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Anti-CD2-induced T cell proliferation was analyzed in the peripheral blood samples of 31 primary and 8 secondary untreated Sjögren's syndrome patients. Anti-CD2-stimulated PBMC proliferation was very low in about one-third of primary Sjögren's syndrome samples, despite the number of CD2+ cells being similar in primary and secondary Sjögren's syndrome and normal PBMC samples. The depressed response to anti-CD2 was mainly found in anti-Ro+/La+ patients. Experiments on purified T cells demonstrated that a defect at the T cell level was responsible for the anti-CD2 unresponsiveness. Cell proliferation failure was associated with poor IL-2 and IL-2 receptor mRNA expression and, consequently, IL-2 and IL-2 receptor synthesis. Since defective anti-CD2-induced mitogenesis could be reversed by phorbol myristate acetate, but not calcium ionophore A23187, it is probably correlated with impaired protein kinase C activation. Comparison of anti-CD2-triggered PBMC proliferation in treated and untreated patients and a long-term study of nine patients showed that the defect is a stable characteristic in primary Sjögren's syndrome patients, but that it can be reversed by pharmacological immunosuppression.

Despite the fact that the percentage of circulating CD3-positive cells is similar in cord and adult blood, the proliferative response induced by anti-CD3 monoclonal antibody (mAb) was impaired in the majority of human cord peripheral blood mononuclear cell (PBMC) samples we tested. The cell proliferative defect was associated with low interleukin 2 (IL 2) gene expression and scant IL 2 production. However, interleukin 2 receptor was fully expressed at both the mRNA and protein levels. Such a finding is consistent with the observation that exogenous recombinant IL 2 is able to boost the anti-CD3-mediated response of cord PBMC. Furthermore, when anti-CD3 and phorbol myristate acetate (PMA) were added together, they exerted a very marked synergistic effect on both the proliferation of, and IL 2 production by, cord PBMC. The addition of allogeneic antigen presenting cells plus soluble anti-CD3 or Sepharose-coupled anti-CD3 mAb to the cord T cell cultures had no significant effect on proliferation, whereas both elicited good mitogenesis of adult T cells. Moreover, addition of exogenous recombinant interleukin 1 to anti-CD3-stimulated T cells failed to trigger any proliferation in either adult or cord samples. Since the combination of PMA and calcium ionophore A23187 is effective in triggering optimal proliferation of cord T cells, the defect would seem to be associated with a failure in transmembrane transduction of the activation signals provided by the anti-CD3 stimulus for the cord T cell.

Alcoholic liver disease (ALD) patients had normal absolute lymphocyte counts, increased percentage of Leu3+/T4+ cells (p less than 0.001) and raised T4/T8 ratio (p less than 0.01). Double-colour immunofluorescence analysis using isotype-specific goat anti-mouse immunoglobulins, fluorescein or rhodamine-conjugated, demonstrated that the rise in inducer (Leu3+/T4+) T-cells was almost entirely represented by an expanded population of T4+TQ1- and 5/9+ true helper lymphocytes. T4+ cells also expressed IL2 receptors, as detected by the anti-Tac monoclonal antibody (range 1-18%). On the other hand, the percentage of Leu3+/T4+ cells which bind the K562 cell-line or co-express NK markers on their surface, such as Leu7 (HNK-1), was within the normal range in the majority of ALD patients. Functional studies on patients' cultured total or B-enriched lymphocytes in a pokeweed-mitogen-driven B-cell differentiation assay showed an enhanced plasma cell generation even in unstimulated cultures. Co-culture experiments with normal enriched-B lymphocytes demonstrated that both irradiated and non-irradiated patient T cells led to an increased plasma cell generation. These findings indicate that helper T cells and B cells are all simultaneously activated in vivo, and that the suppressor T lymphocyte function is normal in ALD.

Lactic dehydrogenase (LDH) was quantitated and the isozyme pattern studied in lymphocyte subpopulations from normal people and patients with chronic lymphocytic leukemia (CLL). Normal T lymphocytes differed from normal B lymphocytes in having greater total LDH activity (597.2 versus 252.1). Total LDH activity in CLL T cells (347.1) was lower than normal T cells., but not significantly different than normal B cells. Total LDH activity in CLL B cells (124.6) was lower then normal B cells and normal T cells. The isozyme pattern of normal T lymphocytes showed a higher activity in the LDH-1 band (26.7% versus 5.4%) but showed a lower activity in LDH-5 band (4.3% versus 16.3%) compared to normal B cells. Chronic lymphocytic leukemia T cells could be distinguished from CLL B cells by a high LDH-5 band (22.3% versus 7.6%) and from normal T cells by a high LDH-5 band (22.3% versus 4.3%) and a low LDH-1 band (7.3% versus 26.7%). CLL B cells could be distinguished from normal B cells by a low LDH-5 band (7.6% versus 16.3%). Thus, the LDH isozyme pattern distinguishes normal T lymphocytes from normal B lymphocytes, and normal T and B lymphocytes from CLL T and B lymphocytes.

