Are macrophages the bad guys in Hodgkin lymphoma?

The Neutrophil to Lymphocyte and Lymphocyte to Monocyte Ratios as New Prognostic Factors in Hematological Malignancies - A Narrative Review

Despite the presence of many hematological prognostic indexes, clinical course and overall survival are often highly variable even within the same patient subgroup. Recent studies suggest that simple, cost-effective, low-risk tests such as neutrophil to lymphocyte ratio (NLR) and lymphocyte to monocyte ratio (LMR) may be used to evaluate the prognosis. Their role has been well confirmed in diffuse large B-cell lymphoma (DLBCL), Hodgkin lymphoma (HL) and multiple myeloma (MM), but until now the prognostic significance of NLR and LMR in leukemias has not been widely reported. In this article, we analyze the literature data on prognostic value of NLR and LMR in haematological malignancies in the context of classic prognostic factors and clinical course.

Prognostic value of lymphocyte-monocyte ratio at diagnosis in Hodgkin lymphoma: a meta-analysis

BACKGROUND

Prognoses of most adult Hodgkin lymphoma (HL) patients are excellent; most of them can achieve permanent remission that can be considered cured. However, many are under-treated or over-treated by standard modern therapies. An accurate determination of prognosis may allow clinicians to design personalised treatment according to individual risk of disease progression and survival. Lymphocyte monocyte ratio (LMR) at diagnosis has been investigated as a prognostic biomarker in patients with HL. Our objective with this meta-analysis was to explore the prognostic value of the LMR at diagnosis in adult HL, by investigating the association between LMR and survival outcomes.

METHODS

PUBMED and EMBASE were searched for relevant articles. Survival outcomes that we investigated included overall survival (OS), progression-free survival (PFS), event-free survival (EFS), lymphoma-specific survival (LSS), and time to progression (TTP). No restriction to the language, date, study country, or sample size was applied. Final search of databases was performed on 2 April 2018. We performed random-effects meta-analysis to aggregate and summarise the results from included studies, where four or more studies on a particular outcome were available.

RESULTS

A total of eight studies (all retrospective cohort studies) involving 3319 HL patients were selected for analysis. All studies except one reported the effect of LMR on OS; five reported on PFS, three reported on TTP and LSS, respectively, and one reported on EFS. The pooled estimates showed low LMR was associated with poor OS (hazard ratio [HR] 2.67, 95% CI 1.67, 4.26) and PFS (HR 2.19, 95% CI 1.46, 3.29). Subgroup analyses of OS stratified by LMR cut-off values and sample sizes both indicated that low baseline LMR was associated with poorer prognosis.

CONCLUSIONS

Low LMR at diagnosis was associated with poor OS and PFS in HL. LMR is easy and cheap to determine and has a potential role in daily clinical management. More studies are needed to validate this biomarker and explore its interaction with known prognostic factors.

[Tumor-associated macrophages: Function and differentiation]

Macrophages are important factors in the pathogenesis and prognosis of malignant tumors and represent a possible target for therapeutic intervention. Depending on the tumor entity and the prevalent polarization status, macrophages can be associated with a favorable or unfavorable clinical outcome. It is becoming clear, however, that the conventional definitions of M1 polarized tumor inhibitory and M2 polarized tumor promoting macrophages do not adequately reflect the heterogeneity and plasticity of macrophages. Macrophages can support tumor growth through direct interactions with the neoplastic cells, by promoting tissue remodeling and angiogenesis and by inhibiting local immune reactions. To achieve comparability of clinical studies, it will be necessary to reach a consensus nomenclature of macrophage polarization. Furthermore, methods for the quantitative characterization of macrophage populations in malignant tumors will have to be standardized. It is unlikely that single marker immunohistochemistry will be adequate in this context. In any case it is necessary to provide unequivocal information regarding the markers or marker combinations used.

