Karlis Pauksen

Respiratory virus infections after stem cell transplantation: a prospective study from the Infectious Diseases Working Party of the European Group for Blood and Marrow Transplantation

Community-acquired respiratory virus infections are a cause of mortality after stem cell transplantation (SCT). A prospective study was performed at 37 centers to determine their frequency and importance. Additional cases were also collected to allow the analysis of risk factors for severe infection. Forty episodes were collected in the prospective study and 53 additional episodes through subsequent case collection. The frequency of documented respiratory virus infections was 3.5% among 819 allogeneic and 0.4% among 1154 autologous SCT patients transplanted during the study period. The frequency of lower respiratory tract infections (LRTI) was 2.1% among allogeneic and 0.2% among autologous SCT patients. The mortality within 28 days from diagnosis of a respiratory viral infection was 1.1% among allogeneic SCT while no autologous SCT patient died. The deaths of five patients (0.6%) were directly attributed to a respiratory virus infection (three RSV; two influenza A). On multivariate analysis, lymphocytopenia increased the risk for LRTI (P = 0.008). Lymphocytopenia was also a significant risk factor for LRTI in patients with RSV infections. The overall mortality in RSV infection was 30.4% and the direct RSV-associated mortality was 17.4%. For influenza A virus infection, the corresponding percentages were 23.0% and 15.3%. This prospective study supports the fact that community-acquired respiratory virus infections cause transplant-related mortality after SCT. Bone Marrow Transplantation (2001) 28, 479–484.

Serum measurements of human neutrophil lipocalin (HNL) discriminate between acute bacterial and viral infections

Human neutrophil lipocalin (HNL) is a recently identified protein from human neutrophil granules. The concentrations of HNL in the circulation were measured, in a group of patients with acute infections, using a radioimmunoassay. The concentrations of HNL in patients infected by viruses and bacteria were 93.78 +/- 45.30 micrograms l-1 (SD), 404.14 +/- 355.02 micrograms l-1 (SD) in serum, and 47.81 +/- 18.18 micrograms l-1 (SD), 145.46 +/- 194.32 micrograms l-1 (SD) in plasma, respectively. The differences between the two patient groups were highly significant. There was a significant correlation between serum HNL and plasma HNL levels in bacterial infections (r = 0.73, p < 0.0001). The HNL serum levels also correlated with those of C-reactive protein (CRP) (r = 0.59, p < 0.0001). Determination of HNL in serum was more specific and sensitive than CRP in the distinction between viral and bacterial infections. At a cut-off of 155 micrograms l-1 (HNL in serum), the positive and negative predictive values for the diagnosis of bacterial infections were 92 and 96%, respectively, which were superior to the optimal predictive values of CRP. Thus, the determination of HNL level is useful in the diagnosis of acute bacterial infections.

Pneumococcal immunity and response to immunization with pneumococcal vaccine in bone marrow transplant patients: the influence of graft versus host reaction

The aim of this study was to evaluate levels and subclass distribution of pneumococcal antibodies in 40 bone marrow transplant (BMT) and 42 autologous bone marrow transplant (ABMT) recipients during the first year after transplant, and response to vaccination with a polyvalent pneumococcal vaccine. Before transplantation, 35/40 recipients of allogeneic grafts, all 42 autologous BMT recipients and 38/39 donors had adult levels of anti-pneumococcal antibodies of the IgG2 subclass. During the first year after transplantation, antibody levels decreased in 29 BMT patients while 11 retained their pretransplant antibody levels. No change was noted among ABMT patients. In the 8 BMT patients who had chronic graft versus host disease (GVHD), none showed normal levels of anti-pneumococcal antibodies 1 year after BMT as compared to 11/32 without chronic GVHD. Three different response patterns were seen after vaccination of 29 BMT patients who lost immunity with a polyvalent pneumococcal vaccine. Ten patients responded with an increase in IgG2 antibodies, 8 responded with an increase in IgG1 and 11 patients did not respond at all. In the 8 patients with chronic GVHD, none responded with an increase in IgG2 antibodies and 6/8 did not respond at all. The results of this study suggest that chronic GVHD is the main factor contributing to loss of immunity to pneumococci and lack of responsiveness to vaccination with pneumococcal polysaccharides after BMT. Furthermore, the difference in capability, between BMT and ABMT recipients, of retaining anti-pneumococcal activity may explain the clinical experience of severe pneumococcal infections in these patients.

