Monitoring of peripheral blood cytotoxic T-cells under fluvastatin treatment in renal transplant recipients.

Flow cytometric T-cell analysis is capable of adding valuable information for balancing immunosuppression in transplant recipients as it can take into account individual effects of immunosuppressive drugs on each patient as well as effects of other drugs which may modify the overall immunosuppression. Studies suggest that HMG-CoA-reductase-inhibitors (statins) reduce the frequency of organ rejection, although the precise mechanism of this effect is unknown. We therefore evaluated the effect of fluvastatin on size and activation of T-cell subpopulations and NK-cell activity in renal transplant recipients. At baseline, the population size of activated (HLA-DR+) T-cells was negatively correlated to serum HDL cholesterol suggesting an increased T-cell activation at low HDL levels. Fluvastatin treatment of a hypercholesterolemic group of patients for two months significantly decreased the LDL cholesterol. A longitudinal analysis revealed a relative increase in non-MHC restricted cytotoxic T-cells (CD3+/CD16+ or CD56+) over time which was significantly attenuated in fluvastatin treated patients but not in normocholesterolemic controls. Moreover, a relative decrease of activated MHC class I-restricted cytotoxic CD8+ T-cells was only observed upon fluvastatin treatment. NK-cell number and activity did not differ between groups. In summary, fluvastatin treatment of hypercholesterolemic renal transplant recipients is associated with a specific modulation of T-cells exerting cytotoxic effector functions.

Identification of naturally processed T cell epitopes from glutamic acid decarboxylase presented in the context of HLA-DR alleles by T lymphocytes of recent onset IDDM patients.

Glutamic acid decarboxylase (GAD) has been defined as a major target antigen in insulin-dependent diabetes mellitus (IDDM). To identify the molecular ligands triggering a T cell response to GAD, a panel of human GAD65-specific T lymphocyte lines was generated from peripheral blood of three recent onset IDDM patients. All lines derived from a patient expressing the high-risk-conferring HLA-DR*0301/ *0401 haplotypes recognized a single epitope localized between amino acid positions 270 and 283 of GAD65, a stretch that is located in close proximity to the homology region shared with Coxsackie virus P2-C protein. All lines with this specificity were restricted to the DRA, B1*0401 product of the DR4 haplotype. Analysis of the GAD-specific T cell response in a second patient homozygous for DR4 haplotypes demonstrated that the same DRA, B1*0401 allele selected T cells specific for a different determinant. The T cell response profile in a third patient showed that DR*1501/ *1601-encoding haplotypes could present at least three different epitopes to GAD65-specific T lymphocytes. One of these epitopes was presented by a DR allele associated with the resistance-conferring DRB1*1501 haplotype. GAD-specific T cell lines could not be isolated from HLA class II-matched normal individuals. Our data reveal that (a) the T cell response to GAD65 is quite heterogenous in recent onset IDDM patients; (b) HLA-DR, not DQ, seems to be the principal restriction element used by T cells present at the onset of the disease; and (c) T cells responding to epitopes containing identical sequences to Coxsackie virus P2-C protein were not detected.

Atrial natriuretic factor and digoxin-like immunoreactive factor in diabetic patients: their interrelation and the influence of the autonomic nervous system.

In diabetic patients, several factors contribute to volume expansion and have to be counteracted by humoral and neuronal feedback control systems. We investigated N-terminal proatrial natriuretic factor (ANF1-98) and digoxin-like immunoreactive factor (DLIF), which are two counteracting hormones, and their interrelationship, with additional consideration given to autonomic nervous function in diabetic patients. ANF1-98 and DLIF were measured in 64 diabetic patients. Autonomic nervous function was assessed using nine autonomic nervous function tests. The patients were subdivided into two groups, one with four or more (group 1) and one with less than four abnormal results in autonomic function tests (group 2). Compared with group 2, group 1 demonstrated detectable DLIF levels less often (17.2 vs. 45.7, P = 0.0195) and increased levels of ANF1-98 (mean +/- SEM: 850.0 +/- 108.8 vs. 554.8 +/- 45.9 pmol/L, P = 0.0099). However, the groups did not differ in blood pressure, daily sodium, and daily potassium excretion. The number of abnormal autonomic function tests correlated significantly with ANF1-98 (P = 0.0002). In patients with detectable DLIF, DLIF correlated with ANF1-98 (P = 0.0080). These results demonstrate close interactions between the autonomic nervous system and the two natriuretic hormones. In patients with autonomic nervous dysfunction, higher levels of ANF may possibly compensate for the lack of the natriuretic DLIF to counteract hypertension and chronic volume expansion.

Influence of digoxin-like immunoreactive factor on late complications in patients with diabetes mellitus.

The aim of this study was to compare the intensity of typical late complications in diabetic patients (n = 65, 28 type I, 37 type II) who were not on glycoside drugs with low vs. high serum levels of digoxin-like immunoreactive factor (DLIF: group I, n = 42, DLIF < or = the detection limit of 0.2 ng ml-1; and group II, n = 23, mean +/- SEM: 1.17 +/- 0.31 [0.25-4.96] ng ml-1). For detection of nephropathy, urinary albumin excretion (24 h) and creatinine clearance tests were used. For coronary heart disease a questionnaire and standard ECG; for peripheral occlusive vascular disease a questionnaire; for eye disease a fundoscopy; for neuropathy a neurological score system; and for autonomic neuropathy a standardized test battery was employed. Patients with high DLIF levels showed better test results in vibratory perception (95.7 +/- 1.5 vs. 82.8 +/- 3.8%, normal finding = 100%, 2p = 0.016), had better percentile localizations concerning maximal pupillary area in darkness (28.4 +/- 6.6 vs. 8.1 +/- 1.8%, 2p = 0.0004), contraction velocity at 1 s (21.5 +/- 5.8 vs. 8.0 +/- 2.2%, 2p = 0.012), and dilation velocity at 6 s (23.0 +/- 6.8 vs. 10.5 +/- 2.5%, 2p = 0.041), had less retinopathy (with retinopathy: 26.1% vs. 64.3%, 2p = 0.0028), and better percentile localizations in the respiratory sinus arrhythmia test (68.4 +/- 7.3 vs. 44.1 +/- 4.9%, 2p = 0.0064). There was no difference concerning nephropathy, blood pressure, coronary heart disease and peripheral vascular disease. Separate analysis according to the type of diabetes confirmed the results in each group.(ABSTRACT TRUNCATED AT 250 WORDS)