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M Stetler-Stevenson

Publications and source records attributed to M Stetler-Stevenson.

At least 55 records · Page 3Linked to original sources
PubMed1996

Detection of HHV-8/KSHV DNA sequences in AIDS-associated extranodal lymphoid malignancies.

Herpesvirus-like DNA sequences have been identified in a high proportion of both AIDS-associated and classical Kaposi's sarcoma, and in a small percentage of AIDS-associated malignant lymphomas. To determine the extent of involvement of this new agent designated HHV-8 (human herpesvirus type 8) or KSHV (Kaposi's sarcoma-associated herpesvirus) in human malignant lymphomas, we analyzed 24 AIDS-associated lymphoid malignancies and 100 non-AIDS-associated lymphomas by PCR and Southern blot analysis. Three of 24 lymphoid malignancies from patients with AIDS demonstrated HHV-8 sequences by Southern blot and PCR analyses. The fourth was positive by PCR only. None of the non-AIDS-associated lymphomas contained HHV-8 sequences. All three Southern blot positive samples were derived from extranodal regions, two from pleural effusions, and one from a soft tissue mass in the thigh. This latter patient initially presented with a pleural effusion. The fourth PCR positive but Southern blot negative tumor was from a gingival lymphoma in a patient with a history of Kaposi's sarcoma. All tumors positive for HHV-8 were also positive for EBV. These results confirm a recent report that this novel herpesvirus may play a role in AIDS-associated lymphomas especially in those with body cavity presentation.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Mesangial cells from transgenic mice with progressive glomerulosclerosis exhibit stable, phenotypic changes including undetectable MMP-9 and increased type IV collagen.

Mice transgenic for bovine growth hormone (bGH) develop progressive mesangial sclerosis resulting in uremia. Mesangial cells from bGH mice were isolated to determine whether the cells maintained a stable phenotypic change in the synthesis and degradation of extracellular matrix, which contribute to the glomerular lesions in vivo. The bGH mesangial cells were 1.2-fold larger than cells from control mice. They had a 1.7-fold increase in doubling time, a 7-fold decrease in labeling index (p < 0.0001), and a 2.4- and 2-fold decrease in c-myc (p < 0.05) and insulin-like growth factor I gene expression, respectively. Collagen synthesis and degradation were studied by PCR, ELISA, and gelatin zymography. bGH mesangial cell alpha 1 collagen IV mRNA levels were increased 2.3-fold (0.47 +/- 0.25 versus 0.20 +/- 0.09 attomoles/500 cells, p < 0.01) whereas secreted collagen IV and collagen IV in the cell lysates were increased 1.4-fold (25.1 +/- 5 versus 17.2 +/- 4 ng/ml/10(5) cells) and 1.8-fold (30.5 +/- 3 versus 16.7 +/- 3 ng/ml/10(5), p < 0.05), respectively. There were no differences in collagen I mRNA levels or in the protein content of either the media or cell lysates. We were not able to detect metalloproteinase 9 (MMP-9) mRNA expression or MMP-9 protein in bGH mesangial cell medium, whereas both mRNA and protein were present in controls. MMP-2 mRNA and enzyme activity in bGH cells were, however, elevated 1.5-fold (p < 0.05) and 2.1-fold (p = 0.05) over controls. Transforming growth factor beta 1 mRNA in bGH cells was 1.6-fold higher than that of controls (p < 0.05). The data suggest that (a) mesangial lesions may result from stable, genetically induced, phenotypic changes in mesangial cells, and (b) alterations of MMP-9 and collagen IV expression by mesangial cells may contribute to an imbalance between extracellular matrix synthesis and degradation and play a critical role in the genesis of glomerulosclerosis.

Animals↗
PubMed1995

Expression of mdr-1 in refractory lymphoma: quantitation by polymerase chain reaction and validation of the assay.

