T cell activation through different membrane structures (T3/Ti, T11, T44) and frequency analysis of proliferating and interleukin-2 producer T lymphocyte precursors in aged individuals

Characteristics and Distribution of Surgical Diseases in North Korean Research Papers Published between 2006 and 2017

BACKGROUND

Little is known about the surgical discipline in North Korea from the perspective of the outside world. This study aimed to examine the disease entities covered by articles published in the major medical journal in North Korea, "Surgery."

METHODS

Content and frequency analyses of 2,132 articles published in "Surgery" from 2006 to 2017 were conducted. Two medical doctors who majored in surgery and anesthesiology perused the articles and compiled the diseases being elucidated in each article. The diseases described in each article were stratified into 13 surgical subspecialties.

RESULTS

Articles from "Surgery," similar to articles from the Western surgical community, also covered a wide variety of surgical diseases from different subspecialties, and the number of publications continued to grow consistently. Moreover, a number of studies focused on the fields of orthopedics and general surgery dealing with benign diseases. Some articles focused on minimally invasive surgeries using laparoscopy.

CONCLUSION

The studies published in the North Korean journal "Surgery" encompass various clinical areas, but their quality is unclear.

Evidence of the efficacy and safety of house dust mite subcutaneous immunotherapy in elderly allergic rhinitis patients: a randomized, double-blind placebo-controlled trial

Background

Allergen specific immunotherapy (AIT) in elderly patients is controversial, and there is still little evidence supporting the safety and efficacy of this treatment in this population. The study objective was to evaluate the safety and efficacy of AIT for house dust mite allergens in patients over 65 years of age with allergic rhinitis (AR) and a documented allergy to house dust mites. The primary endpoint was the change from baseline in the mean average adjusted symptom score (AAdSS) and the total combined rhinitis score (TCRS) difference in the least square means for the label compared to placebo.

Methods

Fifty-eight AR elderly patients who were monosensitized to house dust mites were individually randomized in comparable numbers to one of two parallel groups with the following interventions: 2 years of perennial AIT using PURETHAL Mites or placebo. The symptoms and medication scores were presented as the AAdSS and TCRS. Quality of life, based on the rhinoconjunctivitis quality of life questionnaire (RQLQ), nasal allergen provocation responsiveness, serum allergen-specific IgG4 to D. pteronyssinus and D. farinae and Der p1 and Der p2 were monitored. The intent-to-treat population was analysed.

Results

After 24 months of AIT, AAdSS significantly decreased from 4.27 ± 1.58 to 1.82 ± 0.71 (p < 0.05). The TCRS was significantly decreased after 2 years of AIT. Serum-specific IgG4 against D. pteronyssinus, D. farinae, Der p1, and Der p2 increased during the AIT trial in the study group. The RQLQ score was significantly improved in patients who received AIT, from 1.86 (95% CI 1.51–1.78) to 1.26 (95% CI 1.09–1.55). Two mild systemic anaphylactic reactions (degree I) were reported after injections in the active group during the AIT therapy.

Conclusion

The DBPC trial showed AIT for house dust mite allergens was effective and safe in elderly patients with allergic rhinitis.

Trial registration

This randomized, double-blinded placebo-controlled (DBPC) trial was conducted at one centre (ClinicalTrials.gov no. NCT03209245)

Age-related impairment of T cell proliferative responses related to the decline of CD28+ T cell subsets

The impairment of phytohaemagglutinin-triggered lymphocyte proliferation represents a prominent immunologic abnormality in elderly individuals. To assess whether the reduced function is related to a CD28/B7 signalling deficiency, purified T lymphocytes and antigen presenting cells (APCs) were analyzed for their phenotypic profile and/or functional capacities. T cell responses to immobilized OKT3 monoclonal antibodies (mAb) or a combination of anti-CD2 mAb and phorbol esters were unaffected in old subjects when compared to the younger counterpart. In contrast, CD28 costimulation in the presence of OKT3 or anti-CD2 mAb, gave rise to significantly diminished T cell proliferative responses. These findings correlated with a marked decline of CD28(+) T cell frequency, which mainly involved the CD4(-)CD45RO(-) cell subset. The defect in CD28 expression could not be reversed by T cell stimulation, as a comparable increase in CD28 levels occurred in both 'aged' and 'young' T cells after in vitro activation. Moreover, the elderly group did not exhibit a reduction of interleukin (IL)-2 synthesis, as assessed at 24 h of culture, regardless of the stimulant used. Finally, B7.2 (CD86) expression by 'aged' CD14(+) APCs was unaffected in both resting and interferon-gamma activated cells. These results suggest that an intrinsic defect in CD28 expression might in part account for the age-related decline of T cell proliferative responses.

