Decreased number of granzyme B+ activated CD8+ cytotoxic T lymphocytes in the inflammatory background of HIV-associated Hodgkin’s lymphoma

Clinical features in Hodgkin lymphoma patients living with human immunodeficiency virus: A meta-analysis in the antiretroviral therapy era

OBJECTIVE

Evaluate the clinical features in people with Hodgkin's lymphoma living with HIV (HIV-HL) during the combination ART (cART) era.

DESIGN

Systematic review and meta-analysis.

METHODS

The study was conducted in accordance with the recommendations of 2020 PRISMA and MOOSE statements. The protocol was prospectively registered through the PROSPERO (CRD42021289520). Manuscripts published until July 2023 were systematically searched in the PubMed, EMBASE, Cochrane Library, and Web of Science databases, with no language and year of publication restriction. Meta-analysis was performed to estimate a pooled proportion of each outcome using a random-effect analysis. Quality assessment was performed by using New-Castle Ottawa scale. Certainty of evidence was graded using the GRADE.

RESULTS

Sixteen cohorts, representing 3.882 HIV-HL patients, were included in this review. Our findings indicate that HIV-HL patients showed a 2-year overall survival (OS) of 92% (95% CI 0.87, 0.95). However, the 5-year overall survival decreased to 79% (95% CI 0.74, 0.83), with a high certainty of evidence according to GRADE. Additionally, the 5-year progression-free survival declined to 79% and complete remission rate increased to 81%. Our meta-analysis indicates an increase for B symptoms (80%, 95% CI 0.75, 0.84) and extranodal involvement in bone marrow (43%, 95% CI 0.30, 0.47) among HIV-HL patients.

CONCLUSION

The HIV-HL patients showed a 2-year OS of 92%. However, the 5-year OS decreased to 79%. The reported main cause of mortality among HIV-HL patients was progression of HL. Our systematic review and meta-analysis suggest that cART is associated with improved short-term survival of HIV-HL patients.

The Hodgkin Lymphoma Immune Microenvironment: Turning Bad News into Good

The classic Hodgkin lymphoma (cHL) tumor microenvironment (TME) is by far the most abundant component of tumors and is responsible for most of their biological and clinical characteristics. Recent advances in our knowledge of these networks in cellular interactions allow us to understand that the neoplastic Hodgkin and Reed Sternberg (HRS) cells, although they are in the minority, are the main architects of this dysregulated immune milieu. Here, we review the major changes that have happened in recent years: from TME as a helpless bystander, reflecting an ineffective immune response, to a dynamic tumor-promoting and immunosuppressive element. The HRS cells promote survival through interconnected intrinsic and extrinsic alterations, boosting pro-tumoral signaling pathways through genetic aberrations and autocrine growth signals, in parallel with abnormal cytokine secretion for the recruitment and selection of the best cell partners for this immunosuppressive TME. In turn, cHL is already proving to be the perfect model with which to address an immune checkpoint blockade. Preliminary data demonstrate the utility of druggable key signaling pathways in this ensemble, such as JAK-STAT, NF-κB, and others. In addition, myriad biomarkers predicting a response await validation by new in situ multiplex analytical methods, single-cell gene expression, and other techniques. Together, these components will define the functional phenotypes with which we will elucidate the molecular pathogenesis of the disease and improve the survival of patients who are refractory to conventional therapies.

CD68-positive tumour associated macrophages, PD-L1 expression, and EBV latent infection in a high HIV-prevalent South African cohort of Hodgkin lymphoma patients