Measurement of P-glycoprotein and the gene that encodes it, mdr-1, is an important tool for assessing the impact of multidrug resistance in clinical cancer. We evaluated mdr-1 expression by a quantitative polymerase chain reaction (PCR) assay in 78 biopsy samples from 48 patients with refractory lymphoma enrolled on a trial of infusional chemotherapy (EPOCH) in which R-verapamil was added as an antagonist of P-glycoprotein in a subset of patients whose tumors were unresponsive to treatment. Expression of mdr-1 was detectable in all biopsies at the time of enrollment on study, and a fourfold or greater increase in mdr-1 expression was noted in 42% of patients at the time of treatment failure. Expression of mdr-1 was also detectable in biopsies from patients at the time of diagnosis of lymphoma. An endogenous control gene, beta 2-microglobulin, was quantitated for normalization of the mdr-1 values. The use of beta 2-microglobulin expression for normalization was validated in a subset of samples by comparing Northern blots detecting beta 2-microglobulin, beta actin, and GAPDH gene expression. Immunoblot analysis suggested that no major discrepancy was present between mRNA expression and protein level. Immunophenotyping of lymphomatous lymph nodes showed that infiltration of tumor cells ranged from 8% to 95% and of normal T cells from 1% to 83%. Expression of mdr-1 in normal T cells and monocytes was also shown to be low. The mdr-1 levels in patient samples were independent of T-cell contamination, suggesting that the presence of normal cells has at best a small impact on mdr-1 measurements. Expression of mdr-1 in lymphoma can be quantitated by PCR, and wide variations in expression can be observed. Increased expression in patients with refractory disease supports an important role for Pgp in drug resistance in lymphoma. These studies will aid in the design and interpretation of clinical trials in lymphoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Continuous infusion of the anti-CD22 immunotoxin IgG-RFB4-SMPT-dgA in patients with B-cell lymphoma: a phase I study.

IgG-RFB4-SMPT-dgA consists of deglycosylated ricin A chain (dgA) coupled to the monoclonal antihuman CD22 antibody, RFB4. This study determined the maximally tolerated dose (MTD) of this immunotoxin (IT) administered as a continuous 8-day infusion to 18 patients with B-cell lymphoma (30% CD22+ tumor cells) over 8 days. The MTD was 19.2 mg/m2/192 h (maximum toxicity grade 1), with vascular leak syndrome (VLS) as dose-limiting toxicity (DLT) at 28.8 mg/m2/192 h (grades 3 through 5 in 7 of 11 patients). Predictors of severe VLS included serum IT concentrations greater than 1,000 ng/mL and the absence of circulating tumor cells. Decreased urine sodium excreted in 24 hours provided evidence for mild VLS without notable changes in serum albumin. Four partial responses, 3 minor responses, 6 stable disease, and 3 progression of disease were observed. The mean maximal serum concentration (Cmax) in initial courses at the MTD (19.2 mg/m2) was 443 +/- 144 ng/mL (n = 3; range, 326 to 604). At 28.8 mg/m2/192 h, the Cmax was highly variable (n = 11; mean, 1,102 +/- 702; range, 9.6 to 2,032 ng/mL). Human antimouse or antiricin antibodies developed in 6 of 16 (37.5%) patients after one course of IT. However, 10 eligible patients received multiple courses of IT. Changes in serum cytokines and cytokine receptors did not correlate with toxicity but decreased soluble interleukin-2 receptor concentrations correlated with clinical response. Comparison to a prior study with the same IT administered by intermittent bolus infusions (Amlot et al, Blood 82:2624, 1993) suggests similar clinical response, toxicity, and immunogenicity.

Adult↗
PubMed1995

Debris compensation of DNA histograms and its effect on S-phase analysis.

Debris compensation is an important variable affecting S-phase fraction (SPF) analysis in flow cytometric DNA histograms. The SPF was estimated in fresh frozen breast carcinomas using the following four debris subtraction algorithms: modeling debris as an exponential curve (EXP); the incorporation of nuclei cut a single time into the exponential moel (EXP-SC); the random cutting of nuclei into multiple pieces of varying sizes (MC); and a combination of both nuclear cutting models (SC-MC). Comparison of SPF estimates indicated that the various debris subtraction models yielded differences in SPF, with SPF values obtained using the exponential model having considerable variation compared to SPF estimates from histograms where debris was modeled by algorithms based on nuclear slicing and fragmentation. However, SPF estimates could be affected by initial placement of the nuclear debris boundaries, the coefficient of variation of the G0/1 peak, and the relative amount of debris. Using the ratio of the height of the G0/1 peak to the height of the debris between the chicken red blood cells (CRBC) and G0/1 peaks as an objective measurement of nuclear debris, debris compensation was necessary in diploid DNA histograms where this ratio was as low as 1.5%. Taken in the context of SPF prognostic cutoff levels, variation in debris models and boundaries can change the classification of cases with borderline SPF levels into the poor prognostic high SPF categories, thereby making the comparison of SPF values derived from different studies difficult.

Adenocarcinoma↗
PubMed1995

Extramedullary myeloid cell tumors. An immunohistochemical study of 29 cases using routinely fixed and processed paraffin-embedded tissue sections.

