Transduction of human NOD/SCID-repopulating cells with both lymphoid and myeloid potential by foamy virus vectors

The efficiency of gene transfer into human hematopoietic stem cells by oncoretroviral vectors is too low for effective gene therapy of most hematologic diseases. Retroviral vectors based on the nonpathogenic foamy viruses (FV) are an alternative gene-transfer system. In this study, human umbilical cord blood CD34(+) cells were transduced with FV vectors by a single 10-h exposure to vector stocks and then injected into sublethally irradiated nonobese diabetic-severe combined immunodeficiency (NOD/SCID) mice. At 5-7 weeks after transplantation, high transgene expression rates were observed in engrafted human hematopoietic cells, including over 60% of clonogenic progenitors. Significant transgene silencing did not occur. We developed an approach for expanding human cell populations derived from transplanted mice to show that multiple SCID repopulating cells (SRCs) had been transduced, including some that were capable of both lymphoid and myeloid differentiation. These findings demonstrate for the first time that human pluripotent (lympho-myeloid) hematopoietic stem cells repopulate NOD/SCID mice and can be efficiently transduced by FV vectors.

[Cytokine system in patients with chronic hepatitis C during treatment with interferon-alfa]

AIM

To study changes in serum levels of interleukine-1 beta (IL-1b), IL-6, TNF-alpha (TNFa), HM-HMF and TFR-1 beta (TFR-1b), expression of surface antigens CD14 and CD95 on blood monocytes from patients with chronic hepatitis C (CHC) treated with interferon-alpha (INFa).

MATERIAL AND METHODS

Examinations covered 25 CHC patients and 25 healthy controls. Concentrations of proinflammatory cytokines and growth factors in blood serum were measured with ELISA (kits by "R&D systems", USA). CD14 and CD95 antigen expression on monocytes of venous blood were studied using flow cytoflowmeter (Partes, USA) before and after a 12-week course of INFa.

RESULTS

Before INFa treatment CHC patients had significantly elevated serum concentrations of TNFa, HM-KSF and TFR-1b. Coexpression of antigens CD14+ and CD95+ was found on 61% of blood monocytes. Three-month INFa treatment lowered levels of TNFa, GM-KSF and CD95+ expression on monocytes as well as TFR-1b concentration in the serum which correlated with a positive trend in the standard clinicolaboratory and virusological indices in the examinees.

CONCLUSION

Changes in serum indices of proinflammatory cytokines and growth factors, in expression of CD95 on blood monocytes from CHC patients treated with INFa show an important role of cytokines system activation and mechanisms of programmed cell death in pathogenesis of chronic HCV infection.

Uneven distributions of naïve and memory T cells in the CD4 and CD8 T-cell populations derived from a single stem cell in an atomic bomb survivor: implications for the origins of the memory T-cell pools in adulthood

The processes that lead to the establishment and maintenance of memory T-cell pools in humans are not well understood. In this study, we examined the emergence of naïve and memory T cells in an adult male who was exposed to an atomic bomb radiation dose of approximately 2 Gy in 1945 at the age of 17. The analysis presented here was made possible by our earlier observation that this particular individual carries a hematopoietic stem cell mutation at the hypoxanthine phosphoribosyltransferase (HPRT) locus that is almost certainly a result of his exposure to A-bomb radiation. Our key finding is that we detected a very much higher HPRT mutant frequency in the naive (CD45RA(+)) cell component of this individual's CD4 and CD8 T-cell populations than in the memory (CD45RA(-)) cell component of his CD4 and CD8 T-cell populations. This stands in marked contrast to our finding that HPRT mutant frequencies are fairly similar in the naïve CD45RA(+) and memory CD45RA(-) components of the CD4 and CD8 T-cell populations of three unexposed individuals examined concurrently. In addition we found that the HPRT mutant frequencies were about 30-fold higher in the naïve (CD45RA(+)) CD4 T cells of the exposed individual than in his memory (CD45RA(-)) cell populations, but that the effect was a little less striking in his CD8 cell populations, where the HPRT mutant frequencies were only about 15-fold higher in his naïve T-cell pools than in his memory T-cell pools. We further found that 100% of the HPRT mutant cells in both his CD4 and CD8 naïve cell subsets appeared to have originated from repeated divisions of the initial HPRT mutant stem cell, whereas only 4 of 24 and 5 of 6 mutant cells in his CD4 and CD8 memory cell subsets appeared to have originated from that same stem cell. The most straightforward conclusion may be that the great majority of the T cells produced by this individual since he was 17 years old have remained as naïve-type T cells, rather than having become memory-type T cells. Thus the T cells that have been produced from the hematopoietic stem cells of this particular A-bomb-exposed individual seldom seem to enter and/or to remain in the memory T-cell pool for long periods. We speculate that this constraint on entry into memory T-cell pools may also apply to unirradiated individuals, but in the absence of genetic markers to assist us in obtaining evidential support, we must await clarifying information from radically different experimental approaches.

