Astrid Kok

Survival in Early Breast Cancer Patients Is Favorably Influenced by a Natural Humoral Immune Response to Polymorphic Epithelial Mucin

PURPOSE Polymorphic epithelial mucin (PEM or MUC1) is being studied as a vaccine substrate for the immunotherapy of patients with adenocarcinoma. The present study analyzes the incidence of naturally occurring MUC1 antibodies in early breast cancer patients and relates the presence of these antibodies in pretreatment serum to outcome of disease. MATERIALS AND METHODS We measured immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies to MUC1 with an enzyme-linked immunoassay (PEM.CIg), which uses a MUC1 triple-tandem repeat peptide conjugated to bovine serum albumin, in pretreatment serum samples obtained from 154 breast cancer patients (52 with stage I disease and 102 with stage II) and 302 controls. The median disease-specific survival time of breast cancer patients was 74 months (range, 15 to 118 months). A positive test result was defined as MUC1 IgG or IgM antibody levels equal to or greater than the corresponding rounded-up median results obtained in the total breast cancer population. RESULTS A positive test result for both MUC1 IgG and IgM antibodies in pretreatment serum was associated with a significant benefit in disease-specific survival in stage I and II (P =.0116) breast cancer patients. Positive IgG and IgM MUC1 antibody levels had significant additional prognostic value to stage (P =.0437) in multivariate analysis. Disease-free survival probability did not differ significantly. However, stage II patients who tested positive for MUC1 IgG and IgM antibody and who relapsed had predominantly local recurrences or contralateral disease, as opposed to recurrences at distant sites in the patients with a negative humoral response (P =.026). CONCLUSION Early breast cancer patients with a natural humoral response to MUC1 have a higher probability of freedom from distant failure and a better disease-specific survival. MUC1 antibodies may control hematogenic tumor dissemination and outgrowth by aiding the destruction of circulating or seeded MUC1-expressing tumor cells. Vaccination of breast cancer patients with MUC1-derived (glyco)peptides in an adjuvant setting may favorably influence the outcome of disease.

Amyloid-β(1–42), Total Tau, and Phosphorylated Tau as Cerebrospinal Fluid Biomarkers for the Diagnosis of Alzheimer Disease

BACKGROUND To improve ante mortem diagnostic accuracy of Alzheimer disease (AD), measurement of the biomarkers amyloid-beta(1-42) (Abeta42), total tau (Tau), and tau phosphorylated at threonine(181) (pTau) in cerebrospinal fluid (CSF) has been proposed. We have used these markers and evaluated their performance. METHODS From January 2001 to January 2007, we assessed Abeta42, Tau, and pTau by commercial ELISAs in CSF from 248 consecutive AD patients and 131 patients with subjective memory complaints attending our outpatient memory clinic. Diagnoses were made blind to the results of the biomarker assays. We assessed sensitivity and specificity and analyzed trends over time. RESULTS Interassay CVs from analysis of pools of surplus CSF specimens were mean 11.3% (SD 4.9%) for Abeta42; 9.3% (1.5%) for Tau, and 9.4% (2.5%) for pTau, respectively (n = 7-18). To achieve 85% sensitivity, cutoff values were 550 (95% CI 531-570) ng/L for Abeta42; 375 (325-405) ng/L for Tau, and 52 (48-56) ng/L for pTau. Corresponding specificities were 83% (95% CI 76%-89%) for Abeta42, 78% (70%-85%) for Tau, and 68% (60%-77%) for pTau. Logistic regression to investigate the simultaneous impact of the 3 CSF biomarkers on the diagnosis yielded a sensitivity of 93.5% and specificity of 82.7%, at a discrimination line of Abeta42 = 373 + 0.82 x Tau. The area under the ROC curves of Tau and pTau showed significant fluctuation over time. CONCLUSIONS CSF biomarkers Abeta42 and Tau can be used as a diagnostic aid in AD. pTau did not have additional value over these 2 markers. Cutoff values, sensitivities, specificities, and discrimination lines depend on the patient groups studied and laboratory experience.

CSF biomarker levels in early and late onset Alzheimer's disease

OBJECTIVE To compare CSF levels of beta-amyloid 1-42 (Abeta(1-42)), total tau (tau) and tau phosphorylated at threonine 181 (ptau-181) between AD patients and controls according to age. METHODS 248 AD patients (48% men) and 127 controls (51% men, 22 volunteers and 105 subjective complainers) underwent lumbar puncture. Both patients and controls were divided into a young (<65 years) and old (>or=65 years) group. RESULTS All three biomarkers showed main effects of diagnosis (p<0.001). There was an interaction between diagnosis and age for all three biomarkers (p<0.05), as old controls had lower Abeta(1-42) and higher (p)tau than young controls (Abeta(1-42) 699+/-250 versus 866+/-191pg/ml, tau 408+/-245 versus 243+/-102pg/ml, ptau-181 60+/-28 versus 42+/-15pg/ml), but there was no difference according to age among AD patients (Abeta(1-42) 451+/-178 versus 425+/-146pg/ml, tau 741+/-460 versus 798+/-467pg/ml, ptau-181 91+/-42 versus 91+/-41pg/ml). CONCLUSION We found that the older control group had lower Abeta(1-42) and higher (p)tau compared to the younger control group. This suggests that older individuals may have AD pathology, even in the absence of objective cognitive impairment.

