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Background A possible connection between allergy and cancer has been suspected, but allergy-related conditions or atopy have been inconsistently associated with reduced risks of non-Hodgkin lymphoma. We investigated this association in a population-based case-control study and in a prospective study with prediagnostic blood specimens. Methods We carried out a population-based study of 3055 case patients with non-Hodgkin lymphoma and 3187 control subjects in Denmark and Sweden, including questionnaire information on allergy and blood specimens, and a nested case-control study within a prospective cohort of more than 400000 Finnish women. In the second study, serum specimens from the 198 case patients who developed non-Hodgkin lymphoma within a median of 8.9 years after the blood was drawn were matched with serum specimens from 594 control subjects. In both studies, laboratory-based evidence of allergy (atopy) was determined in serum on the basis of specific IgE reactivity to common inhalant allergens. Dissemination of disease was classified by the Ann Arbor system. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by logistic regression. Results In the first study, ever having hay fever, but not other allergic conditions, was associated with a reduced risk of non-Hodgkin lymphoma. In particular, subjects with specific IgE reactivity in serum had a 32% (95% CI = 20% to 42%) lower risk of overall non-Hodgkin lymphoma than those without such reactivity. However, among case patients, dissemination of the disease was strongly inversely associated with specific IgE reactivity. In the second (i.e., prospective) study, no association was found between non-Hodgkin lymphoma and specific IgE reactivity, except possibly immediately before a diagnosis of non-Hodgkin lymphoma (≥10 years before diagnosis, OR = 1.00, 95% CI = 0.48 to 2.09; 5-9 years before, OR = 0.95, 95% CI = 0.50 to 1.84; 1–4 years before, OR = 0.33, 95% CI = 0.11 to 1.02; and <1 year before, OR = 0.27, 95% CI = 0.03 to 2.31). Conclusion Allergy may not be causally associated with the risk of non-Hodgkin lymphoma. The inverse association observed in some case-control studies may arise because non-Hodgkin lymphoma suppresses the immunologic response to allergens. [ABSTRACT FROM AUTHOR]

A case-control study was nested within two maternity cohorts with a total of 7 million years of follow-up for assessment of the role of bacterial infections in childhood leukemia. Offspring of 550,000 mothers in Finland and Iceland were combined to form a joint cohort that was followed for cancer up to age 15 years during 1975–1997 through national cancer registries. For each index mother-case pair, three or four matched control mother-control pairs were identified from population registers. First-trimester serum samples were retrieved from mothers of 341 acute lymphoblastic leukemia cases and 61 other leukemia cases and from 1,212 control mothers. Sera were tested for antibodies to the genus Chlamydia, Helicobacter pylori, and Mycoplasma pneumoniae. Odds ratios and 95% confidence intervals, adjusted for sibship size, were calculated as estimates of relative risk. M. pneumoniae immunoglobulin M appeared to be associated with increased risk (odds ratio (OR) = 1.6), but the association lost statistical significance when the specificity of the immunoglobulin M was considered (OR = 1.5, 95% confidence interval: 0.9, 2.4). In Iceland, H. pylori immunoglobulin G was associated with increased risk of childhood leukemia in offspring (OR = 2.8, 95% confidence interval: 1.1, 6.9). Since H. pylori immunoglobulin G indicates chronic carriage of the microorganism, early colonization of the offspring probably differs between Iceland and Finland, two affluent countries. [ABSTRACT FROM AUTHOR]

Human papillomaviruses (HPVs) play the major role in cervical carcinogenesis. The authors reevaluated the role of herpes simplex virus type 2 (HSV-2) in this multistage process by conducting a longitudinal, nested case-control study using 1974-1993 data and comparing the results with those from a meta-analysis of studies. A Nordic cohort of 550,000 women was followed up for an average of 5 years, after which 178 cervical carcinoma cases and 527 controls were identified. HSV-2; HPV-16, HPV-18, and HPV-33; and Chlamydia trachomatis antibodies were determined at baseline by HSV-2 glycoprotein gG-2 and HPV virus-like-particle enzyme immunoassays and by using the microimmunofluorescence method. The relative risk of cervical carcinoma was calculated by conditional logistic regression. Longitudinal studies on HSV-2 and cervical neoplasia were identified through MEDLINE (National Library of Medicine, Bethesda, Maryland), and weighted mean relative risks were calculated. Smoking (relative risk = 1.6, 95% confidence interval (CI): 1.1, 2.3) and HPV-16/HPV-18/HPV-33 (relative risk = 2.9, 95% CI: 1.9, 4.3) were both associated with cervical carcinoma. The smoking- and HPV-16/HPV-18/HPV-33--adjusted relative risks for HSV-2 were 1.0 (95% CI: 0.6, 1.7) and 0.7 (95% CI: 0.3, 1.6), respectively, for HPV seropositives. In the meta-analysis, the relative risk for HSV-2 was 0.9 (95% CI: 0.6, 1.3). In both sets of data, HSV-2 did not play a role in cervical carcinogenesis. [ABSTRACT FROM AUTHOR]

