Pattern of CD14+ follicular dendritic cells and PD1+ T cells independently predicts time to transformation in follicular lymphoma

PURPOSE

Transformation of follicular lymphoma is a critical event associated with a poor prognosis. The role of the tumor microenvironment in previous transformation studies has yielded conflicting results.

EXPERIMENTAL DESIGN

To define cell subtypes associated with transformation, we examined tissue specimens at diagnosis from patients with follicular lymphoma that later transformed and, using immunohistochemistry (IHC), stained for CD68, CD11c, CD21, CXCL13, FOXP3, PD1, and CD14. Cell content and the pattern of expression were evaluated. Those identified as significantly associated with time to transformation (TTT) and overall survival (OS) were further characterized by flow cytometry and multicolor IHC.

RESULTS

Of note, 58 patients were analyzed with median TTT of 4.7 years. The pattern of PD1(+) and CD14(+) cells rather than the quantity of cells was predictive of clinical outcomes. On multivariate analysis, including the follicular lymphoma international prognostic index score, CD14(+) cells localized in the follicle were associated with a shorter TTT (HR, 3.0; P = 0.004). PD1(+) cells with diffuse staining were associated with a shorter TTT (HR, 1.9; P = 0.045) and inferior OS (HR, 2.5; P = 0.012). Multicolor IHC and flow cytometry identified CD14(+) cells as follicular dendritic cells (FDC), whereas PD1(+) cells represented two separate populations, TFH and exhausted T cells.

CONCLUSION

These results identify the presence of PD1(+) T cells and CD14(+) FDC as independent predictors of transformation in follicular lymphoma. Clin Cancer Res; 20(11); 2862-72. ©2014 AACR.

Prognostic significance of pretreatment serum cytokines in classical Hodgkin lymphoma

PURPOSE

Although the International Prognostic Score (IPS) is the gold standard for risk-stratifying patients with classical Hodgkin lymphoma (cHL), these criteria do not accurately predict outcome. As cytokines are critically involved in driving cHL, we tested whether pretreatment serum cytokine levels could provide additional prognostic information.

EXPERIMENTAL DESIGN

Thirty cytokines were measured in pretreatment serum from 140 patients with cHL and compared with 50 nonlymphoma controls. Patients were followed for event-free survival (EFS) and overall survival (OS), and Cox proportional hazards regression models were used to assess the association of individual cytokines and the cytokine profiles with outcome via unadjusted and IPS-adjusted HR.

RESULTS

Twelve cytokines (EGF, bFGF, G-CSF, HGF, IL-6, IL-8, IL-12, IL-2R, IP-10, MIG, TNF-α, and VEGF) were significantly (P < 0.05) higher in patients with cHL than controls; elevated levels of HGF, IL-6, IL-2R, IP-10, and MIG were all associated with poorer EFS. Only interleukin-2 receptor (IL-2R; P = 0.002) and interleukin (IL)-6 (P < 0.001) were independently prognostic. Patients with increased IL-6 and IL-2R had a significantly higher risk of early relapse and death, a finding that remained significant even after IPS-based risk stratification. Although elevated IL-6 and IL-2R correlated with the IPS, soluble CD30 (sCD30), and thymus and activation-related chemokine (TARC) levels, the two-cytokine model remained independently predictive of prognosis.

CONCLUSIONS

Elevated pretreatment serum cytokines are associated with increased disease relapse and inferior survival in cHL. Thus, the pretreatment cytokine profile, particularly serum levels of IL-6 and IL-2R, may be used to identify patients with cHL at high risk for early-disease relapse.

Cytokine gene polymorphisms and progression-free survival in classical Hodgkin lymphoma by EBV status: results from two independent cohorts

BACKGROUND

Cytokines are important immune mediators of classical Hodgkin lymphoma (CHL) pathogenesis, and circulating levels at diagnosis may help predict prognosis. Germline single nucleotide polymorphisms (SNPs) in immune genes have been correlated with cytokine production and function.

METHODS

We investigated whether selected germline SNPs in IL10 (rs1800890, rs1800896, rs1800871, rs1800872), TNFA (rs1800629), IL6 (rs1800795), ILRN (rs419598), INFG (rs2430561) and CCL17 (rs223828) were associated with circulating levels of related cytokines at diagnosis and progression-free survival (PFS) in CHL. Patients were from France (GELA, N=464; median age=32years) and the United States (Iowa/Mayo Specialized Program Of Research Excellence [SPORE], N=239; median age=38years); 22% of 346 CHL cases with EBV tumor status were positive.

RESULTS

There was no association with any of the SNPs with cytokine levels. Overall, there was no association of any of the SNPs with PFS. In exploratory analyses by EBV status, TNFA rs1800629 (HRAA/AG=2.41; 95%CI, 1.17-4.94) was associated with PFS in EBV-negative GELA patients, with similar trends in the SPORE patients (HRAA/AG=1.63; 95%CI, 0.61-4.40). In a meta-analysis of the two studies, TNFA (HRAA/AG=2.11; 95%CI, 1.18-3.77; P=0.01) was statistically significant, and further adjustment for the international prognostic system did not alter this result.

CONCLUSIONS

This study showed that germline variation in TNFA was associated with CHL prognosis for EBV-negative patients, which will require confirmation. These results support broader studies on the differential impact of genetic variation in immune genes on EBV-positive vs. EBV-negative CHL pathogenesis.

