Quantifying the effect of weathering on acute oil toxicity using the PETROTOX model

Following accidental release into marine environments, crude oil progressively weathers, influencing composition, fate, and toxicity. However, published studies draw conflicting conclusions on the effects of oil weathering on ecotoxicity. Using the PETROTOX model, this study characterized the effect of weathering on acute oil toxicity for four aquatic species. Results indicated that predicted acute toxicity decreased with increased oil weathering, due to reductions in overall concentrations and bioavailability of hydrocarbon constituents.

Binding properties to nicotinic acetylcholine receptors can explain differential toxicity of neonicotinoid insecticides in Chironomidae

Neonicotinoids are neuroactive insecticides commonly detected in freshwater ecosystems. Recent studies have indicated that these compounds are markedly toxic to Chironomidae, a widespread family of ecologically important aquatic insects. However, despite their sensitivity, the pharmacological mechanisms driving neonicotinoid toxicity have yet to be characterized in these insect species. Here, we used a combination of saturation and competition binding studies to characterize neonicotinoid binding properties to nicotinic acetylcholine receptors (nAChR) in two different Chironomidae (Chironomus riparius and Chironomus dilutus) at two different life stages (larval and adult). Using radiolabeled imidacloprid ([³H]-IMI), we characterized and compared receptor density (B_max), imidacloprid binding affinity (K_D), and receptor binding affinity (K_i) to three different neonicotinoid competitors (imidacloprid, clothianidin, and thiamethoxam). We then compared receptor density and binding affinity parameters derived for Chironomidae to data previously generated for other dipterans and agricultural pests. We found that there were limited differences in neonicotinoid binding between C. riparius and C. dilutus, with both organisms demonstrating high affinities for imidacloprid (K_D = 0.22-0.87 nM) and high receptor densities (B_max = 0.92-6.53 pmol/mg). However, there were significant differences between life-stages, with larvae expressing higher densities of nicotinic acetylcholine receptors and higher imidacloprid affinities than adults. Moreover, there were compound-specific differences in receptor affinity, with larval stages displaying relative affinities (K_i) that generally correlated with acute neonicotinoid toxicity (e.g. clothianidin ≥ imidacloprid >>> thiamethoxam). Finally, compared to other dipterans and agricultural pests, Chironomidae display very high densities of high affinity nicotinic acetylcholine receptors, which likely contribute to their sensitivity. Results indicated that receptor-level differences in neonicotinoid binding may be responsible for ecotoxicological differences amongst distinct insect species, and they likely play a role in life stage-, and compound-level toxicity differences previously observed for Chironomidae. Overall, this study highlights the value of understanding the toxicological mechanisms of action of neonicotinoids in sensitive, non-target aquatic insects, to better predict adverse effects associated with unintentional neonicotinoid exposure.

Cryptic Species Account for the Seemingly Idiosyncratic Secondary Metabolism of Sarcophyton glaucum Specimens Collected in Palau

Sarcophyton glaucum is one of the most abundant and chemically studied soft corals with over 100 natural products reported in the literature, primarily cembrane diterpenoids. Yet, wide variation in the chemistry observed from S. glaucum over the past 50 years has led to its reputation as a capricious producer of bioactive metabolites. Recent molecular phylogenetic analysis revealed that S. glaucum is not a single species but a complex of at least seven genetically distinct species not distinguishable using traditional taxonomic criteria. We hypothesized that perceived intraspecific chemical variation observed in S. glaucum was actually due to differences between cryptic species (interspecific variation). To test this hypothesis, we collected Sarcophyton samples in Palau, performed molecular phylogenetic analysis, and prepared chemical profiles of sample extracts using gas chromatography-flame ionization detection. Both unsupervised (principal component analysis) and supervised (linear discriminant analysis) statistical analyses of these profiles revealed a strong relationship between cryptic species membership and chemical profiles. Liquid chromatography with tandem mass spectrometry-based analysis using feature-based molecular networking permitted identification of the chemical drivers of this difference between clades, including cembranoid diterpenes (2R,11R,12R)-isosarcophytoxide (5), (2S,11R,12R)-isosarcophytoxide (6), and isosarcophine (7). Our results suggest that early chemical studies of Sarcophyton may have unknowingly conflated different cryptic species of S. glaucum, leading to apparently idiosyncratic chemical variation.

Neonicotinoid insecticide mixtures: Evaluation of laboratory-based toxicity predictions under semi-controlled field conditions

Neonicotinoid insecticide mixtures are frequently detected in aquatic environments in agricultural regions. Recent laboratory studies have indicated that neonicotinoid mixtures can elicit greater-than-additive toxicity in sensitive aquatic insects (e.g. Chironomus dilutus). However, this has yet to be validated under field conditions. In this study, we compared the chronic (28- and 56-day) toxicity of three neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) and their mixtures to natural aquatic insect communities. Using experimental in-situ enclosures (limnocorrals), we exposed wetland insects to single-compounds and binary mixtures at equitoxic concentrations (1 toxic unit under the principle of Concentration Addition). We assessed the composition of all emerged insect taxa and the cumulative Chironomidae emergence and biomass over time. In treated limnocorrals, there were subtle shifts in community composition, with greater mean proportions of emergent Trichoptera and Odonata. Cumulative emergence and biomass increased over time and there was a significant interaction between time and treatment. At 28 days, cumulative Chironomidae emergence and biomass were not significantly different between neonicotinoid treatments and controls. However, cumulative emergence in the imidacloprid, clothianidin, and clothianidin-thiamethoxam treatments were 42%, 20%, and 44% lower than predicted from applied doses. At 56 days, effects on cumulative emergence and biomass were significant for imidacloprid, clothianidin, and the clothianidin-thiamethoxam mixture. Contrary to laboratory predictions, mixtures were not more toxic than single compounds under semi-controlled field settings. Furthermore, only clothianidin significantly shifted sex-ratios towards female-dominated populations. Results showed that the responses of natural Chironomidae populations to neonicotinoids and their mixtures cannot be adequately predicted from laboratory-derived single-species models, and although occasional overdosing may have influenced the magnitude of effects, reductions in Chironomidae emergence and biomass can occur at average neonicotinoid concentrations below some current water quality guidelines. Therefore, neonicotinoid guidelines should be revised to ensure that Chironomidae and other sensitive aquatic insects inhabiting agricultural wetlands are adequately protected.

Can chronic exposure to imidacloprid, clothianidin, and thiamethoxam mixtures exert greater than additive toxicity in Chironomus dilutus?

Widespread agricultural use of neonicotinoid insecticides has resulted in frequent detection of mixtures of these compounds in global surface waters. Recent evidence suggests that neonicotinoid mixtures can elicit synergistic toxicity in aquatic insects under acute exposure conditions, however this has not been validated for longer exposures more commonly encountered in the environment. Therefore, we aimed to characterize the chronic (28-day) toxicity of imidacloprid, clothianidin, and thiamethoxam mixtures under different doses and mixture ratios to determine if the assumption of synergistic toxicity would hold under more environmentally realistic exposure settings. The sensitive aquatic insect Chironomus dilutus was used as a representative test species, and successful emergence was used as a chronic endpoint. Applying the MIXTOX modeling approach, predictive parametric models were fitted using single-compound toxicity data and statistically compared to observed toxicity in subsequent mixture tests. Imidacloprid-clothianidin, clothianidin-thiamethoxam and imidacloprid-clothianidin-thiamethoxam mixtures did not significantly deviate from concentration-additive toxicity. However, the cumulative toxicity of the imidacloprid-thiamethoxam mixture deviated from the concentration-additive reference model, displaying dose-ratio dependent synergism and resulting in up to a 10% greater reduction in emergence from that predicted by concentration addition. Furthermore, exposure to select neonicotinoid mixtures above 1.0 toxic unit tended to shift sex-ratios toward more male-dominated populations. Results indicate that, similar to acute exposures, the general assumption of joint additivity cannot adequately describe chronic cumulative toxicity of all neonicotinoid mixtures. Indeed, our observations of weak synergism and sex-ratio shifts elicited by some mixture combinations should be considered in water quality guideline development and environmental risk assessment practices for neonicotinoid insecticides, and explored in further investigations of the effects of neonicotinoid mixtures on aquatic communities.

