从外周血单个核细胞扩增多样性人免疫球蛋白基因的研究

目的 建立成熟的体外扩增多样性人免疫球蛋白基因的实验方法。方法 设计多对具有简并性特点的人IgG、IgM扩增引物，从人外周血单个核细胞(PBMCs)中提取RNA并反转录为cDNA，以其为模板聚合酶链反应(PCR)扩增人免疫球蛋白κ轻链基因和重链Fd段基因，对扩增产物进行凝胶电泳和DNA指纹分析鉴定。结果 利用不同引物进行的PCR反应均成功扩增出相应的免疫球蛋白基因，经鉴定所获得的基因产物具有良好的多样性，在天然抗角蛋白自身抗体研究和抗体库的构建中得到初步应用。结论 合理设计引物能够从PBMCs中成功扩增出多样性的人免疫球蛋白基因，为人抗体和相关免疫分子以及自身免疫性疾病的研究提供了方便条件．     

Ganglioside GD1b supresses immunoglobulin production by human peripheral blood mononuclear cells.

Gangliosides are sialic acid-containing glycolipids, that have various immunomodulatory effects. We previously reported that various gangliosides in vitro either inhibited or enhanced spontaneous immunoglobulin (Ig) production by human peripheral blood mononuclear cells (PBMC). GD1b was one of the inhibitory gangliosides. In this study, we further examined the mechanism for the inhibitory effect of GD1b. The inhibitory effect of GD1b was revealed at 0.1 microM, increased dose dependently, and was maximized at 10 microM, which reduced spontaneous IgG, IgM, and IgA production of human PBMC by 50.5%, 52.0%, and 48.3% compared with controls, respectively. GD1b did not affect the proliferation and viability of PBMC. GD1b did not alter Ig production of B cells alone. Interleukin 6 (IL-6) and IL-10 each partially reversed the GD1b-induced inhibition of Ig production by PBMC, and the addition of both cytokines completely reversed the inhibition. When endogenous IL-6 and IL-10 were neutralized by specific antibodies, GD1b did not reveal inhibitory effects on the Ig production. GD1b inhibited IL-6 and IL-10 production of CD4+ T cells, without affecting those of CD8+ T cells, monocytes, or B cells. When CD4+ T cells were preincubated with GD1b and washed and cultured with B cells and monocytes, Ig production was also suppressed. These results suggest that GD1b may indirectly suppress Ig production of B cells in whole PBMC by reducing IL-6 and IL-10 production of CD4+ T cells. GD1b may act as an important inhibitor of human humoral immune responses.     

Ganglioside GD1a enhances immunoglobulin production by human peripheral blood mononuclear cells

We previously reported that ganglioside GD1a greatly enhanced spontaneous immunoglobulin (Ig) production by human peripheral blood mononuclear cells (PBMC) in vitro. We herein examined the mechanism for the stimulatory effect of GD1a.PBMC from healthy volunteers were cultured with GD1a. The amounts of IgG, IgM, and IgA and cytokine activity in the culture supernatants were measured by enzyme-linked immunosorbent assays. Proliferation was determined by [3H] thymidine uptake.GD1a at 10(-6) M increased IgG, IgM, and IgA production by PBMC 2.10-fold, 2.10-fold, and 2.23-fold above the control values, respectively. GD1a did not affect the proliferation and viability of PBMC. GD1a did not alter Ig production of B cells alone. Anti-interleukin-6 (IL-6) or anti-IL-10 antibody each partially blocked the GD1a-induced enhancement of Ig production by PBMC, and the addition of both antibodies completely blocked the enhancement. GD1a increased IL-6 and IL-10 production of monocytes without altering those of T cells or B cells. The supernatant from GD1a-treated monocytes enhanced B cell Ig production to a greater extent than that from medium-treated monocytes. The supernatant-mediated effect of GD1a was partially blocked by anti-IL-6 or anti-IL-10 antibody, and the addition of both antibodies completely blocked the GD1a effect. GD1a-induced increases of IL-6 and IL-10 production in monocytes were both blocked by Ca(2)+/calmodulin (CaM)-dependent phosphodiesterase (PDE) inhibitors, 8-methoxymethyl-3-isobutyl-1-methylxanthine and vinpocetin, but not by other signal-transducing enzyme inhibitors. The culture with GD1a enhanced Ca(2)+/CaM-dependent PDE activity in monocytes.These results suggest that GD1a may indirectly enhance B cell Ig production in whole PBMC by increasing IL-6 and IL-10 production of monocytes via promoting Ca(2)+/CaM-dependent PDE activity.     

