Phenotypic and functional analysis of the HLA-class I-specific inhibitory receptors of natural killer cells isolated from peripheral blood of patients undergoing bone marrow transplantation from matched unrelated donors

INTRODUCTION

Limited information is available on the natural killer cell reconstitution after bone marrow transplantation and on the possible role of these cells in graft-versus-host-disease.

MATERIALS AND METHODS

Blood samples were collected at different time intervals after transplantation. Lymphocytes were analyzed for informative markers by immunocytofluorimetric analysis. Natural killer cells derived from patients undergoing matched unrelated donor transplant were cloned by limiting dilution in the presence of phytohemoagglutinin and IL2. The natural killer cell clones were analyzed for cytolytic activity.

RESULTS

In the nine patients analyzed undergoing transplantation from sibling donors, the majority of peripheral blood lymphocytes during the first 80 d after BMT were represented by T lymphocytes, while in the 15 patients undergoing matched unrelated donor transplant natural killer cells consistently outnumbered T lymphocytes. During the early phases after transplantation, most CD56+CD3- natural killer cells did not express CD16 which was expressed at later intervals. Analysis of the inhibitory receptors specific for HLA-class I molecules showed that CD94/NKG2A, specific for HLA-E, unlike normal donors, was expressed by all natural killer cells including the early appearing CD16-negative ones. Killer inhibitory receptors of the Ig superfamily were expressed late and in low percentages after transplantation and were always coexpressed with CD94/NKG2A. Natural killer-cell clones efficiently lysed the HLA-class I-negative cell lines K562 and 721-221. Natural killer-cell populations or clones isolated from patients with graft-versus-host-disease, failed to lyse donor or recipient derived phytohemoagglutinin-induced lymphoblasts.

CONCLUSION

Our analysis shows that (1) recipients of matched unrelated donors transplants exhibit a high proportion of NK cells (2) all NK cells express CD94/NKG2A while the HLA-class I-specific inhibitory receptors of Ig superfamily appear at later stages and (3) donor NK cells do not lysed donor or recipient target cells.

Effect of estradiol valerate alone or in association with cyproterone acetate upon vascular function of postmenopausal women at increased risk for cardiovascular disease

OBJECTIVES

a large body of evidence has been accumulated suggesting that impairment of vascular endothelial function is an initial step in the development of atherosclerosis. Recent studies have shown that estrogen replacement therapy in postmenopausal women (PMW) improves endothelium-dependent, flow-mediated dilatation (FMD) while the cyclical adjunct of a progestin may reverse this effect.

METHODS

the purpose of this study was to evaluate endothelium-dependent, FMD in the brachial artery and the plasma levels of Endothelin-1 in menopausal females treated with estradiol valerate with and without cyclical cyproterone acetate in 20 PMW (mean age 64+/-6 years) with more than one risk factor for coronary artery disease. After a baseline evaluation, PMW entered a double-blinded, placebo controlled single cross-over study and were randomized to receive either estradiol valerate (2 mg) for 21 days or estradiol valerate (2 mg) for 11 days and estradiol valerate (2 mg) and cyproterone acetate (1 mg) for 10 days. Patients were crossed-over the complementary treatment 7 days after completing the first treatment phase. The study of forearm blood flow was repeated at the end of each treatment period.

RESULTS

estradiol valerate significantly increased FMD as compared with baseline (12+/-3 vs. 7+/-4%, P<0.01) the adjunct of cyproterone acetate did not affect the effect of estradiol valerate upon FMD (12+/-3 vs. 11+/-4%, P=NS). Similarly reactive hyperemic flow increased after estradiol valerate alone (24%) or in association with cyproterone acetate (24%) compared with baseline. Plasma levels of Endothelin-1 were significantly reduced by estradiol valerate alone or in association with cyproterone acetate.

CONCLUSIONS

in conclusion hormone replacement therapy with estradiol valerate and cyproterone acetate improves endothelial function and reduces plasma levels of Endothelin-1 in PMW at risk of coronary artery disease. These effects may be relevant for cardioprotection.