Trimethoprim-sulfonamide use during the first trimester of pregnancy and the risk of congenital anomalies

BACKGROUND

Sulfonamide antibacterials are widely used in pregnancy, but evidence about their safety is mixed. The objective of this study was to assess the association between first-trimester sulfonamide exposure and risk of specific congenital malformations.

METHODS

Mother-infant pairs were selected from a cohort of 1.2 million live-born deliveries (2001-2008) at 11 US health plans comprising the Medication Exposure in Pregnancy Risk Evaluation Program. Mothers with first-trimester trimethoprim-sulfonamide (TMP-SUL) exposures were randomly matched 1:1 to (i) a primary comparison group (mothers exposed to penicillins and/or cephalosporins) and (ii) a secondary comparison group (mothers with no dispensing of an antibacterial, antiprotozoal, or antimalarial medication during the same time period). The outcomes were cardiovascular abnormalities, cleft palate/lip, clubfoot, and urinary tract abnormalities.

RESULTS

We first identified 7615 infants in the TMP-SUL exposure group, of which 7595 (99%) were exposed to a combination of TMP-SUL and the remaining 1% to sulfonamides alone. After matching (1:1) to the comparator groups and only including those with complete data on covariates, there were 20 064 (n = 6688 per group) in the primary analyses. Overall, cardiovascular defects (1.52%) were the most common and cleft lip/palate (0.10%) the least common that were evaluated. Compared with penicillin/cephalosporin exposure, and no antibacterial exposure, TMP-SUL exposure was not associated with statistically significant elevated risks for cardiovascular, cleft lip/palate, clubfoot, or urinary system defects.

CONCLUSIONS

First-trimester TMP-SUL exposure was not associated with a higher risk of the congenital anomalies studied, compared with exposure to penicillins and/or cephalosporins, or no exposure to antibacterials.

Nonsteroidal Anti-Inflammatory Drug and Aspirin Use, and Mortality among Critically Ill Pandemic H1N1 Influenza Patients: an Exploratory Analysis

We explored nonsteroidal anti-inflammatory drug (NSAID) and aspirin (ASA) use and mortality in the U.S. Department of Health and Human Services' registry of 683 adult and 838 pediatric critically ill pandemic 2009 H1N1 influenza (pH1N1) patients. Among adults, 88 (12.9%) and 101 (14.8%) reported pre-admission use of an NSAID and ASA, respectively; mortality was similar (23-24%) regardless of NSAID or ASA use. Mortality among 89 pediatric NSAID users and 749 nonusers did not differ significantly (10.1% and 8.8%, respectively). One of 16 pediatric ASA users died. Among pediatric patients, the adjusted relative risk estimate for NSAID use and 90-day mortality was higher when influenza vaccination was included in the model (risk ratio [RR] = 1.5; 95% confidence interval, 0.7-3.2), although not statistically significant. Among adults, RR estimates did not change appreciably after adjusting for age, sex, health status, or vaccine status. We found no compelling evidence that NSAID or ASA use influenced mortality in severe pH1N1.

Humoral immune response to HTLV-1 basic leucine zipper factor (HBZ) in HTLV-1-infected individuals

Background

Human T cell lymphotropic virus type 1 (HTLV-1) infection can lead to development of adult T cell leukemia/lymphoma (ATL) or HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in a subset of infected subjects. HTLV-1 basic leucine zipper factor (HBZ) gene has a critical role in HTLV-1 infectivity and the development of ATL and HAM/TSP. However, little is known about the immune response against HBZ in HTLV-1-infected individuals. In this study, we examined antibody responses against HBZ in serum/plasma samples from 436 subjects including HTLV-1 seronegative donors, asymptomatic carriers (AC), ATL, and HAM/TSP patients using the luciferase immunoprecipitation system.

Results

Immunoreactivity against HBZ was detected in subsets of all HTLV-1-infected individuals but the test did not discriminate between AC, ATL and HAM/TSP. However, the frequency of detection of HBZ-specific antibodies in the serum of ATL patients with the chronic subtype was higher than in ATL patients with the lymphomatous subtype. Antibody responses against HBZ were also detected in cerebrospinal fluid of HAM/TSP patients with anti-HBZ in serum. Antibody responses against HBZ did not correlate with proviral load and HBZ mRNA expression in HAM/TSP patients, but the presence of an HBZ-specific response was associated with reduced CD4⁺ T cell activation in HAM/TSP patients. Moreover, HBZ-specific antibody inhibited lymphoproliferation in the PBMC of HAM/TSP patients.

Conclusions

This is the first report demonstrating humoral immune response against HBZ associated with HTLV-I infection. Thus, a humoral immune response against HBZ might play a role in HTLV-1 infection.

Anogenital human papillomavirus in sexually abused and nonabused children: a multicenter study

OBJECTIVES

To characterize the epidemiology of genital human papillomavirus (HPV) infection in children without previous consensual sexual activity, comparing HPV prevalence by certainty of child sexual abuse (CSA).

PATIENTS AND METHODS

Patients presenting for evaluation of CSA in 8 sites in Atlanta, Houston, Harrisburg, and New York City were recruited along with patients presenting for unrelated health visits. CSA certainty was classified as definite, probable, possible, or no evidence following published guidelines and the results of history, physical examination, and laboratory tests. Urine and swabs of external genitalia were tested for HPV using L1 consensus polymerase chain reaction.

RESULTS

The study included 576 participants (89.9% female) aged 6 months to 13 years (mean: 7.9); 534 of whom were evaluated for CSA and 42 for unrelated reasons. Of those evaluated for CSA, 14 had genital warts. One or more HPV types were detected in 11.8% (61 of 517) of participants with adequate samples. HPV detection was more likely among abused participants (definite, probable, or possible) than among participants without evidence of CSA (13.7% and 1.3%, respectively; P < .0001) and increased with certainty of abuse (8.4%, 15.6%, and 14.5% in participants with possible, probable, and definite CSA, respectively; P < .0001). Participants aged 10 years or older had a higher prevalence of HPV (20.6%) than others (5.6%) (P < .0001). CSA, anogenital warts, and age were independently associated with HPV detection.

CONCLUSIONS

HPV detection was associated with CSA and increased with CSA certainty. In this population, genital HPV seemed to behave as a sexually transmitted infection.

Gynecological history in chronic fatigue syndrome: a population-based case-control study

BACKGROUND

Chronic fatigue syndrome (CFS) affects disproportionately more women than men, and the condition is more common at perimenopause. We examined gynecological history events as risk factors for CFS.

METHODS

In a case-control study from a randomly selected population sample from Wichita, Kansas, 36 women with CFS and 48 nonfatigued controls, of similar age, race, and body mass index (BMI), answered a structured gynecological history questionnaire.

RESULTS

CFS cases and controls had the same mean age (51 years) and age at menarche (12 years). Overall, a greater proportion of women with CFS than controls reported pelvic pain unrelated to menstruation (22.2% vs. 1.7%, p = 0.004), endometriosis (36.1% vs. 16.7, %, p = 0.046), and periods of amenorrhea (53.9 % vs. 46.2%, p = 0.06). Compared to controls, women in the CFS group had a higher mean number of pregnancies (2.8 vs 2.0, p = 0.05) and gynecological surgeries (1.8 vs. 1.1, p = 0.05). Similar proportions of the CFS (69.4%) and control (72.9%) groups were menopausal. Although menopausal women in the CFS and control groups had similar mean age (55.5 and 55.8, respectively), menopause occurred about 4.4 years earlier in the CFS group (41.7 years vs. 46.1 years, respectively, p = 0.11). Among menopausal women, 76% of the CFS group reported hysterectomy vs. 54.6% of controls (p = 0.09), and 56% of women with CFS reported oophorectomy vs. 34.3% of controls (p = 0.11).

