Association of diabetes with age-related macular degeneration in the EUREYE study

OBJECTIVE

To examine the association between self-reported diabetes history and early or late age-related macular degeneration (AMD) in the European population.

METHODS

Participants aged 65 years and over in the cross-sectional population-based EUREYE study underwent an eye examination including digital retinal photography. The images were graded at a single centre. A structured questionnaire was administered by trained field workers for putative risk factors for AMD including history of diabetes mellitus. Logistic regression models were used to examine the association between diabetes and stages of AMD, taking account of potential demographic, behavioural, dietary and medical (history of cardiovascular disease) confounders.

MAIN OUTCOME MEASURES

Photographic images were graded according to the modified International Classification System for AMD and stratified into five exclusive stages from no signs of AMD (AMD stage 0), early AMD (Stages 1-3) and late AMD (Stage 4). Late AMD was subdivided in neovascular AMD (NV-AMD) or geographic atrophy (GA).

RESULTS

Data on diabetes history and potential confounders were available in 2117 control subjects without AMD, 2182 with early AMD, 49 with GA and 101 with NV-AMD. Of all participants, 13.1% reported a history of diabetes. After adjusting for potential confounders, subjects with neovascular AMD compared with controls had increased odds for diabetes (odds ratio 1.81; 95% confidence interval, 1.10 to 2.98, p = 0.02). Subjects with AMD grades 1 to 3 or GA had no increased odds for diabetes compared with those without AMD.

CONCLUSIONS

In the EUREYE study, after multiple adjustments, positive association of diabetes mellitus with neovascular AMD was found. The hypothesis that diabetes is associated with neovascular AMD but not with geographic atrophy may suggest a different pathogenesis of the two advanced forms of the disease and needs to be further evaluated.

The prognostic significance of immune changes in patients with renal cell carcinoma treated with interferon alfa-2b

PURPOSE

To evaluate the response rate and the immunorestorative properties of subcutaneously administered interferon alfa-2b (IFN-A2b) in patients with advanced renal cell carcinoma (RCC) and to correlate the immune status with the clinical responses.

PATIENTS AND METHODS

Twenty-six patients with advanced RCC were treated with recombinant IFN-A2b. The dose was increased progressively from 5 x 10(6) IU the first week to 10 x 10(6) IU the second week, and thereafter to 15 x 10(6) IU subcutaneously.

RESULTS

Four patients (15%) achieved partial responses (PRs), and five patients (19%) had stable disease (S), whereas 17 patients (65%) progressed. In all patients, blood was withdrawn before IFN treatment and monthly thereafter. T lymphocytes after isolation from peripheral blood were tested for proliferation in the autologous mixed lymphocyte reaction (autoMLR) and allogeneic mixed lymphocyte reaction (alloMLR), interleukin-2 (IL-2) production, expression of IL-2 receptors during the alloMLR, and the production of interleukin-1 (IL-1) by peripheral-blood monocytes. Twelve patients were assessable, four patients had a PR, one patient had S, and seven patients had progressive disease. Striking increases were demonstrated in all parameters 1 month after treatment with IFN-A2b in the four patients who responded and the patient with S. Namely, the autoMLR responses showed a mean increase of 250%, the IL-2 production 247%, the expression of IL-2-specific receptors 446%, the alloMLR responses 160%, and the production of IL-1 262%. On the contrary, the nonresponders did not show any change in their overall immune status, and in some, deterioration of the already depressed immunologic functions was observed.

CONCLUSIONS

Administration of IFN-A2b results in a marked potentiation of deficient cellular immune response in vitro in those patients with RCC who respond to the treatment. This may have prognostic significance, and certainly more patients are required to be studied for definite conclusions.