A higher proportion of CD68-positive tumour associated macrophages (TAMs) has been associated with poorer outcomes in HIV-negative patients with Hodgkin lymphoma (HL), but whether this is true in HIV-positive patients with HL is not known. In this study, we investigated the number of CD68-positive TAMs and expression of programmed cell death-ligand 1 (PD-L1) in lymph node specimens from HL patients and correlated expression with clinical features (HIV status, disease severity and survival) and histopathological features (EBV latent positivity and subtype of HL). We stained archived lymph node specimens from 77 patients diagnosed with HL for CD68 and PD-L1. Stains were graded as: CD68 low (≤25%), CD68 high (>25%), PD-L1 low (≤50%), and PD-L1 high (>50%). Expression levels were correlated with the clinical and histopathological features using bivariate and multivariate analyses. Survival was analysed by overall and progression-free survival. Thirty-four of the 77 included patients (44%) were HIV-positive. EBV latency was detected in 97% of HIV-positive HL patients and in 14% of HIV-negative HL patients. A high CD68 score was associated with lower median haemoglobin levels (9.4 vs 11.4 g/dL; p=0.02), platelet numbers (262 vs 424 cells ×10⁹/L; p=0.01), and lymphocyte numbers (0.99 vs 1.70 cells ×10⁹/L, p=0.01) and a trend towards advanced disease (international prognostic score ≥4; hazard ratio 2.4; confidence interval 0.89-6.47; p=0.08). HIV status did not affect CD68 or PD-L1 expression. A higher proportion of CD68-positive TAMs was found in samples that were EBV-positive. HIV positivity and EBV negativity correlated with poorer survival. CD68 and PD-L1 expression were not predictive of survival. High CD68 expression was associated with EBV positivity but not HIV positivity and did not predict adverse outcomes. PD-L1 expression was unaffected by HIV status or EBV positivity and did predict adverse outcomes.

How I treat classical Hodgkin lymphoma in patients infected with human immunodeficiency virus

HIV-associated classical Hodgkin lymphoma (HIV-cHL) is an important complication of HIV disease in the era of effective combination antiretroviral therapy (cART). Generally, newly diagnosed HIV-cHL should be managed with curative intent. With modern HIV therapeutics, HIV-cHL treatment outcomes are largely comparable to those of the background population with cHL (non-HIV-cHL). To achieve these outcomes, particular attention must be given to managing HIV. This management includes understanding HIV as a comorbid condition with a spectrum of impact that is unique to each patient. Meticulous attention to drug-drug interactions is required to avoid toxicity and pharmacokinetic effects that can undermine cure. Relapsed and refractory HIV-cHL poses additional therapeutic challenges. The standard management in this setting should also be based on that for non-HIV-cHL, and includes the use of salvage chemotherapy followed by autologous stem cell transplant in chemosensitive disease. The role of allogeneic hematopoietic stem cell transplant is less clear but may be useful in select cases. Newer agents with activity in cHL are being tested as part of primary and salvage therapy and are also highly relevant for HIV-cHL.

The role of the microenvironment in human immunodeficiency virus-associated classical Hodgkin lymphoma

AIMS

To characterize the microenvironment of classical Hodgkin lymphoma (cHL) in people living with human immunodeficiency virus (PLWH). The objective was to identify and then quantify the immune cells present in the microenvironment.

METHODS AND RESULTS

Ten samples of cHL from PLWH were compared with 10 samples of cHL from the general population using tissue microarray technology and immunohistochemistry. Sections were immunostained with antibodies for CD30, CD3, CD4, CD8, CD20, CD68R, CD56, CD57, CD123, FoxP3 and granzyme B. A statistically significant reduction of CD4(+) T cells, CD56(+) cells, CD57(+) cells, CD123(+) cells and B cells and an increase in numbers in FoxP3(+) CD8(+) cells was observed in cHL diagnosed in PLWH. No significant differences were seen in the number of CD8(+) T cells, CD4(+) FoxP3(+) T cells and macrophages.

CONCLUSION

There are considerable differences in the microenvironment of cHL occurring with and without HIV.

[Lymph node pathology - an update]

Immune suppression is a risk factor for malignant lymphoma development. Progress in medical science has increased the numbers of immunosuppressed patients due to organ transplantations or successful treatment of autoimmune diseases. Different forms of immune suppression and the respective lymphoma entities are discussed in this article. Another issue treated are gray zone lymphomas between Hodgkin's lymphoma and diffuse large B cell lymphoma. This category not only represents a diagnostic challenge but also represents more a true biological continuum.

