Effects of complement inactivation and IgG depletion on skin reactivity to autologous serum in chronic idiopathic urticaria.

BACKGROUND: Intradermal injection of autologous serum elicits a wheal-and-flare response in about 60% of patients with chronic idiopathic urticaria (CIU). This reactivity has been attributed to the presence of IgG autoantibodies directed against IgE or the alpha-chain of the high-affinity IgE receptor (FcepsilonRIalpha) expressed on basophils and mast cells, leading to the hypothesis that at least some forms of CIU could be sustained by an autoimmune process. OBJECTIVES: The aim of this study was to investigate the relationship between the presence of anti-IgE or anti-FcepsilonRI antibodies and the ability to induce wheal-and-flare responses in CIU sera selected for the capacity to give a positive skin test response. METHODS: Fifteen patients with CIU and a positive skin test response to autologous serum were injected intradermally with native serum and with serum heated at 56 degrees C for 30 minutes and then adsorbed on Sepharose-protein G to obtain IgG depletion. Serum levels of anti-IgE and anti-FcepsilonRIalpha antibodies were measured by ELISA by using purified IgE and recombinant RIalpha-soluble double-fusion protein RIalpha-human serum albumin-RIalpha, respectively. The histamine-releasing activity of sera was tested by using ELISA with whole human blood from a healthy donor. RESULTS: All patients had positive cutaneous responses to native serum injection. Anti-FcepsilonRIalpha antibodies were present in 14 of 15 native sera, only two of which were able to induce in vitro basophil degranulation. On the contrary, detectable amounts of anti-IgE antibodies were not found in any serum. IgG depletion by protein G resulted in complete (10/14 samples) or considerable (4/14 samples) removal of anti-FcepsilonRIalpha antibodies. The two sera endowed with functional activity lost their capacity to trigger histamine release from basophils after heating and protein G adsorption. Nonetheless, heat-decomplemented/IgG-depleted sera elicited wheal-and-flare reactions comparable with those observed with untreated sera. CONCLUSIONS: These results strongly suggest that skin reactivity to autologous serum could be due to as yet unidentified non-Ig reactants present in the sera of patients with CIU.

Hemopoiesis in healthy old people and centenarians: well-maintained responsiveness of CD34+ cells to hemopoietic growth factors and remodeling of cytokine network.

In vitro hemopoiesis and hemopoietic cytokines production were evaluated in 9 centenarians (median age 100.5 years, age range: 100-104 years), 10 old people (median age: 71 years, age range: 66-73 years), and 10 young people (median age: 35 years, age range: 30-45 years), all carefully selected for their healthy status. The main findings were the following: (i) a trend towards a decreased absolute number of CD34+ progenitor cells in the peripheral blood of old people and centenarians, in comparison to young subjects; (ii) a well-preserved capability of CD34+ cells from old people and centenarians to respond to hemopoietic cytokines, and to form erythroid (BFU-E), granulocyte-macrophagic (CFU-GM), and mixed colonies (CFU-GEMM) in a way (number, size, and morphology) indistinguishable from that of young subjects; (iii) an age-related decreased in vitro production of granulocyte-macrophagic colony-stimulating factor (GM-CSF) and a decreased production of interleukin-3 (IL-3) in centenarians by phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC); (iv) a linear increase of the serum level of stem cell factor (SCF), measured in the above-mentioned subjects and in 65 additional subjects, including 4 centenarians. These data suggest that basal hematopoietic potential is well preserved in healthy centenarians, and that the hemopoietic cytokine network undergoes a complex remodeling with age.

Inhibitory effect of heparin on skin reactivity to autologous serum in chronic idiopathic urticaria.

