The prevalence of autoantibodies in an elderly sub-Saharan African population

Lupus and other autoimmune diseases: Epidemiology in the population of African ancestry and diagnostic and management challenges in Africa

Autoimmune diseases are prevalent among people of African ancestry living outside Africa. However, the burden of autoimmune diseases in Africa is not well understood. This article provides a global overview of the current burden of autoimmune diseases in individuals of African descent. It also discusses the major factors contributing to autoimmune diseases in this population group, as well as the challenges involved in diagnosing and managing autoimmune diseases in Africa.

Severe COVID-19 patients exhibit elevated levels of autoantibodies targeting cardiolipin and platelet glycoprotein with age: a systems biology approach

Age is a significant risk factor for the coronavirus disease 2019 (COVID-19) severity due to immunosenescence and certain age-dependent medical conditions (e.g., obesity, cardiovascular disorder, and chronic respiratory disease). However, despite the well-known influence of age on autoantibody biology in health and disease, its impact on the risk of developing severe COVID-19 remains poorly explored. Here, we performed a cross-sectional study of autoantibodies directed against 58 targets associated with autoimmune diseases in 159 individuals with different COVID-19 severity (71 mild, 61 moderate, and 27 with severe symptoms) and 73 healthy controls. We found that the natural production of autoantibodies increases with age and is exacerbated by SARS-CoV-2 infection, mostly in severe COVID-19 patients. Multiple linear regression analysis showed that severe COVID-19 patients have a significant age-associated increase of autoantibody levels against 16 targets (e.g., amyloid β peptide, β catenin, cardiolipin, claudin, enteric nerve, fibulin, insulin receptor a, and platelet glycoprotein). Principal component analysis with spectrum decomposition and hierarchical clustering analysis based on these autoantibodies indicated an age-dependent stratification of severe COVID-19 patients. Random forest analysis ranked autoantibodies targeting cardiolipin, claudin, and platelet glycoprotein as the three most crucial autoantibodies for the stratification of severe COVID-19 patients ≥50 years of age. Follow-up analysis using binomial logistic regression found that anti-cardiolipin and anti-platelet glycoprotein autoantibodies significantly increased the likelihood of developing a severe COVID-19 phenotype with aging. These findings provide key insights to explain why aging increases the chance of developing more severe COVID-19 phenotypes.

ASSOCIATION OF SERUM AUTO-ANTIBODIES AND THYROID FUNCTION TEST IN PATIENTS WITH NON-NEOPLASTIC THYROID DISEASES IN SHENDI LOCALITY, SUDAN

Background:  Thyroid disorders are the most second endocrine problem after diabetes mellitus in society. Environmental, immunological, and genetic factors   lead to the development of thyroid disorders.  Objectives: The study intended to evaluate the role of thyroid antibodies and hormones in the diagnosis of thyroid diseases, as well as the prevalence of thyroid antibodies in patients having thyroid disorders living   in Shendi locality. Study design: The current research was prospective, case - control, hospital-based study carried out from 2013-2017, in El-Mek Nimir Uiversity Hospital in Shendi town- Northern Sudan.-. River Nile State. Two hundred and eighty-three (283) participants selected randomly as study population, of whom Hundred and eleven (111) patients with hypothyroidism; Seventy-two (72) patients with hyperthyroidism; Hundred (100) healthy normal subjects as control group.  Participants were recruited from outpatient clinics in El-Mek Nimir Uiversity Hospital in Shendi Thyroid hormones profile (TSH, T4, T3, fT3, and fT4) and Thyroid antibodies (Anti-thyroid peroxidase and antithyroglobulin) were measured. Results: The study revealed that (60.7%) had hypothyroidism, (39.3%) had hyperthyroidism, (91.9%) of hypothyroidism were female, and only (8.1%) were male, while (84.7%) of hyperthyroidism were female while male represented only (15.3%) of them. The current study revealed that 107 of the case group (58.5%) were positive when evaluated for thyroid peroxidase antibodies (TPO Ab), with level more than (40.0 IU/ml).  72 (64.9%) of them were hypothyroidism, whereas a 35 (48.6%) of them were hyperthyroidism. As regard Thyroglobulin antibodies (Tg Ab), 73 (39.9%) of the case studied were positive, 51 (69.9%) of them were hypothyroidism, and 22 (30.1%) of them were hyperthyroidism. The study also revealed statistically significant positive correlation between the presence of TPO Ab and the values of fT3

Autoantibodies Among HIV-1 Infected Individuals and the Effect of Anti-Retroviral Therapy (ART) on It

BACKGROUND

Antiretroviral therapy (ART) has led to a decline in autoimmune diseases but lacks studies on its effect on autoantibodies.