OBJECTIVE: Extramedullary myeloid cell tumors (EMCTs) may be unsuspected clinically and difficult to recognize histologically. Fresh or frozen tissue is often not available for analysis. We studied 29 cases of EMCT using routinely fixed and processed paraffin-embedded tissue, an immunohistochemical method, and a panel of antibodies. PATIENTS: We studied 29 patients with EMCTs: 22 males and 7 females, with a median age of 48 years (range, 5 to 80 years). Histologically, 9 tumors were well differentiated, 16 were poorly differentiated, and 4 were blastic. RESULTS: The Leder stain (napthol-ASD-chloroacetate esterase) was positive in 21 (77.7%) of 27 tumors. Immunohistochemically, the following antibodies reacted with the greatest number of cases: Leu-22 or MT1 (CD43) in 28 (96.6%) of 29, antilysozyme in 27 (96.4%) of 28, and antimyeloperoxidase (MP07) in 21 (91.3%) of 23 cases. Other myeloid lineage-associated antibodies were positive in a subset of cases: antineutrophil elastase (NP57) in 10 (62.5%) of 16, Leu-M1 (CD15) in 7 (46.6%) of 15, and Mac-387 in 6 (40.0%) of 15 cases. The well-differentiated EMCTs reacted with most myeloid-associated antibodies; poorly differentiated and blastic tumors were more often negative. The pan-leukocyte antibody LCA (CD45RB) reacted with 15 (60%) of 25 neoplasms. Three (16.6%) of 18 tumors contained numerous p53-positive cells, ranging from 10% to 50% of the tumor cell population. In 10 cases, exons 5 through 8 of the p53 gene were analyzed using the polymerase chain reaction and single-stranded conformational polymorphism analysis. Gel shifts consistent with mutations were identified in exon 8 of one tumor (10%) that exhibited abundant p53 immunostaining. CONCLUSIONS: Immunohistochemical studies using fixed, paraffin-embedded sections are very useful in the diagnosis of EMCTs. The most sensitive antibodies are anti-CD43, antilysozyme, and antimyeloperoxidase. Immunohistochemical methods are more sensitive than the Leder stain. We found p53 staining in a small subset of cases, in which we were able to confirm evidence of p53 gene mutation using the polymerase chain reaction and single-stranded conformational polymorphism analysis in one case; p53 gene mutations appear to be uncommon in EMCTs.

Adult↗
PubMed1994

Artifactual staining of monoclonal antibodies in two-color combinations is due to an immunoglobulin in the serum and plasma.

Two-color whole blood lysis is the assay of choice for lymphocyte immunophenotyping because of the additional information it provides. Recently, artifactual double-staining of some specimens has been observed with this assay. In these cases, the samples appear to be uncompensated for spectral overlap or to inappropriately coexpress two antigens simultaneously. This artifact can result in the apparent coexpression of CD4 and CD8 (observed in lymphoblastic processes) or of CD5 and CD20 (characteristic of chronic lymphocytic leukemia) in normal persons, leading to an erroneous diagnosis. Using plasma, serum, or immunoglobulin preparations from donors who exhibit this artifact we sought to determine 1) the source of the artifact and 2) ways to overcome it. This staining is apparently due to an immunoglobulin in the donors' serum and plasma which does not have specific reactivity with mouse immunoglobulin. Washing whole blood samples or blocking with mouse immunoglobulin is a convenient way of avoiding this artifact.

Antibodies, Monoclonal↗
PubMed1994

Chimeric fusion protein toxin DAB486IL-2 in advanced mycosis fungoides and the Sezary syndrome: correlation of activity and interleukin-2 receptor expression in a phase II study.

