Serum factors inhibiting some leukocytic functions in Hodgkin's disease

Common and Trace Metals in Alzheimer's and Parkinson's Diseases

Trace elements and metals play critical roles in the normal functioning of the central nervous system (CNS), and their dysregulation has been implicated in neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). In a healthy CNS, zinc, copper, iron, and manganese play vital roles as enzyme cofactors, supporting neurotransmission, cellular metabolism, and antioxidant defense. Imbalances in these trace elements can lead to oxidative stress, protein aggregation, and mitochondrial dysfunction, thereby contributing to neurodegeneration. In AD, copper and zinc imbalances are associated with amyloid-beta and tau pathology, impacting cognitive function. PD involves the disruption of iron and manganese levels, leading to oxidative damage and neuronal loss. Toxic metals, like lead and cadmium, impair synaptic transmission and exacerbate neuroinflammation, impacting CNS health. The role of aluminum in AD neurofibrillary tangle formation has also been noted. Understanding the roles of these elements in CNS health and disease might offer potential therapeutic targets for neurodegenerative disorders. The Codex Alimentarius standards concerning the mentioned metals in foods may be one of the key legal contributions to safeguarding public health. Further research is needed to fully comprehend these complex mechanisms and develop effective interventions.

Metal Toxicity Links to Alzheimer's Disease and Neuroinflammation

As the median age of the population increases, the number of individuals with Alzheimer's disease (AD) and the associated socio-economic burden are predicted to worsen. While aging and inherent genetic predisposition play major roles in the onset of AD, lifestyle, physical fitness, medical condition, and social environment have emerged as relevant disease modifiers. These environmental risk factors can play a key role in accelerating or decelerating disease onset and progression. Among known environmental risk factors, chronic exposure to various metals has become more common among the public as the aggressive pace of anthropogenic activities releases excess amount of metals into the environment. As a result, we are exposed not only to essential metals, such as iron, copper, zinc and manganese, but also to toxic metals including lead, aluminum, and cadmium, which perturb metal homeostasis at the cellular and organismal levels. Herein, we review how these metals affect brain physiology and immunity, as well as their roles in the accumulation of toxic AD proteinaceous species (i.e., β-amyloid and tau). We also discuss studies that validate the disruption of immune-related pathways as an important mechanism of toxicity by which metals can contribute to AD. Our goal is to increase the awareness of metals as players in the onset and progression of AD.

Disorders of neutrophil function

Major bacterial infections are most commonly associated with agranulocytosis or an abnormality of immunoglobulins or complement. Occasionally, repeated infections cannot be attributed to these relatively common causes. In such cases, a quantitative abnormality in neutrophil function should be sought. Complete evaluation of neutrophil function, including: chemotaxis, adhesion, aggregation, phagocytosis, granule content and degranulation, respiratory burst activity and bacterial killing is expensive and requires the services of a specialized laboratory. However, preliminary screening of a patient with a predisposition towards infection can be carried out using simple and inexpensive methods. These include examination of blood films, chemotaxis assay, NBT test and peroxidase staining. For final diagnosis and determination of genetic transmission and treatment, specific tests are indicated. Investigation of neutrophil functions may be useful for the diagnosis of congenital and acquired neutrophil disorders. These assays may also be useful in research, diagnosis and follow up of non-infectious diseases with active inflammatory component.

3H-NECA binding to polymorphonuclear membrane: effect of sera from patients with Hodgkin's disease

Several studies have shown that sera from patients with Hodgkin's disease contain factors capable of inhibiting polymorphonuclear functions, among them chemotaxis. In the present study, we investigated whether these sera, which were able to inhibit PMN chemotaxis in the agarose test, were also able to affect the 3H-NECA binding to PMN membrane obtained from healthy donors. Control experiments were carried out using PMN incubated with a pool of sera from healthy volunteers. No significant difference was found in the maximum number of binding sites; on the contrary, the equilibrium dissociation constant was significantly increased in the membrane preparation of PMN incubated with pathological serum.

Dysfunction of monocytes in Hodgkin's disease by excessive production of PGE-2 in long-term remission patients

The candidacidal activity and the production of oxygen radicals by monocytes were investigated in untreated and long-term remission patients with Hodgkin's disease (HD). Both groups showed a decreased candidacidal function of monocytes with a chemiluminescence (CL) response significantly lower and delayed with respect to normal controls. Indomethacin at 1 microgram/ml corrected the monocyte deficiency increasing the CL response to normal values and normalizing the kinetics in the untreated patients. However, in patients in remission, the peak was delayed and followed by a significant increase in the production of oxygen radicals compared with untreated patients. A direct linear correlation was found between the percentages of lysed Candida and maximum CL peak of stimulated monocytes. When prostaglandin E2 (PGE-2) levels, measured in supernatants of cultured mononuclear cells, were plotted against the percentages of killed Candida, an inverse linear correlation was found. Therefore, monocytes from HD patients have a dysfunction in the generation of oxygen radicals and a decreased candidacidal activity associated with excessive production of PGE-2. Indomethacin can correct the oxidative metabolism in the untreated patients while in apparently "cured" patients the disorder persists.