METHODS

It is a cross-sectional study with archived samples from 100 paired HIV-1 infected ART naïve and experienced individuals and 100 prospectively collected matched blood-donor controls. Antinuclear antibody, IgG anticardiolipin antibody, IgM and IgG β2 glycoprotein-1 antibodies, and total IgG levels were detected. Results are expressed as mean with standard deviation (SD), median, percentage positivity, and a p<0.05 is considered significant. The study was approved by the Institutional Review Board.

RESULTS

The median viral load of the treatment naïve samples was 4.34 Log copies/mL, while all were virally suppressed post ART with a median duration of treatment for 12 months (range: 3-36 months). The percentage of antinuclear antibody positivity was 5% among ART naïve and controls, with a decrease of 2% post ART (p= 0.441). The positivity for anti-cardiolipin antibody was 15% among ART naïve while none of the ART experienced or controls were positive (p<0.05). IgM β2 glycoprotein-1 were 4%, 1% and 3% among ART naïve, treated and controls, respectively (p<0.05). IgG β2 glycoprotein-1 was 2% among ART naïve while none of the treated and controls were positive (p<0.05). The mean total IgG level among ART naïve, experienced, and controls were 21.82 (SD 6.67), 16.91 (SD 3.38), 13.70 (SD 2.24) grams/Litre, respectively (p<0.05).

CONCLUSION

ART has a significant effect on IgG anti-cardiolipin antibody and total IgG but only a marginal effect on ANA, IgM, and IgG β2 glycoprotein-1 antibodies.

Helminth infections and immunosenescence: The friend of my enemy

Age-associated alterations of the immune system, which known as "immunosenescence", is characterized by a decline in innate and adaptive immunity, which leading to increased susceptibility to age-associated diseases, such as infectious diseases, rheumatic disease and malignancies. On the other hand, helminth infections are among the most prevalent infections in older individuals, especially in the nursing homes. Most of helminth infections have minor clinical symptoms and usually causing chronic infections without treatment. Nevertheless, chronic helminthiasis alters immune responses somewhat similar to the immunosenescence. Some similarities also exist between helminth infections and immunosenescence: 1) both of them led to declining the immune responses; 2) undernutrition is a consequence of immunosenescence and helminthiasis; 3) vaccine efficacy declines in aging and individuals with helminth infections; 4) increase incidence and prevalence of infectious diseases in the elder individuals and patients with helminth infections; and 5) both of them promote tumorigenesis. Hence, it is probable that helminth infections in the elderly population can intensify the immunosenescence outcomes due to the synergistic immunoregulatory effects of each of them. It would be suggested that, diagnosis, treatment and prevention of helminth infections should be more considered in older individuals. Also, it would be suggested that helminths or their antigens can be used for investigation of immunosenescence because both of them possess some similarities in immune alterations. Taken together, this review offers new insights into the immunology of aging and helminth infections.

Cellular aging over 13 years associated with incident antinuclear antibody positivity in the Baltimore Longitudinal Study of Aging

Age-associated increases in antinuclear antibodies (ANA) in the general population are commonly noted but the mechanisms underlying this observation are unclear. This study aims to evaluate whether shorter peripheral blood mononuclear cell (PBMC) telomere length, a marker of more advanced biological age, is associated with ANA positivity prevalence and incidence in middle and older aged autoimmune disease-free individuals from the Baltimore Longitudinal Study of Aging (BLSA). Telomere length was measured by Southern Blot and categorized into tertiles. ANA was measured in a 1:80 and a 1:160 dilution of sera by immunofluorescence using HEp-2 cells (seropositive = 3 or 4). Multiple logistic regression was used to estimate the odds ratios and 95% confidence intervals of ANA positivity comparing the shorter tertiles of telomere length to the longest tertile for two cross-sectional points in time and then longitudinally to assess the association between shorter telomere length and incident ANA positivity. Cross-sectional analyses were adjusted for sex, race and BMI (N = 368 baseline, N = 370 follow-up) and longitudinal analyses were adjusted for sex, race, BMI and time between baseline and follow-up (N = 246). No statistically significant cross-sectional associations were observed at baseline or follow-up. Among those where ANA negative at baseline, individuals with shorter telomeres were more likely to be ANA positive at follow-up, an average 13 years later. Individuals with short telomeres at both time periods were more likely to be ANA positive. Findings suggest that ANA positivity in the general population may be indicative of immune dysfunction resulting from advanced cellular aging processes.

