Patients with abnormal proportions of T-lymphocyte subsets have reduced in vitro cellular immunity

Lymphocytopenia in a hospital population--what does it signify?

BACKGROUND

Lymphocytopenia is a common finding in hospital patients especially since the advent of automated differential leukocyte counters. The causes and significance of lymphocytopenia are generally poorly understood. There has been no large-scale study of its significance for 25 years. The HIV epidemic, and the recently described idiopathic CD4+ T-lymphocytopenia have raised interest in this finding.

AIMS

To describe the spectrum of lymphocytopenia in an adult teaching hospital and investigate its clinical significance.

METHODS

Using the available computer facilities, patients with significant lymphocytopenia (< 0.6 x 10(9)/L) were identified over a 102 day period and diagnoses, operations and medication lists obtained. Where necessary, patient histories were examined to supplement the above information. If feasible, previous and subsequent lymphocyte counts were checked to establish if the lymphocytopenia were temporary or longstanding.

RESULTS

One thousand and forty-two patients were identified, with a mean age of 59.6 years, of whom 563 were male, and 757 were inpatients. Thirty-six patients were pancytopenic. We checked previous and subsequent counts for 698 patients and found 45 patients who were consistently lymphocytopenic, some for more than ten years. Thirty-four patients with previously normal counts remained lymphocytopenic throughout follow up, while 457 had at least one subsequent lymphocyte count > 1 x 10(9)/L. We found only one patient who was suspected of having idiopathic CD4+ T-lymphocytopenia. Patients fell into several categories (with some overlap): bacterial/fungal sepsis (250), post-operative (228), corticosteroid therapy (definite 159, suspected 53, inhaled steroids alone 14), malignancy (174 definite, six probable), cytotoxic therapy and/or radiotherapy (90), trauma or haemorrhage (86), transplants (73-38 renal and 35 bone marrow), 'viral infections' (26) and HIV infection (13). Thirty-four patients died within the study period.

CONCLUSIONS

Lymphocytopenia in hospital patients is most frequently reversible, and due to acute illness, notably sepsis and trauma (including surgery). Malignancy, with or without chemotherapy, and steroid use are also common causes, but HIV infection is a relatively uncommon cause in our hospital.

In vitro mitogen responses and lymphocyte subpopulations in cheetahs

Lack of genetic variability and apparent susceptibility of cheetahs (Acinonyx jubatus jubatus) to coronavirus infection has lead to speculation that this species may have immune system deficits. To establish a foundation for evaluation of the immune function, cheetah peripheral blood mononuclear cells (PBM) were stimulated by a panel of six mitogens, and responses compared with those of domestic cat PBM. Individual responses in both species were variable, but evenly distributed throughout the range of stimulation for each mitogen. Proliferation by PBM from domestic cats occurred within the same range as that of the cheetahs. However, a significantly lower response to peanut agglutinin (PNA) was observed with domestic cat PBM. Although responses varied between animals, certain individual cheetahs were consistent low responders. The decreased values could not be explained by lack of IL-2 responsiveness since exogenous IL-2 significantly enhanced mitogen-stimulated proliferation in 11 of 12 cheetahs tested. The phenotypic distribution of domestic cat and cheetah lymphocyte subpopulations was similar as assessed by immunofluorescence staining for surface immunoglobulin (sIg) and cytotoxic T (Tc) cells (using a specific monoclonal antibody, FT2). Values for B cells (31.2% sIg+) and Tc (28.7% FT2+) were slightly higher in domestic cats as compared with cheetah PBM (13.3% sIg+; 19.0% FT2+). Even though no species-specific deficits were detected, a significant negative correlation between PHA-stimulated proliferation and percent FT2+ (Tc) cheetah cells was observed. This indicates that proliferation can be used indirectly to assess relative numbers of functional T helper cells in cheetahs. Our studies suggest that these aspects of the cheetah's immune system are comparable with the domestic cat, and establish a basis for in vitro assays evaluating antigen-specific responses.

