Mixed type I and type II collagen scaffold for cartilage repair: ultrastructural study of synovial membrane response and healing potential versus microfractures (a pilot study).

The association between microfracture of the subchondral plate and a coverage scaffold has emerged as a promising strategy to treat cartilage lesions in a one-step procedure. Between different types of scaffolds (e.g. collagen, hyaluronic acid, polyglycolic acid) currently studied, type I collagen scaffold is the most used for this purpose, and is currently adopted for humans. The aim of this study was to test a novel scaffold made of mixed type I and II collagen (I-IICS) in order to define the immunological reaction of the synovial tissue and the repair capabilities induced by the collagen membrane when associated with microfracture. Eight New Zealand White rabbits, aged 180 days, were operated on bilaterally on the medial femoral condyle. A circular cartilage lesion was performed up to the calcified layer of the medial femoral condyle, and the centre of the lesion was microfractured. Randomly, one of the two lesions was covered with the I-IICS (treated), and the other was left uncovered (control). The synovial membrane reaction and the quality of the cartilage tissue repair were investigated at 2, 90, 180 and 270 days macroscopically, histomorphologically and ultrastructurally. Expression of tumor necrosis factor-alpha (TNF-alpha) in synovial tissue by immunocytochemistry analyses was also investigated. In the control group, at 2 days gold particles were localized mainly on synoviocyte type A, less on synoviocytes type B and on collagen bundles; in the treated group the reaction is more intense in cells in the matrix, but at 180 days controls and treated joints were very similar. The synovial membranes of the joints receiving the I-IICS did not reveal significant changes compared to the age-matched controls. Signs of inflammation were present at the 90-day time-point, and became less evident at afterwards. The degradation of the scaffolds was already evident at the 90-day time-point. The quality of the cartilage repair of the rabbits treated with the I-IICS was slightly better in 5 cases out of 6 in comparison to the controls. However, a statistically significant difference was not detected (p=0.06). Scaffolds made of mixed type I and II collagen exhibited good biocompatibility properties in vivo and favoured cartilage restoration when associated with microfracture, as shown in this pilot study.

Apoptosis-resistant phenotype in HL-60-derived cells HCW-2 is related to changes in expression of stress-induced proteins that impact on redox status and mitochondrial metabolism.

The onset of resistance to drug-induced apoptosis of tumour cells is a major problem in cancer therapy. We studied a drug-selected clone of promyelocytic HL-60 cells, called HCW-2, which display a complex resistance to a wide variety of apoptosis-inducing agents and we found that these cells show a dramatic increase in the expression of heat shock proteins (Hsps) 70 and 27, while the parental cell line does not. It is known that stress proteins such as Hsps can confer resistance to a variety of damaging agents other than heat shock, such as TNF-alpha, monocyte-induced cytotoxicity, and also play a role in resistance to chemotherapy. This elevated expression of Hsps is paralleled by an increased activity of mitochondrial metabolism and pentose phosphate pathway, this latter leading to high levels of glucose-6-phosphate dehydrogenase and, consequently, of glutathione. Thus, the apoptotic-deficient phenotype is likely because of the presence of high levels of stress response proteins and GSH, which may confer resistance to apoptotic agents, including chemotherapy drugs. Moreover, the fact that in HCW-2 cells Hsp70 are mainly localised in mitochondria may account for the increased performances of mitochondrial metabolism. These observations could have some implications for the therapy of cancer, and for the design of combined strategies that act on antioxidant defences of the neoplastic cell.

Leukaemic transformation in a case of thrombocythaemia. Case report and review of the literature.

The authors describe a case of thrombocythaemia, with subsequent leukaemic transformation. Cytochemical and immunocytochemical investigations indicated a trilineage involvement of the myeloid series, compatible with a leukaemic transformation at the level of the colony-forming unit granulocytes, erythrocytes, macrophages, megakaryocytes. No cytogenetic abnormalities were observed. The criteria which have been proposed to differentiate essential thrombocythaemia from pre-fibrotic thrombocythaemia, as an early phase of idiopathic myelofibrosis, are discussed. The differentiation is not only of academic interest but has relevant practical implications, since survival in the two conditions is significantly different. The possible significance of an accompanying monoclonal gammopathy is discussed.

[Association between motoneuron disease and Waldenström macroglobulinemia]. / Associazione tra malattia dei motoneuroni e macroglobulinemia di Waldenström.