BACKGROUND: Most patients with chronic idiopathic urticaria (CIU) show cutaneous reactivity to intradermal injection of autologous serum. In some cases this reactivity is associated with the presence of autoantibodies directed against IgE or IgE receptors expressed on mast cells, whereas in others no autoimmune mechanisms can be documented. OBJECTIVES: The aims of this study were to compare the cutaneous reactivity to serum and plasma samples in a series of patients with active CIU and to address the mechanisms of the inhibitory effect exerted by heparin on the cutaneous responsiveness to the histamine-releasing factors (HRFs) present in CIU serum. METHODS: Fourteen patients with CIU were injected intradermally with autologous serum, plasma (anticoagulated by either heparin or EDTA), or serum samples to which heparin had been added. The effects of heparin injection on cutaneous responsiveness to allergens was tested in 5 atopic patients. Moreover, in a set of experiments sera were also adsorbed with Sepharose-conjugated heparin. RESULTS: All the patients had positive cutaneous reactions to autologous serum injection. When heparinized plasma was injected, negative reactions were observed in 12 of 14 patients, and a sizable reduction in the wheal-and-flare reactions was recorded in the remaining 2. Compared with results obtained with serum, no substantial change was observed in 6 of 8 patients injected with EDTA-anticoagulated plasma. When heparin was added to serum, abrogation of skin reactivity was seen; nonetheless, no change in the cutaneous response to allergens was associated with locally administered heparin in 5 atopic patients with no history of CIU. Finally, adsorption of CIU sera with solid-phase heparin abrogated the ability to induce cutaneous reactions in 5 of 7 patients, whereas in the remaining 2 a sizable reduction was observed. CONCLUSIONS: These data indicate that heparin is able to profoundly inhibit the cutaneous response to HRFs present in the sera of patients with CIU. Although the precise level of action of this heparin-mediated effect is unclear from present data, preliminary evidence seems to indicate that heparin could directly interfere with HRFs present in CIU sera.

Constitutive endothelial nitric oxide synthase (ecNOS) gene expression in human monocytes.

This study evaluates using a polymerase chain reaction (PCR)-based molecular biological approach to study the gene expression of the constitutive endothelial isoform of nitric oxide synthase (ecNOS) in human monocytes. When PCR was carried out with specific primers for ecNOS, 302 bp product was amplified, which sequence analysis determined as having 100% identity to the reported human ecNOS isoform gene sequence. The data presented here demonstrate a reliable technique for assessing ecNOS mRNA levels in circulating human monocytes. This then permits use of this easily available cell to monitor ecNOS levels and provides a means to investigate mechanisms involved in controlling NO synthase levels as well as NO synthesis.

Clinical, laboratory and immunogenetic aspects of post-traumatic psoriatic arthritis: a study of 25 patients.

OBJECTIVE: In a previous study we demonstrated that the prevalence of trauma preceding arthritis was higher in patients with psoriatic arthritis (PsA) than in patients with rheumatoid arthritis (RA) or ankylosing spondylitis (AS); of 300 consecutive patients with PsA, 25 (8%) had a history of trauma before (< 3 months) the onset of the disease. The present study was carried out to characterize the clinical, laboratory and immunogenetic profiles of post-traumatic (PT)-PsA. PATIENTS AND METHODS: The clinical and laboratory features of 25 patients with PT-PsA were studied at onset (first 6 months) and after a follow-up period of 1-7 years, and were compared with those of 275 PsA patients without any history of trauma (nonPT-PsA). HLA typing was performed in PT-PsA patients, and synovial fluid (SF) analysis, including interleukin (IL)-1 and IL-6 determinations, was carried out in 12 subjects with PT-PsA and in 32 with nonPT-PsA. RESULTS: No differences were observed between PT-PsA and nonPT-PsA patients with regard to their clinical evolution. ESR (p < 0.0001) and CRP (p = 0.005) were higher in PT-PsA than in nonPT-PsA patients at disease onset but not after follow-up. No differences were found in the other blood indices. SF analysis revealed higher IL-6 levels in PT-PsA than in nonPT-PsA patients (p < 0.0005). CONCLUSION: Our study demonstrates that the prevalence of trauma preceding arthritis is higher in PsA than in RA or AS. Clinical and laboratory findings in patients with PT-PsA differed from those with nonPT-PsA only at disease onset (first six months), however, showing an abrupt clinical presentation and a more acute phase response. This pattern may be related to the higher levels of IL-6 found in the SF of PT-PsA than in nonPT-PsA patients. However, during the follow-up period the two groups became indistinguishable, and no difference was observed between PT-PsA and nonPT-PsA regarding the evolution of the disease.

Growth properties and growth factor responsiveness in skin fibroblasts from centenarians.