Effect of micronutrient status on natural killer cell immune function in healthy free-living subjects aged >/=90 y

BACKGROUND

Natural killer (NK) cells play a role in natural immunity against tumor and infected cells. Advanced aging is associated with functional impairment of NK cells and increased susceptibility to nutritional deficiencies.

OBJECTIVE

Our objective was to test whether micronutrient status affects NK cell activity in an older population.

DESIGN

The relations between NK cell variables (percentage of leukocytes and cytotoxicity) and blood concentrations of selected micronutrients were studied in 62 healthy, free-living northern Italian subjects (25 men, 37 women) aged 90-106 y. Anthropometric measurements were also made.

RESULTS

All subjects were well nourished according to age-specific anthropometric norms but many of them had micronutrient deficiencies. The prevalence of micronutrient deficiency was highest for selenium (in approximately 50% of both sexes), zinc (in 52% of men and 41% of women), and vitamin B-6 (in 40% of men and 59% of women), followed by vitamin A (in 16% of men and 27% of women) and vitamin E, vitamin B-12, and folate (each in <10% of both sexes). Ubiquinone-10 status was inadequate in 40% of women and 24% of men (P = 0.02). The percentage of NK cells was associated with serum zinc (men: r = 0.573, P = 0. 007; women: r = 0.373, P = 0.031) and selenium (women: r = 0.409, P = 0.018) concentrations. In women only, NK cell cytotoxicity at different effector-target cell ratios was positively associated with plasma vitamin E and ubiquinone-10 concentrations (P < 0.05). No significant associations with NK cell variables were found for the other measured nutrients.

CONCLUSIONS

The results of this study strengthen the hypothesis that individual micronutrients may affect the number and function of NK cells in old age. The study also confirms the high prevalence of micronutrient deficiencies in healthy and apparently well-nourished persons aged >/=90 y.

The effect of age on the expression of interleukin-2

Interleukin-2 (IL-2) is a growth promoting cytokine that has received a great deal of attention over the past decade with respect to aging and cancer. It is produced primarily by helper T cells and regulates the growth and function of various cells that are involved in cellular and humoral immunity. The expression of IL-2 has been found to decrease with age in humans and rodents. The decline in IL-2 production has been shown to parallel the age-related decrease in immunologic function. Several studies indicate that treatment of lymphocytes from old subjects with exogenous IL-2 or infusion of IL-2 into old animals partially or completely restores some of the immune functions that decline with age. The age-related decline in IL-2 production has been shown to arise from a decline in IL-2 transcription, and a recent study suggests that the transcription factor NFAT (nuclear factor of activated T cells) may play a role in the decline in IL-2 transcription.

Investigations of the lymphokine system in elderly individuals

Elderly people are at risk from an increased incidence of infections. Therefore we have studied the correlation between the production of several immunological parameters such as interferon-gamma (IFN-gamma), interferon-alpha-2 (IFN-alpha-2), interleukin-2 (IL-2), soluble interleukin-2 receptors (sIL-2R) and interleukin-6 (IL-6) in young controls of 25-34 years old and old individuals with a minimum age of 65 years. All persons were selected according to the basic concept of the 'Senieur protocol'. Heparinized blood was taken and cultured in the whole-blood assay. The determination of all cytokines in the supernatants of stimulated cultures was done by the ELISA technique. We found significantly decreased levels of sIL-2R and IFN-alpha-2 after stimulation, whereas the values of IFN-gamma and IL-2 showed no significant difference between elderly and young persons. The values of IL-6 showed a distinct trend towards an increased synthesis for the elderly. We also studied the lymphocyte subpopulations T4 and T8 by flow cytometry. Elderly individuals showed a significantly increased T4/T8 ratio, caused by a slightly but not significantly decreased level of T8 cells. These results show that the elderly have decreased values of some immunological parameters such as IFN-alpha-2 and sIL-2R, which might explain an increased susceptibility of elderly individuals to bacterial and viral infections.