The authors describe the case of a patient who was referred to their Unit because of polyneuropathy and was subsequently found to be affected by Waldenström's macroglobulinemia. A monoclonal paraproteinemia is frequently described in the serum of subjects with motor neuron disease. The association between motor neuron disease (MND) and lymphoproliferative disease (LPD) could be the result of a coincidence, but LPD seems to be disproportionally frequent in patients with MND, compared to the population in general. The literature has studied the time relationship between lymphoproliferative disease and MND and has examined the different possible mechanisms, which might explain the association between MND and LPD. The presence of a slight increase in the level of IgM and kappa chains in a patient with polyneuropathy induced us to carry out an aspiration and trephine bone marrow biopsies, which revealed the presence of a lymphoplasmocytoid infiltration, compatible with Waldenström's macroglobulinemia. A needle biopsy should be carried out as part of a diagnostic routine procedure in a patient with MND, especially in the presence of a monoclonal paraproteinemia.

Hyaluronan affects protein and collagen synthesis by in vitro human skin fibroblasts.

Given the importance of hyaluronan (HA) for the homeostasis of connective tissues during embryogenesis and aging and its role in tissue repair, the aim of the present study was to examine the effect of exogenous HA on the synthesis of total protein, collagen and HA by in vitro human dermal fibroblasts. With differences between different cell strains, HA, at concentrations between 0.5 and 1 microM, induced a significant decrease in total protein synthesised and secreted into the medium compared to controls (P < 0.05), and particularly in collagen (-40%; P < 0.05). The ratios between collagen types I and III and between collagen types V and I were normal. Pulse and chase experiments showed that protein degradation was normal. The presence of exogenous HA did not affect HA synthesis. Data strongly indicate that a relatively high concentration of HA in the extracellular space, such as during development and in the first phases of tissue repair, would partially limit the deposition of the extracellular matrix, and of collagen in particular. This would suggest a role for HA in delaying tissue differentiation during embryogenesis and in preventing fibrosis and scar formation in fetus and in the early phases of wound healing.

The placenta in pseudoxanthoma elasticum: clinical, structural and immunochemical study.

Pseudoxanthoma elasticum (PXE) is a rare genetic disorder clinically characterized by skin, cardiovascular and eye manifestations, mainly due to calcification and fragmentation of elastic fibres. Although infrequent, complications during pregnancy in women affected by PXE have been reported. The aim of the present study was to compare structural features of placentae at term from 14 control and 15 PXE-affected women, in order to better understand if and how abnormal mineral and/or matrix accumulation might affect placental function in PXE. In all cases, pregnancy, fetus growth and delivery were normal. Both gross and light microscopy examination did not reveal dramatic differences between placentae of PXE patients and controls, with regard to weight, dimensions, infarcts, thrombi, inflammatory lesions or vessels. However, necrotic changes and mineralization appeared statistically more pronounced in PXE. By electron microscopy the most remarkable differences between PXE and control placentae were observed in the localization and morphology of mineral precipitates; a significant higher deposition of mineral precipitates was observed associated with the "matrix"-type fibrinoid and among collagen fibrils, especially on the maternal side. Immunocytochemistry revealed the presence of vitronectin and fibronectin associated with the PXE-specific mineralizations and the absence of mineralization on the small and scarce elastic fibres in either controls or in PXE.

Changes in the expression of surface receptors on lymphocyte subsets in the elderly: quantitative flow cytometric analysis.