Prognostic value of lymphocyte/monocyte ratio in advanced Hodgkin lymphoma: correlation with International Prognostic Score and tumor associated macrophages

We studied the prognostic significance of the absolute lymphocyte/monocyte count ratio (ALC/AMC), its contribution to the prognostic value of the International Prognostic Score (IPS), and evaluated if ALC/AMC could serve as a proxy for the frequency of CD68 + tumor-associated macrophages (TAMs) in 101 patients with advanced Hodgkin lymphoma (HL). The receiver operating characteristic (ROC) curve identified best cut-off values of 2.0 for ALC/AMC and 25% for CD68 + TAM. Patients with ALC/AMC < 2, IPS > 2 and > 25% CD68 + TAM had an inferior overall survival (OS) and event-free survival (EFS). Spearman's test also uncovered a significant correlation between the ALC/AMC and TAM. Multivariate analysis identified ALC/AMC < 2, IPS > 2 and > 25% CD68 + TAM as poor prognostic factors of OS and EFS. After evaluating ALC/AMC and IPS, we stratified patients into three progressively-worse-outcome groups (low-risk: 0 risk factors; intermediate: 1 risk factor; high: 2 risk factors). Our study encourages the combination of ALC/AMC with IPS, for refining risk prediction in advanced HL patients.

Evaluation of the prognostic role of tumour-associated macrophages in newly diagnosed classical Hodgkin lymphoma and correlation with early FDG-PET assessment

In Hodgkin Lymphoma (HL), about 20% of patients still have relapsed/refractory disease and late toxic effects rate continue to rise with time. 'Early FDG-PET' and tissue macrophage infiltration (TAM) emerged as powerful prognostic predictors. The primary endpoint was to investigate the prognostic role of both early FDG-PET and TAM; the secondary endpoint was to test if early FDG-PET positivity could correlate with high TAM score. A cohort of 200 HL patients was analysed. Induction treatment plan consisted of two to six courses of ABVD and, if indicated, involved field radiation therapy. All patients repeated CT scan and FDG-PET after two cycles and after the completion of therapy. TAM in diagnostic specimens was determined by immunohistochemistry with a monoclonal antibody (anti-CD68 KP1). Overall, early FDG-PET was negative in 163 patients (81.5%) and positive in 37 patients (18.5%), showing a significant correlation with the achievement of CR (p < 0.0001). After a median follow-up of 40 months, progression free survival (PFS) was significantly better for PET negative patients (p < 0.0001). CD68 expression was low, intermediate or high in 26 (13%), 100 (50%) and 74 (37%) cases, without difference in the distribution between responders and non-responders. PFS analysis showed no significant difference in any score group. TAM score did not show any correlation with early FDG-PET result. This study confirms that early FDG-PET has a high prognostic power, while TAM score does not seem to influence the outcome; in contrast to our original hypothesis, it does not correlate with FDG-PET assessment. Copyright © 2015 John Wiley & Sons, Ltd.

Macrophage polarization reflects T cell composition of tumor microenvironment in pediatric classical Hodgkin lymphoma and has impact on survival

Macrophages have been implicated in the pathogenesis of classical Hodgkin lymphoma (cHL) and have been suggested to have a negative impact on outcome. Most studies addressing the role of macrophages in cHL have relied on identification of macrophages by generic macrophage antigens, e.g., CD68. We have therefore conducted an in situ analysis of macrophage polarization in a series of 100 pediatric cHL (pcHL) cases using double staining immunohistochemistry, combining CD68 or CD163 with pSTAT1 (M1-like) or CMAF (M2-like). M1- or M2-polarised microenvironment was defined by an excess of one population over the other (>1.5). Expression of STAT1 and LYZ genes was also evaluated by RT-qPCR. Patients <14 years and EBV+ cases displayed higher numbers of CD68+pSTAT1+ cells than older children and EBV- cases, respectively (P=0.01 and P=0.02). A cytotoxic tumor microenvironment, defined by a CD8+/FOXP3+ ratio >1.5 was associated with higher numbers of CD68+pSTAT1+ (P=0.025) and CD163+pSTAT1+ macrophages (P<0.0005). Levels of STAT1 and LYZ expression were associated with the numbers of CD68+pSTAT1+ macrophages. EBV+ cHL cases disclosed a predominant M1 polarized microenvironment similar to Th1 mediated inflammatory disorders, while EBV- cHL showed a predominant M2 polarized microenvironment closer to Th2 mediated inflammatory diseases. Better overall-survival (OS) was observed in cases with higher numbers of CD163+pSTAT1+ macrophages (P=0.02) while larger numbers of CD163+CMAF+ macrophages were associated with worse progression-free survival (PFS) (P=0.02). Predominant M1-like polarization as disclosed by CD163+pSTAT1+/CD163+CMAF+ ratio > 1.5 was associated with better OS (P= 0.037). In conclusion, macrophage polarization in pcHL correlates with prevalent local T cell response and may be influenced by the EBV-status of neoplastic cells. Besides, M1-like and M2-like macrophages displayed differential effects on outcome in pcHL.