Reduction of variation in T-cell subset enumeration among 55 laboratories using single-platform, three or four-color flow cytometry based on CD45 and SSC-based gating of lymphocytes

BACKGROUND

Enumeration of CD4(+) and CD8(+) T-cell subsets provides relevant information for diagnosis and monitoring of patients with cellular immunodeficiencies. As a result, an external quality assurance scheme was implemented in Belgium, The Netherlands, and Luxembourg in 1995. A workshop was held to train the participants in state-of-the art technology for assessment of absolute T-cell subset counts (i.e., a three or four-color, single-platform assay with lymphocyte gating based on CD45 and sideward light scatter) with the aim to achieve between-site coefficients of variation (CVs) <10% and within-site CVs <5% for > or =75% of the participants.

METHODS

Three send-outs of stabilized blood from a healthy donor were distributed to 55 laboratories, each with the request to perform the standard assay on three occasions. For comparison, each laboratory performed its local technique in parallel.

RESULTS

With the standard technique, between-site CVs of approximately 8% (CD3+ T cells), approximately 9% (CD4+ T cells), and approximately 10% (CD8+ T cells) were achieved. Within-site CVs were <5% for 82% (CD3+ T cells) and approximately 70% (CD4+ and CD8+ subsets) of the participants. Local techniques yielded between-site CVs of 13%-17% for CD3+, CD4+, and CD8+ T cells.

CONCLUSIONS

The state-of-the-art technology for T-cell subset enumeration was implemented successfully among 55 Belgian-Dutch laboratories and resulted in significant reductions of between-site variation of absolute CD3+, CD4+, and CD8+ T-cell counts.

T-cell subset counting and the fight against AIDS: reflections over a 20-year struggle

The story of T-lymphocyte subset immunophenotyping technology is reviewed on the occasion of the 20th anniversary of CD4 T-cell enumeration. Over time, immunophenotyping has evolved into precise, reliable, but complicated and expensive technology requiring fresh blood samples. The gating technologies that were universally adapted for clinical flow cytometry for the past decade relied on rapidly deteriorating morphological scatter characteristics of leukocytes. This special issue dedicated to CD4 T-cell enumeration features most of the available new options that will have a significant impact on how this technology will be implemented within the first decade of the 21st century. In a series of original publications, including the new NIH guideline for T-cell subset enumeration, contemporary gating protocols that use immunologically logical parameters are presented as part of the more reliable and affordable immunophenotyping alternative. Some of the improvements addressed here include the costs of the assays and the capacity to monitor interlaboratory and intralaboratory performances. It is clear that an effective attack on the human immunodeficiency virus (HIV) epidemic has to embrace resource-poor regions. Reducing the cost of the assay while improving reliability and durability is a move in the right direction.

Evaluation of a universal template for single-platform absolute T-lymphocyte subset enumeration

The single-platform absolute T-lymphocyte subset analysis was evaluated utilizing a universal protocol in a Canadian multicenter study with the collaboration of the members of the Canadian HIV Trials Network (CTN). Participants used flow cytometers and reagents of their choice for labeling and lysing whole blood. Over a 2-year period, CTN laboratories performed single-platform absolute T-lymphocyte subset enumerations on fresh and commercial stabilized blood products using commercially available microfluorospheres TruCount and Flow-Count. This multicenter evaluation demonstrated that the application of a universal template for single-platform analysis provides a generic approach that embraces a wide array of immunophenotyping settings available in clinical laboratory.