Helicobacter pylori serology in patients with gastric carcinoma

Helicobacter pylori-associated gastritis has been put forward as a distinct risk factor for gastric cancer. Furthermore, among H. pylori-positive individuals a correlation between a high serum level of H. pylori antibodies and the risk of gastric cancer has been found in two different studies. Other studies have challenged this hypothesis. We therefore studied the presence and level of H. pylori serum antibodies, using an enzyme-linked immunosorbent assay technique in 116 gastric cancer patients (65 men; mean age, 67 years; range, 23-92 years) and 116 controls matched for age and sex. Patients and controls were selected on referral for gastroscopy. The prevalence of infection in gastric cancer patients was 77% (89 of 116) and in controls 79% (92 of 116). This difference is not statistically significant, nor is the prevalence of infection in cases and controls of different age cohorts significantly different. High levels of serum antibodies were found in 46% (53 of 116) of gastric cancer patients and 40% (46 of 116) of controls. Comparison of the prevalence of high serum levels of antibodies for the total population and for the different age cohorts did not show significant differences either. We conclude that the comparison of actual H. pylori infection in a cross-sectional study of gastric cancer patients and controls does not enable relative risk calculation in the study of the role of H. pylori infection in gastric carcinogenesis. Prospective studies showing diminishment of the risk for gastric cancer after eradication of H. pylori are required.

Cognitive Impairment in Alzheimer’s Disease Is Modified by APOE Genotype

Aim: We examined whether impairment in specific cognitive domains in Alzheimer’s disease (AD) differed according to APOE genotype and age at onset. Methods: Cognitive functions of 229 consecutive AD patients were assessed using Visual Association Test (VAT), Memory Impairment Screen+ (MIS+), VAT object naming, fluency test and Trail Making Test (TMT). Dementia severity was assessed using MMSE. ANOVAs were performed with APOE genotype and age at onset as independent variables and sex, education and MMSE as covariates. Results: 28% of patients were APOE Ε4-negative, 58% heterozygous and 14% homozygous. A significant association between APOE genotype and VAT and MIS+ was found when correcting for sex and education. An interaction effect between APOE genotype and age at onset on VAT and VAT object naming was found, with young carriers performing worse than young noncarriers. By contrast, when additionally correcting for MMSE, a significant association between APOE genotype and VAT object naming, TMT-A and TMT-B was found, with noncarriers performing worse than carriers. Conclusion: Memory was more impaired among APOE Ε4 carriers than among noncarriers. By contrast, naming, executive functions and mental speed were more impaired among APOE Ε4 noncarriers. This suggests that the APOE genotype modifies the clinical phenotype in terms of cognitive impairment in AD.

Comparison of two consecutive fat-rich and carbohydrate-rich meals on postprandial myeloperoxidase response in women with and without type 2 diabetes mellitus

Patients with type 2 diabetes mellitus (DM2) have an increased risk of cardiovascular disease (CVD). Myeloperoxidase (MPO), expressed in leukocytes and released upon activation, is associated with CVD and endothelial dysfunction. Postprandial leukocyte recruitment and activation with subsequent MPO release may contribute to atherosclerosis and CVD. We hypothesized that MPO may increase in the postprandial state because of postprandial leukocyte recruitment and/or activation, especially in subjects with DM2. One hundred postmenopausal women, aged 50 to 65 years (66 with normal glucose metabolism [NGM] and 34 with DM2), received 2 consecutive fat-rich meals and 2 consecutive carbohydrate-rich meals on separate occasions. Blood samples were taken before (t = 0) and at 2, 4, and 8 hours after breakfast; lunch was given at t = 4. Plasma MPO concentration was measured by sandwich enzyme-linked immunosorbent assay. The number of leukocytes in fasting blood samples was higher in DM2 compared with NGM (6.1 +/- 1.4 and 5.4 +/- 1.2 x 10(9)/L, respectively; P < .05). Baseline MPO concentration did not significantly differ between NGM and DM2 (51.4 +/- 12.9 and 54.5 +/- 18.4 mug/L, respectively; P = .39). Baseline MPO was positively associated with leukocytes (r = 0.20, P < .05) and inversely associated with high-density lipoprotein cholesterol (r = -0.22, P < .05). Leukocytes increased from 5.0 +/- 1.5 to 6.1 +/- 1.5 x 10(9)/L and from 5.8 +/- 1.4 to 6.6 +/- 1.4 x 10(9)/L in NGM and DM2, respectively (both P < .01), after the fat-rich meals. In contrast to our hypothesized increase in MPO, we found a significant decrease in MPO in NGM (both meal types) and DM2 (fat-rich meals only). Our findings provide no support to our initial hypothesis that meal-induced release of MPO might be a mechanism that contributes to CVD risk.

