Robert D. Bigler

Extracorporeal Photopheresis and Recombinant Interferon Alfa 2b in Sezary Syndrome: Use of Dual Marker Labeling to Monitor Therapeutic Response

The purpose of this pilot study was to evaluate the role of recombinant interferon alfa 2b (rIFN-a) as adjunct immunomodulatory therapy in patients with Sezary syndrome who were considered unlikely to respond to ExP alone. Six patients were treated with rIFN-a in doses ranging from 3 to 20 million units three times weekly in addition to two consecutive photopheresis treatments every 4 weeks. In addition, to better measure the effect of treatment on circulating neoplastic T-cells, cryopreserved lymphocytes were studied by two-color immunofluorescence and flow cytometry, using anti-CD4 combined with anti-CD29, anti-CD45RA, or anti-CD7. Minimal clinical improvement was observed in 4 patients treated with low doses of rIFN-a (3 to 5 million units TIW), and the response was sustained in only 1 patient. However, a clinically significant and sustained improvement did occur in 1 patient after the dose of rIFN-a was increased (20 million units TIW). Although the encountered toxicity profile from combined ExP/rIFN-a therapy was similar to that expected for ExP or comparable doses of rIFN-a given separately, treatment was discontinued in 2 patients because of adverse effects. Three antibody pairs, i.e., CD4+CD7-, CD4+CD29+, and CD4+CD45RA- subsets, appeared to be useful to monitor changes in blood Sezary cells during treatment. We conclude that the combination of ExP and low doses of rIFN-a does not appear to be effective for patients with advanced Sezary syndrome in this small patient series. However, escalation of interferon dose may be beneficial as shown in one patient, but it cannot be discerned whether the response was due to a combination of therapies, or whether the same therapeutic response would have been achieved with the higher doses of rIFN-a alone. Moreover, while none of the antibody pairs is unique for Sezary cells, the CD4+CD7- subset in appropriate patients provided a good objective measure of response and correlated well with visual Sezary cell counts.

Fine-Needle Aspiration Biopsy in the Evaluation of Lymphadenopathy Associated With Cutaneous T-Cell Lymphoma (Mycosis Fungoides/Sézary Syndrome)

We studied the role of fine-needle aspiration (FNA) in the evaluation of lymphadenopathy associated with cutaneous T-cell lymphoma (CTCL) in 11 patients with lymphadenopathy and compared findings with corresponding histologic material. Molecular genetic analysis for T-cell clonality by polymerase chain reaction (PCR) was performed on all aspirates. Immunophenotyping was successful in 4 of 7 cases in which flow cytometry was attempted from the aspirated material. Cytologic evaluation of FNA samples correlated strongly with histologic rating of involvement based on numbers of atypical cerebriform lymphocytes in the nodal specimen. Of 7 nodal specimens with scattered or small groups of atypical cells in the background of dermatopathic lymphadenopathy (LN1-2), the cytologic diagnosis was interpreted as reactive in all instances. Of 4 specimens with highly suspect (LN3) or definite histologic involvement (LN4), the cytologic diagnosis was likewise suspect or malignant. The correlation between molecular genetic studies on FNA samples and studies on tissue was not significant; in 2 cases, a T-cell clone was detected in the nodal tissue sample but not in the FNA sample, suggesting undersampling. A T-cell clone was detected by PCR in 5 of 7 nodal specimens judged reactive by FNA biopsy or histologic assessment. FNA for cytologic and molecular genetic analysis is a useful method to evaluate lymphadenopathy associated with CTCL and may obviate the need for surgical biopsy.

Analysis of p53 and mdm-2 expression in 18 patients with Sézary syndrome.

Sézary syndrome is a leukaemic form of cutaneous T‐cell lymphoma which presents with multiple cytogenetic abnormalities and responds poorly to chemotherapy. Because of the importance of the p53 tumour suppressor in maintaining genomic stability and in sensitizing transformed cells to DNA damaging agents, we looked for alterations which may affect p53 functions in 18 patients with Sézary syndrome. Cytogenetic analysis suggested frequent p53 gene inactivation since 6/18 patients had loss of one copy of 17p. However, single‐strand conformational polymorphism (SSCP) revealed that p53 gene mutations are relatively rare, occurring in only two of 18 Sézary patients. Neither of these two patients was missing a copy of 17p. Possible abnormalities of p53 pathway function through mdm‐2 over‐expression were also investigated. Although all 18 patients had normal levels of mdm‐2 RNA, 4/18 over‐expressed mdm‐2 protein. One patient with advanced disease and the highest percentage of malignant cells overexpressed mdm‐2 protein and possessed a nonsense p53 gene mutation. The five patients with abnormalities of p53 or mdm‐2 were found to have significantly higher absolute lymphocyte counts and higher absolute numbers of Sézary cells (P = 0.021 and 0.027 respectively). In summary, molecular alterations of 17p and potential p53 pathway abnormalities are a common event in Sézary syndrome and appear to be associated with more advanced disease.

