iNKT and memory B-cell alterations in HHV-8 multicentric Castleman disease.

Human herpesvirus 8 (HHV-8) is the causative agent of Kaposi sarcoma (KS) and multicentric Castleman disease (MCD), a life-threatening, virally induced B-cell lymphoproliferative disorder. HHV-8 is a B-lymphotropic γ-herpesvirus closely related to the Epstein-Barr virus (EBV). Invariant natural killer T (iNKT) cells are innate-like T cells that play a role in antiviral immunity, specifically in controlling viral replication in EBV-infected B cells. Decline of iNKT cells is associated with age or HIV infection, both situations associated with HHV-8-related diseases. We analyzed iNKT cells in both blood (n = 26) and spleen (n = 9) samples from 32 patients with HHV-8 MCD and compared them with patients with KS (n = 24) and healthy donors (n = 29). We determined that both circulating and splenic iNKT cell frequencies were markedly decreased in patients with HHV-8 MCD and were undetectable in 6 of them. Moreover, iNKT cells from patients with HHV-8 MCD displayed a proliferative defect after stimulation with α-galactosylceramide. These iNKT cell alterations were associated with an imbalance in B-cell subsets, including a significant decrease in memory B cells, particularly of marginal zone (MZ) B cells. Coculture experiments revealed that the decrease in iNKT cells contributed to the alterations in the B-cell subset distribution. These observations contribute to a better understanding of the complex interactions between HHV-8 and immune cells that cause HHV-8-related MCD.

Classic and extracavitary primary effusion lymphoma in 51 HIV-infected patients from a single institution.

Human immunodeficiency virus (HIV)-associated primary effusion lymphoma (PEL) is a rare B-cell non-Hodgkin lymphoma with poor prognosis. Lymphoma cells are always infected with human herpesvirus-8 (HHV-8) and in most cases coinfected with Epstein-Barr virus. In classic presentation, PEL is characterized by body cavity effusions with or without mass lesions. A variant with only extracavitary localization has also been described. We report on a large single-center series of patients with PEL in the era of combined antiretroviral therapy (cART). The main objective was to compare the characteristics and the outcome of patients with classic (n = 34) and extracavitary (n = 17) variant PEL. At PEL diagnosis, no major difference was observed between the two groups in terms of demographic and HIV characteristics. Extracavitary localizations were exclusively nodal in six patients and involved various organs in 11 patients. Another HHV-8-associated disease was observed in 31 patients, Kaposi sarcoma in 25, and multicentric Castleman disease in 18 patients, without difference between the two groups. Thirty-two patients were treated with CHOP associated with high-dose methotrexate, 13 were treated with CHOP-derived regimen alone, and six patients received low-dose/no chemotherapy. Complete remission was achieved in 21 (62%) and seven (41%) patients of the classic and extracavitary groups, respectively. The median overall survival (OS) was 10.2 months. Despite a higher disease-free survival in the extracavitary group, there was no difference in OS between the two variants. Based on this series, characteristics of classic and extracavitary variants were very close. Although prognosis of PEL remains very severe in cART era, the median survival compares favorably with earlier series.

Rituximab decreases the risk of lymphoma in patients with HIV-associated multicentric Castleman disease.

HIV-associated multicentric Castleman disease (MCD) is associated with a high risk of developing non-Hodgkin lymphoma (NHL). Rituximab is effective in HIV-MCD, but its impact on NHL incidence remains unknown. From a single-center prospective cohort, 113 patients were identified with a diagnosis of HIV-MCD for the present study. To compare the incidence of NHL between patients who had received a rituximab-based treatment (R+ group) and those who had not (R- group), data were analyzed before and after matching on propensity scores and after multiple imputation. The mean follow-up was 4.2 years. In the R- group (n = 65), 17 patients developed NHL (incidence, 69.6 of 1000 person years). In the R+ group (n = 48), only 1 patient developed NHL (incidence, 4.2 of 1000 person years). Based on the propensity score-matching method, a significant decrease in the incidence of NHL was observed in patients who had been treated with rituximab (hazard ratio, 0.09; 95% confidence interval, 0.01-0.70). Ten Kaposi sarcoma (KS) exacerbations and 1 newly diagnosed KS were observed in 9 patients after rituximab therapy. Rituximab was associated with an 11-fold lower risk of developing lymphoma. KS exacerbation was the most challenging adverse event after rituximab therapy.

Recalcitrant pseudotumoral anogenital herpes simplex virus type 2 in HIV-infected patients: evidence for predominant B-lymphoplasmocytic infiltration and immunomodulators as effective therapeutic strategy.