How progestins influence the cardiovascular effect of hormone replacement therapy

Hormone replacement therapy aims to protect against osteoporosis and alleviate fastidious menopausal symptoms such as hot flushes, depression, sleep disturbances and vaginal dryness. In view of the acknowledgement of estrogen deficiency as a major trigger for the acceleration of cardiovascular risk after menopause, hormone replacement therapy may also be proposed as a substantial beneficial cardioprotective agent. The effects of progestins on lipoprotein profile and vasomotor tone are dependent on the chemical structure and the scheme of administration of progestins, with androgenic progestins and cyclical therapy having a potential detrimental effect. Prospective primary and secondary prevention studies, however, suggest that the adjunct of non-androgenic progestins to estrogen therapy is at least as effective as estrogen replacement therapy in reducing cardiovascular mortality and morbidity. Data from recent randomized secondary prevention studies have to be viewed with caution.

No evidence of association between CAG expansions and essential tremor in a large cohort of Italian patients

Essential tremor (ET) is one of the most common movement disorders. However the pathogenesis is as yet unknown, although a genetic cause has long been recognised. Clinical and molecular evidences suggested that the ET gene might contain a CAG expanded region. In a cohort of Italian ET patients Repeat Expansion Detection (RED) approach did not demonstrate large CAG expansions. We extended the study towards specific targets: the channel proteins hSKCa3 and CACNL1A4. Direct assessment of CAG stretches within these two genes did not demonstrate any CAG expansion in affected subjects. Also a case-control analysis failed to reveal any evidence of association, thus excluding these genes as a cause of ET.

Spinal-cord compression due to extradural amyloidosis of the cervico-occipital hinge, in a hemodialysed patient. A case report

Long-term dialysed patients can develop an arthropathy, called dialysis arthropathy, due to the deposition and transformation of the beta2 microglobulin into amyloid. The involvement of the spine, called destructive spondyloarthropathy (DSA), occurs between 10 and 25 percent; of these patients, and sometimes causes neurological damage. The disc space narrowing, vertebral body erosion and pseudocystis, in presence of polyarthropathy, chronic renal failure, and carpal tunnel syndrome, allows to make a diagnosis of DSA, which is proved by histological finding of beta2 microglobulin-amyloid. We report a rare case of spinal cord compression due to beta2 microglobulin-amyloid deposit in extradural space of cervico-occipital hinge.

p75/AIRM1 and CD33, two sialoadhesin receptors that regulate the proliferation or the survival of normal and leukemic myeloid cells

Inhibitory receptors originally identified in natural killer (NK) cells have also been detected in other leukocyte types, thus suggesting that they may play a more general role in the control of leukocyte function. Here we report data on p75/adhesion receptor molecule 1 (AIRM1), a surface inhibitory receptor of the sialoadhesin family originally identified in NK cells that is also expressed by normal and leukemic myeloid cells. Given the homology between p75/AIRM1 and CD33, we also reanalyzed CD33, a major myeloid marker of still unknown function. We discuss recent data indicating that engagement of p75/AIRM1 or CD33 sharply inhibits the in vitro proliferation/differentiation of CD34+ myeloid precursors induced by stem cell factor and granulocyte-macrophage colony-stimulating factor. Importantly, a similar in vitro inhibitory effect occurs in monocyte/macrophages as well as in chronic or acute myeloid leukemias. While CD33 appears to act via the induction of apoptosis, p75/AIRM1 blocks cell proliferation but does not appear to induce apoptosis. A synergistic effect in the induction of apoptosis has also been documented between antibodies specific for CD33 and the chemotherapic agent etoposide. Taken together, the use of appropriate ligands against CD33 or p75/AIRM1 may represent a new therapeutic tool for treatment of myeloid leukemias or diseases characterized by overwhelming macrophage activation.

