Association between relative age at school and persistence of ADHD in prospective studies: an individual participant data meta-analysis

BACKGROUND

The youngest children in a school class are more likely than the oldest to be diagnosed with ADHD, but this relative age effect is less frequent in older than in younger school-grade children. However, no study has explored the association between relative age and the persistence of ADHD diagnosis at older ages. We aimed to quantify the association between relative age and persistence of ADHD at older ages.

METHODS

For this meta-analysis, we searched MEDLINE, Embase, CINAHL, PsycINFO, and PubPsych up to April 1, 2022, with terms related to "cohort" and "ADHD" with no date, publication type, or language restrictions. We gathered individual participant data from prospective cohorts that included at least ten children identified with ADHD before age 10 years. ADHD was defined by either a clinical diagnosis or symptoms exceeding clinical cutoffs. Relative age was recorded as the month of birth in relation to the school-entry cutoff date. Study authors were invited to share raw data or to apply a script to analyse data locally and generate anonymised results. Our outcome was ADHD status at a diagnostic reassessment, conducted at least 4 years after the initial assessment and after age 10 years. No information on sex, gender, or ethnicity was collected. We did a two-stage random-effects individual participant data meta-analysis to assess the association of relative age with persistence of ADHD at follow-up. This study was registered with PROSPERO, CRD42020212650.

FINDINGS

Of 33 119 studies generated by our search, we identified 130 eligible unique studies and were able to gather individual participant data from 57 prospective studies following up 6504 children with ADHD. After exclusion of 16 studies in regions with a flexible school entry system that did not allow confident linkage of birthdate to relative age, the primary analysis included 41 studies in 15 countries following up 4708 children for a period of 4 to 33 years. We found that younger relative age was not statistically significantly associated with ADHD persistence at follow-up (odds ratio 1·02, 95% CI 0·99-1·06; p=0·19). We observed statistically significant heterogeneity in our model (Q=75·82, p=0·0011, I2=45%). Participant-level sensitivity analyses showed similar results in cohorts with a robust relative age effect at baseline and when restricting to cohorts involving children with a clinical diagnosis of ADHD or with a follow-up duration of more than 10 years.

INTERPRETATION

The diagnosis of ADHD in younger children in a class is no more likely to be disconfirmed over time than that of older children in the class. One interpretation is that the relative age effect decreases the likelihood of children of older relative age receiving a diagnosis of ADHD, and another is that assigning a diagnostic label of ADHD leads to unexplored carryover effects of the initial diagnosis that persist over time. Future studies should be conducted to explore these interpretations further.

FUNDING

None.

Measuring CHAOS? Evaluating the short-form Confusion, Hubbub And Order Scale

The Confusion, Hubbub and Order Scale (CHAOS) - short form - is a survey tool intended to capture information about home environments. It is widely used in studies of child and adolescent development and psychopathology, particularly twin studies. The original long form of the scale comprised 15 items and was validated in a sample of infants in the 1980s. The short form of the scale was developed in the late 1990s and contains six items, including four from the original scale, and two new items. This short form has not been validated and is the focus of this study. We use five samples drawn from twin studies in Australia, the UK, and the USA, and examine measurement invariance of the CHAOS short-form. We first compare alternate confirmatory factor models for each group; we next test between-group configural, metric and scalar invariance; finally, we examine predictive validity of the scale under different conditions. We find evidence that a two-factor configuration of the six items is more appropriate than the commonly used one-factor model. Second, we find measurement non-invariance across groups at the metric invariance step, with items performing differently depending on the sample. We also find inconsistent results in tests of predictive validity using family-level socioeconomic status and academic achievement as criterion variables. The results caution the continued use of the short-form CHAOS in its current form and recommend future revisions and development of the scale for use in developmental research.

Do student differences in reading enjoyment relate to achievement when using the random-intercept cross-lagged panel model across primary and secondary school?

Recent longitudinal research using the random-intercept cross-lagged panel model (RI-CLPM), which disentangles the within and between variances, has afforded greater insights than previously possible. Moreover, the impact of reading enjoyment and reading for fun on subsequent school achievement, and vice versa, has only recently been scrutinized through this lens. This study's longitudinal data (grades 3, 5, 7, and 9) comprised 2,716 Australian students aged 8 to 16 years, with school reading achievement measured by the National Assessment Program: Literacy and Numeracy (NAPLAN). The RI-CLPMs' within-person effects were not trivial, accounting for approximately two-thirds and one-third of the variance in enjoyment/fun and achievement, respectively, with between-person effects accounting for the balance. Here, we highlight a reversing direction of reading achievement's cross-lagged effect on subsequent reading enjoyment but note that the evidence for this over a reciprocal directionality was marginal. In mid-primary school, achievement at grade 3 predicted enjoyment at grade 5 more than the converse (i.e. enjoyment at grade 3 to achievement at grade 5). By secondary school, however, the directionality had flipped: enjoyment at grade 7 predicted achievement at grade 9 more so than the reverse. We termed this pattern the skill-leisure-skill directionality (S-L-S), as it concurred with the only two former studies that modelled equivalent instruments with the RI-CLPM. This model's cross-lagged estimates represent deviations relative to a student's average (i.e., within-person effect). In other words, students who enjoyed reading more (or less) in grade 7 achieved reading scores that were higher (or lower) than their average in grade 9. The implications for reading pedagogy are further discussed.

The codevelopment of reading and attention from middle childhood to early adolescence: A multivariate latent growth curve study

Attention skills are strong cross-sectional predictors of reading comprehension from childhood through to adolescence. However, less is known about the developmental relations between these two domains across this period. This study examined the codevelopment of reading and attention in a community sample of 614 Australian school students (50% female). Reading and attention were assessed at ages 8, 10, 12, and 14. Results of univariate latent growth models demonstrated, on average, curvilinear trajectories for reading in which rapid growth across younger age spans decelerates as children reach adolescence. By contrast, attention skills remained relatively stable on average. Significant negative correlations were observed between the intercept and slope factors in separate reading (r = -.62) and attention models (r = -.39) suggesting compensatory growth patterns in which poorer performing students in both domains at age 8 have steeper trajectories than their higher performing peers. A comparison of a multivariate latent growth model and an autoregressive latent trajectory model with structured residuals (ALT-SR) examined the interrelatedness of development in reading and attention. Both between-individual and within-individual cross-domain parameters showed reading and attention to be positively related at Grade 3, indicating an association between better attention and higher reading achievement at age 8. However, there was little evidence for interrelated growth across domains in this sample. The results contribute to theories which explain whether and how multiple cognitive domains codevelop over a substantial period of childhood and early adolescence. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Exploring the Associations Between Delayed School Entry and Achievement in Primary and Secondary School

This research investigated whether delayed school entry was associated with higher achievement in national tests of reading and numeracy in Grades 3, 5, 7, and 9 (n = 2,823). Delayed entry was related to advantages in reading (0.14 SD) and numeracy (0.08 SD) at Grade 3, although little variance was explained (1%-2%). This slight advantage persisted for both domains in Grades 5 and 7, albeit with smaller effects. In Grade 9 there was no association between delayed entry and either reading or numeracy. Exploratory analyses with subsamples in each grade (n = 424-667) revealed no associations between delayed entry and achievement after controlling for inattention and hyperactivity, and negative associations between inattention and achievement in all grades in both domains (-0.33, -0.49 SD).