DAB486IL-2 is a recombinant toxin with the cell surface-binding domain of diphtheria toxin (DT) replaced by interleukin-2 (IL-2). To correlate clinical response with expression of components of the IL-2 receptor (IL-2R), 14 patients with cutaneous T-cell lymphoma (CTCL) received five daily 90-minute infusions every 21 days. There were no complete responses, 1 partial response (PR), 2 major biologic effects (major cutaneous improvement without change in circulating neoplastic cells), 3 stable disease (SD), and 8 progressive disease (PD). Responders had easily detected expression of CD25 (Tac; alpha-chain of IL-2R) in skin, and in two responders expression of the beta chain of the IL-2 receptor (beta-IL-2R) was detectable by reverse transcriptase-polymerase chain reaction. CD25 was also detected in 8 of 11 SD or PD patients, with beta-IL-2R in 3 of 8 SD or PD patients. Two of the three responders had anti-DT antibodies before treatment. Reversible increased hepatic transaminases occurred in 13 of 14 patients during the first course, with decreased frequency in repeated courses. The maximal serum concentration after the first infusion of DAB486IL-2 varied (1,369 +/- 1,155 ng/mL [mean +/- SD]; n = 14; range, 55 to 3,999 ng/mL) with a short half-life (T1/2 beta = 0.21 +/- 0.12 h [mean +/- SD]; range, 0.099 to 0.57 h). The area under the concentration curve varied inversely with anti-DT antibody titer. We conclude that DA-B486IL-2 has valuable activity in certain patients with CTCL. Expression of the IL-2R may be necessary but is not sufficient to predict response.

Diphtheria Toxin↗
PubMed1994

Immunodeficiency-associated malignant lymphoma. Three cases showing genotypic evidence of both T- and B-cell lineages.

Dual rearrangement of both immunoglobulin and T-cell receptor (TCR) genes has been described in up to 30% of precursor lymphoid neoplasms, but this phenomenon occurs rarely in lymphomas with a mature phenotype. We describe three cases of immunodeficiency-associated lymphomas, two in patients with acquired immunodeficiency syndrome (AIDS) and one in a patient with a renal transplant, in which both immunoglobulin and TCR gene rearrangements were identified. Two cases exhibited clonal JH, clonal JK, and clonal TCR beta gene rearrangements; the other case had clonal JK and TCR beta gene rearrangements with deletion of JH. Two of these bigenotypic lesions exhibited a B-cell phenotype, and the other exhibited evidence of both a B- and T-cell phenotype, containing cytoplasmic CD3 as well as monoclonal kappa light chain. In addition, two of the cases exhibited the presence of clonal Epstein-Barr viral DNA. These observations suggest that lymphomas arising in immunodeficiency states may be more prone to disordered differentiation than those arising in an intact immune system.

Adult↗
PubMed1993

Alteration of the phosphorylation state of p34cdc2 kinase by the flavone L86-8275 in breast carcinoma cells. Correlation with decreased H1 kinase activity.

The flavone L86-8275 [(-)cis-5,7-dihydroxy-2-(2-chlorophenyl)-8-[4-(3-hydroxy-1-methyl)- piperidinyl]-4H-1-benzopyran-4-one] delayed the progression of aphidicolin-synchronized MDA-468 breast carcinoma cells through S phase and prevented progression through G2. L86-8275 prevented the G2-related increase in histone H1 kinase activity mediated by cyclin-dependent kinase-1 (p34cdc2 kinase). L86-8275 inhibited [32P]orthophosphate labeling of p34cdc2 threonine and tyrosine residues and decreased the phosphotyrosine content of p34cdc2. Diminution of p34cdc2 phosphotyrosine appeared selective, as a general depletion of cellular phosphotyrosine was not observed. The mass of p34cdc2 in L86-8275-exposed cells was not decreased during the period over which these effects occurred. [35S]Methionine labeling of p34cdc2 or other cellular proteins was not inhibited at concentrations that were effective for complete cellular growth inhibition. We hypothesize that L86-8275 interferes with the normal cell cycle-dependent phosphorylation of p34cdc2, resulting in decreased kinase activity and cell cycle arrest.

Amino Acid Sequence↗
PubMed1993

Tumor-infiltrating lymphocytes derived from select B-cell lymphomas secrete granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha in response to autologous tumor stimulation.

Tumor infiltrating lymphocytes (TIL) were cultured from 17 B-cell lymphoma specimens derived from patients with predominantly low-grade malignancies. Specimens included 15 lymph-node biopsies, 1 malignant pleural effusion, and PBL from 1 patient with circulating lymphoma cells. The phenotypic and proliferative characteristics of TIL cultured in interleukin-2 (IL-2) were studied, as well as cytolysis and cytokine secretion in response to autologous tumor. Flow cytometry of fresh tumor suspensions showed that 50% of cells (median) were malignant B cells and 36% were infiltrating T lymphocytes. After culture for approximately 1 month, TIL were 75% +/- 8% CD3+ (mean +/- SEM), 47% +/- 8% CD4+ and 35% +/- 7% CD8+. TIL proliferation was modest in most cases: the median maximum expansion was 32-fold in 25 days. Lysis of autologous tumor in 4-hour 51Cr release assays was mediated by 2 of 12 TIL studied, but was nonspecific. However, these same two TIL, when cocultured with various tumor stimulators, preferentially secreted tumor necrosis factor-alpha and granulocyte-macrophage colony-stimulating factor after autologous tumor stimulation; unstimulated TIL secreted undetectable or barely detectable levels of these cytokines. In one TIL culture, cytokines were secreted by purified CD4+ TIL but not by CD8+ cells, and secretion was completely abrogated by the anti-major histocompatibility complex (MHC) class II antibody IVA12. Thus, although specific cytokine secretion by lymphoma TIL in response to autologous tumor was observed, it occurred in fewer than 20% of patients studied.