Surface expression and function of p75/AIRM-1 or CD33 in acute myeloid leukemias: engagement of CD33 induces apoptosis of leukemic cells

p75/AIRM-1 is a recently identified inhibitory receptor expressed by natural killer and myeloid cells displaying high homology with CD33. Crosslinking of p75/AIRM-1 or CD33 has been shown to sharply inhibit the in vitro proliferation of both normal myeloid cells and chronic myeloid leukemias. In this study, we analyzed acute myeloid leukemic cells for the expression of p75/AIRM-1. p75/AIRM-1 marked the M5 (11/12) and M4 (2/2) but not the M1, M2, and M3 subtypes according to the French-American-British classification. Cell samples from 12 acute myeloid leukemias were cultured in the presence of granulocyte/macrophage colony-stimulating factor. Addition to these cultures of anti-CD33 antibody resulted in approximately 70% inhibition of cell proliferation as assessed by [(3)H]thymidine uptake or by the recovery of viable cells. Anti-p75/AIRM-1 antibody exerted a strong inhibitory effect only in two cases characterized by a high in vitro proliferation rate. After crosslinking of CD33 (but not of p75/AIRM-1), leukemic cells bound Annexin V and displayed changes in their light-scattering properties and nucleosomal DNA fragmentation, thus providing evidence for the occurrence of apoptotic cell death. Remarkably, when anti-CD33 antibody was used in combination with concentrations of etoposide insufficient to induce apoptosis when used alone, a synergistic effect could be detected in the induction of leukemic cell death. These studies provide the rationale for new therapeutic approaches in myeloid leukemias by using both chemotherapy and apoptosis-inducing mAbs.

Unawareness of dyskinesias in Parkinson's and Huntington's diseases

We performed a clinical study to evaluate the unawareness of dyskinesias in patients affected by Parkinson's disease (PD) and Huntington's disease (HD). Thirteen PD patients with levodopa-induced dyskinesias and 9 HD patients were enrolled. Patients were asked to evaluate the presence of dyskinesias while performing specific motor tasks. The Abnormal Involuntary Movement Scale (AIMS) and Goetz dyskinesia rating scale were administered to determine the severity of dyskinesias. The Unified Parkinson's disease rating scale (UPDRS) and Unified Huntington's Disease Rating Scale (UHDRS) were used in PD and HD patients, respectively. In PD we found a significant negative relationship between unawareness score at standing and AIMS score and between unawareness score at hand pronation-supination and AIMS score for upper limbs. In HD we found a significant positive relationship between total unawareness score and UHDRS score and between total unawareness score and disease duration. In PD the unawareness seems to be inversely related with severity of dyskinesias, while in HD it is directly related to disease duration and severity.

Renal stones: from metabolic to physicochemical abnormalities. How useful are inhibitors?

Despite intensive studies in the last decades many aspects of nephrolithiasis still remain to be elucidated. Supersaturation with respect to lithogenic substances explains stones composed of cystine, uric acid, struvite, and calcium stones secondary to systemic diseases. In this subset there is a clear separation between patients and controls, and stone activity is well related to alterations in the physicochemistry of the urine environment. The understanding of the mechanisms of idiopathic calcium nephrolithiasis, on the other hand, is controversial, because we are still unable to establish clear-cut cause-effect relations between metabolic and physicochemical abnormalities and stone formation. Recent studies have been centered on the kidney, not only as the end organ of biochemical derangements due to systemic or environmental factors, but also as a complex laboratory where some events conduct to and others defend from lithogenesis. Many of these phenomena occur in the proximal tubule. Molecular biology has explained some types of hypercalciuria, which are due to genetic mutations altering tubular function, and similar results are expected for hypocitraturia and hyperoxaluria. The latter is conducive to stone formation through several mechanisms including supersaturation, oxidative stress on tubular cells, and interference with some natural inhibitors. The long list of inhibitors includes ionic and macromolecular moieties, some being produced within the nephron in response to lithogenic insults, and some affecting not only crystallization but also crystal cell adherence. Crystal trapping is believed to anticipate a renal stone. However, much has still to be clarified on their actual role in calcium nephrolithiasis, by what mechanisms they act, if patients and controls differ in the excretion and structure of some inhibitors, and whether differences are genetically determined.