Distribution of integrins on human peripheral blood mononuclear cells

The receptors for fibronectin (FN-R) and vitronectin (VN-R) belong to a family of integral membrane glycoproteins known to be involved in cell- extracellular matrix and cell-cell interactions named integrins (FN-R = beta 1 integrin and VN-R = beta 3 integrin). Adhesion studies using FN- coated plastic dishes and highly purified subpopulations of peripheral blood mononuclear cells (PBMCs) showed a strong binding of monocytes and T lymphocytes to FN but virtually no binding of B cells to FN. Binding of monocytes and T cells to FN could be partially inhibited by a hexapeptide (GRGDSP) containing the adhesive peptide sequence Arg-Gly- Asp (RGD) as well as by an anti-FN-R antibody. The distribution of beta 1 and beta 3 integrin complexes on PBMCs was characterized by immunoprecipitation of detergent extracts of 125I-labeled cells using polyclonal antibodies against these two receptors. Two surface polypeptides corresponding to the alpha and beta chains of FN-R and VN- R were found on all three cell types. To characterize these receptors further, monoclonal antibodies (MoAbs) against the very late antigens (VLAs) 1, 3, and 5 were used for immunoprecipitation studies. Monocytes and T cells reacted with VLA 5 that was previously identified as the human FN receptor, whereas no labeling with anti-VLA 5 could be shown for B cells. When cell populations were cultured in 10% human serum for 24 hours, an increase in beta 1-integrin+ monocytes and T cells was observed. The number of beta 3-integrin+ cells remained essentially unchanged. The presence of beta 1 and beta 3 integrins on monocytes as well as on T and B lymphocytes may be of significance in the ability of these cells to interact with each other and participate in hematopoiesis and certain immune reactions.     

Surface phenotypes of human peripheral blood mononuclear cells from patients with gastrointestinal carcinoma

Summary Peripheral blood mononuclear cells (PBMC) from 40 patients with gastrointestinal carcinoma (GIC), 13 patients with primary carcinoma in other localizations(non-GIC), and from 57 apparently healthy donors were isolated by Ficoll-Paque gradient centrifugation. The separated cells were stained with several monoclonal antibodies and subjected to analysis on a fluorescence-activated cell sorter. A decreased percentage of PBMC expressing T cell antigens was noted amongst GIC patients, and was mainly due to a reduction of the Leu 2a subset, thus, leading to an increase in the Leu3a/Leu2a ratio from 1.4 to 2.1. Non-GIC patients had decreased numbers of both T helper and suppressor cells. Amongst PBMC from GIC and non-GIC patients a statistically increased percentage of cells expressed LeuM2 (P<0.001), LeuM3 (P<0.001), OKM 1 (P<0.005), VEP 9 (P<0.001), and HLA-DR (P<0.001) antigens compared to healthy controls. The percentage of cells bearing these monocyte/macrophage antigens correlated well with the number of cells having monocyte morphology, stained for non-specific esterase, phagocytosed latex particles, and expressed Fc IgG receptor. Our results demonstrate clearly that tumor-bearing patients have an incrased relative number of monocytes. The data suggest that cells of the macrophage lineage may be involved in defense mechanisms and changes of the immune system evoked by various tumors.This work was supported by Fonds österreichischer Krebsforschungsinstitute     

