Abnormalities in the proportions of various T lymphocyte subpopulations have been found in a number of autoimmune diseases. Monoclonal antibodies labelled with various fluorochromes were used here to define the percentages of subsets, and especially to divide CD4+ (helper/inducer) and CD8+ (suppressor/cytotoxic) cells into phenotypic subgroups. Blood samples were analysed from 25 patients (age 10.1 +/- 3.7 years) with recently diagnosed insulin-dependent diabetes mellitus (IDDM) and 25 age- and sex-matched control subjects. The percentages of CD4+ cells and CD4+CD45RA+ cells described as naive T helper cells or suppressor/inducers were increased in the IDDM patients (P less than 0.05 and P less than 0.05. Student's t-test, respectively), whereas the percentage of CD4+CD45RA- cells (memory T-helper cells, helper/inducers) was similar in the patients and controls. The percentage of CD8+CD11b+ cells containing suppressor/effector lymphocytes was decreased in the IDDM patients as compared with the controls (P less than 0.01) but no significant difference was seen in total CD8+ cells. The percentages of CD3+ cells and the proportions of these simultaneously positive for HLA-DR antigen (activated T cells) were also increased in the recent IDDM patients (P less than 0.001 and P less than 0.05, respectively), while the proportion of CD20+ B cells was decreased (P less than 0.05). The findings support the view that disturbed immune regulation occurs in IDDM and indicate that further division of T cell subpopulations may clarify our understanding of the disease process.
Although treatment of multiple sclerosis (MS) with the type I interferon (IFN) IFN-ß lowers disease activity, the role of endogenous type I IFN in MS remains controversial. We studied CD4+ T cells and CD4+ T cell subsets, monocytes and dendritic cells by flow cytometry and analysed the relationship with endogenous type I IFN-like activity, the effect of IFN-ß therapy, and clinical and magnetic resonance imaging (MRI) disease activity in MS patients. Endogenous type I IFN activity was associated with decreased expression of the integrin subunit CD49d (VLA-4) on CD4+CD26(high) T cells (Th1 helper cells), and this effect was associated with less MRI disease activity. IFN-ß therapy reduced CD49d expression on CD4+CD26(high) T cells, and the percentage of CD4+CD26(high) T cells that were CD49d(high) correlated with clinical and MRI disease activity in patients treated with IFN-ß. Treatment with IFN-ß also increased the percentage of CD4+ T cells expressing CD71 and HLA-DR (activated T cells), and this was associated with an increased risk of clinical disease activity. In contrast, induction of CD71 and HLA-DR was not observed in untreated MS patients with evidence of endogenous type IFN I activity. In conclusion, the effects of IFN-ß treatment and endogenous type I IFN activity on VLA-4 expression are similar and associated with control of disease activity. However, immune-activating effects of treatment with IFN-ß may counteract the beneficial effects of treatment and cause an insufficient response to therapy.
Previously, we reported a new animal model of an idiosyncratic drug reaction in which nevirapine causes a skin rash in some rats that has characteristics similar to the reaction that occurs in humans. Strong evidence that the reaction is immune-mediated was found; specifically, low-dose pretreatment induced tolerance, while with rechallenge, the time to onset decreased and the severity increased. Furthermore, splenocytes from rechallenged rats transferred rash susceptibility to na?ve recipients. We now report the results of studies to explore the immune aspects of this reaction. T cells were found to play an important role, as demonstrated by their ability to adoptively transfer susceptibility to the skin reaction. Of these T cells, CD4+ cells are the likely effectors because they were capable of transferring susceptibility and the reaction was delayed in rats partially depleted of CD4+ T cells. In contrast, it appears that CD8+ T cells are not essential, as CD8+ T cells were unable to transfer sensitivity to a na?ve animal and rats depleted of CD8+ T cells still developed skin rash. Unlike the penicillamine model, where we have demonstrated that the tolerance induced by low-dose treatment is immune-mediated, tolerance induced by low-dose nevirapine appears to be largely due to induction of metabolism as it can be overcome by inhibition of cytochrome P450. Pretreatment with the immunosuppressants, cyclosporine and tacrolimus, prevented the rash and even led to resolution of the rash during nevirapine treatment. These studies reinforce the hypothesis that the reaction in this model is similar to that which occurs in humans. In particular, the finding that CD4+ T cells may play a central role in this model fits with the observation that the incidence of idiosyncratic reactions to nevirapine in humans appears to be lower in patients with low CD4+ counts.