Soluble and membrane-bound TGF-β-mediated regulation of intratumoral T cell differentiation and function in B-cell non-Hodgkin lymphoma

While the effect of TGF-β on malignant B cells in non-Hodgkin lymphoma (NHL) has been previously evaluated, studies to specifically define the role of TGF-β in tumor immunity in B-cell NHL are limited. We found that soluble TGF-β, secreted by both lymphoma cells and intratumoral T cells, is present in the serum of patients with B-cell NHL. Soluble TGF-β promoted regulatory T (T_reg) cells by enhancing expression of Foxp3 in CD4⁺ T cells and suppressed effector helper T (T_H) cells by inhibiting expression of IFN-γ and IL-17. Blockade of the IL-2 signaling pathway diminished the effect of soluble TGF-β on T cell differentiation. Furthermore, we found that membrane-bound TGF-β is expressed specifically on the surface of malignant B cells in B-cell NHL. TGF-β was able to bind to the surface of lymphoma B cells through an interaction with heparan sulfate (HS) but not through the TGF-β receptor. We showed that pretreatment of lymphoma B cells with TGF-β significantly inhibits the proliferation and cytokine production of intratumoral T cells. Taken together, these results suggest that tumor-associated soluble and membrane-bound TGF-β are involved in the regulation of intratumoral T cell differentiation and function in B-cell NHL.

Pretreatment circulating serum cytokines associated with follicular and diffuse large B-cell lymphoma: a clinic-based case-control study

BACKGROUND

Abnormal immune function is a key factor in predisposition to non-Hodgkin lymphoma (NHL). We evaluated the association of 30 cytokines individually and as a profile with diffuse large B-cell (DLBCL) and follicular (FL) lymphomas.

METHODS

We used a multiplexed assay to measure 30 cytokine concentrations in pre-treatment serum in a case-control study of 234 FL, 188 DLBCL, and 400 control participants. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for age and sex, and polytomous regression was used to evaluate heterogeneity between FL and DLBCL. Principal components analysis (PCA) was used to assess cytokine profiles associated with FL and DLBCL.

RESULTS

In single cytokine modeling, we found that 12 of the 30 circulating serum cytokines were significantly (P<0.05) associated with FL and/or DLBCL after accounting for multiple testing (q<0.05). Soluble IL-2R (sIL-2R) had the strongest association with both FL (OR=6.0 for highest versus lowest tertile, 95% CI 3.8-9.5; p-trend=1.8 × 10(-21)) and DLBCL (OR=7.6, 95% CI 4.5-13.1; p-trend=7.2 × 10(-20)). IL1RA and IL-12p40 also showed similar associations for DLBCL and FL. In contrast, HGF, MIG, and MIP-1α had a stronger association with DLBCL compared to FL, and IL-6, IL-8, IL-10, IFN-γ, IP-10, and VEGF were only statistically significantly associated with DLBCL after accounting for multiple testing. However, in PCA modeling, a cytokine profile based on sIL-2R, IL-1RA, MIG, IP-10, IL-8, and IL-12p40 explained most of the variability between controls and both FL and DLBCL.

CONCLUSIONS

We identified some cytokines unique to DLBCL, but overall cytokine associations were more similar than distinct for DLBCL and FL. While these data are limited by concerns of reverse causality, they do suggest cytokines and cytokine profiles that can be prioritized in future studies.

Elevated pretreatment serum levels of interferon-inducible protein-10 (CXCL10) predict disease relapse and prognosis in diffuse large B-cell lymphoma patients

Although standard clinical prognostic factors predict outcome in diffuse large B-cell lymphoma (DLBCL), predicting the outcome of patients might be further refined using biological factors. We tested whether serum cytokines could provide prognostic information in DLBCL patients. Thirty cytokines were measured in pretreatment samples from newly diagnosed DLBCL patients using a multiplex ELISA. Sixty-nine patients treated with R-CHOP plus epratuzumab were used in an initial cohort and 185 patients treated with standard R-CHOP served as a subsequent validation cohort. In the initial cohort, elevated serum interleukin-10 [IL-10; hazard ratio (HR) = 6.6, P = 0.022], granulocyte macrophage colony-stimulating factor (HR = 10.8, P= 0.027) and IP-10 (interferon-inducible protein-10, CXCL10; HR = 3.32, P = 0.015) were associated with event-free survival (EFS). An identical analysis of the subsequent validation cohort confirmed that elevated serum levels of IP-10 were strongly associated with a poor EFS (HR = 2.42, P = 0.0007); and also identified interleukin-8 (IL-8; HR = 3.40, P = 0.00002) and interleukin-2 receptor (IL-2R, CD25; HR = 2.59, P = 0.0012) as significantly associated with prognosis. The prognostic significance of elevated IP-10 remained significant after adjustment for the International Prognostic Index (EFS - HR 1.99, P = 0.009, overall survival-HR 1.93, P = 0.021). Elevated pretreatment serum IP-10 levels are therefore associated with an increased likelihood of disease relapse and an inferior survival in patients with DLBCL.

IL-12 upregulates TIM-3 expression and induces T cell exhaustion in patients with follicular B cell non-Hodgkin lymphoma

The cytokine IL-12 induces IFN-γ production by T and NK cells. In preclinical models, it contributes to antitumor immunity. However, in clinical testing, it has shown limited benefit in patients with any one of a variety of malignancies. Moreover, in a clinical trial testing a combination of IL-12 and rituximab in patients with follicular B cell non-Hodgkin lymphoma (FL), those treated with IL-12 showed a lower response rate, suggesting that IL-12 actually plays a detrimental role. Here, we investigated whether the failure of IL-12 treatment for FL was due to T cell exhaustion, a condition characterized by reduced T cell differentiation, proliferation, and function, which has been observed in chronic viral infection. We found that extended exposure to IL-12 induced T cell exhaustion and contributed to the poor prognosis in FL patients. Long-term exposure of freshly isolated human CD4+ T cells to IL-12 in vitro caused T cell dysfunction and induced expression of TIM-3, a T cell immunoglobulin and mucin domain protein with a known role in T cell exhaustion, via an IFN-γ-independent mechanism. TIM-3 was required for the negative effect of IL-12 on T cell function. Importantly, TIM-3 also was highly expressed on intratumoral T cells that displayed marked functional impairment. Our findings identify IL-12- and TIM-3-mediated exhaustion of T cells as a mechanism for poor clinical outcome when IL-12 is administered to FL patients.