Spindle-shaped CD163+ rosetting macrophages replace CD4+ T-cells in HIV-related classical Hodgkin lymphoma

Combination antiretroviral therapy is highly effective in HIV infection, leading to decreased incidences of AIDS-defining neoplasms. However, HIV patients still have a 10-fold increased risk of developing classical Hodgkin lymphoma compared with the general population. As Hodgkin- and Reed-Sternberg cells represent only a minority in the tumor infiltrate, the aim of the present study was to characterize the microenvironment of HIV-related classical Hodgkin lymphoma and compare it with classical Hodgkin lymphoma cases of immunocompetent individuals. The major morphologic differences were the presence of necrotic foci and the absence of epithelioid cell formation in HIV-related Hodgkin lymphoma. We observed a significantly decreased number of CD4+ T-cells and a significantly increased number of CD163+ macrophages in HIV-related Hodgkin lymphoma. Cases exhibiting a 'sarcomatoid' pattern of the reactive infiltrate exhibited significantly greater numbers of macrophages, associating the 'sarcomatoid' pattern to the presence of spindle-shaped macrophages. Whereas, rosetting of CD4+ T-cells around Hodgkin- and Reed-Sternberg cells was frequently observed in classical Hodgkin lymphoma in immunocompetent persons; rosetting in a subset of HIV-related Hodgkin lymphoma cases appeared to involve cytoplasmic protrusions of spindle-shaped macrophages. HIV-related Hodgkin lymphoma, therefore, is characterized by unique morphologic features, which should be recognized by pathologists.

High proportions of regulatory B and T cells are associated with decreased cellular responses to pH1N1 influenza vaccine in HIV-infected children and youth (IMPAACT P1088)

HIV-infected individuals have poor responses to inactivated influenza vaccines. To evaluate the potential role of regulatory T (Treg) and B cells (Breg), we analyzed their correlation with humoral and cell-mediated immune (CMI) responses to pandemic influenza (pH1N1) monovalent vaccine in HIV-infected children and youth. Seventy-four HIV-infected, 4- to 25-y old participants in a 2-dose pH1N1 vaccine study had circulating and pH1N1-stimulated Treg and Breg measured by flow cytometry at baseline, post-dose 1 and post-dose 2. Concomitantly, CMI was measured by ELISPOT and flow cytometry; and antibodies by hemagglutination inhibition (HAI). At baseline, most of the participants had pH1N1-specific IFNγ ELISPOT responses, whose magnitude positively correlated with the baseline pH1N1, but not with seasonal H1N1 HAI titers. pH1N1-specific IFNγ ELISPOT responses did not change post-dose 1 and significantly decreased post-dose 2. In contrast, circulating CD4+CD25+% and CD4+FOXP3+% Treg increased after vaccination. The decrease in IFNγ ELISPOT results was marginally associated with higher pH1N1-specific CD19+FOXP3+ and CD4+TGFβ+% Breg and Treg, respectively. In contrast, increases in HAI titers post-dose 1 were associated with significantly higher circulating CD19+CD25+% post-dose 1, whereas increases in IFNγ ELISPOT results post-dose 1 were associated with higher circulating CD4+/C8+CD25+FOXP3+%. In conclusion, in HIV-infected children and youth, influenza-specific Treg and Breg may contribute to poor responses to vaccination. However, robust humoral and CMI responses to vaccination may result in increased circulating Treg and/or Breg, establishing a feed-back mechanism.

Role of immune escape mechanisms in Hodgkin's lymphoma development and progression: a whole new world with therapeutic implications

Hodgkin's lymphoma represents one of the most frequent lymphoproliferative syndromes, especially in young population. Although HL is considered one of the most curable tumors, a sizeable fraction of patients recur after successful upfront treatment or, less commonly, are primarily resistant. This work tries to summarize the data on clinical, histological, pathological, and biological factors in HL, with special emphasis on the improvement of prognosis and their impact on therapeutical strategies. The recent advances in our understanding of HL biology and immunology show that infiltrated immune cells and cytokines in the tumoral microenvironment may play different functions that seem tightly related with clinical outcomes. Strategies aimed at interfering with the crosstalk between tumoral Reed-Sternberg cells and their cellular partners have been taken into account in the development of new immunotherapies that target different cell components of HL microenvironment. This new knowledge will probably translate into a change in the antineoplastic treatments in HL in the next future and hopefully will increase the curability rates of this disease.