The antiproliferative effect of calcitriol on human peripheral blood mononuclear cells

Activation of lymphocytes leads to the expression of receptors for the calcitropic hormone calcitriol [1,25(OH)2D3], and calcitriol is a potent inhibitor of interleukin-2 (IL-2) and of lymphocyte proliferation. We used peripheral blood mononuclear cells (PBM) activated in vitro with phytohemagglutinin to study 1) the relationship between 1,25(OH)2D3 receptor expression, IL-2 production, and 1,25(OH)2D3-induced inhibition of PBM proliferation in connection with the cell cycle; 2) the effect of 1,25(OH)2D3 on PBM activation and on the expression of activation-related molecules including the IL-2 receptor, and 3) the role of calcium in the antiproliferative effect of the hormone. 1,25(OH)2D3 receptor expression occurred when PBM entered the G1a phase of the cell cycle. The concentration of the receptor protein reached a peak at G1b and declined during the S phase. 1,25(OH)2D3 inhibited cell proliferation by blocking PBM at the G1a-G1b border. The antiproliferative effect of calcitriol was not caused by hormonal interference with the calcium-dependent activation process nor with the expression of activation-related molecules including the IL-2 receptor. Moreover, this effect was not influenced by extracellular calcium, suggesting that the hormonal action cannot be due to calcium translocation. These findings support the contention that 1,25(OH)2D3-induced inhibition of PBM proliferation is mediated through selective inhibition of IL-2 production.     

Decreased density of beta-adrenergic receptors on peripheral blood mononuclear cells in patients with rheumatoid arthritis.

There is growing evidence that the autonomic nervous system influences the immune response by activation and modulation of beta 2-adrenergic receptors (beta 2R) on immunocompetent cells. However, little is known about its pathogenetic role in autoimmune disease. Therefore, the number and the dissociation constants (beta 2R-KKD) of beta 2R on peripheral blood mononuclear cells (PBMNC) were determined in 21 patients with rheumatoid arthritis (RA) and 9 healthy age and sex matched controls [healthy donors (HD)] by a radioligand binding assay with [125I]iodocyanopindolol. The density of beta 2R (x +/- SEM = 2,120 +/- 103 binding sites/cell) and the beta 2R-KD (x +/- SEM = 6.8 +/- 0.8 pM) were significantly decreased in patients with RA compared to HD (number of beta 2R: 3,960 +/- 372, beta 2R-KD: 16.7 +/- 3.6, p less than 0.01). In RA, the number of beta 2R was significantly lower in patients with high systemic disease activity (n = 11, number of beta 2R: 1,850 +/- 134) than in patients with low inflammatory activity (n = 10, number of beta 2R: 2,418 +/- 95, p less than 0.004). In addition, there were significant negative correlations between the beta 2R density and an arbitrary systemic activity score (r = -0.74, p less than 0.001), the Ritchie index (r = 0.77, p less than 0.001), and various variables of disease activity (r = 0.59 to -0.78, p less than 0.005), respectively. Our data demonstrate the close interplay between the systemic inflammatory activity and the beta 2R characteristics in patients with RA. Our results provide further evidence that the immune response may be influenced by the sympathetic nervous system.     

Intracellular metabolism of 3'-azidothymidine in isolated human peripheral blood mononuclear cells.