Inhibition of human neutrophil migration by supernatants from Hodgkin's disease-derived cell lines

The contribution of defective neutrophil function to the increased susceptibility to infection observed in patients with Hodgkin's disease is unclear. We describe cell-directed inhibition of normal human neutrophil migration by serum-free culture supernatants of the Hodgkin-derived cell line L428 KSA, tentatively termed Hodgkin-derived leucocyte factor (HDLF). This factor inhibits both random migration and migration toward different chemoattractants, appears to bind to the cell surface and is stable at 56 degrees C but destroyed at 100 degrees C. Hodgkin-derived leucocyte factor also stimulates basal neutrophil superoxide production but the cells remain fully responsive to n-formyl-methionylleucylphenylalanine. Gel filtration chromatography shows a single peak of migration-inhibitory and superoxide-stimulatory activity at approximately 70,000 g mol-1. Hodgkin-derived leucocyte factor migration inhibition persists in neutrophils from a patient with chronic granulomatous disease. Activity of HDLF is completely destroyed by trypsin but unaffected by the protease inhibitor phenyl-methylsulphonylfluoride. Hodgkin's factor appears to be different from previously described neutrophil migration inhibitory factors.

The chemokinetic inhibitory factor (CIF) in serum of CLL patients: correlation with infection propensity and disease activity

We have recently described the partial purification and characterization of a neutrophil migration inhibitory activity present in serum from patients with chronic lymphocytic leukaemia (CLL). This new lymphokine, the chemokinetic inhibitory factor (CIF), is produced by B-CLL cells. It is a heat-labile glycoprotein of an approximate molecular weight (m. w.) of 30000. In this extended investigation 64/89 CLL-patients had CIF in their serum. CLL serum diluted to a concentration of 0.02% gave significantly decreased chemokinetic activity, suggesting that CIF is potent at very low concentrations. 31/89 patients had increased infection propensity. Significantly more patients with CIF in serum had infections compared to the group with normal susceptibility to infections. The combination of low Ig levels and CIF in serum discriminated even better between the infection-prone and non-infection-prone patients. CIF in serum was not correlated to tumour cell mass - estimated by Rai clinical staging - tumour progression or deoxythymidine kinase, S-TK, an enzyme that may reflect proliferating cells. The existence of this new lymphokine in serum seems to contribute to the increased susceptibility to infections seen in CLL patients.

Effect of sera from patients with Hodgkin's disease on normal donor lymphocytes containing parallel tubular structures

Normal donor peripheral blood mononuclear cells incubated for 24 h with sera from patients with Hodgkin's disease were investigated by electron microscopy for the presence of parallel tubular structures (PTS) and/or amorphous electrondense granules (large granular lymphocytes = LGL). In comparison with normal human serum, 14 out of 29 sera of the patients induced a marked increase in the percentage of LGL. From a limited number of experiments it was likely that this increase is paralleled by an increase in Fcgamma receptor-bearing cells after the incubation. This serum effect did not show a correlation with the number of Fcgamma receptor-positive lymphocytes in the peripheral blood of the patients. A difference in the induction effect could be demonstrated between the sera from patients with a favourable and those with an unfavourable clinical course, but this distinction was not absolute. The presence or absence of splenic involvement by Hodgkin's disease does not apparently influence the effect of the sera. From experiments using sera positive for immune complexes or anti-Epstein-Barr virus antibodies, it seems unlikely that these factors are responsible for the observed increase in LGL.

Increased antibody-dependent cytotoxicity mediated by purified monocytes in Hodgkin's disease

Monocyte antibody-dependent cytotoxicity was studied in 19 patients with Hodgkin's disease and 14 normal controls. This function was investigated after isolation of the monocytes by means of a modified elutriation technique. Direct sizing and counting of the cells present in the effluent enabled individual adjustment during each separation procedure. The absolute monocyte count in the peripheral blood of patients with Hodgkin's disease was higher (P less than 0.002) than in normal controls. Nearly 90% pure monocyte suspensions, representing 82% of all elutriated monocytes, were obtained. The elutriation characteristics of the monocytes in both groups were essentially the same, irrespective of marked interindividual differences. Kill of antibody-coated chicken red blood cells was measured by DNA flow cytometry. In comparison to normal controls, a significantly increased (P less than 0.0004), stage-independent, monocyte antibody-dependent cytotoxicity was found in patients with Hodgkin's disease. The percentage of kill in symptomatic patients tended to be higher than in the asymptomatic group; no correlation was found with the absolute number of circulating monocytes.