Leukemic cells from a patient with an 11-yr history of chronic lymphocytic leukemia (CLL) were found to have the surface phenotype Leu-1+, Leu-2a+, Leu-3a-, sheep erythrocyte rosette+, IgGFc receptor+. The cells also bore a receptor for histamine inhibitable by cimetidine (H-2). The clonal nature of the proliferation was documented by the presence of a consistent marker chromosome (22-trisomy) in metaphases elicited by culture with T cell growth factors. Although the surface phenotype suggested that these cells might function as suppressor lymphocytes, they had an enhancing effect on the pokeweed- mitogen- (PWM) driven generation of plasma cells and reverse hemolytic plaque-forming cells in vitro. This helper activity was modified neither by irradiation of the leukemic cells nor by removal of a minor population of Leu-3a+ cells, suggesting that the effects were attributable to the CLL cells themselves. In addition to these functions, the CLL cells were active in antibody-dependent cellular cytotoxicity (ADCC) assays in association with expression of Fc receptors for IgG. The ADCC was diminished when a transient loss of the Fc receptor expression was observed. No activity in natural killer cell assays employing K-562 cells or herpes simplex virus- (HSV) infected cells as targets could be attributed to the leukemic clone. These studies indicate that the cell surface phenotype, as defined by monoclonal antibodies, may not always predict the functional state of a particular cell, and suggest that within the Leu-2a+ (TH-2+) population of human lymphocytes, some helper as well as suppressor/cytotoxic cells are to be found.

An investigation was carried out on the in vitro effect of a calf thymus extract, thymostimulin, on the distribution of T cell phenotypes as defined by OKT3, OKT4, and OKT8 murine monoclonal antibodies and on E-rosetting cells in human cord blood lymphocytes from healthy newborns. The percentages of E-rosette-forming lymphocytes and OKT3+ total T population were lower in newborns than in adults (E-rosettes: 43.8% +/- 13% vs 57.9% +/- 7.9%, p less than 0.01; OKT3+ cells: 53.3% +/- 15.5% vs 79.9% +/- 4.7%, p less than 0.01), while the OKT4+/OKT8+ (helper/suppressor) cell ratio was normal in both (newborns: 3.40; adults: 2.44-NS). Thymostimulin increased the number of E-rosette-forming cells from 43.8% +/- 13% to 49.9% +/- 12.7% (p less than 0.01), as well as the percentage of phenotypic T lymphocytes. The highest increases were observed in the OKT4+ cells (37.7% +/- 14% to 49.1% +/- 13.8%, p less than 0.001), while smaller changes were observed in the OKT3+ cells (53.3% +/- 15.5% to 58.1% +/- 13.3%, p less than 0.02) and OKT8+ cells (12.8% +/- 6.4% to 16.6% +/- 6.5%, p less than 0.02). The results of the present study suggest that thymostimulin mainly provokes an increase in the helper T cell phenotype in cord blood lymphocytes.

Immune function, T-lymphocyte subsets, serum quantitative immunoglobulin levels, serum lysozyme levels, and circulating immune complex levels were analyzed in patients with idiopathic dilated cardiomyopathy (IDCM). The percentage of helper/inducer T cells (OKT4) was higher and the percentage of suppressor/cytotoxic T cells (OKT8) was lower in IDCM patients than in healthy controls and in patients with ischemic heart disease. IDCM patients, in addition, have higher 5/9+ T cells, a T-cell subset known to give maximal helper activity in B-cell differentiation assays. Peripheral blood mononuclear cells (PBMC) from IDCM patients demonstrated a statistically greater ability to induce B-cell differentiation (helper T-cell function) into plasma cells and a hypofunctioning suppressor T-cell population in an in vitro pokeweed nitrogen (PWN)-driven B-cell differentiation assay. Serum immunoglobulin IgM levels were higher in IDCM patients, but serum lysozyme levels and serum immune complex levels in IDCM patients were normal. These data verify that an immunoregulatory defect exists in IDCM.