Comment on Asbury and Wai (2019), "Viewing education policy through a genetic lens," Journal of School Choice

Asbury and Wai (Journal of School Choice, 2019) perform a valuable service by summarizing much available behavior--genetic research on academic achievement. However they consider that no specific policies stem from the research body at this time. Here we do propose a policy based on some of our research using twins, namely that available funding for students struggling with learning to read be targeted to them individually rather than allocated to schools per se. We briefly canvass some practical issues, such as the variety of funding mechanisms, best-practice intervention techniques, and identification of struggling readers. We also outline a general research strategy for uncovering factors contributing to educational attainment that takes behavior-genetic research as its starting point and drills down from there, and advocate including genetically-sensitive methods in a growing list of quantitative research techniques in education.

Aging-dependent changes in the effect of daily melatonin supplementation on rat metabolic and behavioral responses

Pineal melatonin secretion has been reported to commonly decrease with aging, whereas intra-abdominal adiposity, plasma insulin and plasma leptin levels tend to increase. We recently demonstrated that daily melatonin administration starting at middle age suppressed male rat intra-abdominal fat, plasma leptin and plasma insulin to youthful levels, suggesting that aging-related changes in pineal melatonin secretion and in energy regulation may be functionally related. Accordingly, we have now investigated the effects of daily melatonin treatment on energy regulation in young versus middle-aged male Sprague Dawley rats. Addition of melatonin to the drinking water (0.2 microg/mL) produced nocturnal and diurnal plasma melatonin concentrations in middle-aged rats (12 months) equivalent to those of young adult (5 months) rats. Administration of this melatonin dosage every day for 10 wk starting at 10 months of age suppressed (P < 0.01) relative intra-abdominal fat, non-fasted plasma insulin and plasma leptin by 27, 39, and 51%, respectively (vs. vehicle-treated controls). In contrast, administration of melatonin for 10 wk starting at 3 months of age did not significantly alter (P> 0.10) any of these parameters. The melatonin administration stimulated (102%, P < 0.001) behavioral responsiveness of the middle-aged rats in a test of response to novelty, restoring youthful levels, but did not significantly alter behavioral responsiveness of the young rats. These results suggest that suppression of intra-abdominal adiposity and plasma leptin and insulin levels and stimulation of behavioral responsiveness in response to daily exogenous melatonin begins at middle age, coincident with and likely dependent upon the aging-associated decline in endogenous pineal melatonin secretion. These results further suggest that appropriate melatonin supplementation may potentially provide therapy or prophylaxis not only for the insulin resistance, increased intra-abdominal fat and resulting pathologies that occur with aging, but also for some aging-associated behavioral changes.

Chronic daily ethanol and withdrawal: 1. Long-term changes in the hypothalamo-pituitary-adrenal axis

BACKGROUND

Hypothalamo-pituitary-adrenal (HPA) function has been demonstrated to be compromised for weeks and even months after alcoholics cease ethanol consumption. Because nonalcoholic subjects with family history-associated increased risk for alcoholism also exhibit compromised HPA function, it is not clear whether defects in the HPA axis of abstinent alcoholics reflect a preexisting condition that may be responsible for increased risk for alcohol abuse versus a persisting adaptational change in response to prolonged alcohol abuse. Consequently, we investigated whether chronic daily ethanol consumption and withdrawal by male Sprague Dawley rats would induce persistent HPA changes consistent with those demonstrated in abstinent alcoholics.

METHODS AND RESULTS

In an initial experiment in which ethanol (5%, w/v) was incrementally introduced to liquid diet over a 1 week period followed by 4 weeks of chronic ethanol consumption, not only ethanol-treated rats but also pair-fed control rats exhibited decreased (p < 0.05 vs. ad-libitum-fed controls) anterior pituitary pro-opiomelanocortin (POMC) mRNA concentrations and associated decreases in plasma corticosterone and adrenocorticotropin (ACTH) levels for at least 3 weeks after gradual withdrawal of ethanol from the diet. Pair-feeding-induced decreases (p < 0.05) in thymus and spleen weights suggested that the pair-fed controls were likely stressed in this model, probably in response to the marked and irregular suppression of liquid diet consumption immediately after introduction of ethanol. Consequently, a second model was developed in which ethanol was introduced to the liquid diet much more gradually (i.e., over 3 weeks). In contrast with the rapid ethanol-introduction model, this more prolonged ethanol introduction followed by 4 weeks of chronic daily ethanol consumption increased plasma corticosterone levels (p < 0.05), increased adrenal gland weight (p < 0.05), and decreased thymus and spleen weights (both p < 0.01) without altering any of these parameters in the pair-fed controls. Three weeks after gradual withdrawal of ethanol from the diet, anterior pituitary POMC mRNA concentrations were suppressed (p < 0.05) and thymus and spleen weights were increased (p < 0.05) versus both pair-fed and ad-libitum-fed controls, accompanied by trends for decreased basal plasma corticosterone and adrenal weights.

CONCLUSIONS

Chronic daily ethanol treatment induced changes in the HPA axis that persisted for at least 3 weeks after complete cessation of ethanol consumption. These persistent alterations in the HPA axis are similar to the aberrant HPA regulation of abstinent alcoholics, sons of alcoholics, Lewis rats, and individuals who suffer from posttraumatic stress disorder and some types of depression, that is, categories of individuals who all exhibit increased risk for high ethanol consumption. Thus, these chronic daily ethanol-induced persistent changes in the HPA axis may have significant roles in alcohol abstinence syndrome and may increase vulnerability to relapse.

Enzyme-linked immunospot assay for the diagnosis of active Treponema pallidum infection during the various stages of syphilis

BACKGROUND

Specific serologic assays for syphilis cannot differentiate current infections from past infections and are inefficient to monitor efficacy of antibiotic therapy.

GOAL

To develop a new immunologic assay for the identification of active Treponema pallidum infection during the various stages of syphilis.

STUDY DESIGN

Peripheral blood mononuclear cells obtained from patients with syphilis in an STD clinic were tested for T. pallidum-specific circulating antibody-secreting cells (ASC) by an enzyme-linked immunospot assay (ELISPOT).

RESULTS

Specific ASC were demonstrated in all six patients with primary syphilis and in 14 of 16 patients diagnosed with secondary syphilis. ASCs were undetectable in five patients 8 to 16 days after appropriate therapy, but persisted in one case that was considered treatment failure. Among the 13 patients diagnosed with latent syphilis, six (46%) demonstrated ASC, reflecting antigenic stimulation.