Human fibroblast cultures, which have a finite replicative lifespan in vitro, are the most widely used model for the study of senescence at the cellular level. An inverse relationship between replicative capability and donor age has been reported in human fibroblast strains. We studied the growth capacity of fibroblast primary cultures derived from people whose lifespan was as closer as possible to the expected maximum human lifespan, i.e. people over one hundred. Our data suggest that outgrowth of fibroblasts from biopsies, growth kinetics at different population doubling levels, capability to respond to a classical mitogenic stimulus (such as 20% serum) and a variety of growth factors, were remarkably similar in fibroblasts from centenarians and young controls. On the whole, our data challenge the tenet of a simple and strict relationship between in vivo aging and in vitro proliferative capability of human fibroblasts, at least at the individual level.

Clinical, laboratory and immunogenetic aspects of arthritis associated with chronic lymphocytic thyroiditis.

OBJECTIVE: Synovial fluid effusions and/or arthritis may be found in patients with chronic lymphocytic thyroiditis (CLT), even in the absence of hypothyroidism. Sometimes these arthropathies can be attributed to the rheumatic diseases frequently associated with CLT, but in some instances the arthritis seems to be independent of any of the diseases known to cause arthritis, and therefore remains unclassified. This study was carried out in an attempt to characterize the type and outcome of arthritis associated with CLT. METHODS: We performed a prospective study with a follow-up of 6.42 years (range 4-13) on 33 patients affected with CLT and presenting with arthritis. All conditions known to cause arthritis were previously excluded. Investigations included HLA typing, x-ray of the affected joints and, when possible, synovial fluid (SF) analysis with an interleukin (IL)-1 beta determination. Patients were divided based on their clinical presentation into two groups: those with polyarthritis and those with oligoarthritis. RESULTS: During the follow-up, 8 out of 16 patients with polyarthritis developed severe rheumatoid arthritis, characterized by bone erosions, high levels of SF IL-1 beta and an increased frequency of HLA DR4. The other 8 patients had polyarthritis in a mild, non-erosive form, which responded well to symptomatic drugs. Oligoarthritis, found in 17 patients, also showed a mild evolution, with frequent spontaneous remissions. The non-rheumatoid polyarthritis and oligoarthritis patients were characterised by the absence of bone erosions, low levels of SF IL-1 beta and an increased frequency of HLA DR3. CONCLUSIONS: We conclude that it is possible to find in association with CLT a type of inflammatory arthritis characterized by a mild, non-erosive evolution, low SF levels of IL-1 beta and an increased frequency of HLA-DR3. This arthritis seems to be independent of thyroid dysfunction and shows a clinical pattern similar to the arthritis usually found in connective tissue diseases.

Effect of rIL-2 treatment on anti-tetanus toxoid response in the elderly.

To explore the effects of interleukin-2 (IL-2) treatment in a vaccination protocol in the elderly, we administered low-dose rIL-2 to a group of aged subjects before primary tetanus toxoid immunization. A specific antibody response was detectable in the serum of 6/8 treated individuals after primary immunization, but in only 2/6 untreated controls; following antigenic boosting, specific antibody levels remained relatively unchanged in all the seroconverters. The data were confirmed by studying the ability to produce tetanus-specific antibodies in vitro, and by isoelectrofocusing analysis of serum anti-tetanus antibodies; this latter study showed a more restricted clonal response to the immunogen in untreated individuals. On the other hand, the study of the in vitro proliferative response to tetanus toxoid did not evidence clear differences between the two groups. On the whole, these data seem to indicate that a short-term rIL-2 treatment is able to potentiate the antibody response to tetanus toxoid, and may be a useful tool to improve humoral responses to vaccines in aged subjects.

c-fos/c-jun expression and AP-1 activation in skin fibroblasts from centenarians.

In vitro replicative senescence is characterized by an irreversible growth arrest due to the inability of the cell to induce some key regulators of cell cycle progression, such as c-fos and AP-1, in response to mitogenic stimuli. In vitro replicative senescence and in vivo aging have been assumed to be two related phenomena, likely controlled by overlapping or interacting genes. As a corollary, fibroblasts from centenarians, which have undergone a long process of senescence in vivo should have very limited proliferative capability. On the contrary, in a previous work we found that fibroblasts from centenarians exhibited the same capacity to respond to different mitogenic stimuli as fibroblasts from young donors. Here we provide evidences that the well preserved proliferative response is likely due to the fact that some pivotal regulators- c-fos, c-jun and AP-1-are still fully inducible, despite a long process of in vivo senescence. Our data therefore suggest that in vivo and in vitro aging are separate phenomena whose possible relationships, if any, have to be ascertained very carefully.