Denileukin diftitox in combination with rituximab for previously untreated follicular B-cell non-Hodgkin's lymphoma

Follicular lymphoma exhibits intratumoral infiltration by non-malignant T lymphocytes inluding CD4+CD25+ regulatory T (T_reg) cells. We combined denileukin diftitox with rituximab in previously untreated, advanced-stage follicular lymphoma patients anticipating that denileukin diftitox would deplete CD25+ T_reg cells while rituximab would deplete malignant B-cells. Patients received rituximab 375 mg/m2 weekly for 4 weeks and denileukin diftitox 18 mcg/kg/day for 5 days every 3 weeks for 4 cycles; neither agent was given as maintenance therapy. Between August 2008 and March 2010, 24 patients were enrolled. One patient died before treatment was given and was not included in the analysis. Eleven of 23 patients (48%; 95% CI: 27–69%) responded; 2 (9%) had complete responses and 9 (39%) had partial responses. The progression-free rate at 2 years was 55% (95%CI: 37–82%). Thirteen patients (57%) experienced grade ≥3 adverse events and 1 patient (4%) died. In correlative studies, soluble CD25 and the number of CD25+ T-cells decreased after treatment, however there was a compensatory increase in IL-15 and IP-10. We conclude that while the addition of denileukin diftitox to rituximab decreased the number of CD25+ T-cells, denileukin diftitox contributed to the toxicity of the combination without an improvement in response rate or time to progression.

Temsirolimus and rituximab in patients with relapsed or refractory mantle cell lymphoma: a phase 2 study

BACKGROUND

Temsirolimus is a mammalian target of rapamycin (mTOR) inhibitor with single-agent antitumour activity in patients with mantle cell lymphoma. We therefore tested its efficacy and toxicity in combination with rituximab (an antiCD20 antibody) in patients with relapsed or refractory mantle cell lymphoma.

METHODS

In a phase 2 study, patients (aged ≥18 years) at 35 centres in the USA were given temsirolimus 25 mg/week, and rituximab 375 mg/m(2) per week for 4 weeks during the first cycle and thereafter a single dose of rituximab every other 28-day cycle. Both drugs were administered intravenously. Responding patients after six cycles could continue treatment for a total of 12 cycles, and were then observed without additional maintenance treatment. The primary endpoint was the proportion of patients with either rituximab-sensitive or rituximab-refractory disease who had at least a partial response. The analyses were done on all patients who were treated. The study was registered with ClinicalTrials.gov, number NCT00109967.

FINDINGS

71 patients with mantle cell lymphoma were enrolled and 69 were assessable and were included in the final analysis. The overall response rate (ORR) was 59% (41 of 69 patients)-13 (19%) patients had complete responses and 28 (41%) had partial responses. The ORR was 63% (30 of 48; 95% CI 47-76) for rituximab-sensitive patients, and 52% (11 of 21; 30-74) for rituximab-refractory patients. The most common treatment-related grade 3 or 4 adverse events in rituximab-sensitive and rituximab-refractory patients were thrombocytopenia (eight [17%] and eight [38%], respectively), neutropenia (ten [21%] and five [24%], respectively), fatigue (eight [17%] and two [10%], respectively), leucopenia (six [13%] and three [14%], respectively), pneumonia (five [10%] and two [10%], respectively), lymphopenia (five [10%] and two [10%], respectively), pneumonitis (four [8%] and none, respectively), oedema (four [8%] and none, respectively), dyspnoea (three [6%] and two [10%], respectively), and hypertriglyceridaemia (three [6%] and two [10%], respectively).

INTERPRETATION

mTOR inhibitors in combination with rituximab could have a role in the treatment of patients with relapsed and refractory mantle cell lymphoma.

FUNDING

National Institutes of Health and the Predolin Foundation.

GLI2 transcription factor mediates cytokine cross-talk in the tumor microenvironment

Tumor cells interact with their surrounding microenvironment to survive and persist within the host. Cytokines play a key role in regulating this crosstalk between malignant cells and surrounding cells in the microenvironment. Although this phenomenon is clearly established, the molecular mechanisms mediating this cellular event remain elusive. Here, using as a model bone marrow stromal cells, we describe a novel signaling mechanism initiated by CCL5 in these cells leading to up-regulation of immunoglobulin secretion by malignant B cells. CCL5 increases IL-6 expression and secretion in bone marrow stromal cells. IL-6 in turn induces Ig secretion by malignant B cells. Analysis of the mechanism reveals that CCL5 signaling induces GLI2 through a PI3K-AKT-IκBα-p65 pathway and requires GLI2 transcriptional activity to modulate IL-6 expression and Ig secretion in vitro and in vivo. Together, these results identify a novel signaling pathway mediating the stromal-cancer cell interactions, leading to increased Ig production by malignant cells.

A BAFF-R mutation associated with non-Hodgkin lymphoma alters TRAF recruitment and reveals new insights into BAFF-R signaling

The cytokine B cell activating factor (BAFF) and its receptor, BAFF receptor (BAFF-R), modulate signaling cascades critical for B cell development and survival. We identified a novel mutation in TNFRSF13C, the gene encoding human BAFF-R, that is present in both tumor and germline tissue from a subset of patients with non-Hodgkin lymphoma. This mutation encodes a His159Tyr substitution in the cytoplasmic tail of BAFF-R adjacent to the TRAF3 binding motif. Signaling through this mutant BAFF-R results in increased NF-κB1 and NF-κB2 activity and increased immunoglobulin production compared with the wild-type (WT) BAFF-R. This correlates with increased TRAF2, TRAF3, and TRAF6 recruitment to His159Tyr BAFF-R. In addition, we document a requirement for TRAF6 in WT BAFF-R signaling. Together, these data identify a novel lymphoma-associated mutation in human BAFF-R that results in NF-κB activation and reveals TRAF6 as a necessary component of normal BAFF-R signaling.