Azidothymidine (AZT) inhibits the replication of human immunodeficiency virus and it is the only drug so far licensed for treatment of acquired immunodeficiency syndrome (AIDS). A prerequisite for its antiviral activity is phosphorylation by cellular nucleoside kinases to the mono-, di-, and triphosphate levels. This study determined the capacity of isolated peripheral blood mononuclear cells (PBMC), resting or mitogen stimulated, from 36 different people of whom 5 were HIV+, to phosphorylate and accumulate intracellular AZT nucleotides. We found a large variation in the amount of products formed between PBMC treated at different times from the same individual as well as between the PBMC from different individuals. Resting PBMC showed the largest interindividual variation and their levels of AZT nucleotides were about 60-150-fold lower than in activated PBMC. The intracellular half lives of azidothymidine mono-, di-, and triphosphates, constituting, on the average, 96-99.2, 0.7-1.8, and 0.4-2.7% of total nucleotides at 0.08-1.6 microM AZT, respectively, were also determined. In mitogen-stimulated PBMC it was approximately 2.5 +/- 0.6 h for all the azidothymidine metabolites. The half-life for intracellular azidothymidine monophosphate in resting PBMC from two individuals was determined to 1.5 +/- 0.2 h. There appeared to be no significant difference in the AZT metabolism in PBMC from HIV-positive or-negative persons. A relative decrease in the intracellular formation of AZTDP and AZTTP from AZTMP was observed at concentrations of AZTMP above 1 microM. This fact may explain why lowering the doses of AZT still gives therapeutically efficient levels of the active metabolite AZTTP.     

Expression of type I insulin-like growth factor receptors on human peripheral blood mononuclear cells.

Insulin-like growth factor-I and -II (IGF-I and IGF-II), both of which bind to type I IGF receptors, can modulate certain functions of the immune system. We, therefore, studied the expression of type I IGF receptors on purified subpopulations of peripheral blood mononuclear cells. Using two-color flow cytometry, specific binding of a monoclonal antibody directed against the type I IGF receptor (alpha IR3) was found in every subpopulation. Relatively high numbers of receptors were detected on monocytes, natural killer cells, and CD4+ T-helper cells, an intermediate number of receptors on CD8+ suppressor/cytotoxic T-cells, and a relatively low number of receptors on B-cells. The presence of these receptors was confirmed by specific binding of [125I] IGF-I to purified subpopulations. alpha IR3 inhibited the binding of [125I] IGF-I. The specific binding of [125I]IGF-I to monocytes could be completely inhibited by IGF-II and insulin, but higher doses of these peptides were needed than of IGF-I. Scatchard analysis revealed the presence of 734 +/- 426 receptors/monocyte, with a Kd of 0.23 +/- 0.05 nM. A lower number of receptors (230 +/- 52), but with a higher affinity (Kd = 0.05 +/- 0.02 nM), was found on purified T-cells. The positive effect of IGF-I on natural killer cell cytotoxicity indicates that the type I IGF receptors on this cell type are functional. The possibility that IGF-I mediates hormonal effects on the immune system is discussed.     

Proliferation of human peripheral blood mononuclear cells during calcium channel blockade

To evaluate the role of intracellular calcium and particularly Ca²⁺ uptake in the initiation of lymphocyte mitogenesis, the effect of mibefradil—which blocks both L- and T-type calcium channels with a more selective blockade of T-type channels—on the proliferation of human peripheral blood mononuclear cells (PBMC) is compared with the effect of nifedipine, which blocks only the L-type calcium channel. The rate of ³H-thymidine, ³H-uridine, and ³H-leucine incorporation into control and concanavalin A-stimulated PBMC in the presence or absence of the calcium channel blockers mibefradil or nifedipine (1, 10, or 50 μmol/L), and of the intracellular calcium antagonist TMB-8 or the calmodulin antagonist W-7 (1, 10, 25, or 50 μmol/L) was assayed in cells cultured for 3 days. The cellular cytotoxicity and the cell number in growing cultures was also determined in mibefradil- or nifedipine-treated control or stimulated cells. Mibefradil and nifedipine reduced the cell number and the ³H-thymidine, ³H-uridine, or ³H-leucine incorporation or the de novo DNA, RNA, or protein synthesis in control and concanavalin A-stimulated human PBMC in a concentration-dependent manner. Mibefradil exhibited a more pronounced inhibition than nifedipine. The inhibitory effect of mibefradil or nifedipine on DNA synthesis was dependent upon the timing of treatment with the drugs. The inhibitory effect of mibefradil or nifedipine on the lymphoproliferative response was nearly abolished if the drugs were added 20 h after cell stimulation. A markedly reduced inhibitory effect was found when mibefradil or nifedipine were added 1 to 7 h after cell stimulation. However, regardless of time of addition, TMB-8 and W-7 caused a persistent inhibition of the proliferation of human PBMC. Our data show that mibefradil had a more pronounced inhibitory effect on the proliferation of human PBMC than nifedipine and that this inhibitory effect on de novo DNA synthesis was dependent upon the timing of treatment with both drugs. Mibefradil and nifedipine also reduce RNA and protein synthesis in human PBMC.

