Cutaneous granulomas in ataxia telangiectasia and other primary immunodeficiencies: reflection of inappropriate immune regulation?

BACKGROUND: Non-infective cutaneous granulomas with unknown pathogenesis occur in various primary immunodeficiencies (PIDs) including ataxia telangiectasia (A-T). OBJECTIVE: To find a common immunological denominator in these cutaneous granulomas. METHODS: The dermatological and immunological features of 4 patients with A-T and cutaneous granulomas were described. The literature on skin granulomas in A-T and in other PIDs is reviewed. RESULTS: All 4 A-T patients had progressive granulomas on their limbs and showed decreased IgG and IgA concentrations with normal IgM levels. They had a marked decrease in B cells and naïve T cells coinciding with the appearance of the cutaneous granulomas. Similar B- and T-cell abnormalities were described in patients with other PIDs with skin granulomas. CONCLUSIONS: We hypothesize that the pathogenesis of these skin granulomas is related to immune dysregulation of macrophages due to the absence of naïve T cells with an appropriate T-cell receptor repertoire and the unopposed activity of γδ T cells and/or natural killer cells.

Ataxia-telangiectasia patients presenting with hyper-IgM syndrome.

Ataxia-telangiectasia (A-T) is characterised by progressive neurological abnormalities, oculocutaneous telangiectasias and immunodeficiency (decreased serum IgG subclass and/or IgA levels and lymphopenia). However, 10% of A-T patients present with decreased serum IgG and IgA with normal or raised IgM levels. As cerebellar ataxia and oculocutaneous telangiectasias are not present at very young age, these patients are often erroneously diagnosed as hyper IgM syndrome (HIGM). Eight patients with A-T, showing serum Ig levels suggestive of HIGM on first presentation, are described. All had decreased numbers of T lymphocytes, unusual in HIGM. The diagnosis A-T was confirmed by raised alpha-fetoprotein levels in all patients. To prevent mistaking A-T patients for HIGM it is proposed to add DNA repair disorders as a possible cause of HIGM.

Vbeta usage and T regulatory cells in children following partial or total thymectomy after open heart surgery in infancy.

During open heart surgery in infants the thymus was usually removed, partly or completely. Our previous studies on 16 such children indicated reduced T-cell output later in life with signs of extrathymic maturation of the T cells, but no reduction in T regulatory cells (CD4+CD25+). The diversity of the T-cell repertoire in these children was examined to test if the extrathymic microenvironment could alter Vbeta usage. The expression of Foxp3 and CD127 in CD4+CD25(high) T cells was measured in order to determine whether the T regulatory cells had the phenotype of natural T regulatory cells. There was a wide distribution of Vbeta usage in both study and control groups. Significant variability was found in Vbeta usage for CD4+ and CD8+ T cells when the distribution of the percentage of T cells expressing each Vbeta family was analysed between individuals within each group (P < 0.001; Kruskal-Wallis). Significant difference was also found in average usage of Vbeta2, Vbeta5.1 and Vbeta14 chains within CD4+ T cells and Vbeta2, Vbeta8 and Vbeta21.3 chains within CD8+ cells between the groups (P < 0.05; Student's t-test). There was no difference between the two groups with regard to the proportion of CD4+CD25(high) T cells and no difference in the average expression of Foxp3 or CD127 within the CD4+CD25(high) population. Our data provide evidence that cardiothoracic surgery in infants and total or partial thymectomy alters Vbeta usage, suggesting more limited selection in such children than in the control group. The frequency of natural T regulatory cells seems to be unimpaired.

Temporary circulatory support with extra corporeal membrane oxygenation in adults with refractory cardiogenic shock.

OBJECTIVE: Early and long-term survival in patients suffering from cardiogenic shock is poor. Treatment with mechanical assist devices is complicated and expensive but claim to improve survival. We reviewed our experience of venoarterial extracorporeal membrane oxygenation (ECMO) in patients with acute cardiogenic shock. DESIGN: ECMO was used in 52 patients with cardiogenic shock. They were divided into those not operated upon previously (n=19) and those having had cardiac surgery prior to circulatory collapse (n=33). RESULTS: Twenty-six patients were weaned from ECMO. Early mortality for all patients was 48%. Mortality beyond 30 days was 5.8%, with no mortality in the non-cardiotomy group. Long-term survival for patients in the non-cardiotomy group was 63%, as compared to 33% in post-cardiotomy patients (p=0.07). Age over 55 years, female gender or cannulation site did not appear to influence survival. CONCLUSION: Mortality for patients in cardiogenic shock is very high. Treatment with ECMO in patients with refractory cardiogenic shock can be performed with good survival especially in non-surgical patients.