High Seroprevalence of Autoantibodies Typical of Autoimmune Liver Disease in Eastern Ethiopia: Is Chewing of Khat (Catha edulis) a Triggering Factor?

BACKGROUND

Recent studies have identified chewing of khat (Catha edulis) as an independent risk factor for liver injury; however, the pathogenetic mechanism remains poorly understood. Case series have found markers of autoimmune hepatitis in patients with khat-related liver disease, suggesting that khat chewing might trigger an autoimmune response. The aims of the present study were (i) to assess the prevalence of autoantibodies typical for autoimmune liver diseases in a healthy population in Ethiopia and (ii) to explore the hypothesis that khat usage triggers autoimmunity.

METHODS

Consenting adults (≥18 years) without known autoimmune disease or manifest liver disease were included. One-hundred-and-sixty-nine individuals with current khat use were compared to 104 individuals who never used khat. Seroprevalence of antinuclear (ANA), antismooth muscle (SMA), and antimitochondrial antibodies (AMA) were determined and compared between the groups using logistic regression models to adjust for age and sex.

RESULTS

Overall, 2.6% of the study subjects were positive for ANA, 15.4% for SMA, and 25.6% for AMA. When comparing khat users to nonusers, ANA was detected in 4.1% vs. 0% (p=0.047), SMA in 16.0% vs. 14.4% (p=0.730), and AMA in 24.9% vs. 26.9% (p=0.704). ANA was excluded from multivariable analysis since there was no seropositive in the reference group. After adjusting for sex and age, no significant association between khat use and SMA or AMA was found.

CONCLUSIONS

No association between khat usage and the seropresence of SMA or AMA was found, weakening the hypothesis that khat-related liver injury is mediated through autoimmune mechanisms. However, the seroprevalences of AMA and SMA were strikingly high in this Ethiopian population compared to global estimates, suggesting that diagnostic algorithms for autoimmune liver diseases developed in Europe and North America might lead to misdiagnosis of patients on the African continent.

Vitamin D Status and Its Associated Risk Factors among Adults in the Southwest Region of Cameroon

Background

Vitamin D has been shown to exert its actions on the musculoskeletal, gastrointestinal, prostate, renal, endocrine, immune, and cardiovascular systems. Current reported data of hypovitaminosis D reveals a global pandemic, with an estimated one billion people worldwide presenting with hypovitaminosis D.

Objective

This study aimed at investigating the vitamin D status and its associated risk factors in Cameroonians from the South West Region.

Method

The study was a community- and hospital-based prospective longitudinal study. It was carried out during the dry and rainy seasons between the months of July and December 2015 in the South West Region of Cameroon involving 372 participants aged 35 years and above. After obtaining informed consent, a structured questionnaire was used to capture demographic data and risk factors of vitamin D deficiency. Blood samples were collected from the volunteer participants in the peak months of the rainy season and dry season, and the serum used to analyse for vitamin D by ELISA and calcium by spectrophotometry. 25(OH)D levels ≥75 nmol/L (≥30 ng/mL) were considered sufficient while levels <75 nmol/L were considered as hypovitaminosis D (insufficiency/deficiency).

Results

Hypovitaminosis D (deficiency/insufficiency) was prevalent in 25.8% (96) of the study population, with only 3.2% (12) deficiency and 22.6% (84) insufficiency. There was a significant inverse relationship (r=−0.119, p=0.02) between age and 25(OH)D levels; however, this relationship was not significant when controlled for gender, number of hours spent outdoors, and percentage of body covered. Gender, ethnic origin, percentage of body covered, time spent outdoors, and season did not influence serum vitamin D levels.

Conclusion

Results of this study suggest that the prevalence of hypovitaminosis D is relatively low in this study population and only age is a risk factor of vitamin D deficiency.

Is vitamin D deficiency a public health concern for low middle income countries? A systematic literature review

PURPOSE

Vitamin D deficiency has been receiving increasing attention as a potential public health concern in low and lower-middle income countries (LMICs), of which there are currently 83. We aimed to conduct a comprehensive systematic literature review (SLR) of available data on vitamin D status and prevalence of vitamin D deficiency in all 83 LMICs.

METHODS

We followed the general methodology for SLRs in the area of serum 25-hydroxyvitamin D. Highest priority was placed on identifying relevant population-based studies, followed by cross-sectional studies, and to a lesser extent case-control studies. We adopted the public health convention that a prevalence of vitamin D deficiency (serum 25-hydroxyvitamin D < 25/30 nmol/L) at > 20% in the entire population and/or at-risk population subgroups (infants, children, women of child-bearing age, pregnancy) constitutes a public health issue that may warrant intervention.