OBJECTIVE: To analyze the relationship between lymphocyte subsets, different rheumatoid factor (RF) isotypes, and clinical features in patients with rheumatoid arthritis (RA). METHODS: Patients with established RA (n = 95) were examined clinically and blood samples were collected for measurements of RF by ELISA and for analysis of lymphocyte subsets by flow cytometry. RESULTS: IgA RF positive patients had more severe disease and higher prevalence of extraarticular manifestations than the other patients. Patients with elevated IgA RF had a higher percentage of CD5+ B cells and of CD4+CD45RO+ T cells compared to the other patients with RA or controls. High percentage of CD4+CD45RO+ T cells was also significantly associated with extraarticular manifestations. Patients with the sicca syndrome had significantly higher ratio of CD5+ B cells than patients without or with other types of extraarticular manifestations. CONCLUSION: Different disease manifestations in RA may be associated not only with certain RF isotypes and RF isotype combinations but also with changes in lymphocyte subsets in the blood. The relative increase of CD4+CD45RO+ T cells in the blood of IgA RF positive patients with RA might reflect preferential recruitment of CD8+CD45RO+ T cells to inflammatory sites.
Earlier we identified an Immune Risk Profile (IRP) of very old individuals, 86-94 years of age, characterised by an inverted CD4/CD8 ratio and associated with persistent cytomegalovirus infection and an increase in the numbers of CD3+CD8+CD28- cells. In the present study we included data from a population-based sample in the age range of 20-79 years to examine the prevalence of individuals with an inverted CD4/CD8 ratio relative to age and gender across the entire adult lifespan. Immunological monitoring that was conducted included analysis of the numbers of T-cells in the subsets CD3+, CD3+CD4+, and CD3+CD8+ as well as CD3+CD8+CD28+, CD3+CD8+CD28-, and CD8+CD45RA+CCR7+. There was found to be a significant lowering of the numbers of CD3+, CD3+CD4+, and CD3+CD8+, and of the CD8+CD45RA+CCR7+ cells across the adult life-span. Notably, the prevalence of individuals with an inverted CD4/CD8 ratio increased from about 8% in the age range of 20-59 years to about 16% in the age range of 60-94 years. The mortality rate in individuals with an inverted CD4/CD8 ratio also increased significantly above the age of 60. Interestingly, the proportion of individuals with an inverted CD4/CD8 ratio was found to be significantly higher in men, whereas the numbers of CD3+CD4+ helper and CD8+CD45RA+CCR7+ naÃ¯ve cells and the CD4/CD8 ratio were found to be significantly higher in women. These results highlight the importance of functioning of the thymus in the development of IRP and may partly account for the differences between sexes in terms of longevity.
Dysregulation of the immune system has been shown to occur during spaceflight, although the detailed nature of the phenomenon and the clinical risks for exploration class missions have yet to be established. Also, the growing clinical significance of immune system evaluation combined with epidemic infectious disease rates in third world countries provides a strong rationale for the development of field-compatible clinical immunology techniques and equipment. In July 2002 NASA performed a comprehensive immune assessment on field team members participating in the Haughton-Mars Project (HMP) on Devon Island in the high Canadian Arctic. The purpose of the study was to evaluate the effect of mission-associated stressors on the human immune system. To perform the study, the development of techniques for processing immune samples in remote field locations was required. Ten HMP-2002 participants volunteered for the study. A field protocol was developed at NASA-JSC for performing sample collection, blood staining/processing for immunophenotype analysis, whole-blood mitogenic culture for functional assessments and cell-sample preservation on-location at Devon Island. Specific assays included peripheral leukocyte distribution; constitutively activated T cells, intracellular cytokine profiles, plasma cortisol and EBV viral antibody levels. Study timepoints were 30 days prior to mission start, mid-mission and 60 days after mission completion.
The protocol developed for immune sample processing in remote field locations functioned properly. Samples were processed on Devon Island, and stabilized for subsequent analysis at the Johnson Space Center in Houston. The data indicated that some phenotype, immune function and stress hormone changes occurred in the HMP field participants that were largely distinct from pre-mission baseline and post-mission recovery data. These immune changes appear similar to those observed in astronauts following spaceflight.
The immune system changes described during the HMP field deployment validate the use of the HMP as a ground-based spaceflight/planetary exploration analog for some aspects of human physiology. The sample processing protocol developed for this study may have applications for immune studies in remote terrestrial field locations. Elements of this protocol could possibly be adapted for future in-flight immunology studies conducted during space missions.
