccination. Persisting rubella virus was indicated by PCR detection of rubella-specific nucleic acid in whole blood, non-stimulated and stimulated mononuclear cells 8 months following vaccination. Further attempts to detect rubella virus RNA in two subsequent blood samples were negative. Since acute arthritis and arthralgia occurred in the second month (days 51-63) after vaccination, antileukemic chemotherapy had to be interrupted. Evidence of higher risk for chronic or relapsing rubella-associated arthropathy in immunologically compromised patients and the need to interrupt antileukemic chemotherapy should warrant immunoprophylaxis with polyvalent immune globulin in rubella-susceptible patients who are immunocompromised.

[Etiology--characteristics of HIV infection]. / Atiologie--Besonderheiten der HIV-Infektion.

In this study the structures of the AIDS-virus are presented, furthermore the cross-reactivity of HIV-1 and HIV-2 is described as well as the known genes of both viruses. The mechanism of cell infection, its kinetics and the special role of activated T-cells and macrophages in this process are outlined. This interrelation characterized phenomenologically based on the neopterin data available is now supported by experiments at a molecular level. This should lead to therapeutical and diagnostical consequences.

[Increased spontaneous uterine motility with serotonin]. / Steigerung der spontanen Uterusmotilität durch Serotonin.

The influence of serotonine, a vasoactive neurotransmitter, on the spontaneous motility of uterine strips was investigated. A highly significant (p less than 0.001) increase of uterine activity was observed when serotonine 10(-6) M was added to the perfusing medium.

Complement C7 M/N allotyping in infectious diseases.

The allotypes of the C7 M/N polymorphism are determined by ELISA by comparing the reaction pattern of the allospecific monoclonal antibody WU 4-15 with that of polyclonal anti-C7 IgG. In order to find disease associations of the two alleles C7*M and C7*N we tested 528 hospitalised patients, most of them suffering from infectious diseases. No significant association of either of the two C7 M/N alleles to a particular disease was found, in particular refuting the hypothesis that Lyme borreliosis may be more frequent in homozygous carriers of the hypomorphic allele C7*N.

Effect of antiretroviral combination therapy (zidovudine/didanosine or zidovudine/lamivudine) on quantitative plasma human immunodeficiency virus-ribonucleic acid in children and adolescents infected with human immunodeficiency virus.

OBJECTIVE: To assess human immunodeficiency virus (HIV) ribonucleic acid load in children and adolescents with HIV infection who are being treated with antiretroviral combination therapy. STUDY DESIGN: Five patients whose disease progressed with their prior antiretroviral therapy had treatment regimens changed to zidovudine (ZDV)/didanosine (DDI) (group A), and the regimens of six patients were changed to ZDV/lamivudine (3TC) (group B). Patients were followed every 4 to 8 weeks for an average period of 8.6 months. Serial determinations of viral copy numbers and CD4 cells were performed. RESULTS: In group A patients' mean relative changes in CD4 cells showed a 20% increase after 4 months (difference not significant (NS)) and a return to baseline after 8 months; in group B patients' mean relative increases of CD4 cells were 72% (p = 0.046) and 50% (NS), respectively. In group A mean relative viral load increased 21% (0.08 log10, NS) and 71% (0.23(10) log, NS), whereas in group B viral load decreased 22% (0.1 log10, NS) and 74% (0.58 log10, p = 0.03) after 4 and 8 months, respectively. After starting antiretroviral combination therapy in group A, there was a slight trend of a decreasing ratio of viral load per number of CD4 cells, whereas in group B this ratio significantly decreased, indicating a marked suppression of viral turnover with ZDV/3TC treatment. CONCLUSION: In a small cohort of pediatric patients, combination therapy with ZDV/3TC was well tolerated and had a strong and sustained effect on the decrease of viral loads similar to results obtained in adults. In patients with ZDV/DDI therapy the reduction of viral load was less pronounced, but treatment groups A and B were not comparable for statistic evaluation.

Increased serum levels of soluble tumor necrosis factor receptors (sTNF-Rs) in children and adolescents with vertically and horizontally transmitted HIV infection.

