Detection of altered T helper 1 and T helper 2 cytokine production by peripheral blood mononuclear cells in patients with multiple sclerosis utilizing intracellular cytokine detection by flow cytometry and surface marker analysis

Production of T helper 1 and T helper 2 cytokines was investigated in peripheral blood mononuclear cells (PBMCs) from multiple sclerosis (MS) patients by a newly described technique, detection of intracellular cytokines by flow cytometry in conjunction with immunophenotype analysis. T-cell gamma interferon (IFN-gamma) production and interleukin 10 (IL-10) production were examined after PBMC activation with T-cell mitogens at 5 and 24 h, and monocyte spontaneous production of IL-10 and production after PBMC activation with lipopolysaccharide (LPS) for 24 h were also examined. The data indicate that MS patients have decreased percentages of T cells capable of secreting IFN-gama compared with healthy controls, and this change is detectable at 5 and 24 h. the patients displaying decreased T-cell production of IFN-gamma were essentially confined to a group being treated with the newly approved drug Betaseron (berlex Labs, Cedar Knolls, N.J.), a recombinant form of IFN-beta (rIFN-beta 1b). By gating of the entire lymphocyte population, analysis of IFN-gama production in T cells (CD3+ versus that in non-T cells (CD3+) was possible. The percentage of IFN-gamma-producing lymphocytes that was made up of T cells was essentially unchanged between the Betaseron-treated patients, non-Betaseron-treated patients, and controls, indicating that the suppression of IFN-gamma production displayed by betaseron-treated MS patients was a nonspecific suppression of all IFN-gamma-producing lymphocytes as opposed to a suppression of T-cell production only. The data seem to indicate that treatment of MS with Betaseron corresponds to an inhibition of the lymphocyte's ability to produce IFN-gamma. No changes were detected in T-cell production of IL-10 at either time point. We also observed that MS patients in general appear to have small percentages of peripheral blood monocytes spontaneously producing slight but detectable levels of IL-10. No difference was seen regarding monocyte production of IL-10 after PBMC activation with LPS between MS patients and controls. Both populations responded with high percentages of monocytes producing IL-10. The data seem to indicate that treatment of MS with Betaseron, known to decrease the exacerbation rate of relapsing-remitting MS, corresponds to a suppression of peripheral blood lymphocyte production of IFN-gamma. Monocyte production of IL-10 may also play a role in regulating the disease process.

Alterations in peripheral blood mononuclear cell cytokine production in response to phytohemagglutinin in multiple sclerosis patients

Multiple sclerosis (MS) is an autoimmune demyelinating disorder of the central nervous system (CNS). The disease is characterized by inflammatory lesions in the white matter of the CNS, consisting of a specific immune response to the myelin sheath. We investigated peripheral blood mononuclear cell (PBMC) cytokine production by enzyme-linked immunosorbent assays of 21 MS patients and 19 age-matched normal controls in response to the T-cell mitogen phytohemagglutinin (PHA). Peripheral blood mononuclear cells were cultured in medium alone or in medium with 5 micrograms of PHA per ml for 48 h, and culture supernatants were collected for analysis. Cytokines selected for study were interleukin-10 (IL-10), gamma interferon (IFN-gamma), IL-2, and IL-4. All cytokine activities described were expressed as concentrations per 500,000 cells. We found that 48% (10 of 21) of the MS patients produced small but detectable levels of IL-10 in medium alone, compared with 26% (5 of 18) of the controls. We found that the MS patients produced significantly higher quantities of IL-10 protein than the controls in response to PHA (mean supernatant concentrations of IL-10 for patients and controls, 421 and 204 pg/ml, respectively [P < 0.05]). No significant differences were detected in the production of IL-2, IFN-gamma, and IL-4 between patients and controls in response to PHA, although patients appeared to display a trend toward decreased production of IFN-gamma.

Alterations in levels of CD28-/CD8+ suppressor cell precursor and CD45RO+/CD4+ memory T lymphocytes in the peripheral blood of multiple sclerosis patients

A comprehensive peripheral blood immunophenotype analysis of 16 multiple sclerosis (MS) patients was performed by three-color flow cytometric analysis, and the results were compared with those for age-matched healthy controls. The cell subsets quantified included T cells (CD3+), B cells (CD19+), NK cells (CD56+), CD4+ and CD8+ T cells, cytotoxic (CD28+) and suppressor precursor (CD28-) CD8+ T cells, CD45RA+ and CD45RO+ T cells (CD4+ and CD8+), and CD5+ T and B cells. Analysis of MS patients' peripheral blood revealed essentially normal levels of total T, B, and NK cells. In agreement with results obtained by other investigators, it was found that MS patients had an increased CD4/CD8 ratio, primarily due to a decrease in CD8+ T cells. MS patients were found to have a significantly decreased level of suppressor precursor (CD28-) CD8+ T cells compared with that of controls but to have normal levels of cytotoxic (CD28+) CD8+ T cells. These data indicate that MS patients do not have a general decrease in CD8+ T cells but that they have a specific decrease in the suppressor precursor subset only and normal levels of cytotoxic CD8+ T cells. MS patients also had a significant increase in memory (CD45RO+) CD4+ T cells and displayed a trend towards a decrease in naive (CD45RA+) T cells in the peripheral blood.

Probing for answers. Use of DNA probes in infectious diseases

Diagnostic molecular biology is at the forefront in the diagnosis of infectious diseases. Through the use of deoxyribonucleic acid (DNA) probes in conjunction with other molecular techniques such as polymerase chain reaction (PCR), physicians will be able to more rapidly and accurately diagnose causative agents in a variety of infectious diseases. This article will focus on the molecular basis of these techniques, how they may aid the physician in patient diagnosis, and the shortcomings of this new and exciting technology.

Susceptibility in vitro of Nocardia species to antimicrobial agents

Fifty-four clinical isolates of Nocardia spp. were tested in vitro for susceptibility to several antimicrobial agents. Of these, 89% were susceptible to ciprofloxacin, 86% to imipenem, 85% to fusidic acid, and 71% to cefotaxime. Some of the agents may be suitable alternative or adjunctive drugs to sulfonamides and aminoglycosides for chemotherapy of Nocardial infections.

Evaluation of antibiotic susceptibility testing by agar dilution and the Micro Media system (Fox Panel)

The susceptibilities of 350 gram-positive cocci and 638 gram-negative bacilli to various antimicrobial agents were compared by using the Micro-Media system (MMS) (Fox Panel) (Micro-Media Systems, Inc., Potomac, Md.) and a standard agar dilution procedure. Major discrepancies occurred with enterococci, among which 48 of 53 isolates (91%) were found to be resistant to penicillin G by agar dilution and reported as susceptible by the MMS. Other large discrepancies occurred with Staphylococcus aureus and Acinetobacter calcoaceticus subsp. anitratus, among which more than 40% of the isolates were judged to be resistant to ampicillin by agar dilution and susceptible by the MMS. In terms of overall agreement in interpretation of MICs by the two systems, an agreement of greater than 84% was seen for both gram-positive and gram-negative organisms when ampicillin and cephalothin (68 and 78% agreement for gram-positive cocci, respectively) were excluded. These disagreements in MIC interpretations may result in part from the small number of organisms tested per well (4,000 CFU) in the MMS, as compared with 10,000 CFU per test in the agar dilution method.