CONCLUSION

The ELISPOT assay is effective for the diagnosis of primary and secondary syphilis. The presence of circulating ASC suggests persistent active infection in some patients during the latent disease stage.

Quality assessment activities in Latin America and the Caribbean

The Pan American Health Organization (PAHO) supports performance evaluation programs in clinical chemistry, Caribbean. Much more work remains to be done before many labs in this part of the world can be certified as providing accurate results, but PAHO has taken an important first step toward establishing benchmarks and rallying for labs to improve test quality.

Cross-reactivity to Borrelia burgdorferi proteins in serum samples from residents of a tropical country nonendemic for Lyme disease

Reports of Lyme disease from areas where the disease is not endemic have increased. Eighty-six human serum samples from Papua New Guinea (nonendemic for Lyme disease) were examined for the presence of IgG antibodies that recognize Borrelia burgdorferi antigens, using the currently recommended two-tiered system of analysis (sensitive ELISA with Western blot). The percentage of positive tests dropped from 50% to 10% when individual negative controls were included in the two-tiered analysis. Positive serum samples failed to inhibit the growth of B. burgdorferi in culture and did not yield positive reactions in the fluorescent treponemal antibody-absorption test. These characteristics, together with atypical Western blot antigen recognition patterns and the absence of known vectors, provide evidence that seropositive results for these persons are not the result of exposure to B. burgdorferi. Individual negative controls may minimize false-positive results for serologic tests for Lyme disease, and these tests must be interpreted in the context of clinical and epidemiologic data.

Crack cocaine smoking and oral sores in three inner-city neighborhoods

Crack cocaine causes blisters, sores, and cuts on the lips and in the mouths of persons who smoke it, and such sores may facilitate the oral transmission of HIV. We recruited young adults aged 18-29 years, who either were current regular crack smokers, or who had never smoked crack, from inner city neighborhoods in New York, Miami, and San Francisco. Participants were interviewed for HIV risk behaviors and history of recent oral sores and were tested for HIV, syphilis, and herpes simplex virus (HSV) antibodies. Among the 2,323 participants recruited, 1,404 (60%) were crack smokers. Crack smokers (10.0%) were more likely than nonsmokers (4.5%) to report having had oral sores in the past 30 days [prevalence odds ratio (POR) 2.4, 95% confidence interval (CI) 1.7-3.4]. Sores were also more prevalent among those who had ever injected drugs (14.3%) than among those who had not (6.7%; POR 2.3, 95% CI 1.7-3.4), and among those with HIV infection (14.3%) than among those without it (8.0%; POR 1.9, 95% CI 1.3-2.8). Among the 429 participants who reported receptive oral sex, those who reported oral sores were more likely than those who did not to have HIV infection, after other HIV risk factors were controlled for (adjusted POR 1.9, 95% CI 1.0-3.6). Our results confirm that crack smokers have a high prevalence of oral sores and provides evidence that these sores, although infrequently, may facilitate oral transmission of HIV.

Laboratory diagnosis of sexually transmitted diseases in facilities within the United States. Results of a national survey

BACKGROUND AND OBJECTIVES

The diagnosis of many sexually transmitted diseases (STD) requires laboratory testing. The authors assessed the effects of the introduction of new tests and regulations on STD testing.

STUDY DESIGN

A questionnaire survey was mailed to a random sample of facilities listed in the STD Referral Database inquiring about tests offered, changes in testing, and reasons for changes.

RESULTS

Responses from 405 facilities were analyzed. Most responding facilities collected specimens for nontreponemal tests for syphilis (352 of 405 [86.9%]). Since each facility's information was last updated, the number reporting testing for Chlamydia trachomatis rose from 160 of 405 (39.5%) to 288 of 405 (71.1%), but testing for gonorrhea and chancroid decreased (365 of 405 [90.1%] to 328 of 405 [81%], and 182 of 405 [44.9%] to 32 of 405 [7.9%], respectively). Of 364 responses to a question on changes in tests performed in the last 2 years, 249 (68.4%) reported no change, 81 (22.3%) reported an increase, and 37 (10.2%) reported a decrease. The most frequently added tests were nonculture tests for C. trachomatis (34 of 81 [42%]) and the most frequent reason for adding tests was targeted funding (25 of 81 [30.9%]). The most frequently discontinued tests were cultures and gram stains for gonorrhea (15 of 37 [40.5%]) and other in-house tests (9 of 37 [24.3%]). Most facilities that discontinued testing cited the Clinical Laboratory Improvement Act as the reason (34 of 37 [91.9%]; 95% confidence interval = 78.1%, 98.3%).

CONCLUSIONS

The number of facilities testing for C. trachomatis has increased with funding and with the availability of nonculture tests, but the number of those testing for chancroid and gonorrhea has decreased. Implementation of the Clinical Laboratory Improvement Act may be associated with a decrease in the number of facilities performing tests for STD.

Instrument-dependent fluorochrome sensitivity in flow cytometric analyses

Flow cytometry has become the preferred technique by which critical clinical evaluations are made such as CD4 counts and aneuploid analyses. Mounting concern has arisen over the numerous techniques, reagents, and different flow cytometric employed to determine these data. Several studies have documented significant differences in results when different flow cytometers are utilized to analyze the same sample. Fluorochrome-dependent instrument sensitivity also has been reported by numerous investigators. As more and more procedures are performed by cytometric analysis, light scatter and fluorescence limitations, which appear to be instrument dependent, demonstrate that not all flow cytometers have the same capabilities. Attempts were made to calculate molecules of equivalent soluble fluorochrome (MESF) values on nine different flow cytometers using fluorescein isothiocyanate (FITC) and R-phycoerythrin (R-PE) labeled microsphere reference standards produced by Flow Cytometry Standards Corporation (FCSC). Dramatic differences were observed in the ability of some cytometers to resolve these microspheres. The diminished resolution appeared to be instrument model and fluorochrome dependent. We propose that diminished fluorescence resolution in certain flow cytometers could be responsible for significant variability in clinical values reported from laboratories utilizing different flow cytometers.

Pathology of the umbilical cord in congenital syphilis: analysis of 25 specimens using histochemistry and immunofluorescent antibody to Treponema pallidum

Identification of Treponema pallidum in the placenta is important for diagnosis of congenital syphilis; however, spirochetes are difficult to observe in chorionic villi. To determine the sensitivity of umbilical cord examination for T pallidum, and the association of spirochetes with cord pathology, placentas were prospectively obtained from 25 women with untreated syphilis. The most common finding using hematoxylin-eosin staining was a normal-appearing umbilical cord (48%); necrotizing funisitis was the most frequent pathological lesion (36%). Spirochetes were detected using silver and immunofluorescent staining in 89% of cords, including 92% of histologically normal and 84% of abnormal cords. Three specimens showed subamnionic aggregates of spirochetes, consistent with amniotic fluid infection. Necrotizing funisitis was strongly associated with umbilical artery infection by spirochetes (P = .008). There was a 100% correlation between results of silver and immunofluorescent staining. The umbilical cord is a sensitive site for morphological confirmation of T pallidum; it is significant for the pathologist that spirochetes may often be detected in the absence of overt tissue inflammation or necrosis.