A shift to Th0 cytokine production by CD4+ cells in human longevity: studies on two healthy centenarians.

Centenarians, particularly healthy centenarians, constitute the example of successful aging and the study of their immune status can help to define the endpoint of the changes occurring throughout life. We characterized T cell clones (TCC) of two healthy centenarians, studying their phenotypes and production of representative Th1 and Th2 cytokines (IFN-gamma and IL-4) and compared them with TCC obtained by three young normal subjects; in all 180TCC were analyzed. In young donors, 35TCC were CD4+, 56CD8+ and 2 were alpha beta +CD4-CD8- (double negative). In centenarians, we obtained 46CD4+TCC, 38CD8+, 2CD4+CD8+ (double positive) and 1 gamma delta + double negative. Of the young subjects' TCC, 71% produced IFN-gamma but no IL-4 (Th1 pattern) and this prevalence decreased to 39% in TCC from the centenarians. The number of clones showing the opposite Th2 pattern was similar in young and aged donors (3 out of 93TCC and 2 out of 87TCC, respectively). The intermediate profile of TCC producing both IL-4 and IFN-gamma (Th0) was found in 25.8% of clones from young people, but it almost doubled to 58.6% in centenarians. The analysis shows that the Th profiles of CD8+TCC is nearly superimposable in the two groups, whereas a major shift from a Th1 to a Th0 pattern is presented by CD4+TCC. The balance provided by a majority of CD4+TCC showing a Th0 pattern may ensure both humoral and cell-mediated defences. In CD8+TCC, however, a Th1 pattern still is present, possibly for efficient generation of cytotoxic responses. These findings should be extended by studying other centenarians and elderly subjects.

An immunological and genetic study of patients with gestational diabetes mellitus.

The aim of the study was to evaluate the frequency of islet cell (ICA) and insulin (IAA) antibodies and of HLA antigen typing in a group of subjects diagnosed with gestational diabetes mellitus (GDM) in a screening-diagnostic program during pregnancy. ICA, complement-fixing (CF) ICA and other autoantibodies, absolute number and percentage of lymphocyte subpopulations, and HLA antigens were evaluated in 68 women with GDM and compared with those of matched controls. ICA were found in 2 (2.9%) and IAA in 1 (1.5%). Both ICA-positive women had CF-ICA; one of them was receiving insulin therapy. while the other was on a special diet. No correlations were found between ICA and IAA, nor between IAA and insulin treatment. As far as lymphocyte subsets were concerned, we found a significant increase in the absolute number of total and activated (CD3+HLA-DR+) T lymphocytes and a significant increase in the absolute number and percentage of suppressor/cytotoxic T lymphocytes (CD8) and NK lymphocytes (CD57) in GDM patients compared with normal pregnant controls. Concerning frequency for HLA A, B, C, DR antigens in the GDM population, only Cw7 was found to be significantly increased and A10 significantly decreased in comparison with controls. Our study suggests that GDM is a heterogeneous disorder in which few patients present with the immunologic and genetic markers of type 1 diabetes.

CD45 isoforms expression on CD4+ and CD8+ T cells throughout life, from newborns to centenarians: implications for T cell memory.