Evidence for extrathymic T cell maturation after thymectomy in infancy.

Our previous study showed that children who had been partially or completely thymectomized during heart surgery as infants had lower proportions and numbers of total lymphocytes and reduced proportions of T cells (CD3(+)), helper T cells (CD4(+)) and naive T cells (CD3(+) CD4(+) CD45RA(+)), but normal proportion of cytotoxic T cells (CD8(+)). In this study T lymphocytes from a selected group of eight of these children and age- and gender-matched controls were characterized further using flow cytometry to determine phenotypes of T cells and T cell subsets related to T cell regulation and phenotypes suggestive of extrathymic maturation. Immune function was assessed by measuring autoantibodies and antibodies against vaccines. The study group had significantly lower numbers of all the main subsets of T lymphocytes and the composition was different. Thus, the proportions of lymphocytes with the following phenotypes: CD3(+), CD2(+), CD7(+), CD4(+), CD62L(+), CD4(+) CD62L(+) and CD4(+) CD69(-) were significantly reduced in the study group compared with the control group, but significantly higher proportions were seen of lymphocytes expressing CD8alpha(+) CD8beta(-) and TCRgammadelta(+) CD8alpha(+) CD8beta(-). The absolute number and proportion of CD4(+) CD25(+) cells were reduced but the proportions of the subgroup of naive regulatory T cells (CD4(+) CD25(+) CD62L(+)) and non-activated regulatory T cells (CD4(+) CD25(+) CD69(-)) were not reduced in the thymectomized children. We conclude that the phenotypic characteristics of T lymphocytes of children who have lost their thymus in infancy are indicative of extrathymic maturation. T regulatory cells appear to be less affected than other subsets by the general reduction in T cell numbers.

Vernix caseosa as a multi-component defence system based on polypeptides, lipids and their interactions.

Vernix caseosa is a white cream-like substance that covers the skin of the foetus and the newborn baby. Recently, we discovered antimicrobial peptides/proteins such as LL-37 in vernix, suggesting host defence functions of vernix. In a proteomic approach, we have continued to characterize proteins in vernix and have identified 20 proteins, plus additional variant forms. The novel proteins identified, considered to be involved in host defence, are cystatin A, UGRP-1, and calgranulin A, B and C. These proteins add protective functions to vernix such as antifungal activity, opsonizing capacity, protease inhibition and parasite inactivation. The composition of the lipids in vernix has also been characterized and among these compounds the free fatty acids were found to exhibit antimicrobial activity. Interestingly, the vernix lipids enhance the antimicrobial activity of LL-37 in vitro, indicating interactions between lipids and antimicrobial peptides in vernix. In conclusion, vernix is a balanced cream of compounds involved in host defence, protecting the foetus and newborn against infection.

Increased frequency of C4B*Q0 alleles in patients with Henoch-Schönlein purpura.

Henoch-Schonlein purpura (HSP) is a vasculitis of unknown aetiology, possibly involving immune complexes. The complement system is essential for the clearance of immune complexes. Our aim was to explore the hypothesis that patients with HSP have abnormal complements, contributing to the development of the disease. The study included 56 patients diagnosed with HSP at the Children's Hospital, Iceland between 1984 and 2000, and 98 blood donors as controls. Serum levels of immunoglobulin A, C4A, C4B and mannan-binding lectin were measured and compared between the two groups. C4 null alleles were significantly more common in HSP patients than in controls (P = 0.018) and were carried by 66.1% of the patients compared with 41.2% of the controls. This difference was due to an increased frequency of C4B*Q0 allele in the HSP group (0.25 versus 0.11 in the control group; P = 0.002). The fact that the majority of our patients carried a C4 null allele indicates that children with C4 deficiencies may have an increased risk of developing HSP. This may reflect inadequate complement activity and possibly present an opportunity to identify patients at risk of developing serious morbidity associated with HSP.

The improved survival of experimental animals fed with fish oil is suppressed by a leukotriene inhibitor.

Fish oil is believed to alter the immune response and improve survival after infections in experimental animals. This effect may be due to altered production of the leukotrienes (LT). We, therefore, performed a study in order to evaluate whether the effect of fish oil on the immune response of experimental animals is mediated through altered production of the LT. Female NMRI mice in four groups were fed with fish oil, fish oil with 5-lipoxygenase (5-LO) inhibitor (Zileuton, Abbott Laboratories, Chicago, IL, USA), corn oil or corn oil with 5-LO inhibitor. After 6 weeks, the mice were infected with Klebsiella pneumoniae and the survival was monitored. The experiment was performed twice. Analysis was performed mainly on data pooled from both experiments. The survival of the groups fed with fish oil was increased, compared to that of all the other groups and when compared to the groups fed with fish oil with 5-LO inhibitor (log-rank test) the difference was significant (P = 0.007). It has been postulated that the effect of fish oil on the immune system is mediated through altered production of LT. In our study, blocking of the production of the LT eliminated the beneficial effects of fish oil. Our results are in concord with the hypothesis that the effect of fish oil is, at least partly, mediated through altered production of LT.

