Can blood immunocytes be used to study neuropsychiatric disorders?

The evidence that demonstrates a structural and functional interrelationship between the immune system and central nervous system is reviewed. Based on striking analogies between these two systems, the proposal was made that at least some neuropsychiatric diseases can be evaluated by functional studies of peripheral blood immunocytes. This hypothesis was supported by the results of immunologic function studies of various subpopulations of immunocytes obtained from patients with Alzheimer's disease and retinitis pigmentosa.

Lymphocyte stimulation in vitro by orosomucoid glycoprotein

Mitogenesis of human peripheral blood lymphocytes as measured by the uptake of [3H]thymidine was stimulated in vitro by pure orosomucoid glycoprotein when used at concentrations that are considerably lower than the physiological plasma level. The lymphocyte cultures stimulated with PHA or PWM were not affected by low concentration (67 micrograms/ml), but they were mildly suppressed by high concentration (1 mg/ml) of this glycoprotein. The stimulatory response was relatively greater with fractionated T cells than the non-T cells (B cells and monocytes). At 50 micrograms/ml concentration of orosomucoid, the lymphocyte activation was found in randomly selected blood donors which included normal healthy volunteers and patients with T cell immunodeficiency or Alzheimer's disease, demonstrating a consistent immunostimulatory action of this glycoprotein.

Does normal lymphocyte DNA synthesis in response to PHA exclude cell-mediated immunodepression?

PHA stimulation assay was the first in vitro method for evaluating the T-cell function, and this T-cell proliferative response has been routinely used to discriminate between normal subjects and patients with deficiency in cell-mediated immunity. However, [3H]thymidine incorporation into lymphocyte DNA can be studied by using additional in vitro assay methods since they measure different lymphocyte activation pathways. In the present study we selected three different tests to investigate the reliability of this single approach: PHA induced lymphocyte DNA synthesis; T lymphocyte DNA synthesis to anti-T3 monoclonal antibody (OKT3); autologous mixed lymphocyte reaction (AMLR). In addition, IL-2 receptor expression on the membrane of T-cell stimulated in AMLR both with PHA and anti-T3 was evaluated. This study was performed in various groups of subjects: normal young controls, aged healthy individuals, and patients with Alzheimer's disease (AD), Retinitis Pigmentosa (RP), and with cell-mediated immunodeficiency and clinical evidence of recurrent viral infections (ID). The data reported herein show heterogeneity of results in each group studied and demonstrate the necessity of employing more than one laboratory test for the routine evaluation of T-cell-mediated immunity.

Chronobiologic quantification of nocturnal low-dose dopamine effect on circadian rhythms of thyroid-related hormones and prolactin (PRL)

Six clinically-healthy young men provided plasma samples every 30 min for 24 h (from 09:00-09:00 on 2 occasions. TSH, free T3 and free T4 were determined in the 30-min samples, while prolactin was determined in samples 1-3h apart. During the first test span, each man received an infusion of physiologic saline between 21(00)-01(00). Upon re-sampling several weeks later, 3 men received a low dose of dopamine (0.1 microgram/kg/min) and 3 men received a high dose (1.0 microgram) over the same hours (21:00-01:00). The least-squares fit of a 24-h cosine to each data series described a statistically-significant circadian rhythm (p less than 0.01) for each subject on each day of study. While overall group comparisons revealed no significant difference in mesor for any hormone studied, some intra-individual differences in rhythm parameters between saline and dopamine infusion were found. Dopamine Rx produced a statistically-significant increase in amplitude for PRL and T4 and an advance in acrophase for TSH, T3 and T4, but a delay for PRL. Studies measuring hormones of interest for the 24th immediately preceding and the 24th immediately following dopamine infusion at varying circadian stages (rather than only between 21:00-01:00) are warranted and have to be individualized--one of the points of this paper. The other main point is that data reduction to a mean and a standard deviation entails loss of information that can be recovered by chronobiologic methods, here used only as a model, in view of the limitations of the sampling design on hand.

Detection of brain autoantibodies in the serum of patients with Alzheimer's disease but not Down's syndrome

The immunofluorescent staining of antibodies specifically binding to rat brain tissue sections was investigated in 95 human sera including 30 cases of Alzheimer's disease. A high incidence of specific antibrain antibody was found among Alzheimer's patients (57% positive) compared to other neurological disease controls (only 8% positive) or normal young and aged healthy controls (none positive).

Rubella-associated arthritis. II. Relationship between circulating immune complex levels and joint manifestations

The role played by raised circulating immune complex (CIC) levels in the pathogenesis of rubella-associated joint reactions has been assessed during the course of RA 27/3 rubella immunisation and epidemic wild rubella infection. CIC levels were evaluated by C1q microplate enzyme-linked immunosorbent assay (ELISA) and Raji cell ELISA techniques. Mean CIC levels were generally higher both before and after immunisation among individuals developing vaccine-associated arthritis than among those developing arthralgia or no joint symptoms. However, these differences reached statistical significance only with CIC (Raji) techniques at six and 12 weeks postimmunisation. The proportion of individuals within each group having raised CIC levels (greater than or equal to 2SD above normal control values) was also higher in the postvaccine arthritis group, though statistically significant differences were not found with either Raji or C1q techniques. These data do not support a direct role for raised CIC levels in the pathogenesis of rubella-associated arthritis or arthralgia.