Laboratory diagnosis and interpretation of tests for syphilis

The lack of a method for demonstrating the presence of Treponema pallidum by growth necessitates the use of alternative methods. Traditionally, these methods are divided into direct detection methods (animal inoculation, dark-field microscopy, etc.) and serologic tests for the presence of patient antibody against T. pallidum. Serologic methods are further divided into two classes. One class, the nontreponemal tests, detects antibodies to lipoidal antigens present in either the host or T. pallidum; examples are the Venereal Disease Research Laboratory and rapid plasma reagin and tests. Reactivity in these tests generally indicates host tissue damage that may not be specific for syphilis. Because these tests are easy and inexpensive to perform, they are commonly used for screening, and with proper clinical signs they are suggestive of syphilis. The other class of test, the treponemal tests, uses specific treponemal antigens. Confirmation of infection requires a reactive treponemal test. Examples of the treponemal tests are the microhemagglutination assay for antibodies to T. pallidum and the fluorescent treponemal antibody absorption test. These tests are more expensive and complicated to perform than the nontreponemal tests. On the horizon are a number of direct antigen, enzyme-linked immunosorbent assay, and PCR techniques. Several of these techniques have shown promise in clinical trials for the diagnosis of congenital syphilis and neurosyphilis that are presently difficult to diagnose.

Syphilitic endometritis causing first trimester abortion: a potential infectious cause of fetal morbidity in early gestation

This report describes a 30-year-old woman with a history of prostitution and "crack" cocaine use during pregnancy. After an incomplete abortion at 11 weeks' gestation, a suction dilatation and curettage of uterine contents was done. Histopathologic examination revealed lymphoplasmacytic deciduitis and decidual necrosis, as well as rare first trimester chorionic villi. Silver staining using the Steiner technique showed numerous spirochetes, morphologically consistent with Treponema pallidum, in the decidualized endometrial tissues. This case of syphilitic endometritis, which appears to be the first reported, suggests that treponemal infection can cause fetal morbidity during early gestation.

Prevalence, incidence, and correlates of syphilis seroreactivity in multiethnic San Francisco neighborhoods

To examine the extent of infection with syphilis in an inner-city community, we determined the prevalence, incidence, and correlates of syphilis seroreactivity in a representative sample of unmarried whites, African Americans, and Hispanics living in San Francisco during 1988 to 1989 and again 1 year later in 1989 to 1990. One thousand seven hundred seventy single men and women aged 20 to 44 were surveyed in a random household sample drawn from three neighborhoods of varying geographic and cultural characteristics. Syphilitic infection was determined by testing specimens with the microhemagglutination assay for antibodies to Treponema pallidum (MHA-TP). Of blood samples available from 1262 participants from the initial survey, 32 (2.5%) were MHA-TP reactive. After adjustment for age, a reactive syphilis serology was significantly predicted (P < 0.05) by African American race, homosexual activity (men), and less education. In homosexually active men, lifetime number of male sex partners and the presence of antibody to the human immunodeficiency virus (HIV) significantly predicted syphilis seroreactivity (P < 0.01). One year later, of 841 specimens available for testing, an additional 13 (1.5%) had become MHA-TP reactive. Eleven (85%) of the new cases were in heterosexual men and women. Although San Francisco citywide incidence data indicate that syphilis may be decreasing for the city as a whole, incidence data on a community level suggests that syphilitic infection is increasing in high-risk heterosexual communities. Thus, syphilis prevention programs should rely on serologic testing at the community level to plan effective intervention strategies.

Flow cytometric analysis of peripheral blood lymphocyte immunophenotypes in persons infected with Treponema pallidum

To characterize the human immune response to syphilis, we determined the effect of infection with Treponema pallidum on the percentage of the various lymphocyte subpopulations in the peripheral blood of infected and uninfected persons. Monoclonal antibodies labeled with either fluorescein isothiocyanate or phycoerythrin were used to perform dual color analysis on a FACScan with the following markers: CD3 for total T cells, CD4 for T helper cells, CD8 for T suppressor cells, CD19 for B cells, and CD16 plus CD56 for natural killer cells. Lymphocyte immunophenotype results were analyzed by the stage of untreated syphilis and by gender. Although they were within the ranges of the normal distribution of immunophenotypes, the percentages of CD4+ cells were significantly lower (P < 0.001) and those of CD8+ cells were higher (P = 0.03) in patients with syphilis than in the uninfected population. For infected versus uninfected subjects, both women and men, the differences in the mean percentages of CD3+ and CD4+ cells were significant (P < or = 0.05). Significant differences were noted between the sexes in secondary syphilis only in the mean percentages of cells positive for CD3, CD4, CD8, and CD16 plus CD56. Gender had no effect on lymphocyte subpopulations in subjects with primary or latent syphilis. In the control population, significant differences due to gender were observed in the percentages of cells positive for CD3, CD4, and CD16 plus CD56.

Comparison of the fluorescent treponemal antibody absorption (FTA-ABS) test with the FTA-ABS double staining test for detection of antitreponemal immunoglobulin M in the 19S fraction of human serum

A widely used immunoglobulin M (IgM) detection assay for the diagnosis of neonatal congenital syphilis is the fluorescent treponemal antibody absorption test used with fractionated serum (FTA-ABS 19S IgM test). Reading the results of the FTA-ABS test is more cumbersome than reading those of the FTA-ABS double staining (FTA-ABS-DS) test, a confirmatory test for specific IgG. To verify that the FTA-ABS-DS test used with an anti-human IgM conjugate could detect specific IgM in fractionated serum samples (FTA-ABS-DS 19S IgM test), 164 fractionated (QUIK-SEP IgM Isolation System; ISOLAB, Inc., Akron, Ohio) serum specimens from infected neonates or adults or from IgG-seronegative subjects were tested by both techniques. The sensitivity limits of the two tests were assessed with reactive serum samples diluted to an endpoint titer. Samples nonreactive by the FTA-ABS 19S IgM test (n = 74) were either nonreactive (n = 65), minimally reactive (n = 5), or reactive (n = 4) by the FTA-ABS-DS 19S IgM test. Samples minimally reactive by the FTA-ABS 19S IgM test (n = 32) were minimally reactive (n = 1) or reactive (n = 31) by the double staining test. All samples reactive by the FTA-ABS 19S IgM test (n = 58) were also reactive by the FTA-ABS-DS 19S IgM test. There was a directly proportional linear relationship (r = 0.9794) between titers obtained by both tests. FTA-ABS-DS 19S IgM titers were constantly equal to or higher than FTA-ABS 19S IgM titers. Fluorescence intensity reading repeatability was 91.4% for the FTA-ABS-DS 19S IgM test and 81.7% for the FTA-ABS 19S IgM test (P = 0.015). Because the more easily read FTA-ABS-DS 19S IgM test is at least as sensitive as, if not more sensitive than, the FTA-ABS 19S IgM test, it is a good alternative to the latter test for the detection of specific IgM in human fractionated sera for those using fluorescence microscopes with incident light.