Evaluation of stabilized blood cell products as candidate preparations for quality assessment programs for CD4 T-cell counting

BACKGROUND

Exceptionally robust cell preparations are needed for quality assessment programs (QAPs) such as the International Program for Quality Assessment and Standardization for Immunological Measures (QASI) relevant to HIV/AIDS. A suitable product must withstand environmental stress related to transportation for a minimum of 6 days. The two objectives of this study are (1) to evaluate the performance of various commercial preparations with multicenter participation and (2) to evaluate the robustness of stabilized blood cell products.

METHODS

Phase 1: The performance of stabilized blood cell products was evaluated in a multicenter QAP utilizing various staining procedures and flow cytometers. Absolute cell enumeration was achieved using single-platform T-cell subset methodology. Phase 2: The robustness of stabilized blood cell products was evaluated by monitoring T-cell subset values from samples stored at 4 degrees C, 22 degrees C, and 37 degrees C for up to 10 days.

RESULTS

The largest interlaboratory variation in both absolute and relative T-cell values was 16% in samples with CD4 levels > or =400 cells per microliter and 21% in samples with CD4 levels <400 cells per microliter. Six preparations retained their phenotypic expression for 7 days at 4 degrees C and 22 degrees C. However, only two preparations remained stable for 4 days at 37 degrees C.

CONCLUSION

Some stabilized cell preparations are more robust and therefore more suitable for quality assessment purposes.

Quality control of CD4+ T-lymphocyte enumeration: results from the last 9 years of the United Kingdom National External Quality Assessment Scheme for Immune Monitoring (1993-2001)

The human immunodeficiency virus (HIV) global epidemic has necessitated the routine enumeration of T-lymphocyte subsets, which has created a need for external quality assurance (EQA). The United Kingdom National External Quality Assessment Scheme (UK NEQAS) for Immune Monitoring provides EQA for 296 laboratories in 40 countries. In 1993, UK NEQAS developed and incorporated into its program stabilized whole blood that enables the accurate monitoring of laboratory performance. Overall, the mean interlaboratory coefficient of variation (CV) for percentage CD4(+) T-lymphocyte subset enumeration has fallen from 15% to less than 5%, as a direct result of the increased use of CD45/ side scatter (SSC) gating. Laboratories using alternative gating strategies (i.e., CD45/CD14 or forward scatter [FSC]/SSC) were about 7.4 times more likely to fail an EQA exercise. Furthermore, the adoption of single-platform technology resulted in a reduction of the overall mean interlaboratory CV for absolute CD4(+) T lymphocytes from 56% (prior to the widespread use of single-platform technology) to 9.7%. Individual laboratory deficiencies were also identified using a performance monitoring system and, through re-education by collaboration with the coordinating center, satisfactorily resolved. In conclusion, during the last 9 years, the UK NEQAS for Immune Monitoring program has highlighted the significant technological advances made by laboratories worldwide that undertake lymphocyte subset enumeration.

BD Biosciences contributions in CD4 counting and immune status for HIV/AIDS

BD Biosciences is a leader in the use of flow cytometry for determining immune system status and for counting CD4 cells in patients with human immunodeficiency virus (HIV) infection. The company has gained this position through many years of basic research and product development in immunology and cell biology, dye chemistry, immunoassays, instrumentation, and software. Some of the highlights of these developments and their historical perspective are described in this review.

The increased interleukin-13 in patients with systemic lupus erythematosus: relations to other Th1-, Th2-related cytokines and clinical findings

The levels of interleukin-13 (IL-13) in patients with systemic lupus erythematosus (SLE) were examined and related to other Th1-/Th2- related cytokines, clinical manifestations and other markers. Serum levels of IL-13 and other cytokines, soluble markers were measured by enzyme-linked immunosorbent assay (ELISA). Patients with active SLE had a significantly increased level of IL-13. Most patients with high levels of IL-13 had higher levels of IL-6, and some patients had high levels of gammaIFN. These patients were divided into two groups according to the patterns of these increased cytokines; one with a high level of only Th2 related cytokines (IL-13 or IL-6) and another with high levels of both Th2 related and Th1 related cytokines (gammaIFN or IL-2). The latter patients had high levels of soluble CD8 and CD23, and some of them had hemolytic anemia or pulmonary involvement, while most of the former patients had nephropathy. Thus, in SLE, the levels of IL-13 were increased, and the heterogeneity of increased Th2- and Th1-related cytokines was related to that of activation markers and clinical manifestations.