Characterization of HIV-associated Hodgkin's lymphoma in HIV-infected patients: a single-center experience

INTRODUCTION

Although the incidence and prevalence of AIDS-defining malignancies has decreased in the era of highly active antiretroviral therapy (HAART), the incidence and prevalence of Hodgkin's lymphoma (HL) in the HIV-infected population continues to rise. Compared with the general population, HIV-infected patients exhibit a 5-10-fold increased risk for developing HL.

METHODS

A retrospective review of charts and electronic records from 2000-2010 at the HIV outpatient clinic (HOP)-Louisiana State University in New Orleans was conducted, and pathologically confirmed cases of HIV-HL were identified within this cohort.

RESULTS

We found a prevalence of 6.3 cases per 1,000 patients per year of HIV-HL over a period of 10 years in our HIV outpatient clinic. The mean absolute CD4 count before treatment was 284 cells/mm(3) and after treatment was 194 cells/mm(3). The average time from the diagnosis of HIV infection to the diagnosis of HIV-HL was 7.6 years. The most common histopathologic type was mixed cellularity followed by lymphocytic predominance. The majority of patients had 6 cycles delivered. In terms of HL staging 87% presented with advanced stages (III B or IV). To the best of our knowledge 5 out of the 14 patients remain alive.

CONCLUSIONS

Patients in our cohort were older than most patients identified in other cohorts. All of our patients had coexisting chronic illnesses associated with inflammation, as well as detectable HIV viral loads and CD4 count >200, suggesting a role for both HIV- and non-HIV-associated inflammation in HIV-HL pathogenesis in this population. The role of HIV virus and other oncogenic viruses (EBV, HPV, and others) in the pathogenesis of Hodgkin's lymphoma in this group of patients needs to be elucidated.

Tumor microenvironment and immune effects of antineoplastic therapy in lymphoproliferative syndromes

Lymphomas represent a wide group of heterogenic diseases with different biological and clinical behavior. The underlying microenvironment-specific composition seems to play an essential role in this scenario, harboring the ability to develop successful immune responses or, on the contrary, leading to immune evasion and even promotion of tumor growth. Depending on surrounding lymphoid infiltrates, lymphomas may have different prognosis. Moreover, recent evidences have emerged that confer a significant impact of main lymphoma's treatment over microenvironment, with clinical consequences. In this review, we summarize these concepts from a pathological and clinical perspective. Also, the state of the art of lymphoma's anti-idiotype vaccine development is revised, highlighting the situations where this strategy has proven to be successful and eventual clues to obtain better results in the future.

Clinical, phenotypic and genetic similarities and disparities between post-transplant and classical Hodgkin lymphomas with respect to therapeutic targets

OBJECTIVE

Post-transplant Hodgkin lymphoma (ptHL) is a rare but serious complication. We explored the clinical, phenotypic and genetic similarities and disparities between ptHL and classical Hodgkin lymphoma (cHL) in immunocompetent patients and sought proteins/pathways in ptHL that might have potential as therapeutic targets.

RESEARCH DESIGN AND METHODS

Eight ptHL cases in solid organ recipients (mean patient age 36 years; mean duration between organ transplant and onset of ptHL 80 months) were phenotypically and genotypically analyzed and the results were compared with known phenotypic and molecular characteristics of cHL.