Malignant B cells skew the balance of regulatory T cells and TH17 cells in B-cell non-Hodgkin's lymphoma

Using biopsy specimens from patients with B-cell non-Hodgkin's lymphoma, we observed a significantly low frequency of T(H)17 cells, including several samples with no detectable amount of interleukin (IL)-17-producing cells present in the tumor microenvironment. We found that, in the absence of lymphoma B cells, treatment with IL-1beta/IL-6 or lipopolysaccharide (LPS) enhanced IL-17 expression in CD4(+) T cells and this enhancement was attenuated when CD4(+) T cells were cocultured with lymphoma B cells. Blockade of CD27-CD70 or CD28-CD80/86 interactions by anti-CD70 or anti-CD80/86 antibodies restored LPS-mediated induction of IL-17 expression in CD4(+) T cells cocultured with lymphoma B cells. Because a subset of lymphoma B cells express IL-2 and given that IL-2 signaling is critically important in the development of regulatory T (T(reg)) cells, we tested the role of IL-2 signaling in T(H)17 cell development. We found that treatment with anti-IL-2 antibody to interrupt IL-2 signaling significantly inhibited Foxp3 expression in CD4(+) T cells. In contrast, interruption of IL-2 signaling up-regulated IL-17 expression in CD4(+) T cells and restored lymphoma-mediated down-regulation of IL-17-producing cells. Furthermore, the reversal of T(reg) cell activity by LPS or CpG-A resulted in an enhancement of IL-17-producing cells. Taken together, our study indicated that lymphoma B cells play an important role in skewing the balance between T(reg) and T(H)17 cells resulting in the establishment of a profoundly inhibitory tumor microenvironment.

A role for IFN-lambda1 in multiple myeloma B cell growth

Multiple myeloma (MM) is a progressive disease that results from dysregulated proliferation of plasma cells. Although, causative factors such as genetic events and altered expression of anti-apoptotic factors have been described in a number of patients, the mechanistic details that drive myeloma development and continued growth of malignant cells remain largely undefined. Numerous growth factors, including interleukin (IL)-6, Insulin-like growth factor-1 and IL-10 have been shown to promote growth of MM cells suggesting a significant role for cytokines in this disease. Interferon (IFN)-lambda1 is a new member of the Class II cytokine family that, similar to IFN-alpha, has been shown to mediate viral immunity. In light of data supporting a role for cytokines in myeloma, we investigated the significance of IFN-lambda1 on myeloma cell biology. Our studies show for the first time that myeloma cells bind to soluble IFN-lambda1, and that IFN-lambda1 induces myeloma cell growth and protects against dexamethasone-induced cell death. Our data also show that IFN-lambda1 induces phosphorylation of STAT1, STAT3 and Erk. Taken together, our results suggest that IFN-lambda1 may regulate myeloma cell biology and could prove to be therapeutically important.

CD70+ non-Hodgkin lymphoma B cells induce Foxp3 expression and regulatory function in intratumoral CD4+CD25 T cells

Foxp3 expression was initially thought to be restricted to the CD4(+)CD25(+) regulatory T-cell population. However, recent studies suggest that forkhead box P3 (Foxp3) is expressed in CD4(+)CD25(-) T cells in aged mice. In the present study in B-cell non-Hodgkin lymphoma (NHL), we found that a subset of intratumoral but not peripheral blood CD4(+)CD25(-) T cells, comprising about 15% of intratumoral CD4(+) T cells, express Foxp3 and are capable of suppressing the proliferation of autologous infiltrating CD8(+) T cells. In vitro activation with OKT3/anti-CD28 antibody (Ab) or dendritic cells (DCs) induced Foxp3 expression in a subset of these CD4(+)CD25(-)Foxp3(-) T cells. We found that the presence of lymphoma B cells during activation augmented activation-induced Foxp3 expression in CD4(+)CD25(-) T cells. We also found that CD70(+) lymphoma B cells significantly contributed to the activation-induced Foxp3 expression in intratumoral CD4(+)CD25(-) T cells. Furthermore, the blockade of CD27-CD70 interaction by anti-CD70 Ab abrogated lymphoma B-cell-mediated induction of Foxp3 expression in intratumoral CD4(+)CD25(-) T cells. Taken together, these studies reveal a novel role for NHL B cells in the development of intratumoral regulatory T cells.

Attenuation of CD8(+) T-cell function by CD4(+)CD25(+) regulatory T cells in B-cell non-Hodgkin's lymphoma

The underlying mechanisms by which tumor cells are resistant to CTL-mediated apoptosis are not clear. Using a human model of B-cell non-Hodgkin's lymphoma (B-cell NHL), we show that intratumoral T(reg) cells inhibit the proliferation and granule production of activated autologous infiltrating CD8(+) T cells. Our results also show that degranulation and subsequent cytotoxic activity of infiltrating CD8(+) T cells exposed to lymphoma B cells is completely attenuated by the presence of intratumoral T(reg) cells. Furthermore, we show that increased numbers of intratumoral T(reg) cells correlates with the number of CD8(+) T cells in biopsy specimens from patients with B-cell NHL, supporting the in vitro findings that intratumoral T(reg) cells inhibit proliferation of infiltrating CD8(+) T cells. Taken together, these data indicate that human lymphoma B cells are sensitive to autologous CTL-mediated cell death but are protected by the inhibitory function of intratumoral T(reg) cells.