BACKGROUND: In patients with human immunodeficiency virus (HIV) infection, genital herpetic lesions may be extensive and tend to persist for longer periods; in addition, atypical hypertrophic, ulcerative, or pseudotumor forms have been reported, frequently showing resistance to acyclovir (ACV) treatment. METHODS: Between 2003 and 2011, 10 HIV-1-infected patients presenting with chronic pseudotumoral anogenital herpes simplex type 2 (HSV-2) infections were studied. RESULTS: All patients developed chronic, hypertrophic HSV-2 anogenital lesions with multilesional presentation in 7 cases and involvement of 2 anatomical sites in 6 of them. At the time of diagnosis, the median CD3(+)CD4(+) absolute blood count was 480.5 cells/µL (range, 165-632 cells/µL), whereas the plasma HIV load was undetectable in all cases. Histopathologic analysis of lesion biopsies showed a moderately dense dermal polytypic plasma cell infiltrate. Detection of HSV-2 by culture and/or polymerase chain reaction was positive for all patients, with evidence for ACV-resistant strains in 6 of 8 cases. In addition, viral resistance to ACV was found only in HSV-2 isolated from ulcerative lesions, whereas purely pseudotumoral ones harbored sensitive strains. Durable control was observed with HSV DNA polymerase inhibitors in only 2 cases, and the immunomodulators imiquimod and thalidomide allowed 5 patients to reach sustained complete response. CONCLUSIONS: HSV-2-related pseudolymphoma in HIV-infected patients is characterized by a predominant polyclonal lymphoplasmacytic infiltration, and is frequently refractory to antiherpetic drugs. Immunomodulatory therapeutic strategies using thalidomide showed consistent efficacy, and should be considered early during the course of disease.

Human herpesvirus 8+ polyclonal IgMλ B-cell lymphocytosis mimicking plasmablastic leukemia/lymphoma in HIV-infected patients.

PURPOSE: Multicentric Castleman disease (MCD) is a distinct lymphoproliferative disorder characterized by inflammatory symptoms, lymphadenopathy, splenomegaly, and cytopenia. Kaposi's sarcoma-associated herpesvirus (KSHV), also called human herpesvirus-8 (HHV-8), is the cause of virtually all cases of MCD occurring in patients with HIV infection. MCD lesions characteristically contain HHV-8-infected polyclonal IgMλ plasmablasts. A high frequency of HHV-8-related non-Hodgkin lymphoma has been reported in these patients. PATIENTS AND METHODS: We now report on three patients who presented with severe symptoms of MCD, extreme splenomegaly, and rapid expansion of B-cell lymphocytosis (44-81%) attributable to circulating HHV-8 positive plasmablasts. RESULTS: The circulating plasmablastic cells shared the phenotype (IgMλ, CD19+, CD20- CD138-) of HHV-8-infected cells from MCD lesions, mimicking the leukemic phase of large B-cell lymphoma occurring in HHV-8-related MCD. These patients displayed a very high HHV-8 viral load in blood (>7 logs HHV-8 DNA copies/ml) and high levels of serum vIL-6, the viral homolog of human interleukin 6. Serum IL-6 and IL-10 were also abnormally elevated. HHV-8-infected cells were demonstrated by immunoglobulin gene rearrangement analysis, to be polyclonal and likely represent an expansion of HHV-8-infected cells similar to those found in MCD lesions. CONCLUSION: Thus, the spectrum of HHV-8-related plasmablastic lymphoproliferative disorders in patients with HIV infection is expanded to include HHV-8+ polyclonal IgMλ B-cell lymphocytosis. At onset, this lymphoproliferative disorder may mimic plasmablastic leukemia/lymphoma. Recognizing this unusual complication may have important implications in treatment decision avoiding unnecessary toxicity to the patients.

The complex relationship between human herpesvirus 6 and acute graft-versus-host disease.

The most frequent manifestation of human herpesvirus 6 (HHV-6) reactivation after allogeneic hematopoietic stem cell transplantation (HSCT) is febrile rash, raising the question of its relationship with graft-versus-host disease (GVHD). In this retrospective analysis of 365 patients who underwent allogeneic HSCT, HHV-6 reactivation was significantly associated with cord blood transplantation (hazard ratio [HR], 3.20; P < .0001) and the use of unrelated donors (HR, 2.02; P = .008). On multivariate analysis, previous GVHD was a predictive factor for HHV-6 reactivation (HR, 1.80; P = .01), and previous HHV-6 reactivation was a predictive factor for acute GVHD (HR, 1.66; P = .03). Nineteen patients with no pathological evidence of GVHD later developed severe clinical GVHD (grade III-IV), suggesting the role of HHV-6 as a trigger for severe GVHD. Furthermore, 17 patients without histopathological GVHD demonstrated a significant lymphoid infiltrate suggesting "pure" HHV-6-related manifestations, and these patients could have been spared steroid therapy.