Prothymosin alpha enhances human and murine MHC class II surface antigen expression and messenger RNA accumulation

Prothymosin alpha (ProT alpha) is an acidic polypeptide with potentiating effects on HLA-DR-restricted in vitro cellular immune response systems such as T cell proliferative responses to soluble proteins and cellular auto- or alloantigens. Experiments were performed to investigate the effect of ProT alpha on MHC class II Ag expression in human monocytes, murine splenocytes, and tumor cell lines at both protein and molecular levels. RIA and immunofluorescence analysis revealed that ProT alpha enhances HLA-DR surface Ag expression whereas Northern blot analysis demonstrated that ProT alpha causes significant accumulation of MHC class II mRNA. The enhancing effect of ProT alpha was demonstrated convincingly using precultured human peripheral monocytes, which are known to express decreased amounts of surface HLA-DR Ag, and HLA-DR-positive human cell lines. Moreover, ProT alpha was shown to induce HLA-DR Ag expression in a priori HLA-DR-negative tumor cells. Furthermore, ProT alpha was shown to be active in vivo. Splenocytes from mice pretreated with ProT alpha expressed more surface Ilpha Ag and contained more I alpha-specific mRNA. These findings suggest that ProT alpha may be important in the regulation of the immune response by enhancing MHC class II Ag expression in APC.

Prothymosin alpha enhances human and murine MHC class II surface antigen expression and messenger RNA accumulation

Prothymosin alpha (ProT alpha) is an acidic polypeptide with potentiating effects on HLA-DR-restricted in vitro cellular immune response systems such as T cell proliferative responses to soluble proteins and cellular auto- or alloantigens. Experiments were performed to investigate the effect of ProT alpha on MHC class II Ag expression in human monocytes, murine splenocytes, and tumor cell lines at both protein and molecular levels. RIA and immunofluorescence analysis revealed that ProT alpha enhances HLA-DR surface Ag expression whereas Northern blot analysis demonstrated that ProT alpha causes significant accumulation of MHC class II mRNA. The enhancing effect of ProT alpha was demonstrated convincingly using precultured human peripheral monocytes, which are known to express decreased amounts of surface HLA-DR Ag, and HLA-DR-positive human cell lines. Moreover, ProT alpha was shown to induce HLA-DR Ag expression in a priori HLA-DR-negative tumor cells. Furthermore, ProT alpha was shown to be active in vivo. Splenocytes from mice pretreated with ProT alpha expressed more surface Ilpha Ag and contained more I alpha-specific mRNA. These findings suggest that ProT alpha may be important in the regulation of the immune response by enhancing MHC class II Ag expression in APC.

Monocyte disorders associated with T cell defects in patients with solid tumors

T cells proliferate in response to autologous monocytes in the autologous mixed lymphocyte reaction (AMLR). AMLR was found to be impaired in patients with advanced cancer (stages III and IV), whereas normal values were found in the early stages of the disease (stages I and II). Peripheral T lymphocytes from patients with advanced stages also exhibited a decreased ability to produce Interleukin-2 (IL-2) during an AMLR response, whereas production of IL-2 by T cells in stages I and II was comparable to that of normal donors. The impaired IL-2 production by T lymphocytes in the AMLR was associated with high concentrations of soluble interleukin-2 receptor (sIL-2R) in culture supernatants and reduced expression of membrane-bound interleukin-2 receptors (IL-2R) on the same AMLR-activated T lymphocytes. These abnormalities in T cells from cancer patients were demonstrated to be associated with dysfunctions of autologous monocytes. Thus monocytes from patients with advanced cancer exhibited diminished expression of HLA-DR antigens and produced low levels of Interleukin-1 beta (IL-1 beta) and Tumor Necrosis Factor a (TNFa). No changes were detected in the expression of HLA-A, -B, -C antigens. The results presented here demonstrate that decreased in vitro T cell responses may be attributed to monocyte dysfunctions in these patients and provide new information for a better understanding of the impaired T cell function in cancer patients.