Interleukin 2 responsive lymphocytes in patients with adenosine deaminase deficiency

We evaluated the effects of recombinant interleukin 2 (IL-2) on the proliferative responses to mitogens of peripheral blood mononuclear cells (PBMC) from three adenosine deaminase (ADA)-deficient patients. There was significant enhancement by IL-2 of the proliferative responses to phytohemagglutinin (PHA) and pokeweed mitogen (PWM) of PBMC from all three patients. We found that normal PBMC respond with increased numbers of CD3-positive cells when exposed to PHA or PWM and that the response by normal CD8-positive cells was greater than that by CD4-positive cells. In contrast, we found that in ADA-deficient cells the response is almost entirely due to the CD3/CD4-positive population of lymphocytes. These results could not be explained by either the culture conditions or the possibility of a mixed chimeric state. When we evaluated an in vitro cell model of ADA deficiency using an ADA inhibitor, erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), we found that the inhibitory effect of EHNA plus deoxyadenosine on mitogen-stimulated PBMC could not be prevented by IL-2. These results suggest that the immunodeficiency in ADA deficiency includes the absence or failure of a subset of T cells to make IL-2 and the failure of the CD8-positive subset to respond to IL-2. Also, the in vitro cell model of ADA deficiency using EHNA as the ADA inhibitor is limited in its use in understanding the pathogenesis of this disease.

Rejection of bone marrow transplant and resistance of alloantigen reactive cells to in vivo deoxyadenosine in adenosine deaminase deficiency

Severe combined immunodeficiency disease (SCID) in patients with adenosine deaminase (ADA) deficiency is thought to result from increased levels of purine metabolites. We attempted to immunosuppress a patient with ADA deficiency and SCID using a continuous infusion of deoxyadenosine to obtain engraftment of a T cell-depleted haplocompatible parental bone marrow graft. Before administering the drug in vivo, we investigated hematopoietic colony formation in two children with ADA deficiency (including the potential recipient), the obligate heterozygote donor (father), and normal controls using deoxyadenosine and erythro-9-(2-hydroxy-3-nanyl)adenosine (EHNA), and inhibitor of ADA. Deoxyadenosine alone in concentrations as high as 100 microM had no significant affect on erythroid (BFU-E) or myeloid (CFU-c) colony formation. However, in the presence of EHNA there was a significant reduction in BFU-E and CFU-c growth in all subjects and controls. Increasing doses of deoxyadenosine were given to one patient with ADA deficiency and SCID as a continuous 24-hr intravenous infusion. We found that there was a linear relationship between the dose administered and the plasma level; however, doses greater than 100 mg/day were required to increase erythrocyte dATP levels. We were able to raise intracellular dATP levels to more than three times baseline with doses of deoxyadenosine of 200 mg/day. However, there were no significant effects on the absolute lymphocyte counts or the lymphocyte responses to mitogen or alloantigen, and the haploidentical marrow failed to engraft. Our results suggest that the bone marrow of ADA-deficient patients is normal with respect to standard colony formation, that inhibitors of ADA do not adequately model the deficient state, and that the immunodeficiency in ADA deficiency is not proportionately related to either the deoxyadenosine or dATP levels, both of which were significantly elevated at the time of transplantation.

Tumor necrosis factors alpha and beta in acquired immunodeficiency syndrome (AIDS) and aids-related complex

Human immunodeficiency virus (HIV) infection is associated with abnormalities of both T-cell and B-cell immunity in patients with acquired immunodeficiency syndrome (AIDS). Previous studies demonstrated deficient production of the cytokines interleukin-1 (IL-1), interleukin-2 (IL-2), and gamma interferon (IFN-gamma). Tumor necrosis factor alpha and tumor necrosis factor beta have not been previously investigated in AIDS. In this study we demonstrate that peripheral blood mononuclear cells from patients with HIV infection who have either AIDS-related complex or acquired immunodeficiency syndrome are deficient in the production of tumor necrosis factor alpha and tumor necrosis factor beta. These cytokines, derived predominantly from monocytes or lymphocytes, respectively, function as immunoregulatory, antitumor, and antiinfective proteins. A deficiency in their production may therefore be responsible for many of the complications associated with HIV infection in patients with AIDS-related complex or acquired immunodeficiency syndrome.

