Immunosenescence and anti-immunosenescence therapies: the case of probiotics.

Aging is a complex process that negatively impacts the development of the immune system and its ability to function. Progressive changes in the T and B cell systems over the life span have a major impact on the capacity to respond to immune challenge. These cumulative age-associated changes in immune competence are termed immunosenescence. This process is mostly characterized by: (1) shrinkage of the T cell repertoire and accumulation of oligoclonal expansions of memory/effector cells directed toward ubiquitary infectious agents; (2) involution of the thymus and the exhaustion of naive T cells; and (3) chronic inflammatory status. Here we discuss possible strategies to counteract these main aspects of immunosenescence, in particular the role of the normalization of intestinal microflora by probiotics. A better understanding of immunosenescence and the development of new strategies to counteract it are essential for improving the quality of life of the elderly population.

Alzheimer's disease and genetics of inflammation: a pharmacogenomic vision.

Inflammation plays a key role in Alzheimer disease, and dissecting the genetics of inflammation may provide an answer to the possible treatment. The next-generation therapy is based on a pharmacogenomics that will reconure new approaches to a drug used on definite people with specific dosage. The translation of pharmacogenomics into clinical practice will allow bold steps to be taken toward personalized medicine. In response to tissue injury elicited by trauma or infection, the inflammatory response sets in as a complex network of molecular and cellular interactions, directed to facilitate a return to physiological homeostasis and tissue repair. The role of an individual's genetic background and predisposition for the extent of an inflammatory response is determined by variability of genes encoding endogenous mediators that constitute the pathways of inflammation. Due to its clinical relevance, in this review, the view on genetics of inflammation will be illustrated through a description of the genetic basis of a specific inflammatory disease, Alzheimer's disease (AD). Several studies report a significantly different distribution, in patients and controls, of proinflammatory genes, alleles of which are under-represented in control subjects and over-represented in patients affected by AD. These studies will permit the detection of a risk profile that will potentially allow both the early identification of individuals susceptible to disease and the possible design or utilization of drug at the right dose for a desired effect - a pharmacogenomic approach for this disease.

Genetics of inflammation in age-related atherosclerosis: its relevance to pharmacogenomics.

In response to tissue injury elicited by trauma or infection, the inflammatory response, as a complex network of molecular and cellular interactions, sets an answer directed to facilitate a return to physiological homeostasis and tissue repair. The role of the genetic background and the subsequent predisposition toward the extent of the inflammatory response is determined by gene variability encoding endogenous mediators involved in the inflammatory pathway. Due to its clinical relevance, the genetics of inflammation in aging will be studied using an inflammatory disease like atherosclerosis as an example. Several studies have reported a significant difference in distribution, between patients and controls, of genes involved in inflammation. So, the proinflammatory alleles are underrepresented in control subjects and overrepresented in patients affected by atherosclerosis. These studies will allow building a risk profile that potentially enables the early identification of individuals susceptible to disease and the possible design or use of drug at the right dose for a desired effect, that is, a pharmacogenomic approach for this disease.

PECAM-1/CD31 in infarction and longevity.

Inflammation has recently proven to be associated with the pathogenesis of atherosclerosis and inflammatory genes are good candidates for the risk of developing atherosclerosis. The early phase of atherosclerosis involves the recruitment of inflammatory cells from the circulation and their transendothelial migration. This process is mainly mediated by cellular adhesion molecules, which are expressed by the vascular endothelium and by circulating leukocytes in response to several inflammatory stimuli. Adhesion of circulating cells to the arterial surface is among the first detectable events in atherogenesis. Cellular adhesion molecules, expressed by the vascular endothelium and by circulating leukocytes, mediate cell recruitment and their transendothelial migration. Platelet endothelial cellular adhesion molecule-1 (PECAM-1/CD31), involved in this migration, has been associated with the developmental course of atherosclerosis. Studies have investigated an association between coronary heart disease (CHD) and single nucleotide polymorphisms (SNP) located in functionally important domains of the PECAM-1/CD31 gene, with contrasting results. In particular, we previously analyzed for the following PECAM-1/CD31 SNP: Val125Leu, Asn563Ser, and Gly670Arg. The frequency of the Gly670Arg polymorphism was significantly higher in patients with myocardial infarction (MI), whereas the frequencies of the other two SNP (Leu125Val and Ser563Asn) were not significantly different between patients and controls. To check the validity of our results, we have analyzed the distribution of these SNP in centenarian men (age >99) from our homogeneous Sicilian population, since our previous studies have demonstrated that alleles associated with MI susceptibility are not included in the genetic background favoring longevity. We showed, as regard to polymorphisms of PECAM-1/CD31, that there were no significant differences between male patients affected by MI, male controls, and male centenarians. According to our hypothesis present results seemingly do not support a role for these SNP in conferring the susceptibility to MI at least in this Italian population.