Serum and peritoneal dialysate thyroid hormone levels in patients on continuous ambulatory peritoneal dialysis

Thyroid function tests were performed on 16 clinically euthyroid patients with end-stage renal failure undergoing regular haemodialysis or continuous ambulatory peritoneal dialysis and compared with 8 healthy subjects. The patient groups were carefully matched, especially regarding relative duration of dialysis (mean of 24 months). Total serum thyroxine, total triiodothyronine, free thyroxine, free triiodothyronine and reverse triiodothyronine were significantly lower in both patient groups than control. The thyrothrophin response to the standard thyrotrophin-releasing hormone test was delayed and blunted. Using a novel concentration technique we measured loss of T4 in peritoneal dialysate effluent and found it to be approximately 10% of daily thyroidal T4 release.

Immunologic dysfunction: simultaneous study of Alzheimer's and older Down's patients

Peripheral blood lymphocytes from Alzheimer's disease patients, older patients (aged 25-59 years) with Down's syndrome and closely age-matched healthy controls were tested in vitro for DNA synthesis in response to stimulation by phytohemagglutinin, pokeweed mitogen and OKT3 monoclonal antibody to T3 antigen. All were significantly decreased in Down's and Alzheimer's patients relative to healthy controls. The autologous mixed lymphocyte reaction (AMLR), unstimulated or stimulated with anti-T3. in the 2 patient groups did not differ significantly from the healthy controls. We also quantified the proportions of the T cells staining positive for surface membrane orosomucoid, and found their levels to be either higher or lower than normal in Down's patients, but not in Alzheimer's patients. These results demonstrate the existence of defective cellular immune functions in both elderly Down's patients and Alzheimer's patients.

Chronic treatment with ACTH1-24 does not produce permanent damage to the developing rat brain

Permanent effects of ACTH1-24 on the developing rat brain were investigated. Rats were injected with 20 IU/kg of ACTH1-24 daily for 4 weeks starting at two days of age. Brain weight, protein, DNA and RNA contents, contents of monoamines and their metabolites, 2',3'-cyclic nucleotide 3'-phosphohydrolase and glutamic acid decarboxylase activities were measured at 24 h and 8 weeks after the last injection. There were no significant changes in these indicators compared to saline-injected controls. These results suggest that chronic treatment with ACTH1-24 does not permanently damage the developing rat brain.

Detection of circulating immune complexes by a Clq/protein A-ELISA during the preneoplastic stages of feline leukemia virus infection

A microscale ELISA immune complex assay which utilized a solid phase C1q and a Protein A-peroxidase enzyme conjugate is described. This ELISA was used to detect and quantitate circulating immune complexes (CIC) during the initial feline leukemia virus infection. Significant increases in CIC were seen in the cats which were transiently infected at weeks three through eight after viral exposure. A persistent elevation in CIC was observed in the one cat which developed a persistent viremia. The addition of EDTA to the serum strongly interfered with this assay.

Cells from newborn rat brain established in primary tissue culture will support rubella virus replication

We have initiated an in vitro study comparing the susceptibility of newborn and adult animals to rubella virus (RV) associated encephalitis. Glial cells from injured adult rat brain (RG cells) have been established in continuous culture and these cells were reported to restrict RV replication. When RG cells were infected, no infectious progeny virus particles were detected in tissue culture media and only five intracellular viral polypeptides could be detected using immune precipitation techniques (p75, p60, VP44, VP41, and VP19). Two polypeptides normally associated with a productive infection. VP24 and p30, could not be detected. In this report we have applied these techniques to an investigation of RV replication in newborn brain cells and have shown that relatively normal yields of all seven polypeptides found in RV-infected cells could be detected. These data indicate that some glia from newborn brain in primary culture are permissive for RV replication unlike the restricting RG cells and that this difference in restriction is critical in determining the outcome of their infection by RV.

Quantitation of soluble immune complexes by a microplate Raji cell-ELISA method

A Raji cell microplate-ELISA method has been devised for the detection and quantitation of putative immune complexes present in human sera. The Raji cells immobilized with glutaraldehyde (final concentration 0.67%) were conveniently utilized in the solid phase system. The specific binding of AHG diluted in PBS (without complement) increased linearly in the range of 0.1 to 5 micrograms. The purified human IgG showed some low-affinity binding which was 7-to 14-fold lower than the binding of AHG. The circulating immune complexes positive sera were found to have values above the mean of 11.95 +/- 4.09 micrograms/ml AHG equivalent for normal human sera (n = 72). The method is sensitive, reproducible and it can be performed with simplicity and rapidity.

Detection of antibodies to thymic tissue in human serum

Antibodies specific to thymic tissue were detected in normal human serum by means of an indirect immunofluorescent technique. Approximately 50-88% of the total sera (33) showed positive staining, which was confined to the medullary zone primarily associated with the surface membranes of epithelial cells including Hassall's corpuscles. These observations point to the recognition by the immune-self of antigen(s) of the thymic epithelium in health, and presumably in disease.

Detection of circulating immune complexes by a C1q-microplate ELISA system

A microscale ELISA system, designated as the 'C1q-micro ELISA,' has been developed for the measurement of circulating immune complexes. The sensitivity of the method ranged between 0.1 and 3 microgram equivalents of aggregated human gamma-globulins. The procedure requires small quantities of serum and reagents, and it can be performed with rapidity without the loss of accuracy and reproducibility.