Atypical presentation of adult T-cell leukaemia/lymphoma due to HTLV-1: prurigo nodularis lasting twelve years followed by an acute micropapular eruption.

Prurigo nodularis is a pruritic dermatosis of unknown origin. Human T-cell lymphotropic virus type 1 (HTLV-1) causes adult T-cell leukaemia/lymphoma. HTLV-1 is not considered to be a cause of prurigo nodularis. A 52-year-old black man, from the French West Indies, who had had prurigo nodularis for 12 years, presented with a distinct micropapular eruption with the typical pathological picture of epidermotropic T-cell lymphoma. Based on HTLV-1-positive serology and monoclonal integration of HTLV-1 we diagnosed smouldering adult T-cell leukaemia/lymphoma. Re-examination of previous skin biopsies revealed that the disease had been evolving for 12 years. Treatment with alpha-interferon, 3 x 106 units three times a week, associated with zidovudine, 1 g daily, resulted in complete remission within 4 months. When investigating a prurigo nodularis, we therefore recommend: (i) performing HTLV-1 serology if the patient comes from an endemic area; (ii) if positive, performing CD25 staining and looking for a HTLV-1 clonal integration; and (iii) if positive, using a treatment targeting HTLV-1.

Initial human herpesvirus-8 rash and multicentric Castleman disease.

We describe a human immunodeficiency virus-infected man with relapsing rashes and reactivation of human herpesvirus-8 (HHV-8) infection, which evolved into multicentric Castleman disease. Initial skin biopsy revealed infiltrating HHV-8-positive plasmablasts, a subset of which supported lytic infection. We document the first case, to our knowledge, of HHV-8-induced rash and suggest that circulating plasmablasts drive HHV-8 to target tissues.

Ketosis-prone type 2 diabetes mellitus and human herpesvirus 8 infection in sub-saharan africans.

CONTEXT: An atypical form of type 2 diabetes mellitus (DM-2) is revealed by ketosis (ketosis-prone type 2 diabetes mellitus), frequently occurring in individuals who are black and of African origin, and characterized by an acute onset requiring transient insulin therapy. Its sudden onset suggests precipitating factors. OBJECTIVE: To investigate the putative role of human herpesvirus 8 (HHV-8) in the pathogenesis of ketosis-prone DM-2. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional study in which antibodies were searched against latent and lytic HHV-8 antigens using immunofluorescence. The presence of HHV-8 in genomic DNA was investigated in 22 of the participants at clinical onset of diabetes. We also tested whether HHV-8 was able to infect human pancreatic beta cells in culture in vitro. The study was conducted at Saint-Louis University Hospital, Paris, France, from January 2004 to July 2005. All participants were black and of African origin: 187 were consecutive diabetic patients of whom 81 had ketosis-prone DM-2 and 106 had nonketotic DM-2, and 90 individuals were nondiabetic control participants who were matched for age and sex. MAIN OUTCOME MEASURES: Seroprevalence of HHV-8 and percentage of patients with HHV-8 viremia at onset in ketosis-prone DM-2. RESULTS: HHV-8 antibodies were found in 71 patients (87.7%) with ketosis-prone DM-2 vs 16 patients (15.1%) with nonketotic DM-2 (odds ratio, 39.9; 95% confidence interval, 17.1-93.4; P < .001) and 36 of the control participants (40.0%) (odds ratio, 10.7; 95% confidence interval, 4.9-23.4; P < .001). HHV-8 in genomic DNA was present in 6 of 13 patients with ketosis-prone DM-2 tested at acute onset and in 0 of 9 patients with nonketotic DM-2. HHV-8 proteins were present in human islet cells that were cultured for 4 days in the presence of HHV-8. CONCLUSIONS: In this preliminary cross-sectional study, the presence of HHV-8 antibodies was associated with ketosis-prone DM-2 in patients of sub-Saharan African origin. Longitudinal studies are required to understand the clinical significance of these findings.

Extracavitary tumor after primary effusion lymphoma: relapse or second distinct lymphoma?

HHV-8-associated solid lymphomas which develop in extracavitary sites during the course of primary effusion lymphoma (PEL) could represent the relapse of original PEL tumors in different anatomical sites, or newly occurring distinct HHV-8-associated lymphomas, such as multicentric Castleman disease-related microlymphomas. HHV-8 episome clonality might help identify which event takes place.