RESULTS

Our SLR revealed that of the 83 LMICs, 65% (n = 54 countries) had no published studies with vitamin D data suitable for inclusion. Using data from the remaining third, a number of LMICs had evidence of excess burden of vitamin D deficiency in one or more population subgroup(s) using the above convention (Afghanistan, Pakistan, India, Tunisia and Mongolia) as well as possibly other LMICs, albeit with much more limited data. Several LMICs had no evidence of excess burden.

CONCLUSION

Vitamin D deficiency is a public health issue in some, but certainly not all, LMICs. There is a clear need for targeting public health strategies for prevention of vitamin D deficiency in those LMICs with excess burden.

Vitamin D deficiency as a risk factor for the development of autoantibodies in patients with ASIA and silicone breast implants: a cohort study and review of the literature

The development of autoimmunity and/or autoimmune diseases is multifactorial. Vitamin D is one of the factors that might play a role. We postulated that both the presence of adjuvants and insufficient levels of vitamin D may result in the development of autoimmunity in patients with autoimmune/inflammatory syndrome induced by adjuvants (ASIA) in relation to silicone implant incompatibility. We measured vitamin D levels in 135 patients with ASIA in relation to silicone implant incompatibility and related findings to the presence of autoantibodies that are commonly used to diagnose systemic autoimmune diseases. Furthermore, we systematically reviewed the literature regarding vitamin D deficiency as a risk factor for the development of autoantibodies. Vitamin D measurements were available for analysis in 131 of 135 patients with ASIA in relation to SIIS. Twenty-three patients (18%) tested positive for autoantibodies, from which 18 patients (78%) had either a vitamin D deficiency or insufficiency (median vitamin D level 60.5 mmol/L), whereas five patients (22%) had sufficient vitamin D levels. The risk to develop autoantibodies was significantly increased in vitamin D deficient and/or insufficient patients [RR 3.14; 95% CI, 1.24–7.95; p = 0.009]. Reviewed literature suggested an association between vitamin D levels and the presence and/or titer levels of autoantibodies in different autoimmune diseases. From our current study and from our review of the literature, we conclude that vitamin D deficiency is related to the presence of autoantibodies. Whether vitamin D supplementation results in a decrease of autoimmunity needs to be studied prospectively.

Low level autoantibodies can be frequently detected in the general Australian population

The aim of this study was to determine the prevalence and type of autoantibodies in a general Australian population cohort. Samples collected from 198 individuals included in a cross sectional Busselton Health Study were tested using autoantibody assays routinely performed at Clinical Immunology, PathWest Laboratory Medicine, Western Australia. At least one autoantibody was detected in 51.5% of individuals (males = 45.1%, females = 58.3%). The most frequently detected serum autoantibodies were anti-beta-2-glycoprotein I (12.1%) followed by anti-smooth muscle (11.6%) and anti-thyroid peroxidase (8.6%). Vasculitis associated anti-neutrophil cytoplasmic antibodies were present in 5.1%, while anti-nuclear antibodies were detected in 8.6% of individuals. Notably, 65% of positive results were detected at low levels with the exception of anti-myeloperoxidase and anti-beta 2 glycoprotein I IgG antibodies. Autoantibodies are commonly detected at low levels in a predominantly Australian or European population cohort. No large Australian study has yet provided these data for contemporary routine tests. This paper gives important information on the background frequency of autoantibodies in the general population. Due to the nature of this study we are unaware of whether these individuals have subsequently developed an autoimmune disease, however this was not clinically diagnosed at the time of sample collection.

Reproductive and hormonal risk factors for antinuclear antibodies (ANA) in a representative sample of U.S. women

BACKGROUND

Autoantibodies are of growing interest in cancer research as potential biomarkers; yet, the determinants of autoimmunity are not well understood. Antinuclear antibodies (ANA) are common in the general population and are more prevalent in women and older adults. Here, we examined the relationship of ANA with reproductive and hormonal factors in a representative sample of U.S. women.

METHODS

We analyzed data on reproductive history and exogenous hormone use in relation to serum ANA in 2,037 females ages 12 years and older from the National Health and Nutrition Examination Survey (NHANES; 1999-2004). Estimated ANA prevalences were adjusted for sampling weights. Prevalence ORs (POR) and 95% confidence intervals (CI) were adjusted for age, race, and poverty-income ratio, and models were stratified by menopause status.