The immunophenotype of circulating lymphocytes, including the intensity expression of surface receptors, changes with ageing. Until now, no results of systematic studies on age-dependent changes with respect to the expression of the major lymphocyte surface receptors in healthy elderly subjects have been reported. In order to identify age-related changes in both representation and immunophenotype of lymphocyte populations, we investigated, by means of triple-color whole-blood immunostaining and quantitative flow cytometry, the percent values and the absolute numbers, as well as the levels of surface antigen expression or antigen molecules per cell (ABC values x 10(3)), of different peripheral blood lymphocyte subsets from 23 healthy elderly subjects and 13 young donors. Naive (CD45RA+CD3+) T cells, total B cells, and CD5+ B lymphocytes are decreased (22%, 6%, 0.8% vs. 30%, 12%, 1.4%, respectively), whereas activated (HLA-DR+CD3+) and memory (CD45RO+CD3+) T cells, CD3+CD7- T lymphocytes, and lymphocytes expressing the NK marker CD56 are expanded in the elderly (2%, 53%, 13%, 6% vs. 0.8%, 45%, 8%, 8%, respectively). Moreover, T lymphocytes from elderly individuals express lower CD3 (61 +/- 10) compared to young (69 +/- 10). Considering the different T-cell populations, CD3 antigen is respectively decreased on CD45RO+ T cells (55 +/- 14 vs. 66 +/- 14) and up-regulated on CD56+ T lymphocytes (62 +/- 21 vs. 45 +/- 20). Increased CD8 expression characterizes CD3+CD7- lymphocytes (70 +/- 34 vs. 44 +/- 17) while HLA-DR on activated T cells is lower in old (39 +/- 7) than young (46 +/- 9) donors. CD7 is down-regulated both in T (22 +/- 3 vs. 28 +/- 3) and NK (48 +/- 18 vs. 71 +/- 18) cells, whereas CD2 expression, unchanged on NK cells, is up-regulated on T lymphocytes (54 +/- 10 vs. 41 +/- 8). Age-related changes in B-cell antigen expressions were also found: CD20 is increased (124 +/- 23 vs. 105 +/- 16) whereas, despite the unchanged CD5 expression of T cells, CD5 intensity on the B-cell subset co-expressing this antigen is higher in old (49 +/- 37) than in young (22 +/- 4) people. The observed changes in the expression of functionally important cellular receptors can contribute to the remodeling of immune function characteristic of the elderly. Moreover, since quantitative flow cytometry is becoming widely employed in clinical practice, our results also contribute to the assessment of specific age-dependent antigen expression changes to be considered for diagnostic approaches in the elderly.

[Extranodal localizations of lymphoma. Clinico-epidemiologic study of 353 cases]. / Le localizzazioni extranodali del linfoma. Studio clinico-epidemiologico di 353 casi.

The Authors have carried out a retrospective study on 353 cases of lymphoma, of which 252 of non-Hodgkin lymphoma (NHL) and 101 cases of Hodgkin's disease (HD), during a 17 year period, i.e. from 1982 to 1999, with the purpose of evaluating the frequency of primitive and secondary extra-nodal localizations and assess their influence on the percentage of survival. A highly significant statistical difference was observed comparing patients with nodal LNH and those with a primitive extra-nodal localization of the disease. In HD extra-nodal localizations were observed at the time of diagnosis in 13% of the cases studied, in which however in the great majority of patients presentation was associated with generalized disease and was therefore the consequence of local spread from near-by lymphoid sites. However, primitive localizations were surely observed and carefully documented. In our patients they were detected in the intestine, in the skin and in the mammary gland. In 253 patients with NHL, 123 sites of extranodal localizations were found (50%) and were observed in the skeletal system, in the skin and in the orbital cavity. The Authors underline the need to improve our knowledge on the structures and mechanisms of spread of the mucosal associated lymphoid tissue in order to better understand the clinical aspects and the necessary therapeutic approach in cases of extranodal and especially MALT lymphomas.

[Blood coagulation changes and neoplastic pathology]. / Alterazioni emocagulative e patologia neoplastica.

Cancer patients show an increased susceptibility to develop thromboembolic diseases, suggesting that disorders of coagulation are very common in this pathology. Tumor cells possess the capacity to interact with the hemostatic system, activating the coagulation cascade and stimulating the prothrombotic properties of other blood cell components; the same events while inducing a hypercoagulable state, also contribute to the processes of tumor growth, neoangiogenesis and metastatic formation. Multiple risk factors associated with malignant disease contribute to the hypercoagulability state: stasis induced by prolonged bed rest, vascular invasion by the tumor and iatrogenic complications including the use of central vein catheters and chemotherapy. Several tests have been developed to assess the hypercoagulable state, however their clinical significance still needs to be defined, especially in terms of their predictive value for thrombosis. Clinical manifestations vary from localized deep venous thrombosis (DVT) or pulmonary embolism, more generally associated with solid tumors, to disseminated intravascular coagulation, frequent in hematologic malignancies and metastatic cancer. Diagnosis of idiopathic DVT, in the absence of other risk factors, could indicate the presence of occult cancer, but the usefulness of an extensive work-up to detect malignancy in terms of cost to benefit ratio still has to be demonstrated. Patients with cancer and thromboembolism must be treated with anticoagulant therapy; a large number of studies have shown that either low molecular weight heparins or standard unfractionated heparin for the treatment of acute deep vein thrombosis in hospitalized patients are equally safe and effective; however, the first treatment has been reported to be associated with a lower mortality. After an episode of thrombosis the patients should be protected by a long term course of oral anticoagulation, remaining high the risk of recurrence for as long as the cancer is active.