Evaluation and management of HIV-infected women

The rate of newly diagnosed AIDS in the United States is increasing fastest in women, who are infected with HIV primarily through heterosexual transmission. Approximately 60% of these women are African American, and 18% are Latina. A gynecologic infection is the most common symptom that leads to initial medical evaluation. Specific studies at baseline should include CD4 lymphocyte count, HIV-1 RNA level, and gynecologic examination with Papanicolaou smear. Decisions about initiation of antiretroviral therapy depend on the patient's clinical diagnoses, her willingness to adhere to treatment, and CD4 lymphocyte and HIV-1 RNA levels. Levels of HIV-1 RNA may be somewhat lower in women than in men at the same CD4 count, whereas women have higher CD4 lymphocyte counts at the time of AIDS diagnosis. However, prospective trials have not yet indicated the need to change the threshold CD4 lymphocyte counts or HIV-RNA levels for initiation of therapy in women. The efficacy of antiretroviral therapy appears to be similar in men and women, although women are more likely to experience toxicities. Abnormal Papanicolaou smears occur in approximately 40% of women at baseline, and 58% are infected with human papillomavirus. The prevalence of both conditions increases with lower CD4 lymphocyte counts and higher HIV-1 RNA levels. Precursor lesions to cervical cancer may be effectively treated, but almost 50% recur within 1 year, mandating careful follow-up. Referral should be sought for specialized gynecologic care and for issues related to HIV itself, since survival is prolonged in patients treated by physicians who are experienced in treating HIV. When they are provided the same access to care, HIV-infected women have similar prognoses as HIV-infected men.

Soluble CD4 concentrations predict relapse of post-partum thyroiditis

Post-partum thyroiditis (PPT) is a common autoimmune thyroid disorder which results in significant morbidity at a critical time of a woman's life. The presence of anti-thyroglobulin (anti-TG) and, more so, anti-thryroperoxidase (anti-TPO) antibodies in the first trimester of pregnancy has been reported to forecast subsequent PPT. Despite their predictive value, these tests lack in specificity. We have sought to find an alternative that is more specific and, ideally, which could be tested immediately proximate to the event. We have taken advantage of the high recurrence rate of PPT in subsequent pregnancies to perform a prospective study of serum soluble CD4 (sCD4) and CD8 (sCD8) levels in 22 pregnant women who had at least one previous episode of PPT. This group was matched with 21 pregnant women of comparable age with no evidence of thyroid disease. Both groups of women were sampled in each of the three trimesters of pregnancy, 1 month, 3 months and 6 months post-partum for sCD4, sCD8, thyroid function parameters and antibodies. Twelve of the 22 women with previous PPT had recurrent disease; they were more likely to be cigarette smokers and to have a family history of autoimmune disorders (p<0.05, for both) than those who did not. Half of these women had high anti-TG or anti-TPO each in the first trimester compared to none among those without recurrent PPT and 2/21 controls. Serum sCD8 levels showed no changes over the observation points among the two PPT patient subsets and were comparable to those of the controls. By contrast, serum sCD4 concentrations showed divergent changes in the group with recurrent PPT in the course of pregnancy and postpartum period compared to those without disease recurrence and controls: sCD4 failed to show the physiological fall in the third trimester of pregnancy [19.0+/-1.7 (+/-SD) U/ml vs 15.6+/-2.3 U/ml in controls, NS]. This trend was continued into the first month post-partum when sCD4 levels were clearly higher than in controls (22.1+/-2.6 U/ml compared to 17.9+/-1.9 U/ml in controls, p<0.001) and well before the episode of PPT. An sCD4 serum level outside the 95% reference range at 1 month post-partum (9/12 in recurrent PPT, 1/21 in controls) yields a relative risk of 6.9 (chi2=14.67, p<0.001) compared to 3.3 for first trimester thyroid antibody positivity (p=0.029). In summary, we describe a reliable test for forecasting PPT that can be obtained immediately proximate to the possible event. If our findings are verified in larger studies, the measurement of serum sCD4 concentration drawn in the first month post-partum may prove an ideal test for population screening for impending PPT.