RESULTS

In premenopausal women ages 20 years and older, ANA prevalence was associated with parity (P < 0.001; parous vs. nulliparous POR = 2.0; 95% CI, 1.2-3.4), but in parous women, ANA did not vary by number of births, age at first birth, years since last birth, or breastfeeding. In postmenopausal women, ANA prevalence was associated with an older age at menarche (P = 0.019; age 16-20 vs. 10-12 years POR = 3.0; 95% CI, 1.6-5.9), but not with parity. Oral contraceptives and estrogen therapy were not associated with a higher ANA prevalence.

CONCLUSIONS

Childbearing (having had one or more births) may explain age-associated elevations in ANA prevalence seen in premenopausal women.

IMPACT

These findings highlight the importance of considering reproductive history in studies of autoimmunity and cancer in women.

Relationship of vitamin D insufficiency to AIDS-associated Kaposi's sarcoma outcomes: retrospective analysis of a prospective clinical trial in Zimbabwe

OBJECTIVES

The prevalence of vitamin D insufficiency in Africans with AIDS-associated Kaposi sarcoma (AIDS-KS) and the role of vitamin D in AIDS-KS progression are unknown. We hypothesized that a high prevalence of vitamin D deficiency would be found in Zimbabweans with AIDS-KS and that low baseline vitamin D would correlate with progression of AIDS-KS.

METHODS

Ninety subjects were enrolled in a prospective pilot study investigation of the effect of antiretroviral therapy in the treatment of AIDS-KS in Harare, Zimbabwe. Co-formulated abacavir, lamivudine, and zidovudine was initiated; chemotherapy was provided at the discretion of the provider. Participants were followed for 96 weeks. 25-Hydroxyvitamin D was measured in stored specimens collected at study entry. The relationship between vitamin D and clinical response was described by odds ratio and 95% confidence interval.

RESULTS

Samples were available for 85 participants; 45 (53%) subjects had inadequate (<75 nmol/l) 25-hydroxyvitamin D. HIV-1 RNA was significantly higher among those with insufficient vitamin D (4.7 vs. 4.5 log, p = 0.04). Tumor response, survival, and KS-IRIS were not associated with vitamin D (p ≥ 0.3).

CONCLUSIONS

Vitamin D insufficiency was common among Zimbabweans with AIDS-KS but not associated with outcomes after initiation of antiretroviral therapy.

The uncertain significance of low vitamin D levels in African descent populations: a review of the bone and cardiometabolic literature

Vitamin D levels in people of African descent are often described as inadequate or deficient. Whether low vitamin D levels in people of African descent lead to compromised bone or cardiometabolic health is unknown. Clarity on this issue is essential because if clinically significant vitamin D deficiency is present, vitamin D supplementation is necessary. However, if vitamin D is metabolically sufficient, vitamin D supplementation could be wasteful of scarce resources and even harmful. In this review vitamin D physiology is described with a focus on issues specific to populations of African descent such as the influence of melanin on endogenous vitamin D production and lactose intolerance on the willingness of people to ingest vitamin D fortified foods. Then data on the relationship of vitamin D to bone and cardiometabolic health in people of African descent are evaluated.

A systematic review of vitamin D status in populations worldwide

Vitamin D deficiency is associated with osteoporosis and is thought to increase the risk of cancer and CVD. Despite these numerous potential health effects, data on vitamin D status at the population level and within key subgroups are limited. The aims of the present study were to examine patterns of 25-hydroxyvitamin D (25(OH)D) levels worldwide and to assess differences by age, sex and region. In a systematic literature review using the Medline and EMBASE databases, we identified 195 studies conducted in forty-four countries involving more than 168 000 participants. Mean population-level 25(OH)D values varied considerably across the studies (range 4·9-136·2 nmol/l), with 37·3 % of the studies reporting mean values below 50 nmol/l. The highest 25(OH)D values were observed in North America. Although age-related differences were observed in the Asia/Pacific and Middle East/Africa regions, they were not observed elsewhere and sex-related differences were not observed in any region. Substantial heterogeneity between the studies precluded drawing conclusions on overall vitamin D status at the population level. Exploratory analyses, however, suggested that newborns and institutionalised elderly from several regions worldwide appeared to be at a generally higher risk of exhibiting lower 25(OH)D values. Substantial details on worldwide patterns of vitamin D status at the population level and within key subgroups are needed to inform public health policy development to reduce risk for potential health consequences of an inadequate vitamin D status.