The Effect of Acute and Chronic Protein Loading on Urinary Pepsinogen A Excretion

In 8 healthy male volunteers, urinary excretion (UE) and fractional clearance (FC) of pepsinogen A (PGA), beta 2-microglobulin (beta 2-m) and albumin were measured after 6 days high protein diet (HPD; 2.0 g/kg/day) and compared to values obtained after 6 days low protein diet (LPD; 0.5 g/kg/day). In addition, the effect of an acute protein load (APL; 500 g beef) on these variables were measured. Both chronic and acute protein loading induced a rise in glomerular filtration rate (GFR) of about 10% together with a parallel rise in effective renal plasma flow. UE PGA and FC PGA increased both after HPD (UE PGA 1,707 +/- 1,106 ng/min; FC PGA 23 +/- 12%) as compared to LPD (UE PGA 1,200 +/- 987 ng/min, p less than 0.01; FC PGA 18 +/- 12%, p less than 0.05), and after APL (UE PGA 2,276 +/- 1,389 ng/min; FC PGA 26 +/- 16%) as compared to baseline (UE PGA 1,418 +/- 965 ng/min, p less than 0.02; FC PGA 21 +/- 12%, p less than 0.05). UE and FC of beta 2-m and albumin were not affected by protein loading. As PGA is nearly freely filtered, it is concluded that the increase in fractional PGA clearance reflects a decrease in fractional tubular PGA reabsorption. Our results suggest that an increase in fractional protein clearance after protein loading is not necessarily due to an impaired glomerular permselectivity but represents a decreased fractional tubular reabsorption as a result of a GFR-mediated increase in filtered load without a concomitant increase in tubular reabsorption.

P2-131: Feasibility and usefulness of longitudinal beta-amyloid1-42 levels in CSF of patients with various cognitive and neurological disorders

Background: Measuring protein levels in CSF has gained wide acceptance for the differential and early diagnosis of dementia. Little is known, however, about longitudinal changes in CSF biomarkers that are of potential use to study the course of the disease and effects of treatment. Objective(s): To evaluate changes in CSF -amyloid1-42 levels with time and to assess the influence of storage of specimen and variability of assays on the results. Methods: 114 memory clinic patients (54% male, age 67 9 years, 44% Alzheimer’s disease, 33% mild cognitive impairment, 15% subjective memory complaints, 8% other neurological disease) were recruited between 2000 and 2004. All patients underwent two spinal taps (mean follow-up time 1.8 year). -amyloid1-42 was measured with a sandwich ELISA (Innotest -amyloid1-42; Innogenetics, Ghent, Belgium). The intraassay variability was 6.5%. The inter-assay variability was 6.9%-12.6%. First, baseline and follow-up -amyloid1-42-levels were determined in separate assays, each following spinal tap. Second, to circumvent interassay variability, baseline and follow-up samples were run in the same assay at the time of the second spinal tap. In addition, variance of repeated -amyloid1-42 assessment in baseline CSF-samples was calculated. Results: Mean -amyloid1-42-level at baseline was 477 232 pg/ml. Mean -amyloid1-42-level at follow up was 519 249 pg/ml (p 0.00). Repeated mean baseline -amyloid1-42-level was 481 49 pg/ml (p 0.7). Intraindividual variance of the baseline and follow up CSF-sample pairs run on separate assays was 26% (SD20). In contrast a variance of 14% (SD12) was found within CSF-sample pairs run on the same assay. The variance of repeated -amyloid1-42 assessment in baseline CSF-samples was 19% (SD 17). Storage time was found not to be associated with differences in -amyloid1-42-level. Conclusions: In case of repeated spinal taps, determination of -amyloid1-42-levels should be performed in the same assay. However, the variation of repeated -amyloid1-42 assessment in the same CSF sample is larger than the variance between baseline and follow-up CSF-samples in the same assay. This might imply, that with the methodological limitations of the present ELISA, repeated spinal taps are not feasible in a clinical setting. The biological significance of repeated spinal taps in individual patients remains to be established.