Therefore, administration of these calcium channel blockers to inhibit cellular proliferation might be most beneficial at anatomic sites where cellular proliferation is not already an active process, while being ineffective in the presence of ongoing active proliferation, as suggested by some prospective studies.     

Binding of toxic-shock-syndrome toxin-1 to human peripheral blood mononuclear cells

Toxic-shock-syndrome toxin-1 (TSST-1), produced by Staphylococcus aureus and associated with toxic shock syndrome, functions in vitro as both a lymphoproliferative and immunosuppressive protein for human peripheral blood mononuclear cells (PBMs). We analyzed TSST-1-target cell interactions by receptor-ligand binding analyses. In competitive binding experiments, 2 X 10(5) human PBMs or purified cell populations were incubated in the presence of small amounts of (5-50 ng) of 125I-labeled TSST-1 and increasing amounts of unlabeled TSST-1 (25-10,000 ng). Data were analyzed by the method of Scatchard. Toxin-specific receptors were shown to exist on T lymphocytes within the PBM population. T4+ cells had 27.5 X 10(6) receptors per cell, and T8+ cells had 9 X 10(6) receptors per cell. T4+ and T8+ receptors had dissociation constants of 2.58 X 10(-8) M and 1.8 X 10(-8) M, respectively. These studies confirm earlier work showing that TSST-1 causes the functional activation of a population of T lymphocytes involved in suppression of immunoglobulin responses.     

Age dependent impact of LMP polymorphisms on TNFalpha-induced apoptosis in human peripheral blood mononuclear cells.

As a consequence of inflammatory stimuli (such as TNFalpha and IFNgamma), some constitutive subunits of the proteasome, the principal mediator of nonlysosomal protein degradation, are replaced with other subunits, the large multifunctional proteases LMP2 and LMP7, thus originating the immunoproteasome. An age-related alteration of proteasome activity and susceptibility to TNFalpha-induced apoptosis, in which LMP2 and the nuclear factor (NF)-kappaB activation play an important role has been recently reported. In this paper, we investigated the possible influence of two LMP2 and LMP7 polymorphisms on susceptibility to TNFalpha-induced apoptosis. Our data show that an increase in susceptibility to TNFalpha-induced apoptosis is evident in long-lived people (aged >88 years) in comparison to young individuals. Moreover, the modulation of LMP2 codon 60 polymorphism on TNFalpha-induced apoptosis is evident in long-lived subjects. Genotyping of 311 young people and 157 nonagenarians and centenarians revealed no changes in LMP2 codon 60 genotype frequency distribution. No correlation with TNFalpha-induced apoptosis and no difference in frequency between young people and nonagenarians/centenarians was observed when the LMP7 nucleotide 145 polymorphism was studied.     

HLA-DP-unrestricted TNF-alpha release in beryllium-stimulated peripheral blood mononuclear cells.