CONCLUSIONS

The higher prevalence of gynecological conditions and gynecological surgeries in women with CFS highlights the importance of evaluating gynecological health in these patients and the need for more research to clarify the chronologic and the pathophysiological relationships between these conditions and CFS.

Chronic fatigue syndrome is associated with metabolic syndrome: results from a case-control study in Georgia

We hypothesized that persons with chronic fatigue syndrome (CFS) would have a higher prevalence of metabolic syndrome compared with well controls, and that unwell persons with insufficient symptoms or fatigue for CFS (termed ISF) would have a prevalence of metabolic syndrome intermediate between those with CFS and the controls. We also sought to examine the relationship between metabolic syndrome and measures of functional impairment, fatigue, and other symptoms. Our analysis was based on a population-based case-control study conducted in metropolitan, urban, and rural areas of Georgia, United States, between September 2004 and July 2005. There were 111 persons with CFS, 259 with ISF, and 123 controls. Metabolic syndrome was determined based on having at least 3 of 5 standard risk components (abdominal obesity, high triglycerides, high blood pressure, elevated fasting glucose, and decreased high-density lipids) according to the National Cholesterol Education Program Adult Treatment Panel III definition. Persons with CFS were 2-fold as likely to have metabolic syndrome (odds ratio = 2.12, confidence interval = 1.06, 4.23) compared with the controls. There was a significant graded relationship between the number of metabolic syndrome factors and CFS; each additional factor was associated with a 37% increase in likelihood of having CFS. The association of ISF with metabolic syndrome was weaker (odds ratio = 1.72, confidence interval = 0.94-3.16). Among persons with CFS, the number of metabolic syndrome factors was significantly correlated with worse fatigue on a standardized summary measure of fatigue (r = 0.20, P = .04). In conclusion, CFS was associated with metabolic syndrome, which further exacerbated fatigue.

Further validation of the Multidimensional Fatigue Inventory in a US adult population sample

Background

The Multidimensional Fatigue Inventory (MFI-20) was developed in 1995. Since then, it has been widely used in cancer research and cancer-related illnesses but has never been validated in fatiguing illnesses or in a large US population-selected sample. In this study, we sought to examine the reliability and validity of the MFI-20 in the population of the state of Georgia, USA. Further, we assessed whether the MFI-20 could serve as a complementary diagnostic tool in chronically fatigued and unwell populations.

Methods

The data derive from a cross-sectional population-based study investigating the prevalence of chronic fatigue syndrome (CFS) in Georgia. The study sample was comprised of three diagnostic groups: CFS-like (292), chronically unwell (269), and well (222). Participants completed the MFI-20 along with several other measures of psychosocial functioning, including the Medical Outcomes Survey Short Form-36 (SF-36), the Zung Self-Rating Depression Scale (SDS), and the Spielberger State-Trait Anxiety Inventory (STAI). We assessed the five MFI-20 subscales using several criteria: inter-item correlations, corrected item-total correlations, internal consistency reliability (Cronbach's alpha coefficients), construct validity, discriminant (known-group) validity, floor/ceiling effects, and convergent validity through correlations with the SF-36, SDS, and STAI instruments.

Results

Averaged inter-item correlations ranged from 0.38 to 0.61, indicating no item redundancy. Corrected item-total correlations for all MFI-20 subscales were greater than 0.30, and Cronbach's alpha coefficients achieved an acceptable level of 0.70. No significant floor/ceiling effect was observed. Factor analysis demonstrated factorial complexity. The MFI-20 also distinguished clearly between three diagnostic groups on all subscales. Furthermore, correlations with depression (SDS), anxiety (STAI), and functional impairment (SF-36) demonstrated strong convergent validity.

Conclusions

This study provides support for the MFI-20 as a valuable tool when used in chronically unwell and well populations. It also suggests that the MFI-20 could serve as a complementary diagnostic tool in fatiguing illnesses, such as CFS.

An evaluation of exclusionary medical/psychiatric conditions in the definition of chronic fatigue syndrome

BACKGROUND

The diagnosis of chronic fatigue syndrome (CFS) in research studies requires the exclusion of subjects with medical and psychiatric conditions that could confound the analysis and interpretation of results. This study compares illness parameters between individuals with CFS who have and those who do not have exclusionary conditions.

METHODS

We used a population-based telephone survey of randomly selected individuals, followed by a clinical evaluation in the study metropolitan, urban, and rural counties of Georgia, USA. The medical and psychiatric histories of the subjects were examined and they underwent physical and psychiatric examinations and laboratory screening. We also employed the multidimensional fatigue inventory (MFI), the medical outcomes survey short form-36 (SF-36) and the US Centres for Disease Control and Prevention symptom inventory (SI).

RESULTS

Twenty-nine percent (1,609) of the 5623 subjects who completed the detailed telephone interview reported exclusionary diagnoses and we diagnosed an exclusionary condition in 36% of 781 clinically evaluated subjects. Both medical and psychiatric exclusionary conditions were more common in women, blacks and participants from rural areas. Subjects with and without exclusions had similar levels of fatigue and impairment as measured by the MFI and SF-36; those with CFS-like illness (not meeting the formal CFS definition) were more likely to have an exclusionary diagnosis. After adjusting for demographics, body mass index, fatigue subscales, SF-36 subscales and CFS symptoms, CFS-like illness did not remain significantly associated with having an exclusionary diagnosis.

CONCLUSION

Medical and psychiatric illnesses associated with fatigue are common among the unwell. Those who fulfill CFS-like criteria need to be evaluated for potentially treatable conditions. Those with exclusionary conditions are equally impaired as those without exclusions.

Proviral loads and clonal expansion of HTLV-1-infected cells following vertical transmission: a 10-year follow-up of children in Jamaica

OBJECTIVE

Few studies have specifically examined proviral load (PVL) and clonal evolution of human T-lymphotropic virus type 1 (HTLV-1)-infected cells in vertically infected children.

METHODS

Sequential samples (from ages 1 to 16 years) from 3 HTLV-1-infected children (cases A, B and C) in the Jamaica Mother Infant Cohort Study were analyzed for their PVL and clonal expansion of HTLV-1-infected cells in peripheral blood mononuclear cells (PBMCs) by inverse-long PCR.

RESULTS

The baseline PVL (per 100,000 PBMCs) of case A was 260 (at 1 year of age) and of case B it was 1,867 (at 3 years of age), and they remained constant for more than 10 years. Stochastic patterns of clonal expansion of HTLV-1-infected cells were predominately detected. In contrast, case C, who had lymphadenopathy, seborrheic dermatitis and hyperreflexia, showed an increase in PVL from 2,819 at 1.9 years to 13,358 at 13 years of age, and expansion of 2 dominant clones.

CONCLUSION

The clonal expansion of HTLV-1-infected cells is induced in early childhood after infection acquired from their mothers. Youths with high PVL and any signs and symptoms associated with HTLV-1 infection should be closely monitored.

Higher heart rate and reduced heart rate variability persist during sleep in chronic fatigue syndrome: a population-based study

Autonomic nervous system (ANS) dysfunction has been suggested in patients with chronic fatigue syndrome (CFS). In this study, we sought to determine whether increased heart rate (HR) and reduced heart rate variability (HRV) parameters observed in CFS patients during wakefulness persist during sleep. To this end, we compared heart rate (HR) and HRV as indicators of ANS function in CFS subjects and non-fatigued (NF) controls in a population-based, case-control study. Thirty subjects with CFS and 38 NF controls, matched for age-, sex- and body mass index, were eligible for analysis. Main outcome measures included mean RR interval (RRI), HR, and HRV parameters derived from overnight ECG. Plasma aldosterone and norepinephrine levels, medicines with cardiovascular effect, and reported physical activity were examined as covariates. General Linear Models were used to assess significance of associations and adjust for potential confounders. Compared to controls, CFS cases had significantly higher mean HR (71.4 vs 64.8 bpm), with a shorter mean RRI [840.4 (85.3) vs 925.4(97.8) ms] (p<0.0004, each), and reduced low frequency (LF), very low frequency (VLF), and total power (TP) of HRV (p<0.02, all). CFS cases had significantly lower plasma aldosterone (p<0.05), and tended to have higher plasma norepinephrine levels. HR correlated weakly with plasma norepinephrine (r=0.23, p=0.05) and moderately with vitality and fatigue scores (r=-0.49 and 0.46, respectively, p<0.0001). Limitation in moderate physical activity was strongly associated with increased HR and decreased HRV. Nevertheless, among 42 subjects with similar physical activity limitations, CFS cases still had higher HR (71.8 bpm) than respective controls (64.9 bpm), p=0.023, suggesting that reduced physical activity could not fully explain CFS-associated differences in HR and HRV. After adjusting for potential confounders case-control differences in HR and TP remained significant (p<0.05).