Prothymosin-alpha enhances HLA-DR antigen expression on monocytes from patients with multiple sclerosis

Monocytes from patients with multiple sclerosis (MS) express decreased numbers of class II major histocompatibility complex (MHC) antigens in peripheral blood and are poor stimulators in the autologous mixed lymphocyte reaction (autoMLR). We assessed the effect of prothymosin-alpha (ProT alpha) on the expression of MHC class II antigens by monocytes. Immediately after isolation, monocytes were analyzed for MHC class II antigen expression using a radiolabelled monoclonal antibody specific for a monomorphic determinant on HLA-DR antigens. After incubation with ProT alpha we observed significant increases in HLA-DR antigens on MS monocytes (1.5- to 4-fold increase compared to freshly isolated monocytes). Kinetic analysis revealed that enhancement peaked after 2 days of incubation with ProT alpha. The increase in HLA-DR antigen on MS monocytes resulted in the restoration of the deficient autoMLR in MS patients. This is the first demonstration suggesting a link between HLA-DR antigen expression and cellular immune defects in MS. The significance of low autoMLR responses for T suppressor levels in MS patients is discussed.

Enhancement of human T lymphocyte function by prothymosin alpha: increased production of interleukin-2 and expression of interleukin-2 receptors in normal human peripheral blood T lymphocytes

The in vitro incubation of phytohemagglutinin (PHA)- or alloantigen-stimulated peripheral blood T cells with prothymosin alpha (ProT alpha) resulted in a marked and reproducible increase in the production of interleukin-2 (IL-2). Incubation of T cells with ProT alpha, in the absence of PHA or alloantigen, failed to induce any production of IL-2. ProT alpha by itself did not exert any IL-2 activity. Finally, ProT alpha was shown to increase the expression of IL-2 receptors on phytohemagglutinin- or alloantigen-activated T cells. These data provide the basis for understanding the in vitro immunoenhancing effects of ProT alpha in cellular immune systems.

Decreased expression of HLA-DR antigens on monocytes in patients with multiple sclerosis

Immunofluorescence, cell binding assays and enzyme immunoassays were used to investigate the expression of class II major histocompatibility antigens on peripheral blood monocytes in 67 patients with multiple sclerosis. Monocytes from patients with active disease expressed fewer HLA-DR molecules on their surface than normal monocytes; furthermore the percentage of cells which exhibited detectable amounts of surface HLA-DR antigens was decreased in patients with active multiple sclerosis. During the inactive stage of the disease both deficiencies were milder, probably representing secondary pathogenetic phenomena. Quantitation of monocyte surface HLA-DR antigen expression could be valuable in assessing the clinical disease activity. The demonstration of a molecular defect in patients with multiple sclerosis will improve our understanding of the pathogenesis of the disease.

Peptides of myelin basic protein stimulate T lymphocytes from patients with multiple sclerosis

Peripheral blood T lymphocytes from patients with multiple sclerosis (MS) and other neurological diseases (OND) were tested for primary in vitro proliferation in response to four synthetic peptides derived from the sequence of human myelin basic protein (HuMBP) and to HuMBP 45-89 peptide fragment, using a [3H]thymidine incorporation assay. The synthetic peptides used corresponded to residues HuMBP 15-31, 75-96, 83-96 and 131-141 of human myelin basic protein. Significant proliferation of T lymphocytes to peptides was noted only in the MS group (with the exception of peptide 131-141): the majority of control subjects and OND patients did not respond to the above-mentioned peptides. The sensitized T lymphocytes in MS patients displayed the inducer/helper phenotype and required autologous monocytes for optimal proliferation. An anti-HLA-DR monoclonal antibody, directed against a monomorphic determinant of DR molecules, was able to block the responses in a dose-dependent fashion. These results suggest that autoimmune inducer/helper T lymphocytes in the peripheral blood of MS patients may initiate and/or regulate the demyelination process in patients with MS. Furthermore, our data demonstrate that monocytes and HLA-DR molecules are essential for activation of these cells. Finally primary in vitro T cell proliferation to HuMBP synthetic peptide may be used as an additional diagnostic test in MS.