RESULTS

All ptHL expressed CD15, CD30 and LMP-1 of EBV; the B-cell markers BOB-1, Oct2, CD79a and CD20 were more commonly expressed in ptHL versus cHL (100%, 86%, 50% and 38% in ptHL compared to 6%, 14%, 10% and 33% in cHL, respectively); all ptHL expressed phosphoinositide 3-kinase (PI3K) versus 81% of cHL; 2/6 (33%) ptHL displayed gains at 9p24 that were similar to cHL (32%). The JAK2 downstream pSTAT3 slightly predominated in ptHL versus cHL (60% versus 50%). Clonal immunoglobulin gene rearrangements were found in 2/4 cases.

CONCLUSIONS

ptHL and cHL are closely related, but not identical, neoplasms, with the primary differences being the strict association with EBV infection, persistent phenotypic B-cell signature and high expression of PI3K as well as the slightly CD4-depleted but TIA-1/Granzyme B-enriched cellular background composition in ptHL.

Hodgkin lymphoma: an update on its biology with new insights into classification

In the past few years, there has been a greater understanding of the spectrum and biology of Hodgkin lymphoma (HL). In standard texts, HL is classified as 2 distinct entities, namely nodular lymphocyte-predominant HL and classical HL (CHL). However, recent evidence suggests that CHL is not a single disease. Although the mixed cellularity and lymphocyte-depleted subtypes might be part of a biologic continuum, the nodular sclerosis subtype has a distinct epidemiology, clinical presentation, and histology. Nodular sclerosis HL might also be related to primary mediastinal B-cell lymphoma and mediastinal gray-zone lymphomas. We present an update on the pathobiology of HL and discuss these biologic and clinical differences in this review.

Hodgkin lymphoma in the Swiss HIV Cohort Study

Hodgkin lymphoma (HL) risk is elevated among persons infected with HIV (PHIV) and has been suggested to have increased in the era of combined antiretroviral therapy (cART). Among 14,606 PHIV followed more than 20 years in the Swiss HIV Cohort Study (SHCS), determinants of HL were investigated using 2 different approaches, namely, a cohort and nested case-control study, estimating hazard ratios (HRs) and matched odds ratios, respectively. Forty-seven incident HL cases occurred during 84,611 person-years of SHCS follow-up. HL risk was significantly higher among men having sex with men (HR vs intravenous drug users = 2.44, 95% confidence interval [CI], 1.13-5.24) but did not vary by calendar period (HR for 2002-2007 vs 1995 or earlier = 0.65, 95% CI, 0.29-1.44) or cART use (HR vs nonusers = 1.02, 95% CI, 0.53-1.94). HL risk tended to increase with declining CD4(+) cell counts, but these differences were not significant. A lower CD4(+)/CD8(+) ratio at SHCS enrollment or 1 to 2 years before HL diagnosis, however, was significantly associated with increased HL risk. In conclusion, HL risk does not appear to be increasing in recent years or among PHIV using cART in Switzerland, and there was no evidence that HL risk should be increased in the setting of improved immunity.

Regulatory T cells and EBV associated malignancies

It has been shown that the T-regulatory cells (Tregs) not only play a key role in the establishment and maintenance of peripheral tolerance to prevent the autoimmune disease, but also inhibit the anti-tumor immunity. Recently, many studies have demonstrated that cytotoxicity T cells (CTL) can control the growth of EBV-positive tumor cells in vitro, including Hodgkin's lymphoma (HL), nasopharyngeal carcinoma, posttransplantation lymphoproliferative disorders (PTLD), depending on the large mount of EBV antigens presented by MHC molecules on the surface of these malignant cells. However, limited benefit of CTL adoptive immunotherapy has been reported in the treatment of EBV positive HL and NPC, and Tregs are regarded as a critical hurdle in this issue. In the present review, we discuss the correlation of EBV antigens expression in the tumor cells and the induction of Tregs in tumor microenvironment. Treg subsets and its possible mechanism to attenuate the anti-tumor immunity in EBV associated malignancies are also discussed, following by the possible strategies of targeting Tregs in the future immunotherapy for EBV positive cancers.