We studied the in vitro effect of three different thymic factors on the expression of CD38 (T10) antigen on cord T-lymphoid cell surface. The results showed that cord mononuclear cell populations contain variable percentages of CD38+ cells. The CD38 molecule was expressed on cord T and B lymphocyte and monocyte surfaces. Incubation with thymic agents induced a significant increases in the CD38+ cell percentage only in the samples with low CD38 antigen expression, and this modulation was mainly attributable to the T-cell subset. The effect seems to be specific and not correlated with the known high spontaneous DNA synthesis rate of cord mononuclear cells.

Because T-cell dysfunctions have been reported in patients with primary Sjögren's syndrome (SS), peripheral blood mononuclear cell (PBMC) proliferation obtained with anti-CD3 and anti-CD2 monoclonal antibodies was evaluated in these patients. Anti-CD3-induced mitogenesis, which varied widely among the patients, was lower in subjects with evidence of anti-SSA and anti-SSB antibodies than in controls. Moreover, the anti-CD2-induced response was depressed in about half the patients and the nonresponders were mainly those with anti-SSA and anti-SSB antibodies. Phorbol myristate acetate, a protein kinase C activator, used alone or added to anti-CD3, induced greater proliferation in patients than in control PBMC. In contrast, exogenous recombinant interleukin 2 (rIL-2) did not significantly enhance the anti-CD2-induced response of patients' PBMC, as it did in normal PBMC. Peripheral blood and parotid T cells from a patient with well-defined primary SS and parotid enlargement also responded poorly to anti-CD2 stimulation. Exogenous rIL-2 restored T-cell proliferation only in the salivary gland cultures of this patient. The present findings suggest that there is a T-cell activation defect in subjects with primary SS, particularly in those with circulating anti-SSA and anti-SSB antibodies. In addition, the difference in the response to IL-2 of peripheral blood and parotid-infiltrating T cells would seem to indicate that T-cell subsets are differently distributed in the blood and inflammation site.

A longitudinal study on human T lymphoid surface antigens was performed on blood samples from 6 infants during their first month of life. Although the results indicate a sudden increase in the percentage of OKT3+ and E-RF+ cell types a few hours after birth and a less rapid decrease of OKT6+ and OKT9+ circulating cells, high levels of OKT10+ cells persisted. This finding suggests that infant blood contains immature phenotypic T lymphocytes after birth.

The phenotype and function of T cells circulating in patients with pathological hyperprolactinemia were analyzed and compared to those in sex- and age-matched control subjects. Two-color immunofluorescence study revealed an increased number of CD4+ TQ1+ cells and the presence of phenotypically immature CD1+ T cells, also exhibiting transferrin surface receptor, in peripheral blood of the hyperprolactinemic patients. After chronic treatment with the dopamine agonist bromocriptine, T-cell abnormalities disappeared. In addition, some untreated patients showed enhanced T-cell suppressor activity in an in vitro pokeweed mitogen-driven B-cell transformation assay. These immunological findings confirm a link between neuroendocrine and immune systems in humans.

Expression of TQ1(Leu8) and 2H4 antigens on human cord blood T-cell subsets was evaluated by a double immunofluorescence analysis. In normal adult blood all of the helper function for B-cell differentiation is confined to the smaller OKT4+TQ1-(Leu8-) cell subset, while the OKT4+TQ1+(Leu8+) cell subpopulation includes a subset of suppressor inducer 2H4+(JRA+) cells. Our results indicated that the OKT4+TQ1-(Leu8-) cell subpopulation was decreased and the reciprocal OKT4+TQ1+(Leu8+) cell subset was markedly increased in cord blood E-rosetting OKT3+ cell population. A rise in the number of cord OKT4+2H4+ cells was also found. In addition, TQ1 antigen was present on OKT3+E-, a less mature, cord T-cell subset, not present in adult blood. These findings may not only be of help in understanding lymphoid cell development during ontogeny, but also may agree with the reported strong-suppressor and weak-helper activities exerted by the T-cell subsets circulating in human cord blood.

Double-labelling immunofluorescence analysis within the CD4+ cell subset was carried out in 27 bronchoalveolar lavage fluids and 11 peripheral blood samples of sarcoidosis patients with anti-TQ1, anti-2H4 and anti-4B4 monoclonal antibodies. Helper/inducer CD4+TQ1-/4B4+ cells were strongly increased in the lung and slightly, but significantly, decreased in the blood of sarcoidosis patients with respect to normal controls. No differences were found in the number of both lung and blood CD4+2H4+ cells between sarcoidosis patients and controls. The findings are further evidence for a compartmentalization of T cell subsets in sarcoidosis.