Cell proliferation and apoptosis in the immune system in the elderly.

Loss of the cell proliferative capability and involution of tissues and organs are among the most important phenomena that characterize the aging process. Some of the aged-linked immune dysfunctions could be partly due to a dysregulation of apoptotic processes and to a lower responsiveness of aged lymphoid cells to activation and proliferation signals. The main changes in proliferative activity and cell death during aging and their impact on the process of immunosenescence are discussed. In fact, a very important function that has been suggested to deteriorate with age and to play a major role in the aging process is the capability of cells from aged subjects to respond to mitogenic stimuli and, consequently, to undergo cell proliferation. However, the cellular activation processes are very complex and the proliferative responses can follow different interconnected signal transduction pathways, and only some of them appear to be modified during age. Moreover, cell growth, immunosenescence, and longevity are strictly interconnected and deeply related to programmed cell death or apoptosis. The cellular equilibrium between cell survival and proliferation, on the one hand, and programmed cell death, on the other hand, seems to be unbalanced with advancing age, although in each type of immune cell it could be differentially modulated, resulting in a variety of clinicopathological consequences. Thus, cell proliferation and cell death are two physiologically active phenomena closely linked and regulated and a failure of these mechanisms determines profound dysregulations of cell homeostasis with major consequences in immune functioning and the onset of autoimmune diseases and cancer, whose incidence appears to be increased in the elderly.

Abnormal phenotype of in vitro dermal fibroblasts from patients with Pseudoxanthoma elasticum (PXE).

Pseudoxanthoma elasticum (PXE) is a genetic connective tissue disease, whose gene and pathogenesis are still unknown. Dermal fibroblasts from patients affected by PXE have been compared in vitro with fibroblasts taken from sex and age-matched normal individuals. Cells were grown and investigated in monolayer, into three-dimensional collagen gels and in suspension. Compared with normal cells, PXE fibroblasts cultured in monolayer entered more rapidly within the S phase and exhibited an increased proliferation index; on the contrary, similarly to normal fibroblasts, PXE cells did not grow in suspension. Furthermore, compared with normal fibroblasts, PXE cells exhibited lower efficiency in retracting collagen type I lattices and lower adhesion properties to collagen type I and to plasma fibronectin. This behavior was associated with higher expression of integrin subunits alpha2, alpha5, alphav, whereas beta1 subunit as well as alpha2beta1 and alpha5beta1 integrin expression was lower than in controls. Compared to controls, PXE fibroblasts had higher CAM protein expression in accordance with their high tendency to form cellular aggregates, when kept in suspension. The demonstration that PXE fibroblasts have altered cell-cell and cell-matrix interactions, associated with modified proliferation capabilities, is consistent with the hypothesis that the gene responsible for PXE might have a broad regulatory role on the cellular machinery.

Adhesion molecules on peripheral blood lymphocyte subpopulations in the elderly.