CCR5 receptor: biologic and genetic implications in age-related diseases.

The CC chemokine receptor 5 (CCR5) is a member of CC-chemokine receptor family. CCR5 has the characteristic structure of a seven transmembrane G protein-coupled receptor (GPCR), which regulates trafficking and effector functions of memory/effector Th1 cells, macrophages, NK cells, and immature dendritic cells. CCR5 and its ligands are important molecules in viral pathogenesis. CCR5 represents the co-receptor for macrophage (M) and dual (T cell and M)-tropic immunodeficiency viruses. Recent evidence has also demonstrated the role of CCR5 in a variety of human diseases, ranging from infectious and inflammatory diseases to cancer. In this article, we describe the involvement of CCR5 in two age-related diseases, atherosclerosis and Alzheimer's disease, suggesting a possible role of chemokine system on these diseases' pathophysiology. Finally, we review the data on the probable association between CCR5Delta32 deletion and cardiovascular diseases and Alzheimer's disease.

Alpha1-antitrypsin heterozygosity plays a positive role in attainment of longevity.

Genes involved in cardiovascular diseases (CVD) play an opposite role in human longevity. The alpha1-antitrypsin (AAT) is a serine-protease inhibitor required for the prevention of proteolytic tissue damage, by neutrophil elastase. The role of AAT in CVD has not been definitively assessed and its effect on longevity has not yet fully been studied. To clarify these points, we have studied the distribution of AAT allele variants in 3 cohorts: 127 young patients affected by acute myocardial infarction (AMI), 255 young controls and 143 centenarians from Sicily. The Z allele frequency was most frequent in centenarians (13.3%), intermediate in healthy young controls (3.1%) and less frequent in AMI patients (1.2%) (P = 0.0000001). The heterozygous MZ genotype was significantly over represented in centenarians (38/143) and under represented in AMI patients (3/127) with intermediate values in young controls (16/255) (P = 0.0000001). After adjustment for well-recognized AMI risk factors, the MZ genotype still predicted a significant negative risk factor for developing AMI in the Sicilian population. Thus, our data show a positive role of MZ heterozygosity in attainment of successful ageing linked to the positive effects of this genotype versus the cardiovascular ischemic diseases.

Inflammatory networks in ageing, age-related diseases and longevity.

Inflammation is considered a response set by the tissues in response to injury elicited by trauma or infection. It is a complex network of molecular and cellular interactions that facilitates a return to physiological homeostasis and tissue repair. The individual response against infection and trauma is also determined by gene variability. Ageing is accompanied by chronic low-grade inflammation state clearly showed by 2-4-fold increase in serum levels of inflammatory mediators. A wide range of factors has been claimed to contribute to this state; however, the most important role seems to be played by the chronic antigenic stress, which affects immune system thorough out life with a progressive activation of macrophages and related cells. This pro-inflammatory status, interacting with the genetic background, potentially triggers the onset of age-related inflammatory diseases as atherosclerosis. Thus, the analysis of polymorphisms of the genes that are key nodes of the natural immunity response might clarify the patho-physiology of age-related inflammatory diseases as atherosclerosis. On the other hand, centenarians are characterized by marked delay or escape from age-associated diseases that, on average, cause mortality at earlier ages. In addition, centenarian offspring have increased likelihood of surviving to 100 years and show a reduced prevalence of age-associated diseases, as cardiovascular disease (CVD) and less prevalence of cardiovascular risk factors. So, genes involved in CVD may play an opposite role in human longevity. Thus, the model of centenarians can be used to understand the role of these genes in successful and unsuccessful ageing. Accordingly, we report the results of several studies in which the frequencies of pro-inflammatory alleles were significantly higher in patients affected by infarction and lower in centenarians whereas age-related controls displayed intermediate values. These findings point to a strong relationship between the genetics of inflammation, successful ageing and the control of cardiovascular disease at least in men, in which these studies were performed. These data are also briefly discussed in the light of antagonistic pleiotropy theory and in order to pursuit a pharmacogenomics approach.