Autoimmune thyroid disorders

Purpose of Review. Studies have been published in the field of autoimmune thyroid diseases since January 2005. The review is organized into areas of etiology, autoimmune features, autoantibodies, mechanism of thyroid cell injury, B-cell responses, and T-cell responses. Also it reviews the diagnosis and the relationship between autoimmune thyroid disease, neoplasm, and kidney disorders. Recent Findings. Autoimmune thyroid diseases have been reported in people living in different parts of the world including North America, Europe, Baalkans, Asia, Middle East, South America, and Africa though the reported figures do not fully reflect the number of people infected per year. Cases are unrecognized due to inaccurate diagnosis and hence are treated as other diseases. However, the most recent studies have shown that the human autoimmune thyroid diseases (AITDs) affect up to 5% of the general population and are seen mostly in women between 30 and 50 years. Summary. Autoimmune thyroid disease is the result of a complex interaction between genetic and environmental factors. Overall, this review has expanded our understanding of the mechanism involved in pathogenesis of AITD and the relationship between autoimmune thyroid disease, neoplasm, and kidney disease. It has opened new lines of investigations that will ultimately result in a better clinical practice.

A global representation of vitamin D status in healthy populations

PURPOSE

This paper visualizes the available data on vitamin D status on a global map, examines the existing heterogeneities in vitamin D status and identifies research gaps.

METHODS

A graphical illustration of global vitamin D status was developed based on a systematic review of the worldwide literature published between 1990 and 2011. Studies were eligible if they included samples of randomly selected males and females from the general population and assessed circulating 25-hydroxyvitamin D [25(OH)D] levels. Two different age categories were selected: children and adolescents (1-18 years) and adults (>18 years). Studies were chosen to represent a country based on a hierarchical set of criteria.

RESULTS

In total, 200 studies from 46 countries met the inclusion criteria, most coming from Europe. Forty-two of these studies (21 %) were classified as representative. In children, gaps in data were identified in large parts of Africa, Central and South America, Europe, and most of the Asia/Pacific region. In adults, there was lack of information in Central America, much of South America and Africa. Large regions were identified for which the mean 25(OH)D levels were below 50 nmol/L.

CONCLUSIONS

This study provides an overview of 25(OH)D levels around the globe. It reveals large gaps in information in children and adolescents and smaller but important gaps in adults. In view of the importance of vitamin D to musculoskeletal growth, development, and preservation, and of its potential importance in other tissues, we strongly encourage new research to clearly define 25(OH)D status around the world.

Prevalence of vitamin D deficiency among Turkish, Moroccan, Indian and sub-Sahara African populations in Europe and their countries of origin: an overview

Vitamin D status of nonwestern immigrants in Europe was poor. Vitamin D status of nonwestern populations in their countries of origin varied, being either similar to the immigrant populations in Europe or higher than in European indigenous populations. Vitamin D concentrations in nonwestern immigrant populations should be improved.

PURPOSE

The higher the latitude, the less vitamin D is produced in the skin. Most European countries are located at higher latitudes than the countries of origin of their nonwestern immigrants. Our aim was to compare the serum 25-hydroxyvitamin D (25(OH)D) concentration of nonwestern immigrant populations with those of the population in their country of origin, and the indigenous population of the country they migrated to.

METHODS

We performed literature searches in the "PubMed" and "Embase" databases, restricted to 1990 and later. The search profile consisted of terms referring to vitamin D or vitamin D deficiency, prevalence or cross-sectional studies, and countries or ethnicity. Titles and abstracts were reviewed to identify studies on population-based mean serum 25(OH)D concentrations among Turkish, Moroccan, Indian, and sub-Sahara African populations in Europe, Turkey, Morocco, India, and sub-Sahara Africa.

RESULTS

The vitamin D status of immigrant populations in Europe was poor compared to the indigenous European populations. The vitamin D status of studied populations in Turkey and India varied and was either similar to the immigrant populations in Europe (low) or similar to or even higher than the indigenous European populations (high).

CONCLUSIONS

In addition to observed negative consequences of low serum 25(OH)D concentrations among nonwestern populations, this overview indicates that vitamin D status in nonwestern immigrant populations should be improved. The most efficacious strategy should be the subject of further study.