CONCLUSION

the presence of increased HR and reduced HRV in CFS during sleep coupled with higher norepinephrine levels and lower plasma aldosterone suggest a state of sympathetic ANS predominance and neuroendocrine alterations. Future research on the underlying pathophysiologic mechanisms of the association is needed.

Complementary and alternative medical therapy utilization by people with chronic fatiguing illnesses in the United States

BACKGROUND

Chronic fatiguing illnesses, including chronic fatigue syndrome (CFS), pose a diagnostic and therapeutic challenge. Previous clinical reports addressed the utilization of health care provided to patients with CFS by a variety of practitioners with other than allopathic training, but did not examine the spectrum of complementary and alternative medicine (CAM) therapies used. This study was designed to measure CAM therapy use by persons with fatiguing illnesses in the United States population.

METHODS

During a random-digit dialing survey to estimate the prevalence of CFS-like illness in urban and rural populations from different geographic regions of the United States, we queried the utilization of CAM including manipulation or body-based therapies, alternative medical systems, mind-body, biologically-based, and energy modalities.

RESULTS

Four hundred forty fatigued and 444 non-fatigued persons from 2,728 households completed screening. Fatigued subjects included 53 persons with prolonged fatigue, 338 with chronic fatigue, and 49 with CFS-like illness. Mind-body therapy (primarily personal prayer and prayer by others) was the most frequently used CAM across all groups. Among women, there was a significant trend of increasing overall CAM use across all subgroups (p-trend = 0.003). All categories of CAM use were associated with significantly poorer physical health scores, and all but one (alternative medicine systems) were associated with significantly poorer mental health scores. People with CFS-like illness were significantly more likely to use body-based therapy (chiropractic and massage) than non-fatigued participants (OR = 2.52, CI = 1.32, 4.82). Use of body-based therapies increased significantly in a linear trend across subgroups of non-fatigued, prolonged fatigued, chronic fatigued, and CFS-like subjects (p-trend = 0.002). People with chronic fatigue were also significantly more likely to use body-based therapy (OR = 1.52, CI = 1.07, 2.16) and mind-body (excluding prayer) therapy than non-fatigued participants (OR = 1.73, CI = 1.20 - 2.48).

CONCLUSION

Utilization of CAM was common in fatiguing illnesses, and was largely accounted for by the presence of underlying conditions and poor physical and mental health. Compared to non-fatigued persons, those with CFS-like illness or chronic fatigue were most likely to use body-based and mind-body therapies. These observations have important implications for provider education programs and development of intervention strategies for CFS.

Sleep characteristics of persons with chronic fatigue syndrome and non-fatigued controls: results from a population-based study

BACKGROUND

The etiology and pathophysiology of chronic fatigue syndrome (CFS) remain inchoate. Attempts to elucidate the pathophysiology must consider sleep physiology, as unrefreshing sleep is the most commonly reported of the 8 case-defining symptoms of CFS. Although published studies have consistently reported inefficient sleep and documented a variable occurrence of previously undiagnosed primary sleep disorders, they have not identified characteristic disturbances in sleep architecture or a distinctive pattern of polysomnographic abnormalities associated with CFS.

METHODS

This study recruited CFS cases and non-fatigued controls from a population based study of CFS in Wichita, Kansas. Participants spent two nights in the research unit of a local hospital and underwent overnight polysomnographic and daytime multiple sleep latency testing in order to characterize sleep architecture.

RESULTS

Approximately 18% of persons with CFS and 7% of asymptomatic controls were diagnosed with severe primary sleep disorders and were excluded from further analysis. These rates were not significantly different. Persons with CFS had a significantly higher mean frequency of obstructive apnea per hour (p = .003); however, the difference was not clinically meaningful. Other characteristics of sleep architecture did not differ between persons with CFS and controls.

CONCLUSION

Although disordered breathing during sleep may be associated with CFS, this study generally did not provide evidence that altered sleep architecture is a critical factor in CFS. Future studies should further scrutinize the relationship between subjective sleep quality relative to objective polysomnographic measures.

Longitudinal Measures of Human Papillomavirus 6 and 11 Viral Loads and Antibody Response in Children With Recurrent Respiratory Papillomatosis

OBJECTIVES

To measure human papillomavirus (HPV) 6 and 11 viral load and antibody response in longitudinal specimens obtained from children with recurrent respiratory papillomatosis and to examine the association of type-specific viral load with clinical severity of disease.

DESIGN

Longitudinal pilot study with a median follow-up of 5.4 months.

SUBJECTS

The study included 15 children undergoing therapy for recurrent respiratory papillomatosis at the Egleston Children's Hospital, Atlanta, GA, between January 22, 1999, and June 13, 2000.

MAIN OUTCOME MEASURES

The kinetics of HPV-6 and HPV-11 viral load and antibody level were examined over time. Longitudinal HPV-6 and HPV-11 viral loads were analyzed for associations with clinical indicators of disease severity.

RESULTS

Four children were infected with HPV-11, 4 were infected with HPV-6, and 7 had mixed infections. The HPV-6 and HPV-11 viral loads were stable over time in most of the children. Among children with mixed infections, HPV-6 viral loads were inversely correlated with those of HPV-11 (r = -0.80, P<.001). The HPV-11 infection was significantly associated with more annual surgical procedures (P=.02). Neither HPV-6 nor HPV-11 viral loads were associated with demographic factors or markers of clinical severity. None of the children had detectable antibodies against HPV-6, and only 3 had detectable antibodies against HPV-11 virallike particles.

CONCLUSIONS

Our data support the association of HPV-11 infection with clinical severity. Measures of HPV-6 and HPV-11 viral loads are relatively stable over time in most children with recurrent respiratory papillomatosis, suggesting that multiple samples may not be necessary. Cytobrush samples may substitute for tissue biopsy specimens in HPV detection and typing, but not for absolute viral load determination.

Combinations of single nucleotide polymorphisms in neuroendocrine effector and receptor genes predict chronic fatigue syndrome

OBJECTIVE

This paper asks whether the presence of chronic fatigue syndrome (CFS) can be more accurately predicted from single nucleotide polymorphism (SNP) profiles than would occur by chance.

METHODS

Specifically, given SNP profiles for 43 CFS patients, together with 58 controls, we used an enumerative search to identify an ensemble of conjunctive rules that predict whether a patient has CFS.

RESULTS

The accuracy of the rules reached 76.3%, with the highest accuracy rules yielding 49 true negatives, 15 false negatives, 28 true positives and nine false positives (odds ratio [OR] 8.94, p < 0.0001). Analysis of the SNPs used most frequently in the overall ensemble of rules gave rise to a list of 'most important SNPs', which was not identical to the list of 'most differentiating SNPs' that one would calculate via studying each SNP independently. The top three genes containing the SNPs accounting for the highest accumulated importances were neuronal tryptophan hydroxylase (TPH2), catechol-O-methyltransferase (COMT) and nuclear receptor subfamily 3, group C, member 1 glucocorticoid receptor (NR3C1).