Polymorphisms of pro-inflammatory genes and Alzheimer's disease risk: a pharmacogenomic approach.

Clinically and pathologically Alzheimer's disease (AD) represents a sequential progressive neurodegenerative disorder. AD is etiologically heterogeneous and accounts for a majority of dementia in western societies. Inflammation clearly occurs in pathologically vulnerable regions of the AD brain and the search for genetic factors influencing the pathogenesis of AD has lead to the identification of numerous gene polymorphisms that might act as susceptibility modifiers. Accordingly, several reports have indicated that the risk of AD is substantially influenced by several genetic polymorphisms in the promoter region, or other untranslated regions, of genes encoding inflammatory mediators, although not all the studies were replied. Here, we review several data suggesting that inflammatory genetic variation may contribute to AD susceptibility. All together this information may represent the basis both for future recognition of individuals at risk and for the pharmacogenomic driving of drug responsiveness.

Pharmacogenomics: a tool to prevent and cure coronary heart disease.

Inflammation and genetics play an important role in the pathogenesis of coronary heart disease (CHD). This is supported by epidemiological studies which have thoroughly investigated the association between CHD and gene polymorphisms of the inflammatory molecules. Moreover, efforts to find elective therapy have not been rewarding and, despite the increasing appreciation of the role of genetics in CHD and myocardial infarction (MI) pathogenesis, pharmacogenomic approaches to uncover drug target have not been extensively explored. A critical search of published literature has suggested few inflammatory genes directly involved in the risk to develop CHD and MI. The selected genes are, the pro- and anti-inflammatory cytokines, Toll-like receptor 4 (TLR4), CD14, CCR5, cyclooxygenases (COXs) and lipoxygenases (LOXs). The associations between candidate gene polymorphisms and CHD/MI are difficult and complex as a consequence of pleiotropy, variations with age, selection due to the lethality of the disease, and interactions with other genes and environmental factors. However, current data indicate that screening for interleukin (IL)-6, IL-10, TLR4, CCR5, COX and LOX polymorphisms are likely to be a useful tool for CHD and MI risk assessment. What we believe is that dissecting out the influence of genetics polymorphism within the complex pathophysiology of CHD and MI will help to provide a more complete risk assessment and complement known classical cardiological risk factors. The detection of a risk profile will potentially allow both the early identification of individuals susceptible to disease and the possible discovery of potential targets for drug of lifestyle modification.

Opposite role of pro-inflammatory alleles in acute myocardial infarction and longevity: results of studies performed in a Sicilian population.

The major trait characterizing offspring in centenarians is a reduction in the prevalence of cardiovascular disease. Because a pro-inflammatory genotype seems to contribute significantly to the risk of coronary heart disease, alleles associated with disease susceptibility would not be included in the genetic background favoring longevity, as suggested by our previous studies on inflammatory cytokines. To confirm whether genotypes of inflammatory molecules play an opposite role in atherosclerosis and longevity, we are studying the role of other proinflammatory alleles, such as pyrin and CCR5, in acute myocardial infarction and longevity. The results support the hypothesis that the genetic background favoring cardiovascular diseases is detrimental to longevity. In addition, they suggest that the centenarian genetic background may be useful for investigating genetic key components of age-associated diseases that are characterized by a multifactorial etiology.

Association between +1059G/C CRP polymorphism and acute myocardial infarction in a cohort of patients from Sicily: a pilot study.

Inflammation plays a role in all the phases of atherosclerosis, and increased production of the acute-phase reactant, C-reactive protein (CRP), predicts future cardiovascular events. Furthermore, CRP has been claimed to play a role in the pathogenesis of atherosclerosis; therefore, CRP polymorphisms might be associated with acute myocardial infarction (AMI). We have analyzed male patients affected by AMI and healthy age-related male controls from Sicily for +1059G/C CRP single-nucleotide polymorphism (SNP). There was a significantly higher frequency of +1059C SNP (P = 0.0008; OR 3.86) in patients compared to controls. CRP serum levels were significantly higher in C+ healthy subjects rather than in C- subjects (P = 0.0075). The results of the present pilot case-control study performed in a homogeneous caucasoid population suggest that +1059C CRP gene SNP is associated with AMI. In any case, the results of the present study should add to the growing body of evidence on the role of pro-inflammatory genotypes in unsuccessful aging, determining susceptibility to immune-inflammatory diseases such as coronary heart disease.