Two different receptors exist for tumor necrosis factor-alpha (TNF-alpha), designated as p55 (TNF-RI) and p75 (TNF-RII). Soluble (= s) forms of TNF-Rs are secreted after proteolytic cleavage and block the effects of TNF-alpha. sTNF-RI, sTNF-RII and the soluble interleukin 2 receptor (sIL-2R) were determined by ELISA in serum samples of HIV-infected children and adolescents. Twelve children with vertical HIV infection (mean age +/- SD, 5.9 +/- 3.8 years) and 17 horizontally infected patients (16.1 +/- 7.3 years) were classified according to the revised CDC criteria. Twenty healthy control persons (6.4 +/- 5.8 years) showed the following receptor concentrations (median): sTNF-RI 888 pg/ml, sTNF-RII 1,741 pg/ml, sIL-2R 94 pM. Compared to controls, horizontally HIV-infected patients had significantly (Mann-Whitney U test) higher levels for sTNF-RI (median 1,192 pg/ml), sTNF-RII (3,481 pg/ml) and sIL-2R (128 pM). For vertically infected children only sTNF-RII (2,944 pg/ml) was significantly elevated compared to controls. There were no differences in soluble receptor levels between vertical or horizontal transmission. Surprisingly, no significant differences for sTNF-RI, sTNF-RII and sIL-2R occurred when 19 patients in stage CDC I were compared to ten patients in stages II or III. The clearly elevated sTNF-RII levels in patients with horizontal and vertical HIV infection indicate the activation of the monocyte/macrophage system in both groups.

The Cayapa Indians of Ecuador: a genetically isolated group with unexpected complement C7 M/N allele frequencies.

The Cayapa Indians live in north-western Ecuador in close proximity to a Black population of African ancestry. C7 M/N allotyping has proved to be a good technique for plasma genetic analysis in several populations. Investigation of 124 Cayapa plasma samples revealed the highest allele frequency of C7*N observed in any population examined so far (0.36 versus 0.225 or lower). The marked difference in frequency compared with several Oriental populations, which are believed to have been derived from the same Asian population as native Amerindians, may reflect the effect of a small founder population followed by a high degree of genetic isolation. The allele frequency of 0.12 for C7*N determined for the neighbouring Black population supports the conclusion that there has been a lack of genetic admixture of Cayapas with other populations, confirming the results of ethnohistorical investigations and other protein polymorphism studies.

Neopterin levels and pulmonary tuberculosis in infants.

Neopterin is produced and released by human macrophages in response to stimulation with interferon-gamma and changes in neopterin concentrations indicate cellular immune activation. Pulmonary infection with Mycobacterium tuberculosis is also associated with increased neopterin levels in body fluids. We report the clinical course, the diagnostic results, and the urinary neopterin levels of seven children (ages 10 months-6(6/12) years) with pulmonary tuberculosis. Two of them had progressive primary tuberculosis, in one case caused by isoniazid resistance. Diagnostic criteria included chest radiographs, intradermal tuberculosis skin testing, and culture of aspirated secretions for tuberculosis. Neopterin levels were determined by high performance liquid chromatography. The five patients with uncomplicated primary disease and a good response to therapy with isoniazid, rifampin, and pyrazinamide showed no or slightly elevated neopterin levels (mean, 458 micromol/mol creatinine). In the two patients with progressive primary tuberculosis we documented excessively high neopterin levels (mean, 2170 micromol/mol creatinine). We conclude that neopterin may be a useful parameter for measuring the degree of disease activity and the response to therapy.

Hepatitis A in Western Austria--the epidemiological situation before the introduction of active immunisation.

Several European countries report a decreasing prevalence of antibodies to hepatitis A virus (anti-HAV). This trend is most pronounced in the youngest age groups. In 1979, however, 58% of young Austrians aged 20 to 30 years were shown to possess anti-HAV. Here we describe the current epidemiological situation in western Austria. Prevalence of anti-HAV has decreased to 7% in those 18 to 30 years old. This percentage rises to 20% (31 to 40 years of age) and 57% (41 to 50 years of age) and is highest in those older than 50 years (87%). Of 180 cases of clinical hepatitis A occurring from 1985 to 1992 45% were imported by travel to HAV-endemic areas. Seventy-one percent of the cases in children (59/83) occurred in foreign workers' families and were also predominantly acquired abroad. A change in prevention policy should be considered in this respect, as vaccination is available now.