To investigate the inflammatory and immunological aspects of severe acne, we examined the luminol-enhanced chemiluminescence of whole blood, T-cell subsets and natural killer cell functions in 11 patients with severe nodular acne and 4 patients with acne fulminans. In patients with severe nodular acne, the active phase of the disease, compared to the values in remission (means 47 mV, SD 24.8 and 32 mV, SD 8.3, p
We have previously analysed the T-cell receptor (TCR) V-gene usage in peripheral blood T lymphocytes from a group of healthy Scandinavians, and described a biased representation (i.e. a statistically significant higher median representation) for some of the TCR V genes towards the CD4+ subpopulation. In a subsequent study the usage of the same V genes was analysed in single positive (CD4+ CD8- and CD4- CD8+) human thymocytes, and a similar type of skewness was noted. These observations might be explained by an influence of the specificity of the TCR of thymocytes on the maturation into the CD4+ or the CD8+ lineage. Such a model would assume an interaction between a common determinant on the major histocompatibility complex (MHC) class I or class II molecules, or with a peptide that is preferentially presented by either of the two molecules, and the TCR on the maturing thymocyte. To investigate the possible influence of a different genetic background and environment on skewed TCR V-gene representation, we have in this study analysed the TCR V-gene usage in peripheral blood and umbilical cord blood lymphocytes obtained from Asians, with a different ethnic and environmental background from our previous Scandinavian subjects. In the umbilical cord blood lymphocytes the TCR V-gene usage was close to identical between the two different ethnic groups in both CD4+ and CD8+ subpopulations. Analysing the peripheral blood lymphocyte (PBL) TCR V-gene usage, we found that three of the four monoclonal antibodies (MoAb) with a biased reactivity towards the CD4+ subpopulation in the Scandinavian group also showed a similar skewed reactivity in this study. Thus, the majority of the TCR V genes were used in a similar way. Some minor but definite discrepancies could be detected when comparing TCR V-gene usage in adult individuals from these two different ethnic groups. These differences could be inferred to be due to selective peripheral expansion through environmental pressure of T cells utilizing a specific V beta gene segment. We conclude that a striking preservation of biased TCR V-gene usage does exist in humans of distinctly different ethnic origin.
Ricin, a toxic lectin from castor beans greatly enhances IgE responses to bee venom phospholipase A2 (PLA2) in high and low IgE responder strains of rat. The increase in IgE is accompanied by a 60% reduction in the number of CD8+ but not CD4+ T cells in the spleen. Optimal enhancement of IgE by ricin occurs when it is given at the same time as the antigen or 24 hr later, suggesting that it acts on cells which were activated as a consequence of immunization. Radio ligand-binding studies with 125I ricin were used to compare the number of ricin binding sites on CD4+ and CD8+ T cells. No difference was seen in either the affinity or the number of receptors for ricin on the CD4+ and CD8+ T cells of unimmunized rats. In contrast, CD8+ T cells taken from rats which had been immunized with 10 micrograms of PLA2 24 hr earlier demonstrated considerably more ricin receptors (3.9 x 10(7) +/- 2.2 x 10(6) binding sites/cell) than CD4+ T cells (3.19 x 10(6) +/- 1.08 x 10(6) binding sites/cell). However the affinity of the receptors for ricin was unchanged. Cytofluorographic analysis with fluorescein isothiocyanate (FITC)-labelled ricin confirmed these observations and indicated that increased ricin binding occurred on a subpopulation of CD8+ T cells. The effect of CD8+ T cells on IgE regulation was investigated by adoptive transfer. 1 x 10(8) highly purified (> 98%) splenic CD8+ T cells collected from Brown Norway rats 3 days after immunization with 10 micrograms of PLA2 were adoptively transferred to naive, syngeneic recipients. The IgE antibody response to PLA2 + A1(OH)3 seen in these animals was reduced by 91%. Adoptive transfer of CD4+ T cells from the same donor animals did not induce suppression and nor did adoptive transfer of CD8+ T cells from animals given both ricin and PLA2. However, when recipients of CD8+ T cells taken from rats immunized with PLA2 were immunized with a different antigen [ovalbumin (OVA)] and A1(OH)3 the IgE antibody response was also suppressed, although to a lesser extent (66%). These results show that co-administration of ricin and PLA2 depletes a subpopulation of ricin-sensitive, early activated CD8+ T cells and that these CD8+ T cells are potent suppressors of the primary IgE response.
Activated CD4+ helper T cells have been demonstrated in asthmatic airways and postulated to play a central role in eliciting allergic inflammation; direct evidence of their involvement seems to be lacking. We hypothesized that CD4+ T cells have the potential to induce allergic responses to antigen challenge, and tested this hypothesis in a model of allergic bronchoconstriction, the Brown Norway rat, using the approach of adoptive transfer. Animals were actively sensitized to either ovalbumin (OVA) or BSA and were used as donors of T cells. W3/25(CD4)+ or OX8(CD8)+ T cells were isolated from the cervical lymph nodes of sensitized donors and transferred to naive BN rats. 2 d after adoptive transfer recipient rats were challenged by OVA inhalation, and changes in lung resistance (RL), bronchoalveolar lavage (BAL) cells, and serum levels of antigen-specific IgE were studied. After OVA challenge recipients of OVA-primed W3/25+ T cells exhibited sustained increases in RL throughout the entire 8-h observation period and had significant bronchoalveolar lavage eosinophilia, which was detected by immunocytochemistry using an antimajor basic protein mAb. Recipients of BSA-primed W3/25+ T cells or OVA-primed OX8+ T cells failed to respond to inhaled OVA. OVA-specific immunoglobulin E was undetectable by ELISA or skin testing in any of the recipient rats after adoptive transfer. In conclusion, antigen-induced airway bronchoconstriction and eosinophilia were successfully transferred by antigen-specific W3/25+ T cells in Brown Norway rats. These responses were dependent on antigen-primed W3/25+ T cells and appeared to be independent of IgE-mediated mast cell activation. This study provides clear evidence for T cell mediated immune mechanisms in allergic airway responses in this experimental model.