Berylliosis is a granulomatous disorder of the lung caused by inhalation of beryllium (Be) and dominated by the accumulation of CD4+ T-helper (Th)1 memory T-cells proliferating in response to Be in the lower respiratory tract. Two gene markers have been associated with susceptibility to berylliosis: 1) the human leucocyte antigen (HLA)-DP gene whose allelic variants, carrying glutamate in position 69 of the beta-chain (HLA-DPGlu69), can bind Be directly and present it to interferon (IFN)-gamma releasing Th1 T-cell clones from patients with berylliosis; and 2) the cytokine gene tumour necrosis factor (TNF)-alpha which has been shown to increase berylliosis risk independent of HLA-DPGlu69. In order to determine whether TNF-alpha release was triggered by Th1 T-cell activation by Be stimulation in the context of HLA-DPGlu69 molecules, the proliferation of BeSO4-stimulated blood mononuclear cells and the release of IFN-gamma, TNF-alpha, RANTES (regulated on activation normal T-cell expressed and secreted), granulocyte-macrophage colony-stimulating factor, interleukin (IL)-4, IL-6, IL-8, IL-10 and IL-12 by BeSO4-stimulated blood mononuclear cells was quantified in 11 individuals with berylliosis using an anti-HLA-DP antibody as a probe for HLA-DP restricted T-cell activation. While proliferation and IFN-gamma release were completely abrogated by HLA-DP inhibition (inhibition with anti-HLA-DP monoclonal antibody (mAb): 88+/-16 and 77+/-16%, respectively; anti-HLA-DR: 29+/-38 and 14+/-10%, respectively), the release of TNF-alpha was not (inhibition with anti-HLA-DP mAb: 8.9+/-7.8%). No other cytokine was detected at significant levels. Moreover, Be was able to induce TNF-alpha production in healthy control subjects not exposed to Be in the absence of T-cell proliferation and IFN-gamma production. In conclusion, these data suggest that the tumour necrosis factor-alpha response of mononuclear cells is independent of the activation of beryllium-specific human leucocyte anitgen-DP restricted T-cells, which is consistent with the finding that the tumour necrosis factorA2 and the human leucocyte anitgen-DPGlu69 genetic markers are independently interacting in increasing berylliosis risk.     

Antiproliferative effects of methotrexate on peripheral blood mononuclear cells

Methotrexate was added to cultured mononuclear cells from the peripheral blood of normal individuals and patients with rheumatoid arthritis (RA) to study the drug's effects on mononuclear cell proliferation and antibody synthesis. In the presence of methotrexate, marked antiproliferative effects (to levels less than 15% of baseline) were seen with 3H-deoxyuridine, but not with 3H-thymidine, as the marker of cell division. This difference was not due to altered kinetics of proliferation or the presence of salvage nucleotides in the culture medium. The absence of suppression of antibody production preactivated by pokeweed mitogen in vitro and the low levels of suppression of spontaneous IgM rheumatoid factor production by blood mononuclear cells from RA patients suggested a relative resistance of activated cells to the effects of methotrexate. The effects of methotrexate on both cell proliferation and antibody synthesis were completely reversed by the addition of high concentrations of exogenous folinic acid. The results suggest that methotrexate has effects on immunocompetent cells that may contribute to the efficacy of this drug in the treatment of RA and other autoimmune diseases.     

Sex steroid metabolism in human peripheral blood mononuclear cells changes with aging

CONTEXT: Dehydroepiandrosterone (DHEA) mainly exerts indirect action via downstream conversion toward sex steroids within peripheral target cells including immune cells. In vitro DHEA has been shown to enhance IL-2 release from T lymphocytes, whereas it inhibits IL-6 secretion. Conversely, aging is associated with a decline in both DHEA and IL-2, whereas IL-6 increases. OBJECTIVE: The objective of the study was to investigate age-related differences in expression and functional activity of steroidogenic enzymes involved in downstream conversion of DHEA in peripheral blood mononuclear cells (PBMCs). DESIGN: This study was cross-sectional. PARTICIPANTS/SETTING: Healthy young men (n = 8; age range, 23-29 yr) and healthy middle-aged men (n = 8; age range, 52-66 yr) were studied in an academic setting. MEASURES: mRNA expression of steroidogenic enzymes in PBMCs was measured by qualitative and quantitative RT-PCR analysis and enzyme activity assays after incubation of PBMCs with radiolabeled DHEA, 4-androstene-3,17-dione (androstenedione), and testosterone. RESULTS: RT-PCR analysis showed expression of all enzymes required for DHEA conversion toward active androgens and to the immune-stimulatory metabolite androstenediol. Steroid conversion patterns indicated a particularly increased activity of 17beta-hydroxysteroid dehydrogenase type 5 (17beta-HSD5) in the older men, demonstrated by significantly higher conversion rates of DHEA to androstenediol and of androstenedione to testosterone (all P < 0.05). By contrast, conversion of DHEA to androstenedione via 3beta-HSD occurred at a similar rate. Quantitative RT-PCR analysis revealed increased expression of 17beta-HSD 5 mRNA in PBMCs from the older men. CONCLUSIONS: Our results provide evidence for significant changes in sex steroid metabolism by human PBMCs with aging, which may represent an endocrine link to immune senescence.     