Quantification of diverse subcellular immunohistochemical markers with clinicobiological relevancies: validation of a new computer-assisted image analysis procedure

Tissue microarray technology and immunohistochemical techniques have become a routine and indispensable tool for current anatomical pathology diagnosis. However, manual quantification by eye is relatively slow and subjective, and the use of digital image analysis software to extract information of immunostained specimens is an area of ongoing research, especially when the immunohistochemical signals have different localization in the cells (nuclear, membrane, cytoplasm). To minimize critical aspects of manual quantitative data acquisition, we generated semi-automated image-processing steps for the quantification of individual stained cells with immunohistochemical staining of different subcellular location. The precision of these macros was evaluated in 196 digital colour images of different Hodgkin lymphoma biopsies stained for different nuclear (Ki67, p53), cytoplasmic (TIA-1, CD68) and membrane markers (CD4, CD8, CD56, HLA-Dr). Semi-automated counts were compared to those obtained manually by three separate observers. Paired t-tests demonstrated significant differences between intra- and inter-observer measurements, with more substantial variability when the cellular density of the digital images was > 100 positive cells/image. Overall, variability was more pronounced for intra-observer than for inter-observer comparisons, especially for cytoplasmic and membrane staining patterns (P < 0.0001 and P = 0.050). The comparison between the semi-automated and manual microscopic measurement methods indicates significantly lower variability in the results yielded by the former method. Our semi-automated computerized method eliminates the major causes of observer variability and may be considered a valid alternative to manual microscopic quantification for diagnostic, prognostic and therapeutic purposes.

Tumor-infiltrated immune response correlates with alterations in the apoptotic and cell cycle pathways in Hodgkin and Reed-Sternberg cells

PURPOSE

To analyze tumor-microenvironment relationships in Hodgkin lymphoma (HL) as potential determinants in the decision-making process related to the alterations in cell cycle and apoptotic pathways of Hodgkin/Reed-Sternberg (H/RS) cells.

EXPERIMENTAL DESIGN

Based on a cohort of 257 classic HL patients, we carried out a global descriptive correlational analysis and logistic regression study to identify tumor-infiltrated immune cell rate in HL that could be interconnected with genes involved in the regulation of apoptotic/proliferative pathways in H/RS cells.

RESULTS

Our results reveal the existence of a connection between the reactive microenvironment and molecular changes in apoptotic/proliferative pathways in H/RS cells. A lesser incidence of infiltrated cytotoxic cells in the tumor (CD8(+) T lymphocytes, CD57(+) natural killer, and granzyme B(+) cells) was associated with overexpression of antiapoptotic proteins (Bcl-X(L), survivin, caspase-3, and nuclear factor-kappaB) in tumoral cells. Increased incidence of general infiltrated immune cells, such as CD4(+) T lymphocytes, CD57(+) natural killer cells, activated CTL, and dendritic cells, in the microenvironment of the tumor was associated with increased growth fraction of tumoral cells, including G(1)-S checkpoint (cyclin D and cyclin E) and tumor suppressor pathways (p16 and SKP2), and with the presence of EBV (signal transducers and activators of transcription 1 and 3 expression; STAT1/STAT3).

CONCLUSIONS

A lower level of cytotoxic cells correlated with an increase of antiapoptotic mechanisms in H/RS cells, whereas the global infiltrated immune population correlated with the growth fraction of the tumor. Our collective data suggest a causal relationship between infiltrated immune response and concurrent changes of the different proliferative checkpoints, tumor suppressor, and apoptotic pathways of H/RS cells in HL.

Comparative flow immunophenotypic features of the inflammatory infiltrates of Hodgkin lymphoma and lymphoid hyperplasia

BACKGROUND

Hodgkin lymphoma (HL) is characterized by relatively few malignant Reed-Sternberg (RS) cells admixed within a reactive T cell rich inflammatory infiltrate. There is growing recognition that the HL-associated inflammatory milieu may enhance rather than inhibit growth of RS tumor cells. Since little is known of the immunophenotype of the HL inflammatory infiltrate we have performed a detailed retrospective comparison of the flow immunophenotype of HL and reactive lymphoid hyperplasia (RLH) to identify HL-specific immunophenotypic features.