Flavopiridol in patients with relapsed or refractory multiple myeloma: a phase 2 trial with clinical and pharmacodynamic end-points

Flavopiridol downregulates anti-apoptotic regulators including Mcl-1, upregulates p53, globally attenuates transcription through inhibition of P-TEFb, binds to DNA, and inhibits angiogenesis. Eighteen myeloma patients were treated with 1-hour flavopiridol infusions for 3 consecutive days every 21 days. Immunoblotting for Mcl-1, Bcl-2, p53, cyclin D, phosphoRNA polymerase II and phosphoSTAT 3 was conducted on myeloma cells. Ex vivo flavopiridol treatment of cells resulted in cytotoxicity, but only after longer exposure times at higher flavopiridol concentrations than were anticipated to be achieved in vivo. No anti-myeloma activity was observed in vivo. As administered, flavopiridol has disappointing activity as a single agent in advanced myeloma.

Elevated serum B-lymphocyte stimulator levels in patients with familial lymphoproliferative disorders

PURPOSE

Serum B-lymphocyte stimulator (BLyS) levels have been found to be elevated in a number of immune disease models. Therefore, we sought to establish whether BLyS levels were elevated in patients with B-cell lymphoproliferative disorders and to determine whether elevated BLyS levels correlated with clinical characteristics of the disease.

PATIENTS AND METHODS

Specimens were collected from the peripheral blood of individuals diagnosed with B-cell chronic lymphocytic leukemia (B-CLL; n = 70) or from age- and sex-matched patients seen at the same institution (n = 41). Serum BLyS levels were determined by enzyme-linked immunosorbent assay, and sequencing of the BLyS promoter was performed by conventional methods and confirmed by restriction fragment length polymorphism analysis.

RESULTS

We found that elevated BLyS levels were more common in patients with familial B-CLL than individuals with sporadic B-CLL or normal controls. Because of this association, we sequenced the BLyS promoter in patients with B-CLL and normal controls and identified a polymorphic site, -871 C/T. We found that the wild-type sequence was significantly underrepresented in patients with familial B-CLL (4%) compared with patients with sporadic B-CLL (30%; P = .01) or controls (24%; P = .04). Furthermore, using a luciferase reporter under control of the BLyS promoter containing either a C or a T at position -871, we found that the reporter construct containing a T at -871 had a 2.6-fold increase in activity (P = .004).

CONCLUSION

Our data suggest serum BLyS levels are elevated in patients with familial B-CLL and that elevated BLyS levels correlate with the presence of a T at -871 in the BLyS promoter.

B-lymphocyte stimulator (BLyS) stimulates immunoglobulin production and malignant B-cell growth in Waldenstrom macroglobulinemia

Waldenström macroglobulinemia (WM) is a serious and frequently fatal B-cell malignancy associated with an elevated monoclonal IgM protein in the serum. Many of the mechanisms leading to this disease are not yet known. B-lymphocyte stimulator (BLyS) is a TNF family member that is critical for maintenance of normal B-cell development and homeostasis. BLyS is overexpressed in a variety of B-cell malignancies and has been shown to inhibit apoptosis in malignant B cells. It also regulates immunoglobulin secretion by normal B cells. To determine the relevance of BLyS in WM, we examined the role of BLyS in WM patient samples. Malignant B cells were found to bind soluble BLyS and variably express the receptors BAFF-R, TACI, and BCMA. We also found expression of BLyS in bone marrow specimens by immunohistochemistry and elevated serum BLyS levels in patients with WM. BLyS, alone or in combination with cytokines that induce immunoglobulin production, was found to increase IgM secretion by malignant B cells. Furthermore, BLyS was found to increase the viability and proliferation of malignant B cells from WM patients. Due to the role of BLyS in WM, strategies to inhibit BLyS may potentially have therapeutic efficacy in these patients.

Expression of BLyS and its receptors in B-cell non-Hodgkin lymphoma: correlation with disease activity and patient outcome

BLyS, recently shown to be critical for survival of normal B cells, has been found to be elevated in a number of immune disease models. A role for BLyS in the survival of malignant B cells has also been revealed and we therefore sought to identify a role for BLyS and its receptors in non-Hodgkin lymphoma (NHL). We found that tumor cells from all NHL histologic subtypes expressed one or more of 3 known receptors (BCMA, TACI, and BAFF-R) for BLyS; however, the pattern of expression was variable. We provide evidence that BLyS is expressed in tumors from patients with NHL and that BLyS levels increase as tumors transform to a more aggressive phenotype. Additionally, we provide evidence that serum BLyS levels are elevated in a subgroup of patients with NHL. In patients with de novo large B-cell lymphoma, a high BLyS level correlated with a poorer median overall survival, the presence of constitutional symptoms, and elevated values of lactic dehydrogenase. When BLyS levels were correlated with response to therapy in all patients, responding patients had a significantly lower BLyS level than those with progressive disease. In summary, we found that BLyS and its receptors represent a potentially important therapeutic target in B-cell lymphoma.

Adenoma-specific alterations of protein kinase C isozyme expression in Apc(MIN) mice

Members of the protein kinase C (PKC) family appear to play important roles in colorectal carcinogenesis. To investigate the potential involvement of PKC isozymes in adenomatous transformation induced by inactivation of the adenomatous polyposis coli (APC) gene product, we examined protein levels and localizations of ten PKC isozymes by immunohistochemistry in normal and adenomatous ileal epithelium of ApcMIN mice. Compared with surrounding normal epithelium, adenomas showed dramatically reduced staining for PKCs a, beta1, and zeta, as well as dysplasia-specific punctate nuclear staining of PKC mu. We conclude that reduced protein expression of PKC alpha, beta1, and zeta, and nuclear localization of PKC mu are markers of, and are perhaps involved in, adenomatous transformation induced by APC inactivation in ApcMIN mice.