Seroepidemiological characterization of a syphilis epidemic in the Republic of the Marshall Islands, formerly a yaws endemic area

The annual numbers of reported cases of syphilis in the Republic of the Marshall Islands (RMI) increased from none in 1983 to more than 600 in 1989, suggesting a large outbreak of syphilis. Much of the increase resulted from expanded serological screening. The apparent outbreak of syphilis, therefore, may have been partly the result of increased surveillance or, since the RMI was formerly a yaws endemic area, possibly due to a resurgence of yaws. To address this problem and better characterize the epidemic, we analysed results from a 1989/90 Ministry of Health Services mass serological screening on Majuro Atoll, the main population centre. Serum specimens from 9160 people (86% of residents aged 15-44 years) on Majuro were screened with the rapid plasma reagin (RPR) card test; we repeated the RPR and performed a confirmatory microhaemagglutination assay for Treponema pallidum-specific antibodies (MHA-TP) on a sample of serum specimens. To estimate the seroprevalence of syphilis, we also tested a sample of RPR nonreactive specimens by MHA-TP. Among people less than 45 years of age, total (11.5%) and high-titre (5.2%) seropositivity rates were highest in the 20-24 year age group, as was MHA-TP seroprevalence (15.9%). These results suggested that a large outbreak of syphilis was responsible for the observed seroreactivity. Cumulative incidence modelling and comparisons with the results of a previous serosurvey conducted in 1985 suggested that the duration of the syphilis epidemic was approximately 10 years and that incidence had not increased appreciably since 1985.

Specific immunofluorescent staining of pathogenic treponemes with a monoclonal antibody

Two hybrid cell lines which produced mouse monoclonal antibody to the DAL-1 street strain of Treponema pallidum subsp. pallidum were established. These monoclonal antibodies strongly reacted with T. pallidum subsp. pallidum (Nichols strain, DAL-1, and two other street strains, strains MN-1 and MN-3) and T. pallidum subsp. pertenue by indirect microimmunofluorescent antibody and enzyme-linked immunosorbent assay techniques, but they did not react with normal rabbit testicular tissue. These monoclonal antibodies did not react with nonpathogenic treponemes, such as T. phagedenis Reiter, T. denticola MRB, T. refringens Noguchi, or other spirochetes, such as Borrelia burgdorferi and Leptospira interrogans serovar pomona in microimmunofluorescent antibody smear slides or in Western blots (immunoblots). While unlabeled antibodies are useful for investigating the antigenic structures of T. pallidum, we labeled these monoclonal antibodies with fluorescein isothiocyanate and used them for diagnosing syphilis by direct staining of lesion exudate or T. pallidum subsp. pallidum in formalin-fixed tissues from patients suspected of having syphilis. Both monoclonal antibodies were directed against antigens of T. pallidum subsp. pallidum with a molecular weight of 37,000 as determined by the Western blotting technique.

Anatomical evidence of synaptic plasticity in the cochlear nuclei of white-deaf cats

Synapses are dynamic structures reflecting environmental events. It was observed that densities associated with apposing synaptic membranes were altered in response to changing conditions of auditory stimulation (Gulley et al. 1978. J. Comp. Neurol. 180: 707-742). Synapses also exhibit plasticity during early development of the auditory system (Larsen and Pappas, 1985. Proceedings: 43rd Annual Meeting of the Electron Microscopy Society of America, pp. 493-494). Larsen and Pappas reported that, in young kittens, the end bulb of Held (EBH) terminal was distinguished by excessive density at apposing synaptic membranes which assume gradually the pattern observed in adult cats. The maturation of synapses parallels emerging function and may depend upon auditory stimulation (Larsen and Kirchhoff, 1987. Neurosci. Abstr. 13: 1260). Larsen and Kirchhoff found that EBH synapses on large spherical cells of white-deaf cats resembled the immature synapses found in young kittens (Fig. 1). They also found terminals that had an increased number and length of the membrane densities associated with synapses. Because the number of synaptic vesicles in these presynaptic terminals was equivalent to the number of vesicles found in normal-hearing cats, Larsen and Kirchhoff (1987) suggest that this is evidence of synaptic plasticity. We have completed a quantitative study of the synapses of EBH terminals found in adult cats that had been deaf for at least 3 years.

A population-based serosurveillance of syphilis in Costa Rica

As part of a case-control study to investigate the high incidence of cervical cancer in Costa Rican women, the seroprevalence of the treponematoses, in particular, syphilis was determined. In each age group, women with a history of two or more sex partners were two to four times more likely to be seroreactive in tests for syphilis than women with zero or one sex partner. The highest percentage of reactive results in the microhemagglutination assay for antibodies to Treponema pallidum (MHA-TP) was seen in samples from women aged 50-59 who had had two or more lifetime partners (23.8%). Three observations from our study support reactivity due to syphilis rather than yaws or pinta: (1) a similar percent of reactive rapid plasma reagin (RPR) card test results among MHA-TP reactors in the two age groups of women who were surveyed (42 vs. 49%) was observed; (2) women who were seroreactive in the MHA-TP had multiple risk factors for STD [low socioeconomic status (9.4%), urban residence (22.8%), first intercourse under 16 years of age (14.1%), and multiple sex partners (26.3%)], and (3) only sexually experienced women had reactive results in the MHA-TP test.

Specific immunofluorescence staining of Treponema pallidum in smears and tissues

To date, tissue sections prepared from Formalin-fixed tissues have not been successfully stained with Treponema pallidum subspecies-specific antibody in a direct fluorescent-antibody assay. While current methods stain T. pallidum, they do not distinguish T. pallidum from other spirochetes such as Borrelia burgdorferi (E. F. Hunter, P. W. Greer, B. L. Swisher, A. R. Simons, C. E. Farshy, J. A. Crawford, and K. R. Sulzer, Arch. Pathol. Lab. Med. 108:878-880, 1984). Because trypsin pretreatment of tissue sections has enhanced other immunofluorescent-antibody (IFA) applications, we compared the use of the trypsin digestion method with the current 1% ammonium hydroxide (NH4OH) method as a means to obtain specific staining of T. pallidum in tissues by both direct and indirect IFA techniques. Pretreated T. pallidum-infected tissues sections from rabbits, hamsters, and humans were quantitatively examined with the direct fluorescent-antibody-T. pallidum test conjugate absorbed with Treponema phagedenis, the Reiter treponeme. For indirect staining, a serum specimen from a patients with syphilis absorbed by affinity chromatography with T. phagedenis was used as the primary reagent, and a fluorescein isothiocyanate-labeled rabbit anti-human globulin was used as the secondary reagent. Serum specificity was established first by examining antigen smears of T. pallidum subsp. pallidum, T. pallidum subsp. pertenue, B. burgdorferi, T. phagedenis, and Treponema denticola MRB and then by examining tissues infected with these pathogens plus those infected with four Leptospira serovars. When we stained tissue using the direct IFA method that is currently a standard method for the examination of chancre smears, we found it to be unsuitable for use with tissue. Trypsin digestion did not offer an improvement over the NH4OH pretreatment method in the specific identification of T. pallidum by direct IFA. However, specific identification of T. pallidum in tissue sections was obtained by the indirect IFA technique after either trypsin or NH4OH pretreatment.