The influence of partial or total thymectomy during open heart surgery in infants on the immune function later in life.

Infants undergoing open heart surgery often have all or part of their thymus removed. The activity of the immune system has not been investigated thoroughly in these children, and only shortly after the operation. Therefore, it was decided to investigate the activity of the immune system in more detail in children several years after their operation. Peripheral blood samples from 19 children who had undergone open heart surgery during their first months of life was collected (study group) and from 19 age- and gender-matched children (control group). The activity of the immune system was evaluated by measuring the number of different cell types in peripheral blood, the phenotype of lymphocytes and the response of T cells following in vitro stimulation by mitogen, tetanus toxoid and measles antigen. The study group had significantly lower counts of total lymphocytes, which was reflected in a lower number of T cells but not B cells. Furthermore, the study group had significantly lower proportion of T cells (CD3(+)) and helper T cells (CD4(+)), but not cytotoxic T cells (CD8(+)). The level of neutrophils in peripheral blood was significantly higher in the study group. This may indicate enhanced innate immunity when the acquired immunity is defective. The results indicate a shift to extrathymic T cell maturation, which is less efficient for CD4(+) helper cells than for CD8(+) cytotoxic cells.

Development of immunoglobulin A in infancy and childhood.

Serum and salivary concentrations of immunoglobulin A1 (IgA1) and IgA2 were studied in 105 Icelandic children aged 0-12 years. Serum concentrations of both IgA1 and IgA2 increased slightly (P < 0.001) during childhood. The salivary IgA1/IgA2 ratio tended to decrease during the same period; this trend is less apparent when omitting the youngest children. The salivary IgA1 and IgA2 output could be high, even in children with low levels of serum IgA. Only polymeric IgA was found in whole saliva. Interestingly, in serum, most IgA1 and IgA2 were polymeric during infancy. The proportion of polymeric IgA decreased, when the concentration of IgA increased. The polymeric form of IgA might provide the infant with better protection against invading microorganisms by activation of the innate immune mechanisms.

Findings in familial haemophagocytic lymphohistiocytosis prior to symptomatic presentation.

UNLABELLED: Familial haemophagocytic lymphohistiocytosis (FHL) is a rare, autosomal recessive disease of infancy and early childhood clinically characterized by fever, hepatosplenomegaly, lymphadenopathy, rash, neurological symptoms and icterus. Common laboratory findings include cytopenia, elevated liver enzymes, hyperbiliriubinaemia, hypofibrinogenaemia and hypertriglyceridaemia. The natural killer cell function is frequently decreased or absent. A diffuse lymphohistiocytic infiltration is seen in the reticuloendothelial system, often with haemophagocytosis. Molecular diagnosis is available in a minority of FHL families. Without adequate treatment and bone-marrow transplantation, the disease is fatal. A 6-wk-old child with FHL is presented. Shortly before the clinical onset of the disease, blood testing and bone-marrow examination had been carried out. All results were considered normal at that time. CONCLUSION: Blood tests and bone-marrow examination may be normal shortly before the clinical presentation and therefore do not exclude the diagnosis of FHL. There is a need for extended molecular diagnostic possibilities.

Increased expression of interleukin-13 but not interleukin-4 in CD4+ cells from patients with the hyper-IgE syndrome.

Hyper IgE syndrome (HIES) is a rare immunodeficiency disorder characterized mainly by high levels of polyclonal IgE in serum and recurrent staphylococcal abscesses of the skin and lungs. The raised IgE levels have led researchers to study the synthesis of cytokines that regulate switching of immunoglobulin production towards IgE such as interleukin-4 (IL-4), IL-12 and interferon-gamma (IFN)-gamma. However, the role of IL-13 in the disease pathogenesis has not been investigated extensively. In this study, we investigated intracellular expression of IL-4 and IL-13 in mononuclear cells and CD4+ cells isolated from patients with HIES and healthy controls. Cells were stained intracellularly with antibodies directed against IL-4 and IL-13 and analysed by flow cytometry before and after activation with PMA and calcium ionophore. The mean proportion of resting or activated IL-4 and IL-13 expressing mononuclear cells were comparable in the two groups as well as the proportion of IL-4 expressing CD4+ cells. In contrast, the mean proportion of IL-13 expressing CD4+ cells was increased significantly in patients with HIES in both the resting and the activated state compared to healthy controls. We conclude that increased expression of IL-13 in CD4+ cells from patients with HIES could account, at least partly, for raised IgE levels in those individuals.