Serum levels of granulocyte-colony stimulating factor (G-CSF) in bacterial and viral infections, and in atypical pneumonia

Summary. Serum granulocyte‐colony stimulating factor (G‐CSF) was measured with an ELISA method in patients with acute bacterial and viral infections, or with and atypical pneumonia. Before initiation of antibiotic treatment, G‐CSF was found to be significantly increased (799 ± 1501 ng/1) in sera from 34 patients with and acute bacterial infection compared with the 27 patients with the 27 patients with viral infection (58 ± 34 ng/1; P < 0.001) and with the eight patients with an atypical pneumonia (60 ± 33) ng/1; P < 0.001). No significant difference in G‐CSF levels was seen between gram‐positive and gram‐negative bacterial infections. In septic shock, increased G‐CSF levels were seen both in patients with leucocytosis and leucopenia. In uncomplicated bacterial infections, both G‐CSF and IL‐6 were increased on day 0, and decreased rapidly after initiation of antibacterial therapy and before the patients became afebrile. In bacterial infections on day 0, G‐CSF levels correlated with mononuclear cells (rs=−0.62, p < 0.001), IL‐6 (rs= 0.40, P < 0.05 and S‐MPO (rs=−0.5, P < 0.01). In viral infections, G‐CSF was correlated with mononuclear cells (rs= 0.041, P < 0.05), White blood cell counts (rs= 0.56, P < 0.01), neutorphils (rs= 0.41, P < 0.05) and CRP (rs= 0.47, P < 0.05). We conclude that G‐CSF is rapidly rised in the blood in acute baterica infections but not in acute viral infections or in infections with Mycoplasma pneumonia. Our results also support the theory that G‐CSF is involved in the mechanisms of mobilization of neutrophils into the peripheral circulation.

Skin infection caused by Mycobacterium szulgai after allogeneic bone marrow transplantation

Summary:Infections are responsible for a large part of the morbidity and mortality after BMT because of the sustained impairment of host defenses. We report a case of cutaneous infection caused by Mycobacterium szulgai in a boy who underwent BMT with marrow from a matched unrelated donor.

Cell surface expression of FcγRI (CD64) on neutrophils and monocytes in patients with influenza A, with and without complications

The expression of the Fcγ-receptor I (FcγRI), CD64 on normal neutrophils is up-regulated during bacterial infections. CD64 is a promising diagnostic tool in the diagnosis of acute infections. The aim was to study surface expressions of CD64 on neutrophils and monocytes in patients with influenza A with and without complications and evaluate these as diagnostic tools in comparison with serum levels of HNL (human neutrophil lipocalin). CD64 expression on neutrophils and monocytes was evaluated by flow cytometry. HNL was assayed by a specific radioimmunoassay. 22 patients with influenza A with or without complications were included and the results compared with those of 29 patients with acute bacterial infections and 29 healthy subjects. Neutrophil expression of CD64 was increased in influenza A with raised proportion expressing CD64 in complicated compared to uncomplicated influenza. The expression was significantly higher in bacterial infections compared to both influenza groups. Serum levels of HNL were raised in all infection groups, but significantly more so in the group with bacterial infection. ROC-curve analysis showed that neutrophil expression of CD64 and the serum levels of HNL had similar diagnostic power in the discrimination between acute bacterial infections and influenza A. Monocyte expression of CD64 was raised in all infections with no differences between subgroups. We conclude that neutrophil expression of CD64 and serum levels of HNL are both promising assays in the distinction between infections caused by bacteria or influenza A, whereas CD64 could identify patients with complications of their influenza A infection.