Epidemiology of nephrolithiasis

The overall probability of forming stones differs in various parts of the world: 1-5% in Asia, 5-9% in Europe, 13% in North America, 20% in Saudi Arabia. The composition of stones and their location in the urinary tract, bladder or kidneys may also significantly differ in different countries. Moreover, in the same region, the clinical and metabolic patterns of stone disease can change over time. We examined some epidemiological evidence about the main risk factors for stone formation, both individual and environmental. A slightly higher rate of renal stone disease emerged in males than in females, and in white Caucasians than in Blacks. Stones in the upper urinary tract appear to be related to the life-style, being more frequent among affluent people, living in developed countries, with high animal protein consumption. Bladder stones are nowadays mainly seen in the Third World, on account of very poor socio-economic conditions. A high frequency of stone formation among hypertensive patients has been reported, and among those with high body mass as well. There is no evidence of any rise in the risk of stone formation in relation to dietary calcium intake or tap water hardness.

Synthesis of new aromatic (C17-C20)-locked side-chain analogues of calcitriol (1alpha,25-dihydroxyvitamin D(3))

The synthesis of four new analogues of calcitriol (1alpha, 25-(OH)(2)-D(3)) possessing aromatic and conjugated double bond units at the side chain are described. The triene system is introduced using the Lythgoe-Hoffmann La Roche convergent Wittig-Horner approach. The key steps in the preparation of the requisite upper fragments are the introduction of the side chain with the E-conjugated aromatic system and its photochemical conversion to the Z counterpart.

Idiopathic calcium nephrolithiasis

Calcium nephrolithiasis (CaNL) accounts for more than 70% of all renal stones, and its prevalence has increased in the last decades. Under this definition are included patients passing stones, composed of calcium oxalates and/or calcium phosphates. Current views of the pathogenesis of CaNL are based on the role of metabolic abnormalities which concur to render urines more conducive to crystallization. Therefore, the diagnostic approach is aimed at detecting these abnormalities, and the medical treatment assumes that a decrease in the risk of lithogenesis will result in remission or improvement of recurrences. The workup of the patients with CaNL begins with the analysis of passed stones and X-ray, sonography or other imaging techniques. Eligible patients, that is, both recurrent active stone formers and single-stone formers with individual risk factors, are considered for a metabolic evaluation, by which a number of blood and urine parameters are measured and others calculated. These include estimates of urine state of saturation with calcium and uric acid salts, net gastrointestinal alkali absorption, renal threshold of phosphate and other renal clearances and net acid and total nitrogen excretions. Basically, this screening is informative on renal function, metabolic abnormalities and their pathophysiology, risk of stone formation and dietary habits. During treatment it gives information about patient compliance and adverse effects of therapy. The cost of a comprehensive screening in Piedmont is 192,000 ITL (100 Euro) and rises to 300,000 ITL (154 Euro) if hormones and hydroxyproline are measured. In individual patients second- and third-level studies are performed, in order to detect systemic diseases which account for about 20% of CaNL in our series. Cost-to-benefit analysis has shown that the medical procedures for CaNL yield considerable saving in terms of difference between expenditure for drugs and testing and reduction of stone events. However, the current workup cannot be considered exhaustive, because misleading events may hamper the relation between laboratory findings and clinical outcome, and factors other than urine composition have appeared on the scenario of nephrolithiasis. These represent our challenge for the third millennium.