Adhesion molecules, such as CD49d, CD50 and CD62L, have important roles in many adhesive interactions involving cells of the immune system. Since it has been shown that many immunological alterations are present in aged subjects, we studied, by means of triple colour whole blood immunostaining and multiparametric flow cytometry, the expression and intensity level (MFI) of these molecules on peripheral blood lymphocyte subpopulations from 23 healthy elderly subjects and 13 young controls. In the elderly a decrease in total peripheral blood lymphocytes bearing CD62L antigen was observed (39 +/- 13% vs 63 +/- 6% and 745 +/- 312/mm3 vs 1,393 +/- 407/mm3; p<0.001), whereas the numbers of lymphocytes expressing CD49d and CD50 antigens were comparable in aged and young subjects. In addition, CD50 and CD62L MFI values on total peripheral blood lymphocytes were higher in elderly than in young subjects (5.23 +/- 1.03 vs 4.18 +/- 0.44, p = 0.001 and 2.60 +/- 0.35 vs 2.21 +/- 0.40, p = 0.005 respectively) while the intensity expression of CD49d was unchanged. The percentages and absolute numbers of T and B lymphocytes expressing CD62L were decreased in elderly compared to young subjects (CD62L+CD3+: 43 +/- 15% vs 66 +/- 9% and 581 +/- 257/mm3 vs 1,028 +/- 418/mm3, p<0.001; CD62L+CD19+: 78 +/- 12% vs 90 +/- 4%, p < 0.005 and 103 +/- 64/mm3 vs 207 +/- 98, p < 0.001). A decrease in the proportion of CD62L bearing NK cells was also observed in the elderly (25 +/- 14% vs 46 +/- 24%, p<0.005), although their absolute number was unchanged. No significant differences were detected in the proportion of T, B and NK lymphocytes expressing CD49d and CD50 antigens and only the absolute numbers of B cells expressing these adhesion molecules were lower in elderly (CD49d+CD19+: 121 +/- 71/mm3 and CD50+CD19+: 107 +/- 73/mm3) compared to young donors (CD49d+CD19+: 248 +/- 112/mm3 and CD50+CD19+: 235 +/- 120/mm3, p < 0.001). Moreover, the intensity of adhesion molecule expression was differentially modulated in the elderly depending on the specific lymphocyte cell population considered. The densities of CD49d, CD50 and CD62L antigens on B and NK lymphocytes from the two age groups were not different; on the contrary, T lymphocytes from elderly donors exhibited increased CD49d (1.69 +/- 0.09 vs 1.62 +/- 0.07, p < 0.05), CD50 (4.98 +/- 1.16 vs 3.77 +/- 0.46, p < 0.001) and CD62L (2.26 +/- 0.38 vs 1.99 +/- 0.37, p < 0.05) MFI values compared to young donors.

CD50 and CD62L adhesion receptor expression on naive (CD45RA+) and memory (CD45RO+) T lymphocytes in the elderly.

A complex reshaping characterizes cellular immunity in the elderly. In particular, the hallmark of the "senescence" of the T cell compartment is a decrease in the proportion of CD45RA+ naive T lymphocytes concomitantly with an expansion of CD45RO+ memory T cells. However, in addition to age-dependent changes in their representation, phenotypical and functional anomalies also characterize naive and memory T cell populations in the elderly. Since cell adhesion molecules (CAMs) are multifunctional receptors which play important roles not only in cell-to-cell and cell-to-matrix interactions but also in signal transduction and cell activation, we analysed, by means of a three-colour flow cytometry method, the proportion, absolute number and density expression or mean fluorescence intensity (MFI) of CD50 (ICAM-3) and CD62L (L-selectin homing receptor) adhesion receptors on CD45RA+ and CD45RO+ peripheral blood CD3+ T cell subsets from 10 healthy elderly subjects and 10 young controls. Our aim was to investigate age-dependent changes in the expression pattern of these CAMs on naive and memory lymphocytes which might contribute to the remodelling of the immune system in the elderly. We considered the mean values +/- standard deviations of the percentage, absolute number and MFI of positive cells. The percentage of naive T cells expressing CD50 was not significantly modified in aged (94.8 +/- 5.0%) compared to young individuals (97.8 +/- 3.2%). On the contrary, the percentage of memory T cells exhibiting CD50 was lower in elderly than young donors (92.0 +/- 6.4 vs. 98.3 +/- 2.2%; p < 0.01). The percentage of naive T cells expressing CD62L was decreased in the elderly donors (53.3 +/- 18.8 vs. 80.8 +/- 11.0%; p < 0.001), whereas the proportion of CD62L+ memory T lymphocytes was substantially comparable between the two age groups (63.5 +/- 15.7 vs. 54.7 +/- 12.3%). The absolute number per mm(3) of CD50+ naive T cells from aged individuals was decreased (251.9 +/- 141.9 vs. 621.8 +/- 238.0/mm(3); p < 0.001), whereas memory peripheral blood T lymphocytes expressing CD50 were substantially unchanged (863.8 +/- 260.9 vs. 802.7 +/- 139.6/mm(3)). On the contrary, the absolute numbers per mm(3) of naive and memory peripheral blood T lymphocytes exhibiting CD62L were respectively decreased (190.8 +/- 133.4/mm(3)) and increased (515.1 +/- 146.8/mm(3)) in elderly donors compared to young controls (601.3 +/- 129.1 and 351.8 +/- 195.0/mm(3); p < 0.001 and p < 0.05, respectively). Finally, CD50 MFI values of naive as well as memory T cell subpopulations from aged subjects were increased compared to young donors (14.0 +/- 2.0 vs. 9.8 +/- 1.2 and 14.0 +/- 2.0 vs. 11.6 +/- 1.3; p < 0.001 and p < 0.01, respectively). CD62L was also overexpressed in both naive (8.4 +/- 1.6 vs. 6.7 +/- 1.4; p < 0.05) and memory (10.3 +/- 2.5 vs. 5.4 +/- 1.1; p < 0.001) T subsets in the elderly. CD50 and CD62L upregulation could be interpreted as a compensatory mechanism for a decreased responsiveness and a greater requirement for activation signals rather than an age-related anomaly.