Th1 and Th2 cytokine responses after measles antigen stimulation in vitro in bone marrow transplant patients : response to measles vaccination

In seronegative autologous bone marrow transplanted (ABMT) patients, a sustained cell-mediated immunity (CMI) has been shown to impair the antibody response after measles vaccination. To investigate if this might be caused by a preferential Th1 cytokine response, interferon (IFN)-γ and interleukin (IL)-10 production of peripheral blood mononuclear cells (PBMC) was analyzed after measles antigen (M-ag) stimulation in vitro. The non-specific immune response was measured by IFN-α, and IL-12 analyses. Fifty non-vaccinated patients following ABMT or allogeneic bone marrow transplantation (BMT) were included. IFN-γ production was significantly higher in patients with a retained CMI to measles than in patients without (2.3 vs 0.8 IU/ml; P = 0.01). Only a non-significant tendency was seen in IL-10 production (48.6 vs 26.7 pg/ml; NS), whereas no difference was found in IFN-α or IL-12 production. A positive correlation between IFN-γand IL-10 production was found (rs = 0.49; P < 0.001). after vaccination of 14 abmt children, there was an increase in pbmc ifn-γ production in vitro (2.5 vs <0.1 iu/ml; P < 0.05), whereas no changes were seen in the il-10, ifn-α , or antibody levels. These results suggest that both Th1 and Th2 cytokine production are increased by M-ag stimulation in patients with a retained CMI to measles, but the Th1 response seems to be stronger. The preferential Th1 stimulation and increase in IFN-γ production after vaccination may lead to a reduction in the humoral immune response which may explain the negative correlation between antibody production and T cell reactivity prior to vaccination.

Low utilisation of unactivated protein C in a patient with meningococcal septic shock and disseminated intravascular coagulation

Background:  Activated protein C has recently been shown in a multicentre trial to significantly reduce mortality in patients with septic shock. There are also some case reports and minor studies demonstrating promising results with the unactivated form of protein C. However, in children with severe meningococcal infection, skin biopsies have demonstrated low expression of endothelial thrombomodulin and protein C receptors, suggesting low protein C activation capacity in severe meningococcal sepsis.

Human Neutrophil Lipocalin as a Superior Diagnostic Means To Distinguish between Acute Bacterial and Viral Infections

ABSTRACT The distinction between causes of acute infections is a major clinical challenge. Current biomarkers, however, are not sufficiently accurate. Human neutrophil lipocalin (HNL) concentrations in serum or whole blood activated by formyl-methionine-leucine-phenylalanine (fMLP) were shown to distinguish acute infections of bacterial or viral cause with high accuracy. The aim was therefore to compare the clinical performance of HNL with currently used biomarkers. Seven hundred twenty-five subjects (144 healthy controls and 581 patients with signs and symptoms of acute infections) were included in the study. C-reactive protein (CRP), the expression of CD64 on neutrophils, procalcitonin (PCT), and blood neutrophil counts were measured by established techniques, and HNL concentrations were measured in whole-blood samples after activation with fMLP. All tested biomarkers were elevated in bacterial as opposed to viral infections (P < 0.001). CRP, PCT, and CD64 expression in neutrophils was elevated in viral infections compared to healthy controls (P < 0.001). In the distinction between healthy controls and patients with bacterial infections, the areas under the receiver operating characteristic (ROC) curves were >0.85 for all biomarkers, whereas for the distinction between bacterial and viral infections, only HNL concentration in fMLP-activated whole blood showed an area under the ROC curve (AUROC) of >0.90 and superior clinical performance. The clinical performance of HNL in fMLP-activated whole blood was superior to current biomarkers and similar to previous results of HNL in serum. The procedure can be adopted for point-of-care testing with response times of <15 min.

Dynamics of the Immune Response against Extracellular Products of Group A Streptococci during Infection

ABSTRACT The immune response against the infecting group A streptococcus (GAS) extracellular products (EP) was determined in acute- and convalescent-phase sera from 75 patients with different clinical manifestations of GAS infection. All EP elicited a high proliferative response in human peripheral blood mononuclear cells. In patients with bacteremia, low neutralization in acute-phase sera was associated with development of streptococcal toxic shock syndrome. Lack of neutralization in acute-phase sera was more common in patients infected with the T1emm1 serotype. The majority of patients did not develop the ability to neutralize the mitogenic activity of their infecting isolate despite a significant increase in enzyme-linked immunosorbent assay titer in early convalescent-phase sera. In patients with the ability to neutralize GAS EP, the immune response remained high over at least 3 years. In contrast, the neutralization capacity conferred by intravenous immunoglobulin and/or plasma treatment disappeared within 3 months.