Circulating heat shock protein 70 (Hsp70) in elderly members of a rural population from Cameroon: association with infection and nutrition

Hsp are highly conserved cytoprotective proteins which have been repeatedly portrayed at elevated levels in various infectious diseases, and there are suggestions that the presence of infectious agents may possibly be the root cause of Hsp induction. As organisms age the vulnerability to illnesses such as infection and inflammation increases and late complications due to infectious agents are mostly observed in the older part of the population. Although it is well known that environmental conditions can modulate the susceptibility to infection, and that poor nutritional status can increase the risk of contracting infection when exposed to an infectious agent, the effects of environmental conditions and nutritional status on the heat shock response have not been investigated. Therefore, we studied the heat shock response in a special elderly population living in a remote area in Cameroon, where infection and parasitosis are endemic. Our results indicate a significant increase in Hsp70 serum levels with increasing degree of inflammation. We found negative correlations between Hsp70 levels and micronutrients including vitamin D, vitamin B12, as well as folate, which could be linked to the immune modulating effects of these vitamins.

Fitness correlates of heritable variation in antibody responsiveness in a wild mammal

A functional immune system is important for survival in natural environments, where individuals are frequently exposed to parasites. Yet strong immune responses may have fitness costs if they deplete limited energetic resources or cause autoimmune disease. We have found associations between fitness and heritable self-reactive antibody responsiveness in a wild population of Soay sheep. The occurrence of self-reactive antibodies correlated with overall antibody responsiveness and was associated with reduced reproduction in adults of both sexes. However, in females, the presence of self-reactive antibodies was positively associated with adult survival during harsh winters. Our results highlight the complex effects of natural selection on immune responsiveness and suggest that fitness trade-offs may maintain immunoheterogeneity, including genetic variation in autoimmune susceptibility.

The clinical significance of autoantibodies in gastrointestinal malignancies: an overview

Autoimmunity can be associated with cancer and one of the forms of its expression is the development of antibodies to autologous cellular antigens. The types of cellular proteins which induce autoantibody responses in gastrointestinal malignancies are quite varied and include cellular proteins encoded by mutated normal genes (p53), cellular proteins that are overexpressed and/or aberrantly expressed in malignant tissues (carcinoembryonic antigen), inhibitors of apoptosis (survivin and livin), major components of mucus (mucins), surface receptors of apoptosis (Fas) and nuclear-restricted proteins (double-stranded DNA, single-stranded DNA and Sm family proteins). In the past few years, due to the great clinical interest and the advancement in detection techniques, the above list has grown significantly and a large number of cancer-related antigens, which trigger a specific humoral immune response to the host, have also been identified. The authors review the autoantibodies associated with gastrointestinal malignancies and their clinical implications.

Frequency of diabetes and thyroid autoantibodies in patients with autoimmune endocrine disease from Cameroon

BACKGROUND

Diabetes is a major cause of morbidity and mortality in both industrialized and developing countries. In Africa, there are little data on the prevalence and immunological features of patients with autoimmune endocrine diseases.

AIM OF THE STUDY

The present hospital-based study was carried out to evaluate disease-associated autoantibodies in both type 1 diabetes and thyrotoxicosis attending the Central Hospital of Yaoundee in Cameroon.

PATIENTS AND METHODS

Samples were collected from a total of 101 subjects, 47 of whom clinically had established type 1 diabetes (mean age 30.1 years +/- 7.6, mean disease duration 3.3 years), 18 had thyrotoxicosis (mean age 32.7 years +/- 7.6, mean disease duration 6.3 years +/- 2.8) and 36 normal subjects (mean age 26 years +/- 4.5). All subjects were tested for diabetes-associated glutamic acid decarboxylase (GAD) and tyrosine phosphatase (IA2) autoantibodies using antigen-specific radioimmunoassay as well as thyroiditis-associated thyroglobulin (Tg) and thyroid peroxidase (TPO) autoantibodies using commercially available kits.

RESULTS

Of 47 patients with type 1 diabetes, 16 (34%) had GAD autoantibodies (Abs), 3 (6.4%) had IA2 Abs, and 2 (4.3%) had TPO Abs. Of 18 patients with thyrotoxicosis 4 (22.2%) had GAD Abs, 5 (27.8%) showed IA2 Abs, while 8 patients (44.4%) were TPO Abs positive. No patients in either group had Tg Abs. Among normal subjects, 2 (5.6%) showed GAD Abs, and one of these was also IA2 Abs positive, but none had thyroid autoantibodies.

CONCLUSION

Adult-onset type 1 diabetic patients some years post-diagnosis from central Africa show GAD, IA2 or TPO Abs; and surprisingly, patients with thyrotoxicosis had a similar frequency of diabetes-associated autoantibodies. We conclude that, despite a different genetic and environmental background to European populations, islet cell autoimmunity is common in autoimmune endocrine patients in central Africa.