METHODS

Single cell suspensions from 59 lymph nodes involved by HL (at initial diagnosis) and 38 lymph nodes involved by RLH were subjected to a battery of 3-color combinations of well-characterized fluorochrome-conjugated monoclonal antibodies (DAKO) to a number of lymphocyte subsets. Cells were analyzed on a FACSCalibur flow cytometer with CellQuest software (Becton Dickinson).

RESULTS

Overall, CD4+ T cells are increased and CD19+ B cells decreased in HL vs. RLH, yielding median T:B cell (CD3:CD20) ratios of 2.3:1 and 1.6:1, resp. There is no difference in median CD8+ T cell % (16% in HL & RLH). The T:B cell ratio is highest in nodular sclerosis (NSHL) and lymphocyte depletion (LDHL) subtypes, and lowest in mixed cellularity HL (MCHL). There is no significant difference in CD4:CD8 ratio in any comparison. NKT cells were slightly increased in HL vs. RLH, especially in MCHL. CD4+CD25+ regulatory T cells are significantly increased in HL (9%) vs. RLH (2%), especially in MCHL (29%) and NSHL (12%). EBV positivity in NSHL is associated with older age, decreased CD4+CD25+ regulatory T cells, CD4:CD8 ratio, and CD19/CD20+ B cells, and increased NKT cells, and CD14+ low forward-side scatter-gated monocytes.

CONCLUSION

The cellular composition of the reactive lymphocytic infiltrate in HL differs significantly from that seen in RLH, with significant differences also noted between HL subtypes. In general, the HL infiltrate contains increased T cells (CD4+ and NKT subsets), decreased B cells, and increased regulatory T cells in comparison with RLH. The major difference between HL subtypes is decreased CD4+ T cells in MCHL as compared with NSHL and NLPHL. The most notable EBV-related difference in NSHL is increased regulatory T cells in EBV negative cases. While many differences in the reactive lymphocytic infiltrate of Hodgkin lymphoma and reactive lymphoid hyperplasia were identified, the sole difference that may prove to be of differential diagnostic value in flow cytometric analysis of HL versus RLH is the increased percentage of CD4+ bright CD25+ regulatory T cells in HL.

Update on HIV lymphoma

In industrialized nations people infected with HIV remain at increased risk for malignancies despite highly active antiretroviral therapy. In these countries, lymphoma is the most common HIV-associated malignancy. This review summarizes progress from January 2005 to February 2007. The majority of investigation has been in diffuse large B cell lymphoma, with infusional therapy remaining promising but cumbersome. Rituximab likely improves complete response rates, and, possibly overall survival, but is likely associated with increased infections in a subset of patients with very low CD4 counts. Biologic insights have been attained in the spectrum of HIV-associated non-Hodgkin's lymphoma, Hodgkin's lymphoma, and virologic coinfections. Overall, the outcome for non-Hodgkin's lymphoma and Hodgkin's lymphoma in the setting of HIV continues to improve as insights into the pathophysiology and treatment advance.

Update in HIV lymphoma

PURPOSE OF REVIEW

Despite the control of HIV infection in industrialized nations, individuals infected with HIV remain at increased risk of malignancies. Lymphoma is the most common HIV-associated malignancy in these countries. This review summarizes progress from January 2005 to March 2006.

RECENT FINDINGS

Investigators continue to demonstrate that HIV-associated non-Hodgkin's lymphoma remains a significant problem, even in the era of highly active antiretroviral therapy. The majority of work has been in diffuse large B-cell lymphoma, with infusional therapy remaining promising, and rituximab an area of investigation. The latter improves complete response rates, but is associated with an increased incidence of infections. Biological insights have been gained into the spectrum of HIV-associated non-Hodgkin's lymphoma and Hodgkin's disease, and include further work on virological co-infections.

SUMMARY

The outcome for individuals infected with HIV and developing non-Hodgkin's lymphoma and Hodgkin's disease continues to improve as insights into the pathophysiology and treatment advance.