CONCLUSION

The fact that only 28 out of several million possible SNPs predict whether a person has CFS with 76% accuracy indicates that CFS has a genetic component that may help to explain some aspects of the illness.

Linear data mining the Wichita clinical matrix suggests sleep and allostatic load involvement in chronic fatigue syndrome

OBJECTIVES

To provide a mathematical introduction to the Wichita (KS, USA) clinical dataset, which is all of the nongenetic data (no microarray or single nucleotide polymorphism data) from the 2-day clinical evaluation, and show the preliminary findings and limitations, of popular, matrix algebra-based data mining techniques.

METHODS

An initial matrix of 440 variables by 227 human subjects was reduced to 183 variables by 164 subjects. Variables were excluded that strongly correlated with chronic fatigue syndrome (CFS) case classification by design (for example, the multidimensional fatigue inventory [MFI] data), that were otherwise self reporting in nature and also tended to correlate strongly with CFS classification, or were sparse or nonvarying between case and control. Subjects were excluded if they did not clearly fall into well-defined CFS classifications, had comorbid depression with melancholic features, or other medical or psychiatric exclusions. The popular data mining techniques, principle components analysis (PCA) and linear discriminant analysis (LDA), were used to determine how well the data separated into groups. Two different feature selection methods helped identify the most discriminating parameters.

RESULTS

Although purely biological features (variables) were found to separate CFS cases from controls, including many allostatic load and sleep-related variables, most parameters were not statistically significant individually. However, biological correlates of CFS, such as heart rate and heart rate variability, require further investigation.

CONCLUSIONS

Feature selection of a limited number of variables from the purely biological dataset produced better separation between groups than a PCA of the entire dataset. Feature selection highlighted the importance of many of the allostatic load variables studied in more detail by Maloney and colleagues in this issue [1] , as well as some sleep-related variables. Nonetheless, matrix linear algebra-based data mining approaches appeared to be of limited utility when compared with more sophisticated nonlinear analyses on richer data types, such as those found in Maloney and colleagues [1] and Goertzel and colleagues [2] in this issue.

Chronic fatigue syndrome and high allostatic load

Study population: We examined the relationship between chronic fatigue syndrome (CFS) and allostatic load in a population-based, case–control study of 43 CFS patients and 60 nonfatigued, healthy controls from Wichita, KS, USA. Methods: An allostatic load index was computed for all study participants using available laboratory and clinical data, according to a standard algorithm for allostatic load. Logistic regression analysis was used to compute odds ratios (ORs) as estimates of relative risk in models that included adjustment for matching factors and education; 95% confidence intervals (CIs) were computed to estimate the precision of the ORs. Results: CFS patients were 1.9-times more likely to have a high allostatic load index than controls (95% CI = 0.75, 4.75) after adjusting for education level, in addition to matching factors. The strength of this association increased in a linear trend across categories of low, medium and high levels of allostatic load (p = 0.06). Conclusion: CFS was associated with a high level of allostatic load. The three allostatic load components that best discriminated cases from controls were waist:hip ratio, aldosterone and urinary cortisol.

Allostatic load is associated with symptoms in chronic fatigue syndrome patients

Objectives: To further explore the relationship between chronic fatigue syndrome (CFS) and allostatic load (AL), we conducted a computational analysis involving 43 patients with CFS and 60 nonfatigued, healthy controls (NF) enrolled in a population-based case–control study in Wichita (KS, USA). We used traditional biostatistical methods to measure the association of high AL to standardized measures of physical and mental functioning, disability, fatigue and general symptom severity. We also used nonlinear regression technology embedded in machine learning algorithms to learn equations predicting various CFS symptoms based on the individual components of the allostatic load index (ALI). Methods: An ALI was computed for all study participants using available laboratory and clinical data on metabolic, cardiovascular and hypothalamic–pituitary–adrenal (HPA) axis factors. Physical and mental functioning/impairment was measured using the Medical Outcomes Study 36-item Short Form Health Survey (SF-36); current fatigue was measured using the 20-item multidimensional fatigue inventory (MFI); frequency and intensity of symptoms was measured using the 19-item symptom inventory (SI). Genetic programming, a nonlinear regression technique, was used to learn an ensemble of different predictive equations rather just than a single one. Statistical analysis was based on the calculation of the percentage of equations in the ensemble that utilized each input variable, producing a measure of the ‘utility’ of the variable for the predictive problem at hand. Traditional biostatistics methods include the median and Wilcoxon tests for comparing the median levels of subscale scores obtained on the SF-36, the MFI and the SI summary score. Results: Among CFS patients, but not controls, a high level of AL was significantly associated with lower median values (indicating worse health) of bodily pain, physical functioning and general symptom frequency/intensity. Using genetic programming, the ALI was determined to be a better predictor of these three health measures than any subcombination of ALI components among cases, but not controls.

Human leukocyte antigen concordance and the transmission risk via breast-feeding of human T cell lymphotropic virus type I

OBJECTIVE

We examined the association between mother-to-child human T cell lymphotropic virus type I (HTLV-I) transmission and human leukocyte antigen (HLA) class I types.

METHODS

In 1989, children born to HTLV-I-infected mothers in Jamaica were enrolled and prospectively evaluated for HTLV-I infection. HLA class I types in mothers and children were determined by DNA-based polymerase chain reaction methods. Associations between HLA class I types and transmission of HTLV-I were analyzed using proportional-hazards regression models adjusted for the duration of breast-feeding. Transmission risk in children still breast-feeding at 12 months was determined using actuarial methods.

RESULTS

Of 162 children, 28 (17%) became infected. After Bonferroni's adjustment for multiple comparisons, the transmission risk was not influenced by any specific HLA class type or the A2 supertype. However, compared with children who shared 3 HLA class I types with their mothers (the minimum number possible), the transmission risk increased 1.8-fold with 4 shared types and 3.0-fold with 5 or 6 shared types (Ptrend = .039; 1.75-fold increase for each additional concordant HLA type). This association was independent of maternal HTLV-I proviral level, antibody titer, and household income.

CONCLUSIONS

We found a significant dose-response relationship between HTLV-I transmission via breast-feeding and mother-child HLA class I type concordance. Immunological interactions between a child's cells and maternal cells may influence the risk of HTLV-I infection by breast-feeding, perhaps because antigens on maternal cells are seen by the child as being "self."

Provirus load in breast milk and risk of mother-to-child transmission of human T lymphotropic virus type I

In a prospective study of 101 mother-child pairs in Jamaica, we examined the association of provirus load in breast milk and the risk of mother-to-child transmission of human T lymphotropic virus type I. The provirus load in breast milk was a strong predictor of risk of transmission to children (relative risk, 2.34/quartile), after adjustment for other known risk factors. The risk of transmission increased from 4.7/1000 person-months when the provirus load in breast milk was <0.18% to 28.7/1000 person-months when it was >1.5%. Provirus detection in maternal breast milk predicted transmission months before infection in children was detected by serologic testing.

Prediagnostic Human T Lymphotropic Virus Type I Provirus Loads Were Highest in Jamaican Children Who Developed Seborrheic Dermatitis and Severe Anemia

In a recent clinical analysis of 308 Jamaican children, human T lymphotropic virus type I (HTLV-I) infection was found to be associated with significantly higher incidence rates of seborrheic dermatitis, eczema, and persistent hyperreflexia of the lower limbs and with nonsignificantly increased rates of severe anemia and abnormal lymphocytes. Results of examination of HTLV-I viral markers in the 28 HTLV-I-infected children provided virologic support for the epidemiologic associations of HTLV-I with seborrheic dermatitis and severe anemia in childhood.

A cohort study of health effects of human T-cell lymphotropic virus type I infection in Jamaican children

OBJECTIVE

Human T-cell lymphotropic virus type I (HTLV-I) infection in childhood is believed to play an important role in risk for adult T-cell leukemia/lymphoma. Although HTLV-I is known to be associated with infective dermatitis in childhood, other HTLV-I-associated morbidity in children has not been well studied. We sought to determine the HTLV-I-associated health effects in Jamaican children.