Sensitivity of treponemal tests for detecting prior treated syphilis during human immunodeficiency virus infection

To evaluate the sensitivity of treponemal tests as a marker of prior syphilis in individuals with human immunodeficiency virus (HIV) infection, the syphilis serology of 109 homosexual men with a documented history of treated syphilis was compared with records of prior results and confirmed on stored serum samples. None of the HIV-seronegative individuals lost reactivity to a treponemal test, whereas 7% of the seropositive asymptomatic individuals and 38% of those with symptomatic HIV infection had loss of reactivity. Symptomatic HIV infection was associated with loss of reactivity, as a T4 lymphocyte count less than 200 X 10(6)/1, a T4-to-T8 ratio less than 0.6, a single prior episode of syphilis, and a low VDRL titer at the time of the last documented episode of syphilis. Although no conclusions can be drawn about the sensitivity of treponemal tests in patients with active syphilis and HIV infection, these data suggest that treponemal tests may not identify those previously infected with Treponema pallidum.

Syphilis

The clinical manifestations of syphilis can resemble many diseases. The diagnosis can be confirmed through serologic tests and by direct microscopic observation of Treponema pallidum, subspecies pallidum in lesion, biopsy, or autopsy specimens. Direct microscopic examination may be carried out by darkfield methods or by immunofluorescent staining. The serologic testing sequence is usually a screening nontreponemal test followed by confirmation with a specific treponemal test. Serologic tests for syphilis have been highly standardized in the past, but today quality control lies in the hands of the laboratorian.

Race and the prevalence of syphilis seroreactivity in the United States population: a national sero-epidemiologic study

We used the 1978 National Health and Nutrition Examination Survey to examine the prevalence of positive syphilis serologies in the US population. Analysis of risk markers--gender, age, marital status, education, income, and residence--indicates that all except gender are associated with syphilis seroreactivity, independent of race. Controlling for associated risk markers, the Black-White odds ratio of syphilis seroreactivity is 4.7 (95% CI = 2.7, 8.2). Current knowledge of racial differences in sexual and health care behavior does not explain the Black-White difference in the prevalence of syphilis seroreactivity.

Detection of immunoglobulin M in cerebrospinal fluid from syphilis patients by enzyme-linked immunosorbent assay

Cerebrospinal fluid (CSF) samples were evaluated in an immunoglobulin M enzyme-linked immunosorbent assay (IgM ELISA) for syphilis with sonic extracts of Treponema pallidum coated on polystyrene plates. The ELISA procedure was reproducible, and T. pallidum antigens were stable., A total of 15 CSF samples from patients with neurosyphilis, 18 CSF samples from patients with syphilis, 12 CSF samples from patients treated for syphilis, and 494 CSF samples from patients with neurologic or other systemic diseases were tested. The IgM ELISA gave reactive results in all of six symptomatic and congenital neurosyphilitic patients and none of nine asymptomatic neurosyphilitic patients. Of 524 CSF samples from nonneurosyphilitic individuals, 513 were nonreactive, resulting in 98% test specificity. The IgM ELISA in CSF should prove to be useful for confirmation of symptomatic neurosyphilis.

Four serologic tests for syphilis: results with comparison of selected groups of sera

The specificity of the fluorescent treponemal antibody-absorbed (FTA-Abs) test was assessed for 17 sera from syphilitic patients that were nonreactive in the Treponema pallidum immobilization (TPI) test but reactive in the FTA-Abs test. Thirty-three other sera from syphilitic patients and 19 sera from nonsyphilitic individuals were also examined by fluorescent treponemal and microhemagglutination Treponema pallidum (MHA-TP) tests and by the enzyme-linked immunosorbent assay (ELISA). Specific absorptions of sera with calf thymus DNA or Treponema pallidum biotype Reiter (Reiter treponemes) were performed. In quantitative immunofluorescence assays (IFA) with antihuman IgG and IgM conjugates, results were similar to those for reactive sera from a control group. Results of both the MHA-TP and ELISA tests supported the specificity of the FTA-Abs test; reactivity in the latter was not removed by specific absorption either with calf thymus DNA or with Reiter treponemes. This evaluation suggests a format for serodiagnosis in cases in which test results are discrepant.

Staining intensities in the fluorescent treponemal antibody-absorption (FTA-Abs) test: association with the diagnosis of syphilis

In 1984 the reporting system for the fluorescent treponemal antibody-absorption (FTA-Abs) test was changed by the Centers for Disease Control (CDC; Atlanta, GA) to eliminate the borderline report. Factors influencing the reliability of the FTA-Abs test results, i.e., sensitivity, specificity, prevalence of syphilis, prescreening of sera with nontreponemal tests, and reproducibility, were considered before the change in the reporting system was recommended and are reported here. The borderline report, when associated with syphilis, was most frequently also associated with the diagnosis of early primary, dark-field-positive, nontreponemal test-nonreactive syphilis. Whereas elimination of the borderline report decreased the sensitivity of the FTA-Abs test as a confirmatory test from 100% to 99.5%, the specificity increased from 82.5% to 88.7%. The 1+ staining intensity had an association of approximately 5% with the diagnosis of syphilis. The changes in the reporting system were designed to assist the clinician in interpreting the results of the FTA-Abs test in those cases that present diagnostic dilemmas.

Evaluation of sera from patients with Lyme disease in the fluorescent treponemal antibody-absorption test for syphilis

To determine whether the cross-reactivity between Treponema pallidum and Borrelia burgdorferi affects the specificity of the fluorescent treponemal antibody-absorption (FTA-Abs) test for syphilis, sera from patients with Lyme disease or syphilis were examined in a quantitative FTA-Abs test. Sera were diluted serially in phosphate-buffered saline, then in sorbent, and were tested with T. pallidum and B. burgdorferi antigens. Nine of 40 sera from patients with known Lyme disease were reactive at the 1:5 dilution with antigen from T. pallidum; only one serum was reactive at the 1:10 dilution. When both antigens were tested, the titer against B. burgdorferi was always higher than that against T. pallidum. Similarly, sera from patients with syphilis showed cross-reactivity with B. burgdorferi. Although reactivity could be absorbed with Treponemal phagedenis (Reiter strain), simultaneous titration with both antigens was easily performed and designated the etiologic agent.