Monoclonal antibodies against the human sodium iodide symporter: utility for immunocytochemistry of thyroid cancer

The recent cloning of the thyroidal protein that is responsible for iodide transport, the sodium iodide symporter (hNIS), has made possible studies designed to characterize its structure, function and expression in thyroidal tissues. Using a mannose binding protein (MBP)-hNIS fusion protein as antigen, we have developed mouse monoclonal antibodies against hNIS to utilize as tools in such studies. Twenty-four clones were initially recovered which recognized the MBP-hNIS fusion protein, but only two of them were specific for hNIS while the others recognized MBP alone. Both antibodies were found to be immunoglobulin G (IgG) 1kappa (kappa). The specificity of antibodies was tested by Western blotting using membranes prepared from COS-7 cells transiently transfected with the pcDNA3 plasmid containing the full-length hNIS cDNA, or cells transfected with the pcDNA3 vector. A major band with a molecular weight (MW) of approximately 97 kDa, and several minor bands with MW of approximately 160 kDa, approximately 68 kDa, approximately 30 kDa and approximately 15 kDa, were detected specifically in the hNIS-transfected cells. After enzymatic deglycosylation, the major band was present at 68 kDa, as expected based upon the amino acid sequence of hNIS. Immunohistochemistry was performed with several different types of thyroid tissue and non-thyroidal tissues, using the monoclonal antibodies. Strong immunostaining was observed in Graves' tissue, with intermediate staining in papillary and follicular thyroid cancers and an absence of staining in Hürthle cell cancer. The staining was specific for the follicular epithelium and was concentrated in the basolateral portion of the cell membrane. These monoclonal hNIS antibodies should prove useful in the characterization of NIS expression in benign and malignant thyroid tissue and in studies characterizing its structure and function.

Expression of nm23/nucleoside diphosphate kinase-A protein in endometrial carcinoma

A metastatic tumor suppressor role for the nm23 gene product in breast carcinoma has been proposed. The biologic significance of nm23/NDP kinase-A (NDPK-A) expression in endometrial carcinoma remains undetermined. We sought to (1) characterize the pattern and intensity of nm23 protein expression in endometrial carcinoma and (2) assess the relationship between intensity/pattern of nm23 protein immunostaining and treatment response assessed by progression-free survival and survival to death. Formalin-fixed paraffin-embedded sections from 234 patients with endometrial cancer were immunostained with a mouse monoclonal IgG to nm23/NDPK-A protein. In most specimens of endometrial carcinoma (67.5%), nm23 expression was strongly upregulated. No association was found between either intensity (0 vs 1, 2, 3) or pattern (nuclear membrane vs cytoplasmic) of immunostaining and FIGO stage, ploidy status, histologic subtype, myometrial invasion, progression-free survival, or survival to death. Absence of nm23 staining (0 vs 1, 2, 3) was significantly associated with lower tumor grades (P = 0.02). For stage I patients, moderate to strong nm23 immunostaining intensity (2, 3) was associated with a trend toward diminished progression-free survival (P = 0.08). Our data imply a heterogeneity of nm23 protein expression and possible distinct biologic roles for nm23 in endometrial compared with breast or ovarian carcinoma.

Monoclonal antibodies specific for peptide epitopes of the epidermal growth factor receptor's extracellular domain

The ErbB tyrosine kinase receptor family plays an important role in normal cellular growth and differentiation. In addition, ErbB receptor family members are commonly amplified and overexpressed in various human neoplasms and tumor-derived cell lines, where it is believed that increased signalling as a result of receptor overexpression may play an important role in oncogenesis. Consequently, ErbB receptor family members are being investigated rigorously as potential biomarkers of cancer and as therapeutic targets in malignant tissues. Numerous studies now demonstrate the existence of "soluble" ErbB (sErbB) analogs in normal and cancerous tissues. These sErbB proteins embody the extracellular domain (ECD) of the receptor only; they are generated by either proteolytic cleavage or from truncated, alternatively spliced mRNA transcripts. Recently, we have identified an alternate transcript of the human c-erbB1 (Epidermal Growth Factor Receptor) proto-oncogene from placenta that encodes a sErbB1 protein of 60-kDa. This protein, p60 sErbB1, is glycosylated and secreted when expressed in transfected tissue culture cells in vitro. Although "soluble" receptor analogs may play important physiological roles in intercellular communication, tissue morphogenesis, tissue regeneration and repair, and embryogenesis by inhibiting or stimulating specific mitogenic and pattern forming signals, their mechanism of action has not been thoroughly elucidated. To further characterize sErbB1 expression in human tissues and cell lines and to better understand their role in carcinogenesis and normal development, we have generated monoclonal antibodies (MAbs) toward specific peptide epitopes of ErbB1 extracellular subdomains III and IV. These antibody reagents are described here and should be useful experimental, preparative, analytical, diagnostic, and therapeutic reagents for the study of sErbB1 molecules in normal development and cancer.