The immune system in the elderly: I. Specific humoral immunity.

Profound and complex changes in the immune response occur during the aging process. Immunosenescence is reflected by a sum of disregulations of the immune system and its interaction with other systems. Many of the changes would appear to implicate age-related deficiencies of the immune responses. The term immunosenescence designates therefore a sort of deterioration of the immune function which is believed to manifest itself in the increased susceptibility to cancer, autoimmune disease, and infectious disease. Evidence has been accumulating from several studies which suggest an association between immune function and individual longevity. However, there are observations, especially in very old healthy people, that several immune functions are unexpectedly well preserved and substantially comparable to those observed in young subjects. These findings raise the question of whether the alterations that can be observed in the immune parameters of the elderly are a cause or a result of underlying disease processes. Moreover, studies on centenarians revealed a remodeling of the immune system rather than a deterioration, suggesting that the changes observed during immunosenescence do not correspond to immunodeficiency. The underlying mechanisms of these events are however still unclear. The purpose of the present review is to assess the status of research on the immunobiology of aging. In this first section, we focus attention on the B cell biology of aging. In clinical practice, the changes in humoral immune responsiveness and antibody-mediated defense mechanisms could greatly influence the incidence and outcome of bacterial infections and autoimmune diseases as well as the response to vaccines.

The immune system in the elderly: II. Specific cellular immunity.

Numerous changes occur in the immune system with advancing age, probably contributing to the decreased immunoresponsiveness in the elderly. These changes are often associated with important clinical manifestations such as increased susceptibility to infection and cancer frequently observed in the elderly population. Although both cellular and humoral immune responses are modified with advancing age, much of the decrease in immunoresponsiveness seen in elderly populations is associated with changes in T cell responses. The loss of effective immune activity is largely due to alterations within the T cell compartment which occur, in part, as a result of thymic involution. Substantial changes in both the functional and phenotypic profiles of T cells have been reported with advancing age. In fact, two prominent features of immunosenescence are altered T cell phenotype and reduced T cell response. One of the most consistent changes noted in T cells with advancing age is the decrease in the proportion of naive T cells with a concomitant increase in T cells with an activated/memory phenotype. In addition, there is evidence that the T cell population from aged individuals is hyporesponsive. The observed functional changes include decreased responsiveness to T cell receptor stimulation, impaired T cell proliferative capacity, a decline in the frequency of CD4+ T cells producing IL-2 and a decreased expression in IL-2 receptors. These latter findings probably explain the loss of proliferative capability of T cells from aged individuals. There is also evidence of a decrease in the early events of signal transduction, decreased activation-induced intracellular phosphorylation, and decreased cellular proliferative response to T cell receptor stimulation. The present review analyzes the main changes of the T cell compartment characterizing immunosenescence and discusses the possible mechanisms underlying these disregulations and their clinical implications.

The immune system in the elderly: III. Innate immunity.

The capability to cope with infectious agents and cancer cells resides not only in adaptive immune responses against specific antigens, mediated by T and B lymphocytes clonally distributed, but also in natural immune reactions. These innate defence mechanisms include chemotaxis, phagocytosis, natural cytotoxicity, cell interactions, and soluble mediators or cytokines. However, specific and natural immune mechanisms are always closely linked and interconnected, providing the primary defense against pathogens. The Authors discuss the main changes observed with advancing age in granulocytes and natural killer (NK) cell activity, in the expression and function of adhesion molecules, and in the pattern of cytokine production. Since phagocytic function is the primary mechanism through which the immune system eliminates most extracellular pathogenic microorganisms, analysis of this function is of clinical importance. Neutrophils from aged subjects often exhibit a diminished phagocytic capacity, as well as a depressed respiratory burst, notwithstanding an activated state. The activity of NK cells during aging has been studied extensively and different results have been reported. The most consistent data indicate an increase in cells with high NK activity with advancing age. Cells from healthy centenarians can efficiently kill target cells. This finding seems to suggest that innate immunity and in particular NK cell activity, is not heavily deteriorated with age. Conversely, a low NK activity is a predictor of impending morbidity. Immunosenescence is associated with increased expression of several cell adhesion molecules (CAM) resulting in an augmented capacity to adhere. Finally, also the cytokine network, responsible for differentiation, proliferation, and survival of lymphoid cells, undergoes complex changes with age. The main findings are a Th1 to Th2 cytokine production shift and an increased production of proinflammatory cytokines, which could explain many aspects of age-associated pathological events, such as atherosclerosis and osteoporosis.