Inflammation, longevity, and cardiovascular diseases: role of polymorphisms of TLR4.

The total burden of infection at various sites may affect the progression of atherosclerosis, the risk being modulated by host genotype. The role of lipopolysaccaride receptor TLR4 is paradigmatic. It initiates the innate immune response against gram-negative bacteria; and TLR4 polymorphisms, as ASP299GLY, suggested to attenuate receptor signaling, have been described. We demonstrated that TLR4 ASP299GLY polymorphism shows a significantly lower frequency in patients affected by myocardial infarction compared to controls, whereas centenarians show a higher frequency. Thus, people genetically predisposed to developing weak inflammatory activity, seem to have fewer chances of developing cardiovascular diseases (CVD) and, subsequently, live longer if they do not become affected by serious infectious diseases. These results are in agreement with our other data demonstrating how genetic background may exert the opposite effect with respect to inflammatory components in CVD and longevity. In the present report, to validate this hypothesis, the levels of interleukin (IL)-6, a pro-inflammatory cytokine involved in atherosclerosis and longevity, were determined by an enzyme-linked immuno-sorbent assay (ELISA) in supernatants from a whole blood assay after stimulation with subliminal doses of lipopolysaccaride (LPS) from Escherichia coli (E. coli). The samples, genotyped for the ASP299GLY polymorphism, were challenged with LPS for 4, 24, and 48 h. What we found was that Il-6 values were significantly lower in carriers bearing TLR4 mutation. Therefore, the pathogen burden, by interacting with host genotype, determines the type and intensity of the immune-inflammatory responses accountable for pro-inflammatory status, CVD, and unsuccessful aging. On the other hand, our present data seem to explain the inconclusive results obtained in case-control studies taking into account the role of functional IL-6 polymorphisms in successful and unsuccessful aging. In fact, IL6 levels seem to depend, in addition, on IL-6 polymorphisms and on innate immunity gene polymorphisms as well.

Association between the HLA-A2 allele and Alzheimer disease.

In the elderly, the most common cause of dementia is Alzheimer disease (AD), which is responsible for the age-related progressive neurodegenerative inflammatory condition mediated by the disease. It has been seen that several genetic and environmental factors are involved in AD onset. Epidemiologic data suggest that some genetic determinants of AD might reside in those polymorphisms that regulate immune inflammatory responses, such as the major histocompatibility complex (MHC). Therefore, several MHC polymorphisms have been in the spotlight of a large number of AD association studies. A possible association of HLA-A2 allele with increased susceptibility to AD has been the subject of debate for more than 20 years, even if the results of these studies, in the various populations, are discordant. Thus, to gain insight in this matter, the authors have studied the HLA-A2 allele for a possible association with sporadic AD in a homogeneous population of Italian patients. For this reason, the distribution of HLA-A2 allele in patients with sporadic AD and controls was analyzed by PCR-SSP assay. The results demonstrated a significant difference in the frequency of HLA-A2 allele between patients with sporadic AD and controls (46% versus 38%). Thus, these data confirm a positive role of HLA-A2 allele in the risk of developing AD. However, some of the observed discrepancies may result from clinical or genetic heterogeneity of the populations under study or methodologic biases. Besides, whenever external agents such as viruses play a role, these might different in the various populations leading to various associations. However, it has to be taken into account that there are many molecular HLA-A2 subtypes with different frequencies in various populations. Therefore, further studies should include molecular typing of HLA-A2 subtypes.

The nACHR4 594C/T polymorphism in Alzheimer disease.

Alzheimer disease (AD) is the most common form of dementia with complex etiology and multifactorial origin. Although several neurochemical deficits have been described in AD patients, explanation of the nature of the cognitive disturbance is focused on the "cholinergic hypothesis." The neuronal nicotinic acetylcholine receptor (neuronal nAChR) belongs to the superfamily of ionic channel activated by ligand. This paper presents a population-based population association study, testing the hypothesis that variants of the nAChR gene confer genetic susceptibility to AD. The authors analyzed two cohorts constituted by 60 controls and 80 AD patients in which significant increase of 594T polymorphism in patients affected by AD versus controls was found. However, further studies are necessary to confirm this polymorphism trend and to establish the polymorphism functionality and its correlation with behavioral and cognitive deficit.