Cholesterol regulates the cell surface expression of glycophospholipid-anchored CD14 antigen on human monocytes

The CD14 antigen which is expressed on human monocytes and macrophages is a phosphatidylinositol-linked surface protein. We investigated the effects of cellular cholesterol depletion and repletion on cell surface expression of this glycoprotein. Adherent normal human monocytes were cultured for four days in media containing delipidated fetal calf serum which depleted cellular cholesterol. Immunofluorescence analysis demonstrated a markedly diminished surface expression of CD14 on cells cultured in delipidated serum compared to normal serum. Expression of CD64 (high-affinity Fc receptors, Fc gamma RI) also was reduced under these conditions. This inhibition of CD14 expression was overcome by addition to the culture medium of cholesterol, low density lipoprotein, or very low density lipoprotein. All of these supplements replenished cellular cholesterol. Expression of CD64(Fc gamma RI) was not restored by addition of cholesterol. These observations indicate that cholesterol can regulate the surface expression of some phosphatidylinositol-anchored glycoproteins.

Extracorporeal photopheresis in psoriasis vulgaris: Clinical and immunologic observations*

Four patients with chronic refractory plaque-type psoriasis without arthropathy were treated with extracorporeal photopheresis every other week for 6 to 13 months. In patients 1 and 2, methotrexate was administered concomitantly during the initial part of the trial; the dose was gradually tapered and the drug was discontinued by 6 months. Both patients improved to 23% and 62% of baseline values for percentage of body surface involvement, but their disease then flared when maintenance extracorporeal photopheresis was used alone. Substantial improvement again occurred when lower doses of methotrexate were administered with extracorporeal photopheresis. Patients 3 and 4 were treated initially with extracorporeal photopheresis alone and both improved to 50% and 52% of baseline body surface involvement, respectively, after 4 months of treatment. However, their disease flared because of factors unrelated to treatment. Extracorporeal photopheresis was well tolerated by all patients without evidence of overt toxicity. However, prolonged treatment with extracorporeal photopheresis/methotrexate was accompanied by a decrease in skin reactivity to recall antigens and by decreased capacity of lymphocytes to produce interleukin 2 in response to polyclonal stimuli in vitro. These findings indicate that alternate-week extracorporeal photopheresis has a definite but incomplete suppressive effect on psoriasis vulgaris that may be mediated through an effect on lymphokine production by photomodified cells and that the therapeutic effect of extracorporeal photopheresis may be enhanced by concomitant administration of low doses of methotrexate.

Antitumor effects of interleukin-2 and mismatched double-stranded RNA, individually and in combination, against a human malignant melanoma xenograft

SummaryThe antitumor effects of recombinant interleukin-2 (rIL-2) and mismatched double-stranded RNA (dsRNA) were assessed in tissue culture and in a nude mouse model. Mismatched dsRNA did not show a direct antiproliferative effect against the human malignant melanoma cell line, BRO, in tissue culture. However, treatment of the BRO cells with up to 1000 units/ml rIL-2 in culture showed a slight increase in growth rate. Combined rIL-2/mismatched dsRNA treatment also demonstrated a similar slight enhancement of growth. Nude mice bearing subcutaneous tumors were treated by intraperitoneal injection of low doses (5000–20 000 units) of rIL-2 and mismatched dsRNA (500 µg). The in vivo tumor growth was significantly inhibited by the combined treatments (P <0.05) and survival was significantly increased (P <0.05). Measurement of cytotoxicity using splenocytes from treated animals showed significant augmentation of lytic activity against natural killer(NK)-sensitive YAC-1 cells in all rIL-2/mismatched dsRNA treatment groups, compared to the individual treatments or controls (P <0.05). Cytotoxicity of the splenocytes against the NK-resistant BRO cells was also augmented in animals treated with mismatched dsRNA and the highest rIL-2 dose utilized here (P <0.01). Renal, liver, and hematological toxicity was evaluated by measurement of blood urea nitrogen, creatinine, serum asparrtate aminotransferase, and a complete blood count with differential. There were no significant differences in these parameters in any of the treatment groups. Similarly, no differences in weight of the animals was seen in any treatment group. These results indicate that the combination of low-dose rIL-2 and mismatched dsRNA can potentiate host-mediated antitumor effects, yielding increased survival, without significant toxicity.