Adenovirus ELISA for the evaluation of cerebrospinal fluid in patients with suspected neurosyphilis

An enzyme-linked immunosorbent assay (ELISA) detecting antibodies against the adenovirus group antigen was used to examine cerebrospinal fluid (CSF) of suspected neurosyphilis patients for serum contamination or blood-brain barrier (BBB) leakage. Adenovirus antibodies are ubiquitous, produce high antibody titers, and rarely cause central nervous system (CNS) infections. Of 52 normal adult sera tested with this ELISA, only one lacked antibodies. CSF from 48 healthy individuals did not present a detectable amount of anti-adenovirus antibodies. CSF from 33 suspected neurosyphilis patients with positive results in the fluorescent treponemal antibody-absorption (FTA-ABS)-CSF test were examined. Eighteen showed anti-adenovirus antibodies indicating contamination of the CSF with peripheral blood or damaged BBB by syphilis or other disease, resulting in questionable CSF treponemal results. The remaining 15 of these patients appeared to be producing their anti-treponemal antibodies in the CNS. This procedure may prove to be of considerable help in excluding false positive FTA-ABS results in CSF samples.

Lectin characterization of gonococci from an outbreak caused by penicillin-resistant Neisseria gonorrhoeae

A total of 40 Neisseria gonorrhoeae isolates, representing 19 penicillin-resistant isolates (from 8 heterosexual patients and 11 homosexual patients) and 21 penicillin-susceptible isolates (from 15 heterosexual patients and 6 homosexual patients) and obtained from the same geographic area, were examined. Lectin agglutination patterns were based on the reactivity of the isolates with the following 14 lectins: concanavalin A, Lens culinaris, Trichosanthes kinlowii, Griffonia simplicifolia I, Arachis hypogeae (peanut agglutinin), Glycine max (soybean agglutinin), Dolichos bifloris, Griffonia simplicifolia II, Solanum tuberosum (potato starch agglutinin), Triticum vulgaris (wheat germ agglutinin), Limax flavus, Phaseolus vulgaris, Ulex europaeus I, and Lotus tetragonolobus. All isolates were serotyped with monoclonal antibodies specific for gonococcal outer membrane protein I and auxotyped, and the plasmid content was determined. Resistant patient isolates were selected for their decreased penicillin susceptibility, and control isolates were selected for their penicillin susceptibility. Even though the patient isolates demonstrated resistance to penicillin, no phenotypic differences in lectin-grouping patterns were demonstrated between the two study groups; i.e., two predominant lectin groups were observed. No resistance-associated plasmids were detected. All patient isolates were serogroup IB (serovars IB-1, IB-2, and IB-4), whereas 12 of 21 control isolates were serogroup IA (P less than 0.05). Isolates obtained from different anatomical sites in the same patient (cervical and rectal) agreed with regard to lectin patterns and serovars but not auxotypes.

Epidemiological characterization of Neisseria gonorrhoeae by lectins

A total of 101 isolates of penicillinase-producing and non-penicillinase-producing Neisseria gonorrhoeae with known nutritional requirements, plasmid content, and serovars, were examined for lectin agglutination patterns. These isolates were from outbreaks in Georgia, California, Hawaii, and Pennsylvania. Cell suspensions made from 16- to 18-h cultures were mixed with 14 different lectins, and the resultant agglutination patterns were classified as agglutination groups. Among the 101 isolates tested, 24 different agglutination groups were demonstrated. Of the organisms tested, 55% were located in 3 of the 24 groups, and 86% of the isolates reacted with the lectins Trichosanthes kinlowii, Griffonia simplicifolia I, peanut agglutinin, soybean agglutinin, potato agglutinin, and wheat germ agglutinin. One isolate did not react with peanut or potato agglutinin, five isolates lacked reactivity with potato agglutinin, and six isolates did not react with wheat germ agglutinin. Of the wheat germ-negative isolates, four were from Pennsylvania and were identical with regard to auxotype, plasmid content, serovar, and lectin group. The other two wheat germ-negative isolates were from California and were unrelated by the same criteria to the four Pennsylvania isolates and to each other. Among the isolates tested, there were no differences in lectin groups with regard to the sex of the patient. In the Georgia collection, agglutination with one lectin group was confined to isolates of serogroup IA. This association was not observed for the other geographic areas. Some isolates showing identical auxotype, plasmid content, and serovars could be differentiated based on lectin agglutination patterns, whereas other isolates were identical by all testing criteria.

Rheumatoid factor in syphilis

Immunoglobulin M (IgM) antibodies directed against IgG antibodies (rheumatoid factor [RF]) are known to occur often in patients with syphilis and to interfere with serological tests measuring specific antibodies of the IgM class. In this study we examined the occurrence and specificity of the RF and demonstrated a simple method to detect and eliminate the RF for a specific Treponema pallidum IgM enzyme-linked immunosorbent assay. We measured the occurrence of the RF with a sensitive enzyme-linked immunosorbent assay and found that it increased with the duration of syphilitic disease: 1 of 13 primary syphilis serum specimens, 3 of 13 secondary syphilis serum specimens, and 10 of 27 latent syphilis serum specimens were reactive in this RF test. Those sera containing IgM RF were immunoprecipitated with anti-human gamma chain antibodies and 2% polyethylene glycol until the RF was removed. One serum specimen from a patient in the secondary stage of syphilis and eight serum specimens from patients with latent disease still presented the RF after immunoprecipitation. Removal of the IgG antibodies also improved the sensitivity of the treponemal IgM test, indicating competition of these antibodies for binding sites of the antigen. The enzyme-linked immunosorbent assays for detection of RF and antitreponemal IgM antibodies are performed on the same plate. Theoretically, only sera positive for both tests have to be immunoprecipitated. But our findings indicated an increase in sensitivity of the IgM enzyme-linked immunosorbent assay after removal of IgG antibodies responsible for competition at the binding sites.

New technologies for use in the surveillance and control of yaws

In the Republic of Ghana, treponemal antigen tests performed on finger-prick blood from patients with yaws proved to be as sensitive as those tests performed on whole sera, and this mode of collection was more economical and acceptable than venipuncture. Under field conditions, dark-field microscopic examination of suspect yaws lesions was difficult as compared with collection of serous exudate in heparinized capillary tubes examined later in a reference laboratory. Direct staining of lesion exudate fixed on microscope slides with fluorescein-conjugated human or mouse monoclonal antibody against Treponema pallidum was more sensitive than dark-field examination. However, these techniques could not distinguish between the early lesions of venereal syphilis and those of yaws. An equally sensitive technique used a cloned segment of the T. pallidum (Nichols strain) genome to detect homologous DNA in lesion exudate fixed on nitrocellulose filter paper. The fixation of lesion exudates on microscope slides or nitrocellulose papers may prove to be the easiest method of collecting and transporting such materials to reference laboratories.