Expression of HLA class I-specific inhibitory receptors in human cytolytic T lymphocytes: a regulated mechanism that controls T-cell activation and function

Different families of major histocompatibility complex (MHC)-specific inhibitory receptors (NKRs) play a major role in natural killer (NK) cell function, allowing discrimination between normal cells and cells that do not express adequate amounts of MHC class I antigens. This occurs in most instances as a consequence of viral infection or tumor transformation. In T lymphocytes, expression of NKR is mostly confined to activated CD8+ cytolytic T lymphocytes (CTLs). While NKR expression by CTLs may be viewed as a mechanism preventing damages to normal cells by those CTLs that have acquired NK-like activity, it may also down regulate TCR-mediated T cell activation, thus, impairing CTL functions. The finding that certain cytokines can modulate killer inhibitory receptor expression in CTLs is of major interest and might be instrumental in novel therapeutic approaches aimed at the down regulation ofT-cell function in transplantation or autoimmunity.

Engagement of p75/AIRM1 or CD33 inhibits the proliferation of normal or leukemic myeloid cells

P75/AIRM1 is a recently identified surface molecule that belongs to the sialoadhesin family and displays homology with the myeloid cell antigen CD33. In lymphoid cells, p75/AIRM1 is confined to natural killer cells and mediates inhibition of their cytolytic activity. In this study, we show that p75/AIRM1 is also expressed by cells of the myelomonocytic cell lineage, in which it appears at a later stage as compared with CD33. In vitro proliferation and differentiation of cord blood-derived CD34(+) cells (induced by stem cell factor and granulocyte-macrophage colony-stimulating factor) were consistently inhibited by the addition of anti-p75/AIRM1 mAb. Engagement of CD33 led to inhibition in some experiments. A sharp decrease of cell proliferation/survival was detected in all three p75/AIRM1+ chronic myeloid leukemias analyzed when cultured in the presence of either anti-p75/AIRM1 or anti-CD33 mAbs. Thus, the present study suggests that p75/AIRM1 and CD33 may play a regulatory role in normal myelopoiesis and may be viewed as suitable target molecules to counteract the proliferation/survival of chronic myeloid leukemias.

[Clinical and metabolic features of renal calculi in adults in regard to age of onset]

BACKGROUND

In this paper, the clinical and metabolic patterns of nephrolithiasis in different ages of adulthood are studied.

METHODS

Eight-hundred patients observed at the Mauriziano Hospital between 1990 and 1995, were classified into 3 groups, on the basis of age at the onset of disease: A: 20 through 39 years; B: 40 through 59; C: 60 years and over.

RESULTS

Calcium-oxalate stones had a lower recurrence in C (19.1%) and B (31.5%) than in A (41.7%). Pure uric acid stones recurred in 18.9% of C, 16.7% of B and 4.3% of A. The prevalence of hypercalciuria was higher in A (50.3%) than in B (35.9%) and C (36%); so did hypocitraturia. Hyperuricuria was lower in A (5%, p < 0.05) than in B (9.4%) and C (10%). Low urine pH (< 5.5) was 13% in A, 21.3% in B, 38% in C. Prevalence of hyperoxaluria was about 14% in all groups. The whole prevalence of secondary forms of stone disease was 13% in A, 12% in B and 30% in C. Differences among groups were mainly due to prevalence of urological abnormalities and urinary tract infection. In patients without metabolic disturbances. urological abnormalities or urinary tract infections altogether, were 4.6% in A; 5.2% in B; 33% in C. Urological approach removed 8% of stones in A, 5.6% in B and 10.2% in C.

CONCLUSIONS

Higher morbidity in younger patients could be due to a lower prevalence of easier-passing uric acid stones. The higher occurrence of urological disturbances and struvite stones in the elderly could explain the higher morbidity in this group.

Inhibitory receptors sensing HLA-G1 molecules in pregnancy: decidua-associated natural killer cells express LIR-1 and CD94/NKG2A and acquire p49, an HLA-G1-specific receptor