Contribution of epidemiological studies to gastritis immunology

Chronic gastritis, or chronic inflammation in gastric antral and/or corpus mucosa, is a common pathological condition affecting over half the general population. Progression of chronic gastritis from Helicobacter pylori infection to severe gastric mucosal atrophy usually takes decades and varies considerably from person to person. Therefore, studies of clinically selected material cannot provide a complete picture of natural evolution of the disease or its wide variability. An overview of immunological and morphological aspects of chronic gastritis in an epidemiological context, based on data from the literature and the author's studies, reveal dynamic interaction between H. pylori infection and host response to the organism's antigens, and to gastric autoantigens including gastric H+K+ ATPase. Further population and followup studies of antral and corpus gastritis at different stages of evolution are needed, in combination with new methods, to elucidate further the roles of infection, and gastric-antrum- and corpus-mucosa-related autoimmune responses, in the pathogenesis of chronic gastritis.

Immunity and immunization in elderly

As the average life expectancy increases, retired people want to travel. Five to 8% of travellers in tropical areas are old persons. Immune system suffers of old age as the other organs. The number and the functions of the T-lymphocytes decrease, but the B-lymphocytes are not altered. So, the response to the vaccinations is slower and lower in the elderly. Influenza is a great cause of death rate in old people. The seroconversion, after vaccine, is 50% from 60 to 70 years old, 31% from 70 to 80 years old, and only 11% after 80 years old. But in public health, the vaccination reduced the morbidity by 25%, admission to hospital by 20%, pneumonia by 50%, and mortality by 70%. Antipoliomyelitis vaccine is useful for travellers, as the vaccines against hepatitis and typhoid fever. Pneumococcal vaccine is effective in 60%. Tetanus is fatal in at last 32% of the people above 80 years, therefore this vaccine is very important.

Autoimmunity and geriatrics: clinical significance of autoimmune manifestations in the elderly

The immune system undergoes continuous morphologic and functional changes throughout the years, and it is now believed that the immune response has its peak function in puberty and gradually decreases with age (immunosenescence). Recent studies in healthy octogenarian patients suggest that the immune system, instead of suffering a generalized deterioration, undergoes a remodelling/readjustment of its major functions. Increase in two contrasting phenomena coexist in immunosenescence: on the one hand, a decrease in the capacity of the immune response and, on the other hand autoantibody production. The possible consequences of this progressive 'ageing' of the immune system are the increase in autoimmune phenomena, incidence of neoplasia and predisposition to infections. The study of autoimmune manifestations in elderly populations should be considered a priority for future medical research because of increasing life expectancy, especially in developed countries. This review analyses the main immune disorders associated with immunosenescence, the prevalence and clinical significance of autoantibodies in the elderly and the clinical expression of the main autoimmune diseases in older patients.

Anti-DFS70 antibodies in 597 healthy hospital workers

OBJECTIVE

Autoantibodies against DFS70 (dense fine speckles 70) antigen (also known as lens epithelium-derived growth factor) have been recently identified among the antinuclear antibodies (ANAs) in patients with atopic disorders. We undertook this study to examine the frequency of anti-DFS70 antibodies in a large number of healthy people.

METHODS

Sera of 597 healthy individuals working in a hospital (142 men, 455 women) were analyzed for ANAs and for anti-DFS70 antibodies by indirect immunofluorescence (IIF) with HEp-2 cells as a substrate and by immunoblotting using DFS70 recombinant protein and whole HeLa cell extract.

RESULTS

ANAs were present in 20% of all individuals by IIF. Nine percent of subjects were ANA positive at a serum dilution of 1:40, 4.0% at 1:80, 5.5% at 1:160, 1.0% at 1:320, and 0.3% at 1:640. There were 64 anti-DFS70 antibody-positive individuals. Surprisingly, this was 11% of the whole population and 54% of the ANA-positive population. The percentage of female anti-DFS70 antibody-positive subjects (86%; 55 of 64 subjects) was higher than the percentage of female anti-DFS70 antibody-negative subjects (75%; 398 of 533 subjects) (P < 0.05). The prevalence of anti-DFS70 antibody-positive sera decreased with increasing age (P = 0.0017).

CONCLUSION

Considering that anti-DFS70 antibody positivity is rare in patients with systemic autoimmune diseases, introducing the anti-DFS70 antibody examination as a screening test for ANA-positive persons could be used to rule out systemic autoimmune diseases, resulting in considerable cost-saving potential. In addition, this test defines a subpopulation of healthy people in whom long-term followup might reveal health-related implications of this finding, since anti-DFS70 antibodies have been shown to be associated with some illnesses.