[Effect of PIND-AVI on various ratios of helper and suppressor T lymphocytes]

The immunomodulating effect of a new heterologous antigen (PIND-AVI) on helper (inducer) and suppressor T cells was investigated. Primarily decreased T4 values (less than or equal to mean T4 - 2 S.D.) increased after treatment with PIND (P less than 0.005, using Student's t-test; n = 15). Primarily increased T 8 values (greater than or equal to mean T8 + 2 S.D.; obtained for normal persons) decreased after therapy (P less than 0.001; n = 10). An increase of T4/T8 ratio (P less than 0.005 and less than 0.001) to normal values was observed in both cases. T4 and T8 values within the mean +/- 2 S.D. were not influenced significantly (n = 13). In spite of different primary values, the amount of lymphocytes/mm3 was not significantly influenced. It appears advisable to check the results of treatment continuously every few weeks.

Predictive value of T-cell subset derangements in lung cancer

The proportions of T-lymphocytes, T-lymphocyte subsets, NK cells, DR determinant and interleukin-2 receptor-bearing T-lymphocytes were enumerated in 39 patients with lung cancer prior to any chemotherapy. T-lymphocytes, suppressor/cytotoxic T-cells and interleukin-2 receptor-bearing T-cells were found to be significantly higher in patients responding than in those not responding to chemotherapy. Such mononuclear cell subset analysis by monoclonal antibodies might be additional information to consider before undertaking treatment.

Distribution of T-lymphocyte subsets in different portions of sarcoid granulomas: immunohistologic analysis with monoclonal antibodies

The numbers and the distribution of T-lymphocyte subpopulations in lymph node granulomas from 11 patients with sarcoidosis were studied in cryostat sections by an immunoperoxidase technique. Greater numbers of helper T lymphocytes (Leu-3+) were found at the periphery than in the central portion of the same granuloma. Most of the suppressor T lymphocytes (OKT8+) were present at the periphery of the granulomas. In addition, the Leu-3a/OKT8 ratio varied from 0.7 to 1.8 in the outer compartment, while in the central portion of the granuloma much higher values (3 to 20) were found. These different distribution patterns of T-lymphocyte subsets provide evidence for two different compartments with different immune reactions in sarcoid granulomas.

Peripheral T-cell subsets in asymptomatic hepatitis B-virus carriers

To ascertain whether the abnormalities of circulating T-cell subsets in patients with hepatitis B virus (HBV)-related chronic liver diseases represent the primary immunological process or are secondary to liver disease process, peripheral T-cell subsets were analyzed by indirect immunofluorescence using monoclonal antibodies against total T cells (OKT3), T helper/inducer cells (OKT4), and T suppressor/cytotoxic cells (OKT8), in 30 asymptomatic HBV carriers without biochemical or histological evidence of liver disease, and the results were compared to 15 HBV-induced chronic active liver diseases. The results revealed that OKT4/OKT8 ratios were significantly reduced in 15 hepatitis B e antigen (HBeAg)-positive asymptomatic carriers as compared with controls, with decreased OKT4-positive cells and increased OKT8-positive cells, while T-cell subsets and ratios were normal in 15 hepatitis B e antibody (anti-HBe)-positive asymptomatic carriers. The changes of circulating T-cell subsets in 15 HBe-Ag-positive asymptomatic carriers showed no significant difference from those of 15 HBeAg-positive patients with chronic active liver diseases. These findings suggest that the deranged T-cell subsets in chronic HBV infection are not secondary to liver cell damage, but might represent the underlying immunological abnormalities which are closely related to HBeAg/anti-HBe status, and that the pathogenetic mechanism of liver cell damage in chronic HBV infection may not be simply related to circulating T-cell subsets.

Leukocytic subset distributions of spleen cells obtained from rats bearing variants of the Dunning prostatic adenocarcinoma

Employing monoclonal antibodies, the relative frequencies of mononuclear cell types found in spleen cell populations were compared between rats bearing variants of the Dunning prostate adenocarcinoma and a series of non-tumor bearing control animals. The identification and quantitation of such subsets greatly expands our knowledge of immune status and function. The results indicate that the spleen cell populations from animals bearing either the Dunning R3327-H, G or MAT-LyLu sublines have significant decreases in their helper T cell/suppressor T cell ratios when comparisons are made to cells obtained from non-tumor bearing animals. In addition decreases in total T cell content and increases in splenic monocytes were noted. It appears that most of these deviations are the result of general Dunning tumor presence, rather than due to any particular subline characteristic. These changes may be analogous to similar alterations reported in the peripheral blood of humans bearing Stage D prostatic cancer, suggesting that the Dunning tumor may provide an appropriate model for evaluating interactions between the immune response, the tumor and therapy.