A study was carried out on cord blood T cell activation via the CD2-mediated pathway. Despite similar percentages of circulating CD3+ and CD2+ cells in adult and cord blood, the proliferation of cord PBMC to the anti-CD3 mAb and cord T cells to anti-CD2 mAb were defective. The T cell CD3-surface structure was normally able to control CD2-mediated activation, as its modulation by a non-mitogenic anti-CD3 mAb blocked cord PBMC proliferation induced by anti-CD2 mAb. CD2-stimulated cord T cells did not proliferate and did not produce a significant amount of IL-2 in culture, although they expressed the IL-2R. This observation was confirmed by the optimal proliferation of CD2-induced cord T cells when rIL-2 was added. Despite the alternative T cell activation pathway is monocyte-independent in adults, the defective cord T cell activation via the CD2 molecule could also be bypassed by the addition of PMA, small amounts of either autologous or allogeneic adult and cord AC or simply rIL-1 alone. Our findings provide evidence for an intrinsic functional defect in cord CD2-mediated T cell activation, which is linked to an impaired increase of free cytoplasmic calcium, as confirmed by the effectiveness of calcium ionophore A23187 in restoring a good CD2-induced cord T cell proliferation and by measurement of cellular calcium uptake after activation via the CD2 molecule. The characteristics of cord T cells revealed by this study recall the thymocyte functional pattern and may represent functional expression of the previously described phenotypic immaturity of cord T cells.

T-cell phenotypes, as defined by murine monoclonal antibodies, (OKT3, OKT4, OKT8, OKIa1), and phytohemagglutinin (PHA) reactivity, were evaluated in E-rosette forming cells (T-cells) from 10 untreated chronic myelocytic leukemia patients. The proportion of T4+ cells was lower in patients than in controls (41.6 versus 61.7%, P less than 0.02); whereas the proportion of T8+ cells was similar in patients and controls. The decrease in T4+ cells in CML resulted in a decrease in circulating T4+/T8+ ratio (P less than 0.02). The Ia1+ T-cells were increased in most CML (8 of 9) patients, while control subjects never displayed Ia1+ T-lymphocytes (P less than 0.01). The PHA reactivity of E-rosette forming lymphocytes was significantly impaired in CML patients with respect to controls (P less than 0.02). The presence of Ia antigen on T-cells was positively correlated with the T8+ cell phenotype (P less than 0.001) and inversely correlated with the T4+ (helper) cell phenotype (P less than 0.05). Furthermore, there was a trend towards an inverse correlation between the PHA response and the level of Ia1+ or T8+ cells, there is no correlation between PHA reactivity and T4+ phenotype. The results suggest that the T-lymphocyte population from untreated CML patients is intrinsically abnormal.

Immunologic parameters were evaluated in 22 patients with alcoholic liver disease (ALD). Patients with ALD had increased levels of circulating immune complexes (CIC) and serum immunoglobulins, particularly IgA. The classical complement pathway was preferentially activated in CIC-positive patients. There was no increase in total lymphocyte or total T lymphocyte counts, but a significant rise in both the helper/inducer population (OKT4) and helper/suppressor cell ratio (T4/T8) was noted. The presence of interleukin-2 receptors and HLA-DC/DS and HLA-DR antigens suggested in vivo activation of ALD patients' T cells. The rate of differentiation of B cells to plasma cells was high in both pokeweed mitogen-stimulated and unstimulated cultures of ALD patients' B cells, whereas plasma cell generation doubled when patient T lymphocytes were added to enriched normal B cells. The above data support a role for activated helper (T4+) T cells in the immune response initiated by alcoholic hepatitis. Serum angiotensin-converting enzyme levels and lysozyme levels were increased in ALD patients, and cultured adherent mononuclear cells from ALD patients secreted more lysozyme in vitro than normal cells, suggesting the presence of an activated monocyte-macrophage system in ALD.

Cord blood samples from healthy full-term newborns were tested with antimature and antiimmature lymphoid-cell monoclonal antibodies, as well as more traditional markers, in order to identify the phenotype of circulating precursor cells. The results demonstrated that human cord blood contains a lower number of OKT3+, E-rosetting mature T cells than adult blood, very high levels of OKT10+ cells, and few OKT9+, OKT8+ OKT3-, and OKT4+ OKT3- cells. Although the finding of OKT9+ and OKT10+ cord circulating cells could be indicative of cell activation, double marker studies in newborn blood pointed to phenotypically immature lymphoid subsets at different stages of maturation, according to Reinherz's hypothesis. In addition, the absence of nuclear Tdt-positive and hot-rosetting cells, together with the fact that most of these are OKT3+, OKT10+, OKT4+, or OKT8+ cells, suggests that the surface phenotype of newborn lymphocytes is similar to that of mature thymocytes.