CD4+ and CD8+ peripheral blood T lymphocytes show mutually exclusive expression of CD45RA or CD45R0, two isoforms of the common leukocyte antigen that seem to recognize so-called virgin/unprimed and memory/activated T cells. The expression of these isoforms has been studied by three colour cytofluorimetric analysis on CD4+ or CD8+ peripheral blood CD3+ cells from 22 healthy centenarians, analyzed in a context of 202 healthy donors 0-110 years old. An age-related unbalance of virgin and memory cells was found between CD4+ and CD8+ subsets. As expected, at birgh 95-99% of the CD3+ lymphocytes expressed the CD45RA isoform. A rapid increase of CD45R0+ cells was observed in the first 2-3 decades of life, this phenomenon being much more pronounced on CD4+ cells. Subsequently, the increase of the 'memory' compartment was much less rapid, so that in centenarians a consistent reservoire of CD45RA+ among CD4+ cells was still present (about 20%). In these exceptional individuals the percentage of CD45RA+ cells among CD8+ T lymphocytes was even higher (about 50%), and only slightly lower than that of young donors (about 55-60%). Thus, the main changes occurred at a different rate in CD4+ (about 20%). In these exceptional individuals the percentage of CD45RA+ cells among CD8+ T lymphocytes was even higher (about 50%), and only slightly lower than that of young donors (about 55-60%). Thus, the main changes occurred at a different rate in CD4+ and in CD8+ T cells, at an age of between 0 and 30 years, when the thymus is still functionally active. Interestingly, no difference in the usage of CD45 isoforms was observed within T cells bearing four different V beta-T cell receptor (TCR). The significance of this age-related unbalance is unknown. However, the presence of a great number of CD45RA+ T lymphocytes within the CD4+ and the CD8+ T cell subsets even in the peripheral blood of centenarians poses the problem of their origin (thymus? extrathymic sites?), of their functional role and of their lifespan. Moreover, the data on centenarians suggest that they may represent a very selected population where a slowing of immunosenescence occurs.

Blotting patterns of IgG anti-(U1)RNP antibodies in mixed connective tissue disease.

Serum reactivities towards individual U1 snRNP proteins were determined by immunoblotting in 32 patients with mixed connective tissue disease (MCTD). Time persistence of immunoblot profiles and clinical significance of anti-(U1)RNP antibody specificities were also investigated. IgG anti-(U1)RNP antibodies were found in the sera of 29 out of 32 patients (90.6%): 21 (65.6%) reacted with the 70-kD protein, 25 (78.1%) with A, 23 (71.9%) with C and 20 (62.5%) with B/B' proteins. None were reactive with the Sm-D peptide. Seventy kilodalton antibody specificity was strongly associated with a higher antinuclear antibody titre (> 160) and slightly associated with disease activity; anti-B/B' specificity was associated with lymphadenopathy. Anti-A, -C and -B/B' antibodies were negatively associated with systemic lupus erythematosus (SLE) skin rashes. Two types of anti-(U1)RNP blotting patterns were selected: "full spectrum" (53.1% of cases) and a "partially/no reactive" one (46.9%). Such patterns were unchanged over time in 14 out of 16 cases prospectively examined (87.5%), while the pattern shifted from "full spectrum" to "partially/no reactive" in 2 cases (12.5%): in 1 after a prolonged clinical remission (> or = 4 years) and in the other following immunosuppressive therapy. The anti-(U1)RNP antibody immunoblot profile in MCTD patients consisted of various reactivities and remained unchanged over time in most cases. Antibody reactivity against the 70-kD protein represented the major U1 snRNP specificity. The various anti-(U1)RNP specific reactivities demonstrated poor clinical significance within MCTD. Thus, MCTD seems to be characterized by a longstanding serological heterogeneity whose reactivities do not apparently correspond to distinct features within the broad clinical spectrum of MCTD.

HLA expression in type II mixed cryoglobulinemia and chronic hepatitis C virus.

OBJECTIVE: Hepatitis C virus infection is closely associated not only with hepatic damage, but also with mixed cryoglobulinemia (MC) and other autoimmune and lymphoproliferative disorders. Because HCV is both hepatotropic and lymphotropic, the aim of this study was to investigate whether the genetic background may influence the clinical pattern seen in different patients. METHOD: Two groups of patients with HCV infection were studied: 16 with type II MC and 18 with chronic active hepatitis (CAH). 120 bone marrow donors were considered as the control group. In all patients HLA-A-B-C antigens were evaluated using the microlymphocytoxicity technique, and HLA-DR by the PCR-SSP method. RESULTS: The frequency of the HLA antigens expressed was not precisely defined in the two groups. However, the HLA-B51 and B35 antigens, which are often correlated with autoimmune disorders, were highly expressed in the MC patients (31.2%) compared to the controls (6.9%) and to the CAH group (11%). Moreover, HLA-A9 with its split A24 were present in 50% of the MC patients. More interesting was the expression of the HLA-DR7 antigen, which was found only in the CAH group, suggesting that it may influence the specific liver involvement in HCV infections. CONCLUSION: These findings indicate that the HLA system may play an important role in the clinical manifestations of HCV infection.