Background To re-evaluate the impact of socioeconomic status and human cytomegalovirus (HCMV) seroprevalence during pregnancy, we carried out a population-based cohort study. [ABSTRACT FROM PUBLISHER]

The association of seropositivity to human papillomavirus (HPV) capsids of types 11, 16, 18, or 33 with sexual behavior was investigated. Among 1002 women visiting family planning or youth clinics in Sweden, an age-matched subsample of 274 women stratified according to lifetime number of sex partners was analyzed. The proportion of HPV-16-seropositive subjects increased linearly at ∼4% per partner (P < .001), from 4% among those with 1 lifetime partner to 35% among those with >5 lifetime partners. Also, HPV-33 and HPV-18 seroprevalences were linearly dependent on the number of partners (P < .001, increase with 4% per partner, and P = .008, increase with ∼3% per partner, respectively), providing serologic confirmation that the important mode of transmission of HPV-16, -18, or -33 infection in women is sexual. HPV serology appears to be suitable as a marker of sexual behavior in populations. [ABSTRACT FROM PUBLISHER]

Serodiagnostic methods were evaluated in prenatal screening for primary Toxoplasma infections acquired during pregnancy in the Helsinki area. Altogether 44,181 sera were obtained consecutively during each trimester from 16,733 mothers. All IgG-containing samples were first examined by a sensitive µ-capture (IgM) ELISA, and positive results were reassessed by IgM immunoblotting and indirect IgM ELISA. An assay measuring the avidity of toxoplasma IgG was used for the first time under screening conditions. Patients suspected to have recent toxoplasmosis were reexamined by IgA ELISA and selectively by the differential agglutination assay (HS/AC test) and IgE ELISA; 16 women with diagnostic increases in IgG titer, 36 with IgM fulfilling strict specificity criteria, and 25 with IgG of low avidity were identified. The measurement of IgG avidity was a highly specific and sensitive method suitable for verification of acute primary Toxoplasma infections during pregnancy. [ABSTRACT FROM PUBLISHER]

The stability over time of serum IgG antibody levels to human papillomavirus type 16 (HPV-16) was determined by comparing the HPV-16 capsid antibody levels in serial serum samples of an age-stratified random subsample of 1656 primiparous mothers resident in Helsinki who were followed until their second pregnancy, on average 29.5 months later. The correlation between the first and second pregnancy HPV-16 serum antibody levels of the same woman was high, even when > 4 years had elapsed between pregnancies (r = .822). Between negativity, indeterminate results, or quartiles of positivity, the predictive values for being classified in the same category on both occasions ranged between 42% and 91%. Correlation coefficients, predictive values, and κ coefficients between serial samples all were comparable with those of repeat analyses of the same sample, indicating that HPV capsid antibody levels are generally stable during several years of follow-up. [ABSTRACT FROM PUBLISHER]

Sera from the mothers of all children from the greater Helsinki area who were treated in the Neonatal Intensive Care Unit (NICU) of Children's Hospital (University of Helsinki) during a 22-month period were studied serologically, and antibody levels for mothers were compared with those for matched controls. IgM to Chlamydia trachomatis serotype GFK was detected more often in sera from mothers with children in the NICU than in that from controls; IgM was detected in sera from 39 of 264 mothers vs. 15 of 274 controls (P < .001; two-tailed test). The gestational age of children born to mothers in the IgM-seropositive group was 32.4 weeks whereas that of children born to mothers in the IgG/IgM-seronegative group was 34.3 weeks (all children were treated in the NICU). The frequency of signs of maternal infection (i.e., fever and vaginal discharge), the frequency of meconium-stained amniotic fluid, the frequency of chorioamnionitis, and the mortality rate were higher in the IgM-seropositive group than in the IgM-seronegative group; pneumonia, atelectasis, and pneumothorax occurred more frequently in the seronegative group. Thus, in terms of birth weight and perinatal infections, the outcome was better for children whose mothers did not have antibodies to C. trachomatis. [ABSTRACT FROM PUBLISHER]