Comparison of CD3 and CD2 activation pathways in T cells from young and elderly adults

The ability of purified T cells to be activated by immobilized anti-CD3 and soluble anti-CD2 monoclonal antibodies (mAbs) was compared using cells from young and old donors. Purified T cells from elderly humans activated with immobilized anti-CD3 mAb incorporated less [3H]thymidine (58,780 vs 92,258 cpm; p < 0.02) into cellular DNA, and secreted less IL-2 into the culture supernatants than did T cells from young donors. In contrast, T cells activated with anti-CD2 mAbs displayed no age-related differences in proliferation or IL-2 production. Anti-CD2 stimulation resulted in equal IL-2 synthesis by cells from young and old donors that was comparable to the amount produced by cells from elderly donors stimulated with immobilized anti-CD3. Northern blot analysis of early cell cycle gene expression by anti-CD2 activated T cells demonstrated no age differences in the expression of p55 IL-2R or c-myc specific mRNA, although T cells from elderly individuals activated with immobilized anti-CD3 showed statistically significant decreases in both mRNAs. T cell receptor beta chain mRNA levels did not differ between cells from young or old donors after activation by either anti-CD3 or anti-CD2. The discordance in proliferative ability, IL-2 secretion, and specific mRNA expression between T cells from elderly donors activated through the CD3-TCR complex or by soluble anti-CD2 mAbs provides additional evidence for a multifactorial causation of age-related T cell proliferative defects, and may indicate that the difference in proliferative ability is, in part, attributable to responsiveness to secreted IL-2.

Phytohemagglutinin induced changes of membrane lipid packing, c-myc and c-myb encoded protein expression in human lymphocytes during aging

Three parameters which signal different stages of cell activation were analyzed in lymphocytes from young and old subjects. Merocyanine 540 (MC-540) incorporation into the membrane lipid phase was used as a very early marker of activation and was measured after 1 h of phytohemagglutinin (PHA) stimulation. The proteins coded by c-myc and c-myb protooncogenes were determined by appropriate antibodies and were taken as markers of the G0/G1 and G1/S phase transition, respectively. The number of cells which increased the uptake of MC-540 following PHA stimulation did not differ when comparing young and old individuals. Both the number of the responding cells and the size of the response were decreased during aging when the presence of the c-myc protein was taken into account. A consistent decrease of the percentage of lymphocytes able to express the c-myb protein was observed in the cells from old donors as compared to those from the young ones, but the amount of detectable protein per cell remained unchanged. Our data suggest that the deficiency of responsiveness which accompanies aging is due to impairments at different points of the cell cycle. The very low number of cells expressing the c-myb protein is likely the result of step by step elimination of those cells not able to fulfill the requirements to progress along the cell cycle.

The effect of aging on host defences. Implications for therapy

Immunosenescence is a well known physiological phenomenon resulting from reduced efficiency of the immune system in the elderly. It has been studied both in animal models and in humans. In this review attention is focused on T cell responsiveness, since this cell type is both a marker of the immune response and one of the main targets of several drugs. For this latter reason, most studies of the effect of drugs on the immune system have been performed with reference to the effects on T lymphocytes. In the second part of the article experimental data concerning several drugs and drug classes [steroids, calcium antagonists, theophylline, histamine H1- and H2-receptor antagonists, sodium cromoglycate (cromolyn sodium), pirenzepine, rosaprostol, beta 2-mimetics, antibiotics and antibacterials] and immune responsiveness are reviewed. Lastly, the clinical perspectives of pharmacological treatment in aged subjects in relation to immunosenescence are evaluated.

T-cell function in aging: mechanisms of decline

The above sections have provided numerous facts, many of which are conflicting, regarding the changes that occur with increasing age in T lymphocytes. Although it is impossible to state with absolute certainty the alterations that are responsible for decreased proliferation of lymphocytes from elderly subjects, the following summarizes the current status of the data: 1. The interaction of T lymphocytes with foreign stimuli appears to be generally intact. 2. Changes in numbers of CD3+, CD4+, or CD8+ cells before interaction with foreign stimuli or in the density of these markers or of mitogen receptors on the surface of aged T cells have not been consistently observed. When reported to occur, the changes are not sufficient to account for the significant decrease in T-cell proliferation that occurs with increasing age. 3. A defect in the ability of the membrane interaction with foreign stimulus to signal subsequent internal events may occur, because stimulation with phorbol esters and calcium ionophore can result in increased proliferation in some elderly subjects. 4. Decreased accumulation of cytosolic calcium after stimulation of elderly T cells occurs in mice and may be a major component of the defective activation system. This defect appears to be most apparent in the "memory" T cells (T cells expressing high levels of Pgp-1), which increase in number with increasing age. Decreases in Ca++ accumulation have not been observed in humans, but this may be due to different stimuli used. Further, investigation of an increase in "memory" T cells and of their inability to mobilize Ca++ has not been done in humans and rats. 5. Decreases in mRNA for c-myc, IL-2 receptor, and IL-2 have been reported in some, but not all, species. Whether these decreases are the result of decreases in Ca++ mobilization or are independent events in unknown. 6. Decreases in membrane expression of the activation marker RL388 and of TfR have been reported. 7. Lymphokines: a. Decreases in IL-2 production occur in mice and humans, but not in rats. In individuals with decreased IL-2 production, addition of exogenous IL-2 totally restores proliferative ability in only some individuals. Changes in IL-2R expression (number or affinity) may be an additional defect. b. Decreases in IFN-gamma occur in humans, but not in mice or rats. c. No change in IL-1 occurs in any species. Genotypic effects must be considered when evaluating the preceding observations. The heterogeneity among individuals, even within an inbred strain, cannot be discounted.(ABSTRACT TRUNCATED AT 400 WORDS)