Increased soluble CD4 molecules and the role of soluble CD4 production in patients with rheumatoid arthritis

We investigated the concentration of soluble CD4 molecules (sCD4) in serum, and the mechanism of sCD4 production from T lymphocytes, in patients with rheumatoid arthritis (RA). The concentration of sCD4 molecules was determined using a solid-phase enzyme-linked immunosorbent assay method. Using reverse transcription polymerase chain reaction (RT-PCR) techniques, we studied the presence of alternatively spliced mRNA encoding the transmembrane site of CD4, and the mRNA encoding a conservative region of the CD4 binding site of the human immunodeficiency virus (HIV), in the serum of RA patients. Levels of sCD4 found in RA patients were higher than in normal controls (199 U/ml compared with 8.4 U/ml, respectively), and correlated with additional medical parameters. The results of RT-PCR suggested that the higher sCD4 levels may be due to shedding from the cell membrane after protease digestion, not to alternative splicing or a reaction to viral binding to sCD4.

Ribavirin enhances interferon-gamma levels in patients with chronic hepatitis C treated with interferon-alpha

Some patients with chronic hepatitis C respond to interferon (IFN)-alpha treatment, and the efficiency can be improved by combining it with ribavirin. The mechanism of this improvement is unknown. To investigate the effects of these two regimens on the immune responses in 51 patients with chronic hepatitis C, we examined the hepatitis C core antigen-specific proliferative response and cytokine production profiles, natural killer (NK) cell cytotoxicity and cytotoxic T cell function during treatment. The results are as follows: (1) both viral clearance and biochemical normalization occurred more frequently in patients receiving combination therapy; (2) the function of NK cells increased after treatment in the responders of both groups (p < 0.05); (3) the level of IFN-gamma produced by hepatitis C core antigen-stimulated peripheral blood mononuclear cells was higher in patients receiving combination therapy, especially in responders; (4) the core antigen-specific proliferative response decreased after treatment, and (5) in addition, the core-specific cytotoxic T cell activities of five responder patients also increased significantly after therapy. In conclusion, enhancement of immune responses, especially those related to type-1 T helper cell activity, may contribute to better efficacy in combining ribavirin with IFN-alpha for treatment of chronic hepatitis C.

[Evaluation of helper T lymphocyte subpopulations: naive (CD4+CD45RA+), memory (CD4+CD45RO+) and co-expression of phenotypes CD45RA+ and CD45RO+ in preclinical phases of diabetes type 1 (prediabetes)]

There is an increasing evidence that T helper lymphocytes (CD4+) play a key role in the etiopathogenesis of type 1 diabetes. The aim of the present study was to evaluate the presence of T helper lymphocyte subpopulations: naive (CD4+CD45RA+), memory cells (CD4+CDRO+) and lymphocytes coexpressing both studied phenotypes (CD4+CD45RA+CD45RO+) in subjects at risk of type 1 diabetes (first degree relatives of IDDM patients with autoantibodies) in comparison to age and sex matched controls. We observed higher percentages of lymphocytes coexpressing CD45RA and CD45RO antigens in peripheral blood of first degree relatives with "pro-diabetogenic" DRB1*0401 allele and/or with impairment of first phase of insulin release (FPIR) in IVGTT. The CD4+CD45RA+/CD4+CD45RO+ cells ratio was significantly lower in subjects with protective DQB1*0602 alelle and/or higher FPIR levels. The alterations of CD45RA and CD45RO antigens expression on T helper cells in prediabetics suggest the significant role of naive or/and memory CD4+ T cell subsets in the pathogenesis of diabetes type 1. It could be suggested that CD4+CD45RA+/CD4+CD45RO+ ratio could serve as surrogate marker of diabetes type 1 risk development and presumably for estimation of the efficacy of the preventive procedures in subjects at high risk of IDDM, but further prospective studies are needed.