Absence of mutations in DNA mismatch repair genes in sporadic endometrial tumors with microsatellite instability

DNA mismatch repair genes have been reported to play a role in the pathogenesis of hereditary nonpolyposis colorectal cancer (HNPCC). Mutations of DNA mismatch repair genes have accounted for 90% of HNPCC-related colon and endometrial tumors. These mutations have been associated with microsatellite instability (MIN). Because endometrial cancer (EC) is the most common extracolonic malignancy associated with HNPCC, we hypothesized that similar molecular alterations may occur in sporadic endometrial tumors exhibiting MIN. Mutational analysis of the MSH2 and MLH1 genes was undertaken in sporadic EC that demonstrate MIN to determine the role of these genes in the pathogenesis of sporadic ECs. Established microsatellite markers were used to determine the incidence of MIN from 28 patients with sporadic EC. MIN was observed in 32% (9 of 28) of the tumor specimens analyzed. Mutational analysis of MSH2 and MLH1 genes was performed by immunohistochemical analysis and direct sequencing of tumor specimens that exhibited MIN. All 28 tumor specimens exhibited strong nuclear staining with both MSH2 and MLH1 antibodies, suggesting the absence of mutations. Sequencing of all exons of both the MSH2 and MLH1 genes in the nine MIN-positive tumor specimens demonstrated no mutations. We conclude that the MSH2 and MLH1 genes do not play a role in the pathogenesis of sporadic endometrial cancer.

p53 expression in neurofibroma and malignant peripheral nerve sheath tumor. An immunohistochemical study of sporadic and NF1-associated tumors

Malignant peripheral nerve sheath tumors (MPNST) are highly malignant sarcomas arising either de novo or in transition from neurofibroma. Although relatively little is known of the molecular genetic alterations that underlie their formation, recent DNA sequencing studies have demonstrated the presence of p53 mutations in some MPNST. This tumor-suppressor gene has been implicated in the progression of a variety of human malignancies, including sarcomas. Employing the anti-p53 monoclonal antibody Do-7, this retrospective immunohistochemical study of p53 gene overexpression in MPNST found reactivity to be present in 68% and to be significant in degree in 57%. In contrast, although some degree of p53 overexpression was present in 48% of neurofibromas, none stained strongly and only 1 of the 27 (4%), a cellular example, showed significant staining. No difference in the frequency or degree of p53 staining was noted between MPNSTs from patients with or without neurofibromatosis 1. The observed overexpression of the gene product, possibly the reflection of a p53 gene mutation, suggests a role for p53 in the progression of neurofibroma to MPNST. Although the prognostic of p53 overexpression in MPNST remains to be confirmed, in the present series immunopositive tumors were associated with a shorter median patient survival (18 months) than were tumors showing no reactivity (82 months) (P = .02).

Chronic increases in blood flow upregulate endothelin-B receptors in arterial smooth muscle

Experiments were designed to characterize endothelin receptors in arteries after chronic increases in blood flow. A fistula was created between the femoral artery and vein in one hindlimb of dogs; contralateral blood vessels were sham operated. Sham- and fistula-operated arteries were removed 6 wk postoperatively. Some arteries were prepared for measurement of isometric force or for isolation of membrane proteins. Other arteries were used for histological staining with an endothelin-B (ETB) receptor antibody. In arteries suspended for the measurement of isometric force, endothelin-1 produced concentration-dependent increases in tension that were significantly greater in fistula- than in sham-operated arteries without endothelium. The ETB-receptor-selective peptide sarafotoxin S6c produced concentration-dependent increases in tension only in fistula-operated arteries. In receptor-binding studies of membrane proteins, Scatchard analysis of saturation binding with 125I-labeled endothelin-1 (125I-endothelin-1) indicated that the total number of receptors was greater in fistula-operated arteries; affinity was threefold less in fistula- than in sham-operated arteries. Competitive displacement of 125I-endothelin-1 by endothelin-3 was significant for a two-site model in membranes prepared from sham-and fistula-operated arteries. Competitive inhibition of 125I-endothelin-1 binding by sarafotoxin S6c was significant for a one-site binding model in all arteries. Sarafotoxin S6c binding sites were elevated significantly in fistula-operated arteries. Immunohistochemical staining for the ETB receptor was significantly greater in both the endothelium and smooth muscle of fistula- than in sham-operated arteries. These results suggest that chronic increases in blood flow upregulate endothelin receptors, including ETB receptors in arterial smooth muscle.

Changes in proliferating cell nuclear antigen expression in glioblastoma multiforme cells along a stereotactic biopsy trajectory

Proliferating cell nuclear antigen, an auxiliary protein of deoxyribonucleic acid polymerase-delta, has been shown to be a reliable marker of nuclear deoxyribonucleic acid synthetic activity. We applied a monoclonal antibody to proliferating cell nuclear antigen to a series of serial stereotactic biopsies from patients with glioblastoma multiforme and found the proliferative activity to vary relative to biopsy location within or surrounding the solid tissue component of the tumor. Twenty-seven trajectories in 26 patients were analyzed, each consisting of two to five sequential 10 x 1.5 mm core biopsies (mean = 3). The proliferative index (PI) was greatest in those cells located at the solid tumor-infiltrated parenchyma interface. PI values were significantly lower in those biopsy cores located proximal (within infiltrated parenchyma) and distal (within solid tumor tissue) to the solid tumor-infiltrated parenchyma interface (median PI values, proximal to distal: 0.38, 0.66, 5.45 solid tumor-infiltrated parenchyma interface], 0.39, 0.09%). The mean PI values were significantly lower in neoplastic cells samples from regions of peripheral hypodensity on computed tomographic scans compared with those sampled from contrast-enhancing regions (0.9 and 3.91%, respectively). There was no significant difference in the mean PI values of neoplastic cells sampled from regions of contrast enhancement or central hypodensity (3.91 and 4.31%, respectively).