Immunoglobulin class and subclass concentrations after treatment of childhood leukemia.

With greatly increased survival rates after childhood leukemia during the last 3 decades, the long-term effects of the treatment have become more evident. The disease and its treatment impair the immune system, but the duration of this impairment is unknown. The authors studied the serum concentrations of immunoglobulins and IgG subclasses in 20 Icelandic children cured of leukemia on average 8 years and 3 months after their treatment ended. Although no marked deviations were found in the concentrations of the main immunoglobulin classes IgA, IgM, IgG, and IgE, the IgG subclass levels were below reference values. The patients had on average 0.9 of age standardized reference values of IgG1, 0.5 of IgG2, 0.8 of IgG3, and 0.7 of IgG4. However, none had any autoimmune diseases or a markedly increased tendency for infections. The results indicate that although the immunoglobulin classes regain their normal values within a few years after cessation of treatment, recovery of the IgG subclasses, especially IgG2, is impaired.

[The effect of dietary fish oil on bacterial growth in vivo.].

OBJECTIVE: Epidemiological studies have indicated that high intake of w-3 fatty acids influence various diseases such as cardiovascular diseases and autoimmune disorders. These fatty acids are essential in the diet since the body can not form them de novo. Fish oil is rich in w-3 fatty acids but the w-3 content of vegetable oil is low. The research group has shown increased survival of mice fed cod liver oil enriched diet versus mice fed corn oil enriched diet when infected with Klebsiella pneumoniae intramuscularly. In the present study we investigated the effect of dietary fish oil on bacterial growth in vivo. MATERIAL AND METHODS: Mice were fed fish oil enriched diet and a control group was fed corn oil enriched diet for six weeks and then the mice were infected with Klebsiella pneumoniae intramuscularly. The mice were sacrificed at various time intervals and bacteria were counted in blood and in the infected muscle. RESULTS: The bacteria count in blood and tissue was not significantly different between the two groups although a trend was noted towards more growth in the control group. CONCLUSIONS: We conclude that fish oil does not significantly affect bacterial growth in vivo. Hopefully, future research will reveal the pathophysiological effect of fish oil.

Inhaled prostacyclin and platelet function after cardiac surgery and cardiopulmonary bypass.

OBJECTIVE: To study the effects of 6 h inhalation of aerosolized prostacyclin (PGI2) on platelet function. DESIGN: In a prospective, double-blind, randomized study, 28 patients scheduled for elective cardiac surgery requiring cardiopulmonary bypass (CPB), received either 0.9% sodium chloride (n = 8), PGI2 5 microg x ml(-1) (n = 10) or PGI2 10 microg x ml(-1) (n = 10) as an aerosol for 6 h postoperatively. SETTING: Cardiothoracic intensive care unit at a university hospital. INTERVENTIONS: All patients were studied immediately after surgery during mechanical ventilation and sedation. The PGI2 solutions or saline were administered with a jet nebulizer. MEASUREMENTS AND RESULTS: Bleeding time and chest tube drainage were measured. Blood samples for platelet aggregation, thrombelastography (TEG) and analysis of coagulation parameters and the stable prostacyclin metabolite 6-keto-PGF1alpha were obtained immediately before inhalation and after 2, 4 and 6 h of inhalation. After 6 h of PGI2 inhalation, regardless of administered dose, there was a lower rate of platelet aggregation and a lower maximal increase in light transmission in response to adenosine diphosphate (ADP) than in the control group. The TEG variable reaction time (R) was prolonged after 4 and 6 h of inhalation in the PGI2 group receiving 10 microg x ml(-1). There were no differences between groups with respect to bleeding time and chest tube drainage or any of the other variables examined. CONCLUSION: Inhalation of PGI2 for 6 h in patients after cardiac surgery is associated with impaired platelet aggregation detected by in vitro techniques, with no in vivo signs of platelet dysfunction.

Serum immunoglobulinD in infants and children.