Thyroid autoimmunity and ageing.

Ageing is associated with the appearance of several serum autoantibodies, including thyroid autoantibodies. The biological and clinical significance of this phenomenon is still unknown, since, with the exception of primary myxedema, the prevalence of clinically overt thyroid autoimmune diseases is not increased in the elderly. The peculiar link between autoimmune thyroid failure and ageing is also underscored by the high prevalence of subclinical hypothyroidism in elderly subjects with positive serum thyroid autoantibodies, and could be the consequence of preferential age-dependent expression of destructive effector mechanisms and/or increased target gland susceptibility. Thyroid autoimmunity and subclinical hypothyroidism have also been implicated in the pathogenesis of other age-associated disorders, in particular coronary heart disease. Interestingly, recent data from our laboratories showed that thyroid autoantibodies are rare in healthy centenarians and in other highly selected aged populations, while they are frequently observed in unselected or hospitalized elderly. Taken together, these data suggest that thyroid autoimmune phenomena are not the consequence of the ageing process itself, but rather might be related to age-associated disease.

Humoral response to influenza hemagglutinin: oligoclonal spectrotype and failure of thymopentin as immunoadjuvant.

Influenza remains a serious cause of illness and death among certain populations. Influenza vaccines in use at present are of limited effectiveness due to the high variability of the virus, and trials all over the world are in progress to enhance their immunogenicity. Conflicting results, in fact, have been reported about the immune response to influenza vaccination in diverse populations. In this paper we analyzed the antibody response to the hemagglutinin (HA) of the H3N2 A/Shangai 16/89 strain, which was included into the trivalent 1991-92 influenza vaccine, in four groups of subjects: 8 healthy young, 13 human immunodeficiency virus (HIV)-infected and 37 elderly healthy people, 9 of whom were treated with thymopentin (TP-5). Our results show levels of anti-HA IgG before vaccination in HIV-infected and elderly people significantly lower than those of normal young subjects. After vaccination, HIV-infected and elderly healthy people showed a significant increase of specific antibodies, whereas a failure in the specific response in normal young subjects was observed, thus differences among the groups were no longer present. Moreover, the spectrotypic analysis of antibody response, by isoelectric focusing and reverse blotting, showed oligoclonal but polymorphic pattern in the majority of subjects, irrespective of the group, and more frequently lack of expansion of the spectrotype after vaccination, thus demonstrating the lack of the recruitment of antigen-specific B cells. Finally, the treatment with TP-5 did not influence the outcome of the vaccination in the group of elderly people. These results further emphasize the limited immunogenicity of influenza vaccination and the inefficacy of TP-5 as immunoadjuvant, in this model of vaccination.

Humoral and cellular immune response to influenza virus vaccination in aged humans.

Aging is characterized by an increased susceptibility to infectious diseases; influenza virus infection, which is easily managed by an intact immune system, represents a life-threatening disease in aged subjects. We studied 18 healthy aged subjects (> 65 years of age), vaccinated yearly with conventional anti-influenza vaccine, and 9 healthy young volunteers (mean age 26 years), without previous anti-influenza vaccination, who were vaccinated with the conventional trivalent 1990 anti-influenza preparation. Six out of the 18 aged individuals received a second boost of the same vaccine about 4 months later. In all subjects, we analyzed the humoral response to type A and B influenza viruses and the influenza type A virus-specific CTL generation. Among the elderly population with a single vaccination, 6 and 5 subjects seroconverted against type A and type B influenza virus respectively. Young subjects seroconverted in 5 cases against type A, and in 5 cases against type B influenza virus. Seroconversion took place after the second vaccination in only one subject, and the antibody production was type A specific. Influenza type A virus-specific CTL activity was significantly lower in aged subjects, compared with the values observed in the young volunteers (p = 0.017). The second vaccination partially restored this immunological impairment. These data clearly demonstrate that the elderly do not have the same ability as younger subjects to mount an antibody response, and generate influenza type A virus-specific CTL after conventional anti-influenza vaccination. Moreover, a double anti-influenza vaccination generates CTL activity levels comparable to young subjects, although it does not seem to substantially modify the antibody production.