METHODS

We compared incidence rates of several health outcomes in 28 HTLV-I-infected and 280 uninfected children clinically followed from age 6 weeks to a maximum of 10 years. Cox proportional hazards regression analysis was used to analyze these prospectively collected data, adjusting for confounding effects of other variables as necessary.

RESULTS

HTLV-I-infected children had significantly higher incidence rates of seborrheic dermatitis (rate ratio [RR] = 4.8, 95% confidence interval [CI] = 1.9-12.5), eczema (RR = 3.1, CI = 1.2-7.9) and persistent hyperreflexia (RR = 3.7, CI = 1.6-8.2). Additionally, HTLV-I infected children had increased rates of severe anemia (RR = 2.5, CI = 0.8-7.9) and abnormal lymphocytes (RR = 2.4, CI = 0.8-7.6) that were of borderline statistical significance.

CONCLUSIONS

Our study suggests that HTLV-I-associated skin diseases of childhood may include seborrheic dermatitis and eczema. Additionally, these data suggest that persistent hyperreflexia of the lower limbs may be an early sign of HTLV-I-associated neurologic involvement in children. Expansion and continued clinical observation of this cohort would be valuable.

Virus markers associated with vertical transmission of human T lymphotropic virus type 1 in Jamaica

In a prospective study involving 150 mothers and their offspring in Jamaica, we examined maternal viral factors associated with the risk of transmission of human T lymphotropic virus type 1 (HTLV-1). Overall, the incidence of HTLV-1 infection among children was 8.3 occurrences per 1000 person-months. A higher maternal provirus level (odds ratio [OR], 1.9 per quartile) and a higher HTLV-1 antibody titer (OR, 2.2 per quartile) were independently associated with transmission to children, whereas the presence of anti-Tax antibody was not. Higher maternal antibody titers also were associated with older age at infection among children who were breast-fed for </=12 months, which suggests that passively transferred maternal antibodies confer protection against infection while they persist. These data imply that mothers who have high provirus loads should be encouraged not to breast-feed. Alternatively, the successful reduction of maternal provirus loads or maintenance of passive antibody levels in infants during breast-feeding may lower the risk of transmission.

Increased liver decompensation risk with atypical hepatitis C virus antibody levels

Knowledge of serum markers of liver decompensation would facilitate care of patients with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections. HCV load and anti-c33c and anti-NS5 levels did not distinguish 28 HCV- and HIV-positive predecompensation patients from 28 matched control patients, whereas more patients than controls had high anti-c100(p) and low anti-c22(p). In multivariate analysis, decompensation was associated with high anti-c100(p) titer (>/=1:4050; odds ratio [OR], 3. 4; 95% confidence interval [CI], 1.1-11.5) and low anti-c22(p) (<1:36,450; OR, 3.0; 95% CI, 1.0-10.2) and with antibody band strength at 1:50 dilution (anti-c100[p] OR, 7.0; 95% CI, 1. 7-48.9; anti-c22[p] OR, 7.1; 95% CI, 1.7-49.2). With high anti-c100(p) or low anti-c22(p), sensitivity for decompensation was 86%-96% and specificity was 21%-36%; with both markers, sensitivity was 29%-32% and specificity was 93%-96%. Although the mechanisms for these associations are unknown, if these findings are verified in other populations, anti-c100(p) and anti-c22(p) might be valuable surrogate markers for liver decompensation risk.

Central nervous system activation of the indoleamine-2,3-dioxygenase pathway in human T cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis

Human T cell lymphotropic virus type I (HTLV-I) is associated with a chronic neurologic disease called HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The potential mechanisms of HAM/TSP pathogenesis were assessed by examination of 2 pathways initiated by interferon-gamma, a predominant cytokine in HAM/TSP. Jamaican HAM/TSP patients (n=17) were compared with patients with other neurologic diseases (ONDs; n=13) with respect to cerebrospinal fluid levels of the following: neopterin; nitrite plus nitrate, a stable indicator of nitric oxide; and tryptophan and kynurenine, metabolites of the indoleamine-2,3-dioxygenase (IDO) pathway. HAM/TSP patients had significantly elevated levels of neopterin (P=.003) and kynurenine (P=.05) and a significantly decreased level of tryptophan (P=.003), compared with patients with ONDs. These results support immune activation within the central nervous system and activation of the IDO pathway. Thus, activation of the IDO pathway may play a role in HAM/TSP.

Risk factors for human T cell lymphotropic virus type II infection among the Guaymi Indians of Panama

To examine risk factors for human T cell lymphotropic virus type II (HTLV-II) infection, a case-control study was conducted among the Guaymi Indians of Panama. In females, HTLV-II seropositivity was associated with early sexual intercourse (</=13 vs. >15 years; odds ratio [OR], 2.50; 95% confidence interval [CI], 1.11-6.14) and number of lifetime sex partners. One partner increased risk of seropositivity by 30% (OR, 1.30; CI, 1.05-1.64), and risk increased with number of partners. Similar risk was associated with number of long-term sexual relationships. Among males, intercourse with prostitutes was associated with HTLV-II seropositivity (OR, 1.68; CI, 1.04-2.72). These data support a role for sexual transmission in HTLV-II infection. Association of seropositivity with primary residence in a traditional village (OR, 3.75; CI, 1.02-15.38) and lack of formal education (0 vs. >6 years [OR, 3.89; CI, 1.67-9.82]) observed in males may reflect differences in sexual practices associated with acculturation.

Serum neopterin, beta2-microglobulin, soluble interleukin-2 receptors, and immunoglobulin levels in healthy adolescents

Serum biomarkers, such as neopterin, beta2-microglobulin (B2M), and soluble interleukin-2 receptors (sIL-2R), are elevated in viral infections, including HIV-1 infection, and in inflammatory conditions, autoimmune disease, and malignancies. For many of these conditions, serum levels correlate with disease activity. Application of these biomarkers in adolescents is limited by a lack of information on the range and determinants of variability (age, sex, race) for serum levels of these important molecules in this age group. To address this question, we analyzed serum samples from a well-characterized heterogeneous population of 111 healthy adolescents. White children had significantly higher serum levels of sIL-2R and IgM and lower levels of IgG (P </= 0.001) than black children. Boys had higher sIL-2R and B2M levels (P < 0.005) and lower IgM levels (P < 0.05) than girls. No significant age effect on B2M or neopterin level was observed over the age range of 12-19 years included in this analysis. However, stratification by race showed that serum sIL-2R level was significantly associated with age among whites, but not among blacks. Values of these biomarkers in this population are compared with age-stratified values in the previously analyzed 20- to 69-year-old population from whose households the adolescent subjects were recruited.

Clinical, pathologic, and immunologic features of human T-lymphotrophic virus type I-associated infective dermatitis in children

OBJECTIVES

To define the clinical and laboratory features associated with infective dermatitis (ID) and confirm its association with human T-lymphotrophic virus type I (HTLV-I).

DESIGN

A case series of patients with ID were compared with patients with atopic dermatitis (AD), which is an important disease in the differential diagnosis of ID.

SETTING

Patients were recruited from dermatology and pediatric clinics at the University Hospital of the West Indies and the Bustamante Children's Hospital, Kingston, Jamaica.

MAIN OUTCOME MEASURES

Clinical and laboratory features of patients with AD were compared with those of patients with ID.

PATIENTS

Consecutive patients older than 1 1/2 years diagnosed as having ID (n=50) and AD (n=35) were enrolled based on clinical findings.