Antibodies, Monoclonal↗
PubMed1993

Cell cycle arrest and growth inhibition by the protein kinase antagonist UCN-01 in human breast carcinoma cells.

UCN-01 is a derivative of staurosporine, initially developed as a potentially selective inhibitor of the Ca(2+)- and phospholipid-dependent protein kinase C, but with the capacity to inhibit a number of tyrosine and serine/threonine kinases. UCN-01 inhibits the growth of 5 breast carcinoma cell lines with a 50% inhibitory concentration range of 30-100 nM during 6 days of continuous exposure. In MCF-7, MDA-MB453, and SK-BR-3 cells, UCN-01 is 5-fold more potent in growth inhibition than its diastereomer UCN-02, but the 2 compounds are equipotent in the inhibition of MDA-MB468 and H85787 cell growth. A differential sensitivity to a 24-h period of exposure to UCN-01 followed by drug removal and growth for 5 subsequent days was observed. The rank order for persistent inhibition of cells by UCN-01 was MCF-7, MDA-MB453 >> SK-BR-3 > H85787 > MDA-MB468. MCF-7 and MDA-MB453 cells did not resume proliferation within the 5 days after brief exposure to UCN-01. In contrast, MDA-MB468 and H85787 cells showed no net growth inhibition after a 24-h pulse of UCN-01, followed by 5 more days of growth in drug-free medium. In MDA-MB468 cells, 150 nM UCN-01 retards but does not prevent cell cycle progression through S phase, but the cells are clearly blocked from exit of G1 and entry into S. Progression through S phase is completely inhibited by 600 nM UCN-01. The development of a G1 to S block by UCN-01 in MDA-MB468 cells occurs in conjunction with inhibition of [32P]orthophosphate labeling and decreased phosphotyrosine mass of discrete cellular phosphoproteins.

Alkaloids↗
PubMed1993

Flow cytometry and Zollinger-Ellison syndrome: relationship to clinical course.

BACKGROUND: With successful means of controlling gastric acid secretion in patients with Zollinger-Ellison syndrome, the gastrinoma itself is becoming the major determinant of long-term survival. No methods have yet been described to predict which tumors will have more malignant courses thereby indicating which patients should undergo aggressive surgery or antitumor therapy. Because DNA analysis, using flow cytometry, has proved helpful in this regard in other tumors, the current study was designed to evaluate its utility in gastrinoma patients. METHODS: Flow cytometry was performed on 81 paraffin-embedded gastrinoma specimens from 59 patients. Results were compared with preoperative patient characteristics, findings at surgery, and postoperative follow up. RESULTS: Tumors were diploid in 54% of patients, near diploid in 15%, pure tetraploid in 0%, nontetraploid aneuploid in 25%, and multiple stem line aneuploid in 5%. All patients with multiple stem line aneuploid tumors had wide-spread metastases whereas all patients with nontetraploid aneuploid tumors had localized or regional disease. Median S phase percentage was 3.6. S phase percentages were higher in patients with widespread metastatic disease than in patients with localized or regional disease. Disease extent also correlated closely with fasting serum gastrin level. After removing this variable with logistic regression analysis, the significant correlation between disease extent and DNA analysis persisted. CONCLUSIONS: DNA analysis of gastrinoma tissue specimens correlates independently with the extent of disease and may be useful in planning therapeutic strategies for patients with Zollinger-Ellison syndrome.

Adult↗
PubMed1993

bcl-2 expression in Hodgkin's disease. Correlation with the t(14;18) translocation and Epstein-Barr virus.