Monoglycerides induce apoptosis in human leukemic cells while sparing normal peripheral blood mononuclear cells

A major drawback of the current antineoplastic treatments is their lack of specificity toward cancer cells, because they are most often cytotoxic to normal cells, thus creating related side effects. Hence, the identification of new apoptosis-inducing agents, specifically targeting malignant cells while sparing their normal counterparts, is of crucial interest. We show here that monoglycerides, a family of lipids consisting of a single fatty acid attached to a glycerol backbone, induce cell death in several human leukemic cell lines. Importantly, treatment of primary leukemic cells, obtained from B-cell chronic lymphocytic leukemia patients, resulted in rapid apoptosis. In striking contrast, resting or activated human peripheral blood mononuclear cells from healthy individuals were resistant to the same treatment. Therefore, these compounds could represent potential antileukemic drugs or could allow for the design of novel therapeutic agents applied to leukemia.     

Effect of interferon-α on immunoglobulin production by peripheral blood mononuclear cells in multiple myeloma

Abstract: To test a hypothesis that interferon-α (IFN) treatment might restore normal immunoglobulin (Ig) production in multiple myeloma (MM), the effect of IFN on Ig isotype (IgG and IgA) production by peripheral blood (PB) and bone marrow (BM) mononuclear cells (MNCs) in MM patients was analyzed by ELISA. IFN at a concentration of 1000 U/ml was found to enhance IgA production by PB MNCs in IgA-MM and had a trend to stimulate IgG production in IgG-MM. The effect of IFN on nonparaprotein Ig isotype production was more variable, with mostly neutral or inhibitory effects being seen in both the MM subtypes. In contrast to the influences observed in MM patients, IFN at the same concentration inhibited both IgG and IgA production by PB MNCs in healthy controls. In studying BM cells, IFN was found to reduce IgA production in IgA-MM, but had a neutral effect on IgG production in IgG-MM. In the controls, the production of both the IgG and the IgA isotypes by BM MNCs was decreased by IFN. On the basis of these results it seems that the disease itself somehow affects the Ig-producing cells in MM, when measured as different responses of the cells to exogenous IFN in vitro. The results do not support the hypothesis that IFN treatment could restore normal Ig production in MM patients.     

Infection of peripheral mononuclear blood cells by hepatitis C virus.

We investigated the infection of peripheral blood mononuclear cells (PBMNC) by hepatitis C virus (HCV) in 5 patients with HCV-related chronic hepatitis. The presence of HCV-RNA-positive and -negative strands was tested with the polymerase chain reaction (PCR) method. In all subjects, HCV-RNA was shown in PBMNC. In 3 cases, HCV-RNA was shown in the T- and B-cell populations, with viral RNA also present in the monocyte-macrophage fraction of two of these. HCV-RNA-negative stranded molecules, indicative of the viral multiplication, were significantly increased in cells maintained in cultures with PHA/PMA stimulation. The results indicate that HCV infect blood mononuclear cells, thus suggesting that this cellular tropism may play a role in HCV infection.