Effect of low-density lipoprotein on the expression of high affinity Fcγ receptors

Abstract A substrain of the human monocyte-like cell line U937, which is a cholesterol auxotroph, was used to study the effect of cellular cholesterol depletion on the expression of the type I Fc receptor for IgG (FcγRI). Measurement of FcγRI expression was performed by immunofluorescence and flow cytometry using the monoclonal antibody (mAb) 32.2, which is specific for an epitope on FcγRI, and monomeric IgG 2a , which binds to the ligand binding site of FcγRI. Incubation of these cells for 24 h in growth medium containing delipidated fetal calf serum depletes cellular cholesterol without affecting growth or viability. While incubation of U937 cells with human interferon-γ (IFN-γ) increased FcγRI expression, cholesterol depletion after cell growth in media containing delipidated serum and IFN-γ resulted in reduced binding of both mAb 32.2 and IgG 2a . A significant decrease in the number of cell surface binding sites, as measured by mean fluorescence intensity, was observed after cholesterol depletion. Supplementation of the delipidated serum medium with pure cholesterol in an ethanol/bovine serum albumin mixture, which replenished cellular cholesterol and supported growth, failed to restore antibody binding significantly. In contrast, low-density lipoprotein (LDL) which also delivered cholesterol to the cells restored binding both in terms of the number of the reactive cells and cell surface receptor density. High-density lipoprotein (HDL 3 ), which does not deliver cholesterol to the cells, showed results similar to those obtained with pure cholesterol. This indicates that either LDL cholesterol is better utilized for membrane synthesis than pure cholesterol or that LDL provides another component, in addition to cholesterol, which is required for expression of FcγRI, but not for growth. These studies indicate a role for LDL in regulating the expression of FcγRI on the cell surface.

Potentiated lymphokine-activated killer cell activity generated by low-dose interleukin-2 and mismatched double-stranded RNA

SummaryLymphokine-activated killer (LAK) cell activity was measured in human peripheral blood mononuclear cells (PBMC) treated in vitro for 3 days with recombinant interleukin-2 (rIL-2) and mismatched double-stranded RNA (dsRNA). Lytic activity was measured utilizing K562 (NK-sensitive) and 786-0 (NK-resistant) target cells. PBMC cultured with rIL-2 (10–1000 BRMP U/ml) alone showed concentration-dependent lytic activity against the 786-0 target cells, while cells cultured in unsupplemented medium or medium supplemented with mismatched dsRNA (200 µg/ml) alone could not lyse the 786-0 targets. The combination of mismatched dsRNA with suboptimal concentrations of rIL-2 (10–30 U/ml) showed enhancement of both natural killer (NK) and LAK cell activities. The uptake of [3H]thymidine by treated effector cells was dependent on time and rIL-2 concentration and was not increased in the cells treated with low-dose rIL-2/mismatched dsRNA, compared to those treated with low-dose rIL-2 or mismatched dsRNA alone. Similarly, changes in the expression of CD3, CD4, CD8, CD57, CD16 and CD25 cell surface antigens were dependent on rIL-2 concentration and not altered by the presence of mismatched dsRNA. These results indicate that mismatched dsRNA can potentiate rIL-2-induced LAK cell activity by increasing the functional activity per cell, rather than by increasing the number of activated cells.

Effect of lovastatin on cell surface expression of Fc receptors or CD14 antigen in human monocytes.

Lovastatin is a widely used anticholesterolemic drug which exercises its effect by inhibiting hepatic cholesterol synthesis and up-regulating low density lipoprotein (LDL) receptors. In the present study, we determined that the drug has no adverse effects on the expression of three cell surface antigens of human monocytes, i.e. high affinity Fc receptors (Fc gamma RI), low affinity Fc receptors (Fc gamma RII) and CD14 antigen. We have shown previously these antigens are regulated by cholesterol and lipoproteins. At 0.5 micrograms/mL of culture medium, lovastatin did not reduce the percentage of receptor-positive cells or the average number of receptor molecules per cell. These observations add to the attractiveness of the drug as an anticholesterolemic agent and also indicate that endogenous cholesterol biosynthesis by monocytes is not required for expression of Fc gamma RI, Fc gamma RII, or CD14.