CD4+CD25high regulatory cells in human peripheral blood

Thymectomy in mice on neonatal day 3 leads to the development of multiorgan autoimmune disease due to loss of a CD(+)CD25(+) T cell regulatory population in their peripheral lymphoid tissues. Here, we report the identification of a CD4(+) population of regulatory T cells in the circulation of humans expressing high levels of CD25 that exhibit in vitro characteristics identical with those of the CD4(+)CD25(+) regulatory cells isolated in mice. With TCR cross-linking, CD4(+)CD25(high) cells did not proliferate but instead totally inhibited proliferation and cytokine secretion by activated CD4(+)CD25(-) responder T cells in a contact-dependent manner. The CD4(+)CD25(high) regulatory T cells expressed high levels of CD45RO but not CD45RA, akin to the expression of CD45RB(low) on murine CD4(+)CD25(+) regulatory cells. Increasing the strength of signal by providing either costimulation with CD28 cross-linking or the addition of IL-2 to a maximal anti-CD3 stimulus resulted in a modest induction of proliferation and the loss of observable suppression in cocultures of CD4(+)CD25(high) regulatory cells and CD4(+)CD25(-) responder cells. Whereas higher ratios of CD4(+)CD25(high) T cells are required to suppress proliferation if the PD-L1 receptor is blocked, regulatory cell function is shown to persist in the absence of the PD-1/PD-L1 or CTLA-4/B7 pathway. Thus, regulatory CD4 T cells expressing high levels of the IL-2 receptor are present in humans, providing the opportunity to determine whether alterations of these populations of T cells are involved in the induction of human autoimmune disorders.

Changes of CD14 and CD1a expression in response to IL-4 and granulocyte-macrophage colony-stimulating factor are different in cord blood and adult blood monocytes

Neonates are relatively immature in their immune response; thus, to further clarify the differences of monocyte function and differentiation between neonates and adults, we investigated their CD14(+)CD4(+) and CD14(+)CD16(+) monocyte subpopulations, production of IL-1beta and tumor necrosis factor-alpha induced by lipopolysaccharide, and their CD14 and CD1a phenotypic changes in response to IL-4 and granulocyte-macrophage colony-stimulating factor. Our results showed that 1) the expression of CD14 in cord blood monocytes was significantly lower than that in adult peripheral blood monocytes; 2) both the percentages of CD14(+)CD4(+) cells and CD14(+)CD16(+) cells among CD14(+) monocytes were also significantly lower in cord blood; 3) after stimulation by lipopolysaccharide for 72 h, production of both IL-1beta and tumor necrosis factor-alpha was lower in cord blood than that in adult peripheral blood; and 4) in response to IL-4 or GM-CSF, the phenotype development of CD14 and CD1a in cord blood and adult peripheral blood was different. Down-regulation of CD14 expression in response to IL-4 and GM-CSF was slower in cord blood monocytes than that in adult peripheral blood monocytes. After 9 d of culture in the presence of IL-4 and GM-CSF, the percentage of CD1a(+) monocytes was significantly more increased in cord blood than that in adult peripheral blood. The reduced expression of CD14 and other mature phenotype markers such as CD16 and CD4 as well as the reduced IL-1beta and tumor necrosis factor-alpha production may contribute to the impaired immune response of neonates. Slower down-regulation of CD14 by IL-4 and GM-CSF suggests that differential properties of cord blood monocytes in response to cellular stress signals take a longer time than those of adult peripheral blood monocytes.