Haploidentical bone marrow transplantation for severe combined immunodeficiency disease using soybean agglutinin-negative, T-depleted marrow cells

The major limitation of mismatched bone marrow transplantation is fatal graft versus host disease (GVHD). We processed haplotype-identical parental marrow with soybean agglutinin (SBA), sheep erythrocytes (SRBC), and neuraminidase-treated SRBC (N-SRBC) to enrich for marrow stem cells and remove mature T cells. Nine patients with severe combined immunodeficiency disease (SCID) who lacked histocompatible donors received these SBA-negative, SRBC-negative, N-SRBC-negative marrow transplants (0.5-5.0 X 10(8) cells/kg). Seven of the nine patients (78%) had documented T-lymphocyte engraftment based on HLA typing and/or chromosomal analysis. Six patients showed evidence of B-cell immunity on the basis of increased immunoglobulin levels, isohemagglutinins, and/or HLA-DR typing of non-T cells. Three patients received marrow ablative chemotherapy pretransplant for maternal-fetal GVHD; neutrophil engraftment occurred between 9 and 17 days posttransplantation, erythrocytes engrafted within 3-4 weeks of transplantation, and platelet recovery was seen between day 17 and day 49 following the transplants. No immunosuppression was given prophylactically posttransplant. Three patients had no GVHD, two had transient rash and/or fever, and two developed mild focal (stage I) chronic cutaneous GVHD. Of the seven who engrafted, five (71%) are alive and clinically well without GVHD 18-35 months posttransplant. These data demonstrate that SBA- and SRBC/N-SRBC-treated haploidentical marrow transplantation results in functional lymphocyte engraftment in SCID without significant GVHD, and can be used for some patients who otherwise would have no hope for survival.

Infectious mononucleosis mimicking a B cell immunoblastic lymphoma associated with an abnormality in regulatory T cells

An elderly woman is described with infectious mononucleosis in whom cervical node biopsy was interpreted as showing immunoblastic lymphoma. Concomitant reactive lymphocytosis, Epstein-Barr virus serologic results consistent with an acute infection, and demonstration of polyclonal B cell infiltration of other tissues argued against intervention. Defective in vitro T cell responses were demonstrated during the acute phase of Epstein-Barr virus infection. Infectious mononucleosis has rarely been reported as mimicking a non-Hodgkin's lymphoma. At 18 months, our patient's course has been typical for infectious mononucleosis with no evidence of disseminated malignancy.

Disproportionate lymphoid cell subsets in thalassaemia major: the relative contributions of transfusion and splenectomy

The relative proportions of T-cell (OKT3-positive, OKT4-positive and OKT8-positive) and B-cell (SIg-positive) populations in peripheral blood obtained from 29 chronically transfused patients with beta-thalassaemia major were compared with those of 17 healthy controls. Changes attributable to blood transfusion and/or splenectomy are described. The percentage of OKT8-positive (T-suppressor) cells found in the thalassaemic patients increased linearly (P less than 0.001) with the number of units transfused, irrespective of splenectomy. The percentage of OKT4-positive (T-helper) cells varied inversely with increasing transfusion in nonsplenectomized patients while in those who were splenectomized no significant correlation was apparent. Thus, in both groups of patients the T4/T8 ratio declined in a transfusion-related manner. The splenectomized patients experienced a marked and persistent lymphocytosis due to an increase in the number of both T- and B-cells. When the results were expressed as percentages, the greatest increase occurred in the number of B-cells, this increase being unrelated to the number of transfusions received. None of the serum parameters usually associated with iron overload or abnormal liver function correlated with the observed increases in T-suppressor and SIg-positive cells. These findings corroborate reports that transfusion of blood products may lead to decreased T4/T8 ratios. However, none of the patients studied manifested clinical signs of acquired immune deficiency syndrome (AIDS). Accordingly, studies which define transfusion related AIDS on the basis of analyses with monoclonal antibodies must be viewed with caution.