Biology of longevity: role of the innate immune system.

Genetic factors play a relevant role in the attainment of longevity because they are involved in cell maintenance systems, including the immune system. In fact, longevity may be correlated with optimal functioning of clonotypic and natural immunity. The aging of the immune system, known as immunosenescence, is the consequence of the continuous attrition caused by chronic antigenic overload. The antigenic load results in the progressive generation of inflammatory responses involved in age-related diseases. Most of the parameters influencing immunosenescence appear to be under genetic control, and immunosenescence fits with the basic assumptions of evolutionary theories of aging, such as antagonistic pleiotropy. In fact, by neutralizing infectious agents the immune system plays a beneficial role until reproduction and parenting. However, by determining chronic inflammation, it can be detrimental later in life, a period largely unforeseen by evolution. In particular, the data coming from the long-lived male population under study show that genetic polymorphisms responsible for a low inflammatory response might result in an increased chance of long lifespan in an environment with a reduced pathogen burden. Such a modern and healthy environment also permits a lower grade of survivable atherogenic inflammatory response.

Systemic inflammatory response in erderly patients following hernioplastical operation.

The number of old and oldest old patients undergoing surgery of varying severity is increasing. Ageing is a process that changes the performances of most physiological systems and increases susceptibility to diseases and death; accordingly, host responses to surgical stress are altered with ageing and the occurrence of age-related increase in susceptibility to post-operative complications has been claimed. Twenty-four male patients undergoing Lichtenstein (LH) hernioplasty for unilateral inguinal hernia were included in this study and divided in two groups (Young and Old respectively), according to their age. As expression of the acute phase response, we measured changes in concentration of pro-inflammatory cytokines Tumor necrosis factor-alpha and Interleukin-1beta, leukocytes, acute phase proteins C-reactive protein and alpha 1-antitrypsin. Elderly humans showed prolonged and strong inflammatory activity compared to younger subjects in response to surgical stress, indicating that the acute-phase response to surgical stress of elderly humans varies from that of the young, showing initial hyperactivity and a delayed termination of the response. Thus, the acute phase response to surgical stress is higher in old subjects, but the clinical significance of this remains unclear. It is not known whether a causal relationship exists between this stronger acute phase response and the increases in susceptibility to post-operative complications observed in aged patients.

Role of the pyrin M694V (A2080G) allele in acute myocardial infarction and longevity: a study in the Sicilian population.

A proinflammatory genotype seems to contribute significantly to the risk of developing coronary heart disease (CHD). Conversely, the susceptibility alleles to inflammatory disease should be infrequent in the genetic background favoring longevity. In fact, in a modern environment, attainment of longevity is facilitated by an anti-inflammatory status. To evaluate whether inflammatory alleles of pyrin, the gene responsible for familial Mediterranean fever (FMF) may play an opposite role in CHD and in longevity, we examined three FMF-associated mutations, M694V (A2080G), M694I (G2082A), and V726A (T2177C), encoded by the FMF gene (MEFV) in 121 patients affected by acute myocardial infarction (AMI), in 68 centenarians, and in 196 age-matched controls from Sicily. None of the Sicilian subjects studied carried the V726A and the M694I FMF-related mutations. The proinflammatory M694V (A2080G) mutation was the only one we found, which was over-represented significantly in CHD patients and under-represented in oldest old, and intermediate values were in healthy, young controls. After adjustment for well-recognized AMI risk factors, the M694V allele still predicted a significant risk to develop AMI. So, according to these results, we suggest that carrying the proinflammatory M694V pyrin allele may increase the risk to develop AMI. Conversely, the wild-type pyrin genotype may predispose to a greater chance to live longer in a modern environment with reduced pathogen load and improved control of severe infections by antibiotics. All these data indicate a strong relationship among inflammation, genetics, CHD, and longevity.

Association between the polymorphism of CCR5 and Alzheimer's disease: results of a study performed on male and female patients from Northern Italy.