Serum immunoglobulinD (IgD) concentration is usually low in healthy individuals as compared to other immunoglobulin classes. Most studies on serum IgD are concerned with serum levels in healthy adults but reference values for young children and infants are not easily available. In order to establish age specific reference values we measured IgD levels in serum of 184 healthy Icelandic children, age 0-14 years and 60 healthy blood donors age 18-63, using the ELISA technique. Special attention was paid to the youngest age groups. Results showed low IgD values in infants and young children, gradually increasing until the age of 10 but then decreasing with age. We conclude that IgD gradually increases with age in childhood as other immunoglobulin classes but later declines. These findings can be of importance in revealing the function of IgD in the immune system as well as in the diagnosis of the hyper-IgD syndrome.

[Allergy and asthma in Icelandic children - an epidemiological study.].

OBJECTIVE: The prevalence of allergy and asthma is increasing in Western industrialized countries. The etiology of allergy is multifactorial and only partly understood. In an effort to gather information about asthma and allergy in the pediatric population in Iceland, we have evaluated on a regular basis a cohort of randomly selected children born in 1987. MATERIAL AND METHODS: The first part of the study included 179 children at the age of 18-23 months (mean age 20 months). Of these, 161 children were re-evaluated at four years of age and 134 at eight years. The evaluation included a standardized questionnaire, clinical examination and skin-prick tests. Asthma, eczema, allergic rhinoconjunctivitis and food allergy were diagnosed according to established criteria. RESULTS: At 20 months of age 42% of the children were diagnosed with asthma or allergic disorders, 45% at four years and 34% at the age of eight years. Initially asthma and eczema were most common, but the prevalence and severity of eczema had decreased at four years of age and the prevalence of asthma decreased between four and eight years. No child was diagnosed with allergic rhinoconjunctivitis before two years of age but 7% of four year olds and 10% at the age of eight years. A quarter of the children had at some stage symptoms compatible with more than one allergic disorder. Two-thirds of the children who were diagnosed with eczema and/or asthma before two years of age, were symptom free at eight years. Thirty-eight percent of eight year old children with allergic symptoms had positive skin-prick tests to the allergens used, most commonly to cats. Seventy three percent of eight year old children with allergy and/or asthma, had a first degree relative with a history of allergies. CONCLUSIONS: As in other Western industrialized societies asthma and allergic disorders are common health problems amongst children in Iceland. However, the majority of children with allergic manifestations during the first two years of life, became symptom free before the age of eight years. Conversely, 50% of eight year olds with asthma or allergies were symptom free during the first two years of their life. This suggests that the mechanisms causing allergic symptoms may not be uniform in different age groups.

Immunoglobulin-secreting cells in cord blood: effects of Epstein-Barr virus and interleukin-4.

The contribution of cord blood B lymphocytes to the immune response has been under considerable investigation. Cord blood B cells produce almost no antibodies except of the immunoglobulin (Ig)M isotype, indicating immaturity of the cells or the environment they reside in. The aim of this study was to investigate the number of circulating IgA-, IgM-, IgG-, and IgE-producing cells in cord blood in comparison to adult peripheral blood using the ELISPOT method. Moreover, we studied the effect of transformation with the Epstein-Barr virus (EBV) on the proportion of cells producing different isotypes with or without interleukin (IL)-4. Cord blood had IgM-producing cells circulating predominantly, but also some IgA- and IgG-producing cells, whereas adult peripheral blood contained high amounts of circulating IgA-producing cells and some IgM- and IgG-producing cells. No circulating IgE-producing cells were found in either group. Transformation by EBV caused significant expansion of IgA-, IgM-, and IgG-producing cells in adult peripheral blood, but almost only of IgM-producing cells in cord blood. A low but detectable expansion of IgA- and IgG-producing cells was found. Cells producing IgE were still not found, even after EBV transformation. However, EBV transformation in the presence of IL-4 increased the numbers of IgE-producing cells significantly both in cord blood and adult peripheral blood. These findings indicate that cord blood contains some circulating IgA- and IgG-producing cells that are expanded to some extent after EBV infection. They also indicate that cord blood B cells have a similar capacity for IgE production to adult peripheral blood B cells when appropriately stimulated.

Paediatric burns in Iceland. Hospital admissions 1982-1995, a populations based study.

Epidemiological data of 290 children admitted to the Paediatric Department, University Hospital of Iceland, over a 14 year period, 1982-1995, are presented. The sex ratio boys/girls was 1.6. 72.8% were children four years and younger. Hot fluids was the most common cause of burn injuries, mostly caused by geothermal hot water. Only one child suffered from electricity burn injuries and none from corrosives. Most of the accidents occurred at home (81.4%). A decreasing number of children suffering from electricity and corrosive burn injuries reflects heightened awareness and improved safety in the home. We found a significant increase in the incidence of hot fluid burn injuries in Icelandic children compared to previous studies. This calls for preventive measures with regard to geothermal and other hot water burns in Icelandic children.