Value of immunohistochemistry in the diagnosis of leukemia cutis: study of 54 cases using paraffin-section markers

A grave prognosis is usually associated with leukemic skin infiltrates (leukemia cutis). However, some leukemic skin infiltrates are clinically similar to reactive non-leukemic infiltrates in patients with leukemia; thus it is of great importance to distinguish them. Fifty-four cases which were thought clinically to be leukemia cutis underwent immunophenotyping with a panel of nine T, B, monocytic, and macrophage markers using paraffin sections. Immunohistochemistry helped identify 44 cases with leukemia cutis and 10 with reactive infiltrates. In all cases of leukemia cutis, the staining patterns of skin infiltrates were concordant with cell type in the bone marrow. Furthermore, the panel of markers was usually helpful in distinguishing reactive from leukemia infiltrates, especially in cases with chronic lymphatic leukemia. Immunohistochemistry is a valuable adjunct in histopathologic differentiation of skin infiltrates in most cases of leukemia. With formalin-fixed, paraffin-embedded biopsies, we recommend that CD45 (LCA), CD45RO (UCHL-1), CD3, CD20 (L-26), CD43 (Leu-22), CD68 (KP-1), lysozyme, and chloroacetate esterase be considered in cases of systemic leukemia with cutaneous papules and nodules that prove difficult to interpret with routine section.

Methods for measuring plasma hemoglobin in micromolar concentration compared

Of eight methods examined for measuring plasma hemoglobin in micromolar concentration, all exhibited acceptable linearity, reproducibility, and concurrence except when specimens were icteric or lipemic or contained methemoglobin or methemalbumin. Measurement of absorbance at 578 nm with an Allen correction permits precise assay of plasma oxyhemoglobin concentration as low as 0.01 g/L (1 mg/dL, 0.16 mumol/L), unaffected by hyperlipidemia or hyperbilirubinemia. Discrepancies between methods occurred in 11.6% of a consecutive series of 50 nonicteric patients' plasma specimens. Examination of absorption spectra is helpful when discrepancies are observed between methods. The presence of methemalbumin or methemoglobin in plasma is not recognized by methods that measure only oxyhemoglobin. Increased ceruloplasmin or beta-carotene does not significantly affect results.

Methods for Measuring Plasma Hemoglobin in Micromolar Concentration Compared

Of eight methods examined for measuring plasma hemoglobin in micromolar concentration, all exhibited acceptable linearity, reproducibility, and concurrence except when specimens were icteric or lipemic or contained methemoglobin or methemalbumin. Measurement of absorbance at 578 nm with an Allen correction permits precise assay of plasma oxyhemoglobin concentration as low as 0.01 g/L (1 mg/dL, 0.16 mumol/L), unaffected by hyperlipidemia or hyperbilirubinemia. Discrepancies between methods occurred in 11.6% of a consecutive series of 50 nonicteric patients' plasma specimens. Examination of absorption spectra is helpful when discrepancies are observed between methods. The presence of methemalbumin or methemoglobin in plasma is not recognized by methods that measure only oxyhemoglobin. Increased ceruloplasmin or beta-carotene does not significantly affect results.

Diagnostic accuracy of the immunocytochemical study of body fluids

The diagnostic accuracy of the immunocytochemical characterization of body fluids was evaluated in 100 specimens (35 pleural, 40 peritoneal, 7 pericardial and 18 cerebrospinal [CSF] fluids) in comparison with routine morphologic examination. The immunochemical markers used for all specimens were common-leukocyte antigen, epithelial membrane antigen, epithelial keratin and desmin. Additional immunocytochemical studies for neurofilaments, glial fibrillary acidic protein, vimentin and melanoma-associated antigen were performed on the CSF specimens. The study confirmed the accuracy of the immunocytochemical characterization of cells in body fluids using a panel of immunocytochemical stains. These methods are recommended as an adjunct to improve the accuracy of the cytologic diagnosis of body fluids, especially in cases with diagnostically difficult morphologic features.

Use of azide and hydrogen peroxide as an inhibitor for endogenous peroxidase in the immunoperoxidase method

We describe a simple and effective method for inhibition of endogenous peroxidase activity in the immunoperoxidase technique. Specimens are pre-treated with a mixture of azide and hydrogen peroxide, which is then followed by an indirect immunoperoxidase procedure. Comparison studies showed no significant loss of antigenicity or morphological details by this pre-treatment. The method is most useful for evaluating cell-specific antigens on specimens that have abundant endogenous peroxidase activity, such as blood and bone marrow.

Diagnosis of B-cell non-Hodgkin's lymphoma of the central nervous system by immunocytochemical analysis of cerebrospinal fluid lymphocytes

Diagnosis of central nervous system (CNS) non-Hodgkin's lymphomas may be difficult despite the use of sophisticated scans and routine cytologic methods. The use of an immunoalkaline phosphatase technique to examine cerebrospinal fluid (CSF) containing many mononuclear cells is described. Monoclonal proliferations of B-lymphocytes were demonstrated in six patients with neurologic abnormalities, whose clinical findings and subsequent clinical courses were those of lymphoma. The diagnosis of CNS lymphoma could not be made, despite multiple diagnostic procedures, until the immunocytochemical studies were performed. In three other patients, a lymphoproliferative disorder was suspected; however, examination of CSF showed many T-lymphocytes but no monoclonal B-lymphocytes, consistent with a reactive lymphocytosis. The subsequent clinical courses of these patients have shown no evidence of CNS lymphoma. Immunocytochemical studies of CSF lymphocytes are useful in differentiating benign from malignant proliferations.

Practical immunocytochemical identification of human blood cells

A practical immunocytochemical method of demonstrating surface antigens of human blood cells on air-dried smears or other cytologic preparations has been developed. This method uses monoclonal antibodies as the primary antibodies and calf intestinal alkaline phosphatase as the enzymatic indicator. Combined staining with cytochemical stains for myeloperoxidase or nonspecific esterase on the same slide is also possible when needed. These methods are very useful for accurate identification of human blood cells on the commonly available clinical specimens and are very helpful in the diagnosis and classification of various hematologic neoplasms, including chronic lymphocytic leukemias, acute leukemias, and related diseases.