Alzheimer's disease (AD) is the most common cause of dementia in Western society. The prevalence of AD is greater in women than in men, largely due to longevity and survival differences favoring women. However, some studies suggest that incidence rates may really be increased in women. One possible factor influencing AD incidence in women is the loss of ovarian estrogens production after menopause, which might be involved in AD pathogenesis. Estrogens seem to influence some neuronal functions. Many of these actions appear beneficial (i.e., neuroprotective action against a variety of insults, as oxidative stress, and reduction of beta-amyloid plaques formation). Furthermore, several studies have shown that proinflammatory genotypes seem to significantly contribute to AD risk. In the present study, we evaluated whether the anti-inflammatory allele of chemokine receptor CCR5 is a component of the genetic protective background versus AD neuronal degeneration. We genotyped for Delta32 (a 32-bp deletion of the CCR5 gene that causes a frameshift at amino acid 185) in 191 AD patients (133 women and 58 men; age range: 53-98 years; mean age: 74.88 +/- 8.44) and 182 controls (98 women and 84 men; age range: 65-93; mean age 73.21 +/- 8.24) from northern Italy. No different distribution of the CCRDelta32 deletion in the two cohorts was clearly evident. Statistical analysis by gender stratification, demonstrated no differences in genotype distribution and allelic frequency both in women and in men. Further, studies should focus on identification of proinflammatory genetic variants involved in AD pathogenesis in women.

Association between platelet glycoprotein Ib-alpha and myocardial infarction: results of a pilot study performed in male and female patients from Sicily.

Myocardial infarction (AMI) is a complex multifactorial disorder. Platelet adhesion and thrombosis are pivotal events in the development of atherosclerotic lesions. Occlusive thrombus is almost exclusively initiated by plaque rupture and adhesion of platelets to subendothelial von Willebrand factor (vWf) by its specific platelet receptor, the alpha-chain of glycoprotein (GP) Ib-IX-V complex of the human platelet-specific antigens (HPA). Two polymorphisms have been reported in the sequence of GPIb-alpha. The first, a C/T transition at nucleotide 1018 results in an amino acid dimorphism (Thr/Met) at residue 145 of GPIb-alpha, which is located within the vWF-binding domain of the receptor. The second is a T/C polymorphism in the Kozak sequence at position -5 from the initiator ATG. This affects the receptor density on the platelet surface. We assessed 1018 C/T and -5 T/C Kozak polymorphisms to see whether they are associated with AMI in homogeneous populations of Sicilian patients with AMI. To this end, we have analyzed the distribution of 1018 C/T and -5 T/C Kozak polymorphisms in 105 young Sicilian patients (<46 years) and 110 healthy age-related controls, by PCR-SSP and PCR-RFLP. Our results demonstrate no significant differences in the frequency of 1018 C/T and -5 T/C Kozak polymorphism between patients with AMI and controls. Stratifying by gender, there is no difference between male and female patients and control data. Thus, our results indicate that the HPA-2 polymorphisms are not associated with an increased risk for AMI at early onset (< 46 years) both in men and in women.

Pathogenesis of autoimmune diseases associated with 8.1 ancestral haplotype: a genetically determined defect of C4 influences immunological parameters of healthy carriers of the haplotype.

Subjects with certain HLA alleles have a higher risk of specific autoimmune diseases than those without these alleles. The 8.1 ancestral haplotype (AH) is a common Caucasoid haplotype carried by most people who type for HLA-B8,DR3. It is unique in its association with a wide range of immunopathological diseases. To gain insight into the identification of the mechanism(s) of disease susceptibility of 8.1 AH carriers, we have investigated the prevalence of circulating immune complexes and non-organ-specific autoantibodies in healthy carriers of the haplotype. The results show that carriers of 8.1 AH display both a significant increased prevalence of immune complexes and higher titers of anti-nuclear autoantibodies. This AH carries a single segment characterized by no C4A gene. This null allele does not code for a functional C4A protein that likely plays an anti-inflammatory role being specialized in the opsonization and immunoclearance processes. So, this genetic defect has been claimed to allow that an increased production of autoantibodies directed vs. cells that have undergone apoptosis and are not efficiently disposed because a reduced antigenic clearance. The results obtained in the present study fit very well with this hypothesis. In the AH carriers the simultaneous high setting of tumor necrosis factor (TNF)-alpha may supply the autoantigens (providing an excess of apoptotic cells) that drive the autoimmune response. In conclusion, the C4 defect associated to the increased spontaneous release of TNF-alpha, modifying a certain number of immunological parameter may be the most characterizing feature of the 8.1 AH. In the majority of individuals, an autoimmune response clinically relevant will develop only in the presence of other immunological abnormalities.