A role for TGF-beta in the generation and expansion of CD4+CD25+ regulatory T cells from human peripheral blood

An elusive goal in transplanting organs across histocompatibility barriers has been the induction of specific tolerance to avoid graft rejection. A considerable body of evidence exists that the thymus produces regulatory T cells that suppress the response of other T cells to antigenic stimulation. We report that TGF-beta can induce certain CD4+ T cells in the naive (CD45RA+RO-) fraction in human peripheral blood to develop powerful, contact-dependent suppressive activity that is not antagonized by anti-TGF-beta or anti-IL-10 mAbs. The costimulatory effects of TGF-beta on naive CD4+ T cells up-regulated CD25 and CTLA-4 expression, increased their transition to the activated phenotype, but decreased activation-induced apoptosis. Suppressive activity was concentrated in the CD25+ fraction. These CD4+CD25+ regulatory cells prevented CD8+ T cells from proliferating in response to alloantigens and from becoming cytotoxic effector cells. Moreover, these regulatory cells exerted their suppressive activities in remarkably low numbers and maintained these effects even after they are expanded. Once activated, their suppressive properties were Ag nonspecific. Although <1% of naive CD4+ T cells expressed CD25, depletion of this subset before priming with TGF-beta markedly decreased the generation of suppressive activity. This finding suggests that CD4+CD25+ regulatory T cells induced ex vivo are the progeny of thymus-derived regulatory T cells bearing a similar phenotype. The adoptive transfer of these regulatory T cells generated and expanded ex vivo has the potential to prevent rejection of allogeneic organ grafts.

[Immune events in central nervous system of early and late onset Alzheimer's disease patients]

INTRODUCTION

Alzheimer s disease (AD) is a progressive degenerative disease affecting a significant proportion of the elderly population. The disease is characterized clinically by a progressive loss of memory function and mental impairment associated with the presence of degenerative well known pathological lesions. Although, the pathogenesis of AD is unclear; several reports indicate the involvement of immune factors.

PATIENTS AND METHODS

This paper evaluates some cerebrospinal fluid immune markers from 21 patients with early and late AD and 20 age matched non-demented subjects. The analytical method included the evaluation of T cell subpopulations (using AcMc CD2, CD4, CD8) and activated T cells (AcMc HLA-DR and CD25) from CSF and peripheral blood by immunocytochemical techniques on a fixed cell slide as described by Bernd. The lymphocyte phenotype expressed as a percentage of positively stained cells for each cell surface marker evaluated.

RESULTS

Some significant differences were observed for T cell subpopulations from different compartments, between the different AD groups and the controls (p< 0.05). Nevertheless, the most significant differences were found in the activated T cells from cerebrospinal fluid between AD groups and controls (p< 0.01).

CONCLUSIONS

These results support the theory of neuroimmune dysregulation, probably involved in the progressive neurodegeneration and dementia in some AD.

Research on some parameters of cellular immune response in soldiers undergoing basic training--preliminary report

BACKGROUND

On the basis of available reports it can be stated that physical stress causes changes in distribution and activity of many components of the immune system. It is believed that psychophysical stress in soldiers can influence their immune system depressively and in consequence increase the risk of upper respiratory tract infections. Therefore, it was decided to conduct studies aimed at the estimation of the influence of military training on the some parameters of cellular immune response.

MATERIAL AND METHODS

The study group consisted of 40 draft aged from 18 to 23 years. The research was conducted in the first 8 weeks of service, in the period of the most intense draft stress adaptation. The participants were divide into 2 groups, A and B respectively, 20 soldiers each. Group A derived from an assault unit. Their training induced strenuous physical stress. Group B derived from a support unit. Their training required less physical effort then one of group A. Performed examinations involved: lymphocyte percentage count, lymphocyte proliferative response to mitogen, CD69 antigen expression on T lymphocyte surface, delayed hypersensitivity reaction with CMI Multitest. All assessments were done twice at 8 weeks interval.

RESULTS

After 8 weeks of training in the A group a statistically significant increase in the percentage of lymphocytes revealing antigens of the II Class Main Histocompatibility Complex (MHC) was found. In addition, in this group a statistically significant decrease in the value of lymphocyte stimulation index, a statistically significant increase in the percentage of cells revealing CD69 antigen expression after PHA stimulation were observed. During investigated period in the B group following statistically significant changes were found: an increase in the percentage of CD3+ and CD4+ cells, a decrease in the percentage of CD16+CD56+ and an increase in the CD4+ to CD8+ ratio.

CONCLUSION

The obtained results show that military service conditions influence some parameters of the cellular immune response but do not result in the clinically significant suppression of the immune system.