RESULTS

The mean ages of patients with ID and AD were 6.9 and 7.8 years, respectively. Histologically, both diseases were predominantly chronic dermatitis with propensity for skin colonization with Staphylococcus aureus and beta-hemolytic streptococci; however, the distribution of sites of skin involvement differed. Infection with HTLV-I was the most distinguishing feature among patients with ID, with seropositive results in 100%; only 5 (14%) of the 35 patients with AD had results seropositive for HTLV-I. Infective dermatitis was further characterized by dermatopathic lymphadenitis in 16 (67%) of 24 patients with palpable nodes. Anemia, lymphocytosis, and low albumin and elevated serum globulin levels were more prevalent among patients with ID. Significant elevations of IgA, IgD, and IgG levels were observed among patients with ID compared with those with AD. However, both patients with AD and those with ID had levels of IgD and IgE elevated above the normal range. T-cell subsets among patients with ID revealed T-cell activation with a high percentage of HLA-DR antigen positivity, elevated CD4 (2.4 x 10(9)/L) and CD8 (1.4 x 10(9)/L) cell counts, with an increased CD4/CD8 ratio of 1:73.

CONCLUSION

Infective dermatitis is a distinct clinical entity associated with HTLV-I, which plays a role in the pathogenesis and immune perturbations observed.

Incidence of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in Jamaica and Trinidad

HTLV-I is sexually transmitted more efficiently from men to women than vice versa, and the majority of HTLV-I endemic areas report a female preponderance of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) cases. The objective of this study was to estimate the gender- and age-specific incidence rates of HAM/TSP in the general population as well as in the HTLV-I-infected population in Jamaica and in Trinidad and Tobago. Incidence rates for HAM/TSP were computed based on all reported incident cases in both countries between 1990 and 1994. Population census reports for 1990 were used to calculate the population at risk. The age-standardized HAM/TSP incidence rate (mean +/- standard error of the mean) in Jamaica was 1.8 +/- 0.2/100,000 person years (PY). Among individuals of African descent in Trinidad and Tobago, the rate was 1.7 +/- 0.4/100,000 PY. As in HTLV-I seroprevalence, the incidence rate of HAM/TSP increased with age through the fifth decade of life and was three times as high in women than in men. The HAM/TSP incidence rate, calculated as a function of the number of HTLV-I-infected persons in each age stratum, is higher in women (24.7/100,000 PY) than in men (17.3/100,000 PY). With HTLV-I infection, the lifetime risk of developing HAM/TSP was estimated to be 1.9% overall and is slightly higher in women (1.8%) than in men (1.3%). Thus, the higher prevalence of HTLV-I in women in endemic areas does not fully explain the preponderance of female HAM/TSP, suggesting that other cofactors must be present. The higher incidence rate in women between the ages of 40 and 59 years, as well as the increase in HAM/TSP incidence rates with age, are indicative of the importance of adult-acquired HTLV-I infection, presumably through sexual transmission.

Mother-to-child transmission of human T-cell lymphotropic virus type I associated with prolonged breast-feeding

OBJECTIVES

We assessed the risk of transmitting human T-cell lymphotropic virus type I (HTLV-I) through breast-feeding.

STUDY DESIGN/METHODS

To assess the risk of mother-to-child transmission of HTLV-I, 212 HTLV-I-seropositive women and 145 HTLV-I-seronegative women were enrolled in a prospective cohort study conducted in Kingston, Jamaica. Their offspring were examined at regular intervals, and HTLV-I serostatus was determined at each visit.

RESULTS

Twenty-eight of the 181 children with at least one postnatal visit born to HTLV-I-seropositive women (and none of the children born to HTLV-I-seronegative women) were persistently seropositive and were considered HTLV-I infected (Kaplan-Meier estimated cumulative incidence, 18%; 95% CI, 12%-24%). Among children observed for at least 24 months, 19 (32%) of 60 children breast fed for 12 months or longer were HTLV-I seropositive, compared with only 8 (9%) of 86 children breast-fed for less than 12 months (relative risk, 3.4; 95% CI, 1.7-6.9). Compared with children weaned at younger ages, transmission of HTLV-I was associated with continued breast-feeding of children who were 12 to 18 months of age (relative hazard, 6.4; 95% CI, 2.1-180.2) and older than 18 months (relative hazard, 18.1; 95% CI, 1.4-29.5). Transmission was also associated with higher maternal antibody titer (a possible marker of virus load), prolonged duration of ruptured membranes during childbirth, and lower maternal income.

CONCLUSIONS

These results suggest that limiting the duration of breast-feeding to less than 12 months for children born to HTLV-I-seropositive mothers may significantly reduce mother-to-child transmission of HTLV-I.

Temporal variability in immunological parameters: peripheral blood mononuclear cell subsets, serum immunoglobulins, and soluble markers of immune system activation

T-cell subsets and soluble factors of immune system activation are increasingly used as biologic markers of disease and predictors of disease progression. For example, changes in CD4 cells and CD4:CD8 ratio, sIL-2R, B2M, neopterin, and IgA have been used in predicting AIDS onset and progression. We examined the temporal variability of T-cell subsets, monocytes, natural killer cells, B cells, immunoglobulins, soluble interleukin-2 receptor (sIL-2R), neopterin, and beta-2 microglobulin (B2M) among 135 adults tested at two time points approximately 3 months apart. The purpose of the study was two-fold: (1) to assess the stability of these measures at two points in time, and (2) to investigate which parameters tend to track together over time, i.e., show significant longitudinal correlation. Mean population values for these immunologic parameters remained remarkably stable over the 3-month period. However, individual subjects exhibited significant temporal variability for many parameters. Unlike observations in patients with AIDS, changes in immunoglobulins and other soluble factors were not significantly correlated with changes in cellular subsets over the same period. However, change in B2M was correlated with change in neopterin (r = .35, p < or = .0001), and change in IgA was correlated with changes in IgG and IgM (r = .44, r = .54, P < or = .001 for both). Characterizing this temporal variability in a healthy population provides important information for researchers applying these tests in clinical and epidemiological studies.

Differential patterns of serum biomarkers of immune activation in human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis, and adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) and human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) are associated with differing patterns of immune dysfunction. Biomarkers of immune activation may correlate with perturbations of immune function associated with these diseases. We conducted a pilot cross-sectional study to assess four candidate biomarkers of immune activation. beta 2-microglobulin, neopterin, tryptophan, and kynurenine levels were assayed in stored sera from asymptomatic, human T-cell leukemia virus type I (HTL V-I)-seronegative (HTLV-I-) and HTLV-I-seropositive (HTLV-I+) individuals, and ATL and HAM/TSP patients previously enrolled in seroepidemiological studies in Jamaica. Mean levels of beta 2-microglobulin, neopterin, and kynurenine were significantly elevated among ATL patients compared to the other study groups. Mean tryptophan levels were significantly lower among ATL and HAM/TSP patients than HTLV-I- and HTLV-I+ groups. No significant differences in biomarkers were found between the HTLV-I- and HTLV-I+ groups. Among HAM/TSP patients, a significant association was found between elevated neopterin levels and symptoms of less than 4 years duration. In Cox proportional hazards regression modeling, neopterin and tryptophan were found to be independent predictors of survival among ATL patients. This study demonstrates a differential pattern of biomarkers of immune activation among ATL and HAM/TSP patients compared to HTLV-I- and HTLV-I+ individuals. Neopterin and tryptophan may be useful clinical indicators of disease severity and prognosis among HAM/TSP and ATL patients.

Risk factors and cofactors for human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in Jamaica

Human T-cell lymphotropic virus type I (HTLV-I) has been etiologically associated with a neurologic syndrome called HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) as well as with adult T-cell leukemia/lymphoma. The authors sought to quantify the risk in Jamaica of HAM/TSP associated with HTLV-I infection and cofactors associated with this disease among infected individuals. Between 1988 and 1989, prevalent and incident HAM/TSP patients and controls with other neurologic diseases were enrolled in a retrospective study. A second control group was composed of HTLV-I-seropositive, asymptomatic carriers in Jamaica, ascertained in a separate study conducted in 1988. Although HTLV-I seropositivity was not a component of the case definition for HAM/TSP, all 43 HAM/TSP patients were HTLV-I seropositive compared with two (4.0%) of the controls with other neurologic diseases. Given HTLV-I seropositivity, one cofactor associated with the risk of HAM/TSP was young age at initial heterosexual confidence interval 1.29-12.46 for individuals aged < or = 15; odds ratio = 4.26, 95% confidence interval 1.41-12.90 for individuals aged 16-17 years at initial intercourse). Among individuals who reported this early age at initial sexual intercourse, an increased risk of HAM/TSP was associated with having reported more than five lifetime sexual partners (odds ratio = 2.88, 95% confidence interval 0.90-8.70). Neither an early age at initial sexual intercourse or the number of lifetime sexual partners was a risk factor for adult T-cell leukemia/lymphoma. These data support the hypothesis that HAM/TSP is associated with sexually acquired HTLV-I infection, whereas adult T-cell leukemia/lymphoma is not.