Heterogeneity of changes in lymphoproliferative ability with increasing age

Although mean mitogen-induced lymphoproliferation decreases with increased age, the response of individual subjects demonstrates great heterogeneity. Results of this study clearly illustrate that individual variation is apparent not only in the level of proliferation, but also in the amount of interleukin-2 (IL-2) detectable after mitogen stimulation. Further, addition of exogenous IL-2 significantly increases proliferation in only about one third of elderly subjects. Data from inbred strains of rats housed under identical environmental conditions indicate that although genetic factors greatly influence both the level of proliferation and the rate of decline with age, variation occurs even within one inbred strain of rat.

T cell activation in the elderly: evidence for specific deficiencies in T cell/accessory cell interactions

We studied T cell activation in the healthy aged (greater than 70 years) by examining lymphocyte proliferative responses to various mitogenic stimuli in accessory cell (AC)-dependent and AC-independent systems. Results show that despite a near normal response to the anti-CD3 monoclonal antibody (mAb) OKT3, peripheral blood mononuclear cells (PBM) from the elderly exhibit a profound reduction in phytohaemagglutinin (PHA)-responsiveness (approximately 30% of young adults). This deficit becomes even more severe at suboptimal doses of PHA. Adding exogenous interleukin-2 (IL-2) or pretreating the AC population with gamma interferon (IFN-gamma) returns the level of proliferation to that seen with young adults. Furthermore, replacing "old" AC with AC from young adults or with U937 (a monocytic cell line) in T cell/AC cell-mixing experiments restores PHA-responsiveness in 70% of cases. On the other hand, AC from the aged fully support PHA responses in T cells from young adults. In AC-depleted cultures, purified T cells from the aged respond normally to the co-mitogenic stimuli, PHA + PMA. Taken together, these results suggest that the age-associated diminution in PHA-responsiveness is due, at least in part, to specific deficiencies in T cell/AC communication.

Lymphocyte immunophenotyping in an elderly population: age, sex and medication effects--a flow cytometry study

Flow cytometry studies of 179 individuals aged 55-95 years reveal correlations of various hematological and immune cell measures (quantification of leukocytes, leukocyte subtypes, platelets, and erythrocytes) with age, sex, common medications (aspirin, ulcer therapy, estrogen replacement therapy), and health history variables (minor arthritis, allergy, smoking, stress and exercise). Possible reasons for some of these findings are discussed.

In situ hybridization analysis of the age-associated decline in IL-2 mRNA expressing murine T cells

Only a small decrease in the number of L3T4- cells was observed in the Con A-stimulated splenocyte cultures of old mice as compared to young, which cannot account for the threefold decrease in IL-2 production. Northern and dot blot analysis of RNA from splenocytes containing equivalent numbers of L3T4+ cells from young and old mice showed that cells from old mice express less IL-2 mRNA after mitogenic stimulation than cells from young mice. Direct analysis by in situ hybridization of stimulated splenocytes from young and old mice then showed approximately a threefold decrease in the percentage of IL-2 mRNA expressing cells in the spleens of old mice as compared to young (8.7 +/- 4.1% old; 28.7 +/- 11.7% young). The average level of expression of IL-2 mRNA was not significantly different between cells from young and old mice; however, there were approximately 40% fewer cells expressing an intermediate to high amount of IL-2 mRNA in old mice as compared to young (26.3% vs 41.8%). These data suggest that the decrease in IL-2 production with age is associated primarily with a decrease in the frequency of IL-2 mRNA-expressing cells in old mice, especially in those cells expressing intermediate to high levels of IL-2 mRNA.