Immunological response to interferon-gamma priming prior to interferon-alpha treatment in refractory chronic hepatitis C in relation to viral clearance

The aim of this study was to clarify the immunological and virological responses to pre-administration of interferon-gamma prior to initiation of interferon-alpha treatment in patients with refractory chronic hepatitis C. Twenty-two nonresponders to 6-months of IFN-alpha treatment were enrolled. The hepatitis C virus (HCV) genotype was Ib in all. Natural IFN-gamma (1 MIU/day) was administered daily for 14 days followed by natural IFN-alpha (5 MIU/day) daily for 14 days and then three times weekly for 22 weeks. Serum immunological parameters (IL-10, neopterin, BMG, sCD8, sCD4, IL-6, IL-12) were measured as were the levels of several cytokines (IFN-gamma, TNF-alpha, IL-2, IL-4, IL-5, IL-6, IL-10). Three patients dropped out; two because of the occurrence of other diseases and one because of an adverse effect. At the end of the period of IFN-alpha treatment, HCV-RNA had become negative in six of 19 patients (end-of treatment response; ETR). Six months after the completion of IFN administration, a virological sustained response (SR) was seen in two of 19 patients. The mean serum levels of IL-10 were significantly decreased 6 weeks after the start of treatment. Other immunological parameter levels increased significantly during the period of IFN-gamma administration, and tended to return to the pretreatment level after the start of IFN-alpha administration. Univariate logistic regression analysis showed that the initial change in the levels of these parameters or the change in the ratios of Th1/Th2 parameter levels are useful factors indicative of the end of the treatment response. These findings suggest that priming with IFN-gamma prior to the initiation of IFN-alpha treatment in patients with refractory chronic hepatitis C can modulate the host immune response and this might contribute to viral clearance.

T cell activation in vivo by dengue virus infection

It is accepted that T cells play a critical role during virus infections; however, T cell responses in vivo in acute stage of virus infection are not understood. We examined T cell activation in vivo in two volunteers who developed dengue fever in response to vaccination with a candidate live dengue vaccine. Serial plasma collected from the volunteers from day 0 (before infection) to day 17 after infection were examined for levels of soluble interleukin-2 receptor (sIL-2R), soluble CD4 (sCD4), soluble CD8 (sCD8), interleukin-2 (IL-2) and interferon gamma (INF gamma). Elevation of the levels of sIL-2R, IFN gamma, sCD4 and IL-2 became obvious during the period of viremia and was followed by a later increase in the level of sCD8. The levels of IFN gamma and sIL-2R declined after the end of the period of viremia. These results indicate that i. T cells are activated in vivo by dengue virus infection ii. activation of CD4+ T cells occurs during the period of viremia iii. activation of CD8+ T cells follows CD4+ T cell activation. These results suggest that activation of T cells in vivo may contribute to controlling acute dengue virus infections.

Urinary cytokines for assessing inflammation in HIV-associated wasting

The relationship between cytokines and HIV-related weight loss has not been well established. Unlike most cytokines that are secreted in a paracrine manner, IL-6, sTNFR-II, and IL-1ra are readily detected in the systemic circulation and serve as markers of the inflammatory response. Twenty-four-hour urine concentrations of these proteins are believed to provide an integrative assessment of their systemic levels over the preceding hours. We sought to determine whether spot measurements of IL-6, sTNFR-II, and IL-1ra could be related to subsequent 24 h concentrations and prior weight loss. Eighteen subjects with severe wasting (average BMI=18+/-3 kg/m2with 19+/-13 kg of weight loss) and six HIV-negative healthy subjects were tested. Compared to values in controls, 24-h urinary concentrations of the three proteins adjusted for creatinine excreted were elevated in 44%, 89%, and 72% of patients, respectively. Twenty-four-hour concentrations were highly correlated with the spot concentrations (r=0.80, 0.87, 0.84, respectively, P<0.001). IL-1ra concentrations (24 h and spot) were correlated with weight loss in the previous 6 months, lifetime rate of weight loss and the 6 month rate of weight loss (spot: r=0.66, 0.73, 0.68, respectively, P< or =0.001). These data suggest that spot urinary collections can be used to estimate 24 h excretion rates. This strategy may be useful in assessing the inflammatory response in HIV-associated wasting.