Four-step enzyme-linked immunosorbent assay for detection of Treponema pallidum antibody

Further studies of a four-step enzyme-linked immunosorbent assay procedure to detect Treponema pallidum antibody are described. High-titered antibody, produced in rabbits by intravenous injection of T. pallidum, was used to coat polyvinyl chloride microtiter plates. To these plates a known concentration of T. pallidum was added, followed in successive steps by serial dilutions of human sera and appropriately diluted peroxidase-labeled anti-human immunoglobulin G antibody. O-Phenylenediamine was the substrate. A total of 340 sera were obtained from the DeKalb County Sexually Transmitted Diseases Clinic, Atlanta, Ga., and examined within 3 days of receipt. Ninety-six percent test agreement between the enzyme-linked immunosorbent assay and the fluorescent treponemal antibody absorption-double staining test was obtained. A total of 372 additional sera stored at -20 degrees C were examined. The overall sensitivity of the enzyme-linked immunosorbent assay with sera from patients with various stages of syphilis was 96%. With sera from uninfected individuals, the specificity of the enzyme-linked immunosorbent assay was 95%. No antigen instability was noted with the two antigen preparations used during this evaluation.

Serological response to syphilis treatment. A new analysis of old data

One important aspect of the posttreatment evaluation of patients with early syphilis is assessment of serological test results. Using information previously collected from 818 patients in the Early Syphilis Study, we evaluated the seroresponse of people treated for primary or secondary syphilis. We generated curves describing the VDRL titer declines with time. The VDRL titer declined approximately fourfold at three months and eightfold at six months. These observations will allow clinicians to identify treatment failures or reinfections at the earliest possible time during their follow-up.

Double-conjugate enzyme-linked immunosorbent assay for immunoglobulins G and M against Treponema pallidum

An enzyme-linked immunosorbent assay (ELISA) for the simultaneous measurement of immunoglobulin G (IgG) and IgM was developed to detect antibodies to Treponema pallidum. Wells of polystyrene microtiter plates were coated with T. pallidum antigen, diluted patient serum was added, and IgG and IgM which bound to the T. pallidum antigen were measured by the simultaneous addition of alkaline phosphatase-labeled anti-human IgG and horseradish peroxidase-labeled anti-human IgM. Bound IgG was detected first, followed by bound IgM. After development of the procedure, 145 categorized sera were evaluated: 60 from individuals without syphilis; 62 from patients with syphilis, including 22 with primary, 20 with secondary, and 20 with latent phases of syphilis; and 23 from patients with rheumatoid arthritis. Of the 60 sera from individuals without syphilis, 100% were nonreactive for IgG antibody and 16% were reactive for IgM. Of the 23 sera from patients with rheumatoid arthritis, 3 were reactive for IgG and 3 were nonreactive for IgM. Of the 62 sera from patients with syphilis, 61 (98%) were reactive for IgG antibody with increased titers as the stage of syphilis increased, whereas IgM reactivity decreased. This enzyme-linked immunosorbent assay appears to be a simple method for the simultaneous measurement of antibodies under equal assay conditions.

Interlaboratory comparison of the toluidine red unheated serum test antigen preparation

The toluidine red unheated serum test (TRUST) antigen, a macroscopic flocculation test antigen developed by Pettit et al. (J. Clin. Microbiol. 18:1141-1145, 1983) by modifying the color-coded antigen of Kasatiya and Lambert (Appl. Microbiol. 28:317-318, 1974), was compared with the Venereal Disease Research Laboratory (VDRL) slide and rapid plasma reagin (RPR) 18-mm circle card tests for sensitivity, specificity, and reproducibility. Two lots of TRUST antigen were prepared by two laboratories in the Centers for Disease Control. Both laboratories performed the TRUST and VDRL slide test on serum samples from 1,102 patients attending the DeKalb County, Georgia, Sexually Transmitted Disease Clinic. In addition, one laboratory performed the RPR card test. Reactive sera were quantitated in the three nontreponemal tests and confirmed with the fluorescent treponemal antibody absorption test. The sensitivity in untreated syphilis for all nontreponemal tests involved was 98.4%. The specificity for these tests was 98.6%. The qualitative reproducibility among the four lots of TRUST antigen, VDRL slide, and RPR card tests was 98.2%. Only 20 sera showed discrepant results. Intralaboratory reproducibility of the two TRUST antigens was 100% for one laboratory and 99.6% for the other. Interlaboratory reproducibility for the four lots of TRUST and the VDRL slide test was 99%. Quantitative agreement +/- 1 dilution between the TRUST and RPR card test was 92.3%, and quantitative agreement +/- 1 dilution for the TRUST and RPR card test versus the VDRL slide test averaged 50%. The TRUST appeared to be comparable to the RPR card test in all parameters compared.

A case-control study of stillbirths at a teaching hospital in Zambia, 1979-80: serological investigations for selected infectious agents

Sera were obtained from 266 mothers of singleton stillborn babies (cases) and 266 mothers of live-born babies (controls), matched for parity, who delivered at the University Teaching Hospital, Lusaka, Zambia, between October 1979 and April 1980. Tests were performed on 262 samples from cases and 261 from controls. The microhaemagglutination assay for Treponema pallidum (MHA-TP) was reactive in 54% of cases and 29% of controls; the rapid plasma reagin (RPR) 18-mm circle card test was reactive at a dilution of 1:16 or greater in 29% of cases and in 3.5% of controls. Both these differences are highly significant.Sera from cases and controls were further examined for evidence of cytomegalovirus, human (alpha) herpesvirus, hepatitis B virus, toxoplasma, and plasmodium infections. The only difference between sera from cases and controls was that cytomegalovirus antibody titres >/= 1:1024 occurred more often among cases. There was no relationship between antibody titre and birth weight.The results of this study emphasize the importance of screening pregnant women for syphilis. Treatment of those found to be infected should help prevent stillbirths due to syphilis.

Toluidine red unheated serum test, a nontreponemal test for syphilis

We have shown that a modification of the color-coded antigen developed by Kasatiya and Lambert (Appl. Microbiol. 28:317-318, 1974) can be used as a substitute for other nontreponemal antigens used in screening tests for syphilis. The antigen is based on the Venereal Disease Research Laboratory antigen, with EDTA, choline chloride, and toluidine red toner added. Performance of the toluidine red unheated serum test (TRUST) is identical to that of the rapid plasma reagin 18-mm circle card test (U.S. Department of Health, Education, and Welfare, Public Health Service Publication no. 411). In a series of preliminary evaluations, the TRUST antigen was found to be stable over a period of 6 months at 4 degrees C. In a comparison of TRUST with the rapid plasma reagin card test, the qualitative agreement was 100%, whereas agreement between these two tests and the Venereal Disease Research Laboratory slide test was 99.7%. The quantitative agreement +/- 1 twofold dilution between TRUST and the rapid plasma reagin card test was 100%; between TRUST and the Venereal Disease Research Laboratory slide test it was 75.0%; and between the rapid plasma reagin card and Venereal Disease Research Laboratory slide tests it was 60.0%.