[Biological and clinical characteristics of granular lymphocyte proliferation. Review of the literature and personal experience]. / Caratteristiche biologiche e cliniche delle proliferazioni di linfociti granulari. Revisione della letteratura ed esperienze personali.

The Authors, on the basis of reports from the literature and their personal experience, describe the morphological, immunophenotypic, genotypic and functional features of Large Granular Lymphocytes (LGL). An increased number of the these particular types of lymphocytes may be observed in different pathological conditions and may be interpreted as a reactive process to a possible underlying antigenic stimulation. However, a significant and prolonged increase in LGL's may also identify the existence of a true definite Lymphoproliferative disorder (LGL-PD). It is now well known that phenotypically LGL-PD may be present in two different variants: a CD3+ form, which is more frequent, and a CD3-variant. The former usually is characterized by T-cell receptor monoclonal rearrangement, while CD3- NK cells are frequently polyclonal. However also this latter variant may express clonality and in this case the clinical course is particularly aggressive. Although LGL-PD is a distinct clinical disorder, the Authors underline the extreme variability of the clinical course and the need therefore to adopt a policy of "wait and see" before taking into consideration the choice of different therapeutic options, which are often disappointing and provide remission of only brief duration.

Identification of heterozygote carriers in families with a recessive form of pseudoxanthoma elasticum (PXE).

Skin biopsies of 18 healthy relatives of patients with pseudoxanthoma elasticum (PXE), belonging to six different recessive families, have been examined by optical and electron microscopy in order to determine morphologic alterations potentially useful for the identification of carriers of this genetic disorder. These morphologic features have been compared with those observed in the same tissue areas of eight PXE patients belonging to the same families, with six normal subjects, and to the carrier status of these apparently unaffected relatives as determined by haplotype analysis using informative markers surrounding the locus of the PXE gene on chromosome 16p. The dermis of all the relatives of PXE patients, established by haplotype analysis to be heterozygote carriers of a mutation in the PXE gene, exhibited several alterations very similar, although less severe, to those typical in PXE patients. Alterations were present in the reticular dermis and consisted of irregular-sized collagen bundles and elastic fibers; elastic fibers fragmented, cribriform, and mineralized; numerous fibroblasts, larger than normal, and subendothelial elastin in small vessels. Strikingly, none of these dermal changes were noted in an unaffected relative in one family who was identified as a noncarrier by haplotype analysis. Although many of these alterations are not specific for PXE, the presence of these morphologic changes in unaffected relatives of PXE patients indicates alterations in skin that could be diagnostic for carriers of a subclinical phenotype of PXE.

Immunological changes in the elderly.

Immunosenescence is a complex remodelling of the immune system which may contribute significantly to morbidity and mortality in the elderly. Much evidence suggests an association between immune function and longevity. It was advanced that individuals who have survived in good health to the maximum life span are equipped with optimal cell defense mechanisms. Despite the great number of studies on the immune system in the elderly, little is known of the biological basis of immunosenescence in humans. This is partly due to the contrasting results often obtained by the various investigators. One source of discrepancy is that diseases are frequent in aging, and the alterations observed in the immune parameters of the elderly could be a cause or alternatively a consequence of the underlying pathological processes. Undoubtedly some diseases to which aged people are particularly susceptible, such as infectious, autoimmune and neoplastic pathologies, include dysregulation of several immune functions in their pathogenesis. On the other hand, recent studies in healthy centenarians suggest that the immunological changes observed during aging are consistent with a reshaping, rather than a generalized deterioration, of the main immune functions. Considering that the number of old people is dramatically increasing, and that geriatric pathology is becoming an important aspect of clinical practice, it seems particularly interesting to review the peculiar findings in the immune system of the elderly so as to better understand their susceptibility to certain diseases, and the links between health and longevity.