The relative distribution of T cell subsets is altered in Jamaican children infected with human T cell lymphotropic virus type I

Early childhood infection with human T cell lymphotropic virus type I (HTLV-I) has been suggested to be involved in the pathogenesis of infective dermatitis and adult T cell leukemia/lymphoma. Since only a very small percentage of HTLV-I-infected children develop disease later in life, identification of early interim markers for persons at risk for developing disease would enable monitoring and might provide insight into the pathophysiology of the various diseases associated with HTLV-I infection. A cross-sectional study analyzed T cell subsets in 35 HTLV-I-seronegative and 16 HTLV-I-seropositive Jamaican children 11-31 months old. HTLV-I seropositivity was associated with an increase in the mean percentage of CD4 cells expressing HLA-DR, a marker for T cell activation (P = .02). This increase was positively correlated with duration of infection (r = .74, P = .009). These data demonstrate perturbation of regulatory cells of the immune system in HTLV-I-infected children.

Racial differences in serum immunoglobulin levels: relationship to cigarette smoking, T-cell subsets, and soluble interleukin-2 receptors

To investigate the influence of race, cigarette smoking, and immunologic parameters on serum immunoglobulins, we analyzed serum IgG, IgA, and IgM levels in 455 healthy adults. The study population ranged in age from 20 to 69 years, including 282 whites and 173 blacks, 181 never-smokers, 93 ex-smokers, and 181 current smokers. Race and smoking were independently associated with alterations in serum IgG levels. Blacks had significantly higher IgG levels than whites (1,587 vs. 1,209 mg/dl; P < 0.001), and never smokers had significantly higher levels than current smokers (1,426 vs. 1,287 vs. mg/dl; P < 0.001). IgA and IgM levels were unrelated to race or smoking. Serum IgG was also found to be directly related to the proportion of HLA-DR+ cells and the level of soluble interleukin-2 receptors (sIL-2R) and inversely related to the proportion of CD4+ cells. Investigation of this racial heterogeneity may provide insights into the pathogenesis of immunologic diseases that exhibit unexplained racial variation.

Endemic transmission of HTLV type II among Kayapo Indians of Brazil

Serological studies on 926 blood samples from 703 Brazilian Kayapo (Cayapo) Indians showed, by conventional definition of HTLV seropositivity, a 28% prevalence of human T lymphotropic virus (HTLV) infection, the highest yet reported. Immunoblot (WB) and SYNTH-EIA patterns indicate that the predominant infecting agent is type II. Of children under 15 years old, 12% were positive, and of persons over 60, more than 60%. Perinatal and heterosexual modes of transmission offer an adequate explanation of this incidence. Infection in infancy may include infection via breast milk from women other than the mother. Evidence of new infection in adults is apparent at an earlier age in women than in men. This pattern of antibody prevalence was not determined by cohort effects, as demonstrated by tests of serial specimens. Enzyme immunosorbent assay (EIA) absorbencies were not stable in the paired specimens: five serum pairs reverted and mean absorbencies declined over some age ranges. Many specimens with relatively high, but less than positive, EIA results were positive by immunoblot (WB). This suggests that the standard EIA end point does not identify all infected persons. If the WB alone indicates positivity, 47% of the whole population, and more than 80% of the older age groups, are infected with HTLV-II.

Racial variation in serum-soluble interleukin-2 receptor levels: a population-based study of healthy smokers and nonsmokers

To investigate the influence of race and cigarette smoking on serum levels of soluble interleukin-2 receptors (sIL-2R), we studied a population-based cohort of 282 white and 173 black adults, ages 20-69 years. Serum sIL-2R concentrations in this healthy population ranged from 146 to 2623 U/ml. Whites had significantly higher sIL-2R levels than blacks (455 versus 365 U/ml; P < 0.001), and cigarette smokers had significantly higher levels than nonsmokers (508 versus 420 U/ml; P = 0.01). White smokers had the highest levels (550 U/ml); white nonsmokers and black smokers had intermediate levels (455 and 450 U/ml, respectively); and black nonsmokers had the lowest levels (365 U/ml). Smoking cessation appeared to normalize sIL-2R levels; exsmokers who had not smoked for at least 2 years had sIL-2R levels similar to those of never smokers. These data demonstrate the wide range of serum sIL-2R concentrations found in normal healthy adults and the significant influence of race and cigarette smoking. Further investigation of this natural heterogeneity may provide insights into the mechanisms underlying genetic and environmental influences on this important immunologic parameter.

Endemic human T cell lymphotropic virus type II infection among isolated Brazilian Amerindians

Evidence for human T cell lymphotropic viruses (HTLV) was sought in sera and cells collected from adults in 13 isolated South and Central American Indian tribes. Serologic tests identified frequent HTLV-II-like reactivity among the Cayapo and Kraho tribes, who live 330 km apart in Central Brazil. Polymerase chain reaction analyses of viral DNA in cell pellet and plasma fractions confirmed the virus as HTLV-II. Both tribes speak Gé and, at the time of blood collection (1974), subsisted as hunter/gatherers and slash and burn agriculturalists. Further testing of plasma from Cayapo and Kraho of all ages revealed overall HTLV-II prevalence rates of 33.3% and 12.2%, respectively, with increasing prevalence associated with age and female gender. These data reveal for the first time a high prevalence of HTLV-II infection in remote South American Indians with little contact with non-Indians. Thus, HTLV-II is postulated to be an ancient human virus in the New World.

Human T-lymphotropic virus type I (HTLV-I) seroprevalence in Jamaica. II. Geographic and ecologic determinants

An island-wide cohort of 13,260 Jamaicans who applied for food-handling licenses during 1985 and 1986 were tested for antibodies to human T-cell lymphotropic virus type I (HTLV-I). Demographic and residence history data were linked to geographic and ecologic measures of elevation, rainfall, crop-growing areas, population density, and additional measures of urbanization and correlated with HTLV-I antibody status. By logistic regression analysis (performed separately for men and women), men and women who currently resided at low elevation (less than or equal to 1,000 ft (305 m)) were more likely to be HTLV-I infected than were those residing at high elevation. Men, but not women, who were born in citrus-growing areas were more likely to be HTLV-I infected than were men who were born in other areas. By univariate analysis, there was a significant positive trend of increasing HTLV-I seroprevalence with increasing amount of annual rainfall associated with birthplace and primary residence areas. However, these associations did not remain significant after adjusting for age and sex. These environmental associations raise the possibility of new modes of viral transmission or host response to infection, although they may simply be surrogates for socioeconomic status, breastfeeding habits, or sexual behavior, which are known determinants of HTLV-I zero prevalence.

A survey of the human T-cell lymphotropic virus type I (HTLV-I) in south-western Colombia

To evaluate altitude of birthplace and residence as factors associated with geographic clustering of HTLV-I infection in Colombia, we sampled a total of 670 current residents of the South Pacific coastal lowland and of upland regions (Cali and environs) of the Valle and Cauca Provinces, located at an altitude of 3,100 ft. Among the 255 lowland study subjects, 4.3% had antibody against HTLV-I, compared to 0.9% of the 415 upland study subjects. A hypothesis emerging from this study is that the lower socio-economic status of lowland residents and associated diseases, particularly untreated syphilis and other sexually transmitted diseases, may explain the increased HTLV-I seropositivity rates in this population.