Trophoblastic cells lack classical HLA class I and class II molecules but express HLA-G1. Although this may prevent allorecognition by maternal T cells, it renders trophoblastic cells potentially susceptible to lysis by natural killer (NK) cells. As shown here, only a fraction of peripheral-blood NK cells in pregnant women express the HLA-G1-specific CD94/NKG2A and/or LIR-1 receptors. However, all NK cells isolated from maternal decidua during the first trimester expressed either one or both of these receptors. Perhaps more importantly, a fraction of cells expressed p49, an HLA-G1-specific inhibitory receptor, undetectable in peripheral-blood NK cells. p49 was expressed on virtually all NK cells isolated from placenta at term. Functional analyses revealed that the HLA class I-negative 221 lymphoblastoid cell line transfected with HLA-G1 was only partially protected from lysis by peripheral-blood NK cells isolated from pregnant women, whereas it was fully protected from decidual NK cells. As indicated by the addition of specific antibodies to cytolytic tests, all the above receptors contributed to HLA-G1 recognition by decidual NK cells, although p49 would appear to play a predominant role.

Transforming growth factor-beta-induced expression of CD94/NKG2A inhibitory receptors in human T lymphocytes

Different HLA class I-specific killer inhibitory receptors (KIR) are expressed in vivo by a fraction of activated T cells, predominantly CD8+, in which they may inhibit TCR-mediated cell functions. In an attempt to identify mechanisms leading to KIR expression in T cells, we analyzed the effect of transforming growth factor-beta (TGF-beta) in T cells responding to bacterial superantigens in vitro. We show that TGF-beta induces the expression of CD94/NKG2A in cells responding to toxic shock syndrome toxin 1 or to other staphylococcal superantigens. Remarkably, maximal CD94 expression occurred at (low) TGF-beta concentrations which have no substantial effect on lymphocyte proliferation. Maximal CD94 expression occurred when TGF-beta was added shortly after the cells were placed in culture. No expression could be induced in CD94/NKG2A-negative T cell clones. Although both CD4+ and CD8+ expressed CD94, the simultaneous expression of NKG2A was mostly confined to CD8+ cells. Monoclonal antibody-mediated cross-linking of CD94/NKG2A led to an impairment of T cell triggering via CD3, as determined in a redirected killing assay using the Fcgamma receptor-positive P815 murine target cells.

Transforming growth factor-beta-induced expression of CD94/NKG2A inhibitory receptors in human T lymphocytes

Different HLA class I-specific killer inhibitory receptors (KIR) are expressed in vivo by a fraction of activated T cells, predominantly CD8+, in which they may inhibit TCR-mediated cell functions. In an attempt to identify mechanisms leading to KIR expression in T cells, we analyzed the effect of transforming growth factor-beta (TGF-beta) in T cells responding to bacterial superantigens in vitro. We show that TGF-beta induces the expression of CD94/NKG2A in cells responding to toxic shock syndrome toxin 1 or to other staphylococcal superantigens. Remarkably, maximal CD94 expression occurred at (low) TGF-beta concentrations which have no substantial effect on lymphocyte proliferation. Maximal CD94 expression occurred when TGF-beta was added shortly after the cells were placed in culture. No expression could be induced in CD94/NKG2A-negative T cell clones. Although both CD4+ and CD8+ expressed CD94, the simultaneous expression of NKG2A was mostly confined to CD8+ cells. Monoclonal antibody-mediated cross-linking of CD94/NKG2A led to an impairment of T cell triggering via CD3, as determined in a redirected killing assay using the Fcgamma receptor-positive P815 murine target cells.

Cytokine-induced expression of killer inhibitory receptors in human T lymphocytes

Killer inhibitory receptors (KIRs) represent a new family of HLA-class I-specific receptors. KIRs are involved in the function of Natural Killer cells and allow these cells to discriminate between normal cells and cells with impaired expression of HLA-class I molecules. KIRs are also expressed by a subset of cytolytic T lymphocytes in which they may exert an inhibitory effect on TCR-mediated function. Here we review recent data indicating that cytokines such as IL-15, may induce the de novo expression of CD94/NKG2A (a KIR which operationally detects the expression of various HLA-class I alleles). The expression of CD94/NKG2A has been documented not only in CD34+ precursors undergoing maturation towards NK cells, but also in mature T cells which respond in vitro to superantigens or allogeneic cells.