In a prior study from our laboratory using the polymerase chain reaction (PCR) technique, the t(14;18)(q32;q21) translocation was detected in low copy number in 32% of Hodgkin's disease cases. The cell of origin of the t(14;18), however, was not determined. To further investigate the role of bcl-2 in Hodgkin's disease and the possibility that the translocation resides in Reed-Sternberg and Hodgkin's (RS-H) cells, we analyzed selected cases of Hodgkin's disease immunohistologically using a monoclonal antibody reactive with bcl-2. Because Epstein-Barr virus (EBV) has been reported to upregulate bcl-2 expression, we also used an in situ method for detecting EBV in these tissues. Thirteen cases of Hodgkin's disease were studied, including seven cases with the t(14;18) translocation and six cases without it, as determined by PCR in a prior study. bcl-2 protein was detected immunohistologically in the RS-H cells in eight cases: three with the t(14;18) translocation and five in which the translocation was not detected. EBV RNA was detected in the RS-H cells of four patients, including two in which the RS-H cells also were bcl-2 positive. The presence of bcl-2 staining of the RS-H cells in this series of cases did not correlate with clinical features, histologic subtype, the presence of the t(14;18) translocation, or EBV-positivity. The lack of consistent bcl-2 protein expression in RS-H cells, including EBV-positive RS-H cells, may suggest that the t(14;18) translocation does not reside in RS-H cells in at least a subset of cases of Hodgkin's disease. If this is true, the t(14;18) translocation may not play an important role in the pathogenesis of Hodgkin's disease.

Adolescent↗
PubMed1993

Follicular center cell lymphoma with the t(14;18) translocation in which the rearranged BCL-2 gene is silent.

Using reverse transcription and the polymerase chain reaction (RT-PCR), we determined the level of expression of BCL-2/IgH in 18 follicular center cell lymphomas containing a t(14;18) translocation involving the major breakpoint region and five non-neoplastic lymph nodes. BCL-2/IgH transcripts were demonstrated in 16 follicular center cell lymphoma cases (five high, 11 low) and were not present in any of the five non-neoplastic lymph nodes. In the two follicular lymphoma cases in which BCL-2/IgH transcripts could not be detected by RT-PCR, PCR amplification of genomic DNA indicated this was not due to primer selection. In addition, non-expression was confirmed at the protein level by immunoperoxidase studies. We therefore conclude that these represent true negative cases. This is the first time primary follicular lymphoma cases have been quantitatively studied at the RNA level for expression of BCL-2. We conclude that RT-PCR is a sensitive method for determining levels of expression of this oncogene and may be useful in studying the involvement of BCL-2 in follicular lymphoma.

Adult↗
PubMed1993

Malignant thymoma associated with T-cell lymphocytosis. A case report with immunophenotypic and gene rearrangement analysis.

Patients with malignant thymoma rarely may also have a peripheral T-cell lymphocytosis. "Lymphocyte spillover" from the thymus into the peripheral blood as well as a second, associated neoplasm (ie, T-cell chronic lymphocytic leukemia) are two hypotheses that have been proposed to explain this clinical phenomenon. We describe another patient with a lymphocyte-rich malignant thymoma associated with peripheral T-cell lymphocytosis. At the time of initial diagnosis, the patient's complete blood cell count was unremarkable. However, subsequent to the development of pulmonary metastases, the patient developed persistent lymphocytosis. The total leukocyte count ranged from 20 to 30 x 10(9)/L, 80% of these cells being lymphocytes. Immunophenotypic analysis of peripheral blood specimens from this patient proved that the circulating cells were mature, polyclonal T cells. The cells expressed the alpha/beta T-cell receptor and the pan-T-cell antigens CD2, CD3, CD5, and CD7, and were negative for both terminal deoxynucleotidyl transferase (TdT) and the CD1 antigen. A mixture of T-helper (CD4+) and T-suppressor (CD8+) cells were present in a ratio of 1:1.6. Gene rearrangement studies revealed that the T-cell receptor beta chain and the immunoglobulin heavy-chain genes were in the germline configuration. Serum samples from this patient were also analyzed for thymic hormones; the level of thymosin alpha 1 was markedly elevated, while that of thymosin beta 4 was decreased. These results effectively exclude the hypothesis that the lymphocytosis represents a second, associated neoplasm. The lymphocyte spillover hypothesis also seems unlikely (although not excluded), since the lymphocytes in lymphocyte-rich thymomas usually have an immature thymic cortical immunophenotype. Furthermore, one might expect nonspecific elevation of all thymic hormone levels with lymphocyte spillover. Thus, we suggest that the lymphocytosis results from a poorly defined immunoregulatory disorder, related to the presence of thymoma, and perhaps secondary thymic hormone imbalance.

Aged↗