Complex alteration of thyroid function in healthy centenarians.

Several changes in thyroid function have been described in the elderly and largely attributed to concomitant nonthyroidal illness. The extent to which aging per se contributes to these changes remains to be elucidated, and scanty data are available in extremely old subjects. The present study was designed to focus on thyroid function during physiological aging, taking advantage of two groups of selected aged individuals: group A of healthy centenarians (n = 41; age range, 100-110 yr) and group B including healthy elderly subjects selected by the criteria of the EURAGE SENIEUR protocol (n = 33; age range, 65-80 yr). Control groups included 98 healthy normal adult subjects (group C; age range, 20-64 yr) and 52 patients with miscellaneous nonthyroidal illness (group D; age range, 28-82 yr). Our previous report of a low prevalence of thyroid autoantibodies in centenarians was confirmed and extended by the finding of a similar low autoantibody prevalence in the highly selected healthy elderly population of group B. Subclinical primary hypothyroidism was found in 3 (7.3%) centenarians, and their data were excluded from further statistical evaluation. No significant difference was found in the median serum free T4 levels of groups A-C. Median (and range) serum free T3 (FT3) was lower in centenarians [3.67 pmol/L (2.3-5.5)] than in group B [5.22 pmol/L (3.4-6.1)] and group C [5.38 pmol/L (2.9-8.4); P < 0.0001 vs. both groups]. Similarly, the median serum TSH level of centenarians [0.97 mU/L (< 0.09 to 2.28)] was lower than those in groups B [1.17 mU/L (0.53-2.74)] and C [1.7 mU/L (0.4-4.8); P < 0.0001 vs. both groups]; moreover, serum TSH was also significantly (P < 0.01) lower in group B than in group C. Both serum FT3 and TSH concentrations showed a significant inverse correlation (r = -0.634; P < 0.0001 and r = -0.377; P < 0.0001, respectively) with age. Median serum FT3 in centenarians was lower than that in group D patients [4.61 pmol/L (2.15-6.6); P < 0.0001]. In contrast, median serum rT3 in centenarians [0.40 nmol/L (0.20-0.77)], although higher than those in groups B [0.24 nmol/L (0.15-0.37); P < 0.0001] and C [0.22 nmol/L (0.05-0.46); P < 0.0001], was significantly lower than that in group D [0.60 nmol/L (0.13-2.08); P < 0.0001]. In conclusion, thyroid function appears to be well preserved until the eighth decade of life if healthy subjects are studied, whereas a reduction of serum FT3 is observed in extreme aging.(ABSTRACT TRUNCATED AT 400 WORDS)

Quantitative and qualitative analysis of anti-tetanus toxoid antibody response in the elderly. Humoral immune response enhancement by thymostimulin.

In order to explore the humoral primary and secondary response to tetanus toxoid (TT), and to define the possible immunopotentiating effect of the thymic hormone thymostimulin, we studied 13 elderly people, selected according to the Senieur Eurage protocol, vaccinated against TT, an antigen never encountered before. Six of them were treated with thymostimulin before and during the immunization protocol. Specific anti-TT antibody level measurement and spectrotypic analysis were performed on the sera collected from the subjects at different times over the immunization protocol. In addition, spontaneous in vitro production of anti-TT antibodies as well as cutaneous delayed hypersensitivity reactions were also studied. Only one patient showed a detectable humoral immune response after the first immunization. After the booster, four of six thymostimulin-treated individuals, compared with only two of seven controls, showed in vivo anti-TT humoral response; at the same time, spontaneous anti-TT production was detected in peripheral blood mononuclear cells from five of six thymostimulin-treated individuals but only three of seven untreated controls. These differences were highly significant (p < 0.0001). In addition, only in thymostimulin-treated subjects were the levels of serum anti-TT antibodies 14, 21 and 28 days after the booster significantly (p < 0.05) higher than the baseline values. The spectrotypic analysis of anti-TT antibodies performed by isoelectric focusing and reverse blotting showed total agreement with the results from enzyme-linked immunosorbent assay.(ABSTRACT TRUNCATED AT 250 WORDS)