Lytic EBV infection investigated by detection of Soluble Epstein-Barr virus ZEBRA in the serum of patients with PTLD.

The ZEBRA protein (encoded by the BZLF1 gene), is the major transcription factor of EBV, expressed upon EBV lytic cycle activation. Several studies highlighted the critical role of EBV lytic infection as a risk factor for lymphoproliferative disorders like post-transplant lymphoproliferative disease (PTLD). Here, we use an antigen-capture ELISA assay specifically designed to detecting the circulating soluble ZEBRA (sZEBRA) in serum samples (threshold value determined at 40ng/mL). We retrospectively investigated a population of 66 transplanted patients comprising 35 PTLD. All the samples from a control population (30 EBV-seronegative subjects and 25 immunocompetent individuals with EBV serological reactivation), classified as sZEBRA < 40ng/mL were assigned as negative. At PTLD diagnosis, EBV genome (quantified by qPCR with EBV DNA>200 copies/mL) and sZEBRA were detectable in 51% and 60% of cases, respectively. In the patients who developed a pathologically-confirmed PTLD, the mean sZEBRA value in cases, was 399 ng/mL +/- 141 versus 53ng/mL +/- 7 in patients who did not (p < 0,001). This is the first report relating to the detection of the circulating ZEBRA in serum specimens, as well as the first analysis dealing with the lytic cycle of EBV in PTLD patients with this new biomarker.

Primary Epstein-Barr virus infection with pneumonia transmitted by allogeneic bone marrow after transplantation.

We report a case of primary Epstein-Barr virus infection with lung involvement occurring 1 month after bone marrow transplantation. The transplant recipient had serological test results that were negative for Epstein-Barr virus before transplantation. The virus must have been transmitted by the donor's bone marrow, which was positive for Epstein-Barr virus. The patient recovered after rituximab and corticosteroid therapy.

Epstein-Barr virus and human herpesvirus 8 coinfection and concomitant extranodal nasal-type NK/T cell lymphoma and Castleman disease: case report.

We describe a 36-year-old man uninfected with human immunodeficiency virus who had confirmed concurrent infection with Epstein-Barr virus (EBV) and human herpesvirus 8 (HHV-8) and their respective lymphoproliferative manifestations, nasal-type NK/T cell lymphoma and Castleman disease. Antibodies to HHV-8 and EBV DNA were found in plasma and peripheral blood mononuclear cells. An EBV-positive nasal-type NK/T cell lymphoma infiltrated the splenic red pulp, whereas the white pulp contained HHV-8-positive plasmablasts, as found in Castleman disease.

Epstein-Barr virus (EBV) reactivation in allogeneic stem-cell transplantation: relationship between viral load, EBV-specific T-cell reconstitution and rituximab therapy.

BACKGROUND: Monitoring of Epstein-Barr virus (EBV) reactivation after allogeneic hematopoietic stem-cell transplantation markedly improved with quantitative real-time polymerase chain reaction amplification of EBV DNA and visualization of EBV-specific CD8+ T cells with peptide-human leukocyte antigen (HLA) class I tetramers. We decided to combine these methods to evaluate posttransplant EBV reactivation and rituximab therapy. METHODS: We followed 56 patients treated with an HLA-genoidentical sibling (n=32), an HLA-matched unrelated donor (MUD, n=19), or an unrelated cord-blood transplant (n=5). EBV DNA was quantified in plasma and in peripheral blood mononuclear cells (PBMC). Patient CD8+ T cells were stained with a panel of eight tetramers. RESULTS: EBV DNA was detected in half of the patients, mainly in the MUD group (17/19). In 19 patients, viral DNA was detected only in the cellular compartment. All patients who controlled reactivation without rituximab and despite a viral load of greater than 500 genome equivalents (gEq)/150,000 PBMC mounted an EBV-specific CD8+ T-cell response in greater than 1.4% of CD3+CD8+ T cells. Plasmatic EBV genome was found in nine patients preceded by a high cellular viral load. Three of these patients controlled the reactivation before or without the introduction of rituximab, and they all developed a significant and increasing EBV-specific T-cell response. Patients with EBV-specific T cells at the onset of reactivation controlled viral reactivation without rituximab. CONCLUSION: This study emphasizes the benefit of an early and close monitoring of EBV reactivation and CD8+-specific immune responses to initiate rituximab only when necessary and before the immune response becomes overwhelmed by the viral burden.

Increased infection rate after preemptive rituximab treatment for Epstein-Barr virus reactivation after allogeneic hematopoietic stem-cell transplantation.

BACKGROUND: Preemptive