T-cell subsets in malignant lymphomas and monoclonal gammopathies

159 patients with malignant lymphomas or monoclonal gammopathies were investigated for lymphocytes and their subsets using conventional surface markers and a panel of monoclonal antibodies. In untreated patients with Hodgkin's disease, non-Hodgkin lymphomas and multiple myeloma, (MM) a reduction of T-cells and especially of the "helper/inducer" subset (OKT4+) was found to be a common phenomenon. The major abnormalities occurred in advanced stages of disease. Patients previously treated by chemo- and/or radiotherapy had a further decrease of T-cells, whereas the loss of OKT4+ cells was more pronounced than that of the "suppressor/cytotoxic" lymphocytes (OKT8+). The alterations of lymphocyte subsets persisted even in long-term remitters. Comparing the lymphocyte subsets in MM and benign monoclonal gammopathies (BMG), patients with BMG showed a significant reduction in OKT8+ cells, whereas the OKT4+ population was within normal range, resulting in a significant elevation of the OKT4/OKT8-ratio compared to the controls and untreated multiple myeloma.

Lymphocyte subsets in patients with aplastic anemia

Lymphocyte subsets were enumerated in a group of 31 patients with aplastic anemia. Abnormal numbers of immunoregulatory T-cells were found in some patients: 26% of them showed a reversed helper/suppressor ratio. Seven of 18 patients showed significantly decreased proliferation in response to PWM; this hyporesponsiveness was present in 75% of patients with a reversed helper/suppressor ratio and in 10% of those with a normal helper/suppressor ratio (R = 0.66, P = 0.008). Eight of 18 patients showed suppressor activity over PWM-induced allogeneic cell proliferation. This suppressive activity did not correlate with T-cell phenotype. Of the patients with a low number of T-cells, 73% had responded to treatment, whereas of those patients with a normal number of T-cells, 26% had responded (P = 0.016). The results are consistent with abnormal immune response in selected patients with aplastic anemia, and suggest a possible influence of T-cells on disease process.

Decrease of the OKT8 positive T cell subset in polymyalgia rheumatica. Lack of correlation with disease activity

Peripheral T cell populations were investigated in 35 patients suffering from polymyalgia rheumatica. The total number of T cells was low compared with those of a control group of similar age (P less than 10(-3). This decrease was demonstrated by using both classic E-rosette and monoclonal antibody techniques (OKT3, and OKT4 + OKT8) and was shown to be secondary to a selective T8 defect (P less than 10(-9). There was no correlation between the decrease in T8 (a cytotoxic suppressor T cell subset) and steroid therapy, disease activity, and temporal arteritis, nor between this decrease and the T gamma percentage and the presence of circulating immune complexes (CIC). The T gamma cell percentage was low in the patient group (P less than 10(-5) and correlated with the presence of detectable CIC (P less than 0.05). In contrast to the T8 and T gamma defects, concanavalin A-stimulated cells from 5 selected patients were found capable of suppressing in vitro anti-trinitrophenyl response. This suppression was found in both autologous and allogeneic experiments. From these data one can assume that an immune anomaly (T8 defect) could be the origin of CIC and the disease occurrence.

Changes in purine nucleoside phosphorylase activity during thymosin-induced human null cell differentiation

Purine nucleoside phosphorylase (PNP) is a purine salvage pathway enzyme which we have found to be 8-10 times more active (per cell) in human peripheral blood null lymphocytes than in T lymphocytes. To test the hypothesis that null cells are, in part, pre-T lymphocytes we have defined an in vitro system for null cell differentiation into T cells and examined PNP activity during this differentiation process. We found that about 10% of human null cells could be driven to differentiate into T cells using thymosin fraction 5 (TF5) an extract of bovine thymus glands. The response to TF5 was dose related to up to 250 micrograms/ml with a maximum response occurring by 42-46 hr incubation. Exposure to TF5 was necessary for more than 4 hr but no more than 8 hr in order to obtain a maximum response. Both OKT4 and OKT8 positive cells were present in the newly differentiated T cell population but OKT8 positive cells appeared to predominate (OKT4/OKT8 = 0.698 +/- 0.30, mean +/- 1 SD). The differentiation process did not involve DNA synthesis but was inhibited at 4 degrees C. In the newly differentiated T cells PNP activity per cell was 8- to 10-fold lower (36 +/- 23 nm/hr/106 cells) than in null cells (311 +/- 136), and was at a level similar to mature T cells (56 +/- 7). Thus, human peripheral blood null cells can be induced to differentiate into T lymphocytes which can be characterized by both surface markers and biochemical parameters. Future studies will look at the function of TF5-induced T cells and the regulation of PNP activity during the differentiation process.