CD68 staining correlates with the size of residual mass but not with survival in classical Hodgkin lymphoma

The prognostic role of CD68 tumor-associated macrophages in classic Hodgkin lymphoma (cHL) remains controversial. We stained diagnostic biopsies and scored for CD68 using the PGM1 antibody among 98 consecutive patients with cHL from our center followed over a median of 45 months for progression-free survival (PFS). Among 79 patients we assessed interim and post-treatment positron emission tomography-computed tomography (PET-CT). Residual mass (RM) size was based on the greatest diameter of the largest mass seen in post-treatment imaging, and percent reduction was calculated by comparing RM size with its greatest pretreatment diameter. We found a significant association between CD68 positivity and absolute size of initial disease mass (p = 0.014) and residual mass at the end of therapy (p = 0.006) but no association was observed with interim PET-CT results or PFS. Our findings suggest that macrophages may influence tumor size by altering the microenvironment. This study does not support a prognostic role of CD68 positivity in predicting survival.

CD68 tumor-associated macrophage marker is not prognostic of clinical outcome in classical Hodgkin lymphoma

Abstract A novel biomarker, CD68, which marks tumor-associated macrophages (TAMs) in the microenvironment, has recently been reported to affect the prognosis of Hodgkin lymphoma (HL). We aimed to evaluate its role in our patient cohort (n = 100) by utilizing a routine immunohistochemistry method on whole tissue sections and a semiquantitative method for CD68 scoring. Clinical data were taken from medical records. Correlation with baseline characteristics, attainment of complete remission (CR), progression-free survival (PFS) and disease-specific survival (DSS) was done by categorical analysis using different cut-offs of CD68 score and also by taking absolute CD68 score as a continuous variable. There was no significant association between levels of CD68 expression and baseline characteristics or CR after primary therapy. CD68 score (neither categorical nor absolute continuous values) also did not predict for any difference in PFS or DSS. We conclude that CD68 TAM marker does not have prognostic value in HL.

Lack of association of tumor-associated macrophages with clinical outcome in patients with classical Hodgkin's lymphoma

BACKGROUND

A recent study demonstrated that an increased number of CD68+ macrophages were correlated with primary treatment failure, shortened progression-free survival (PFS) and disease-specific survival (DSS) in patients with classical Hodgkin's lymphoma (cHL).

PATIENTS AND METHODS

The aim of the present study was to verify the relationship between the number of CD68+ and CD163+ macrophages with clinical outcomes in a cohort of 265 well-characterized patients with cHL treated uniformly with the standard doxorubicin, bleomycin, vinblastine and dacarbazine chemotherapy regimen. Two pairs of hematopathologists carried out independent pathological evaluations of tissue microarray slides.

RESULTS

There were no associations between clinical characteristics and the expression of CD68 or CD163. However, higher levels of CD68 and CD163 expression were correlated with the presence of Epstein-Barr virus-positive Hodgkin tumor cells (P = 0.01 and 0.037, respectively). The expression of CD68 or CD163 was not associated with either the PFS or the DSS.

CONCLUSION

CD68 and CD163 expression require further evaluation before their use can be recommended for prognostic stratification of patients with cHL.

The role of CD40/CD40L and interferon regulatory factor 4 in Hodgkin lymphoma microenvironment

Inflammation and cancer are two independent biological events that can play an interdependent role. The model of such interaction is represented by Hodgkin lymphoma (HL), where the microenvironment is dominated by an extensive mixed, potentially cellular inflammatory infiltrate that plays a decisive role in the pathobiology of HL. In this review we summarize updated information on the complex interactions between Hodgkin Reed-Sternberg (HRS) cells and their tissue microenvironment, highlighting the functional role of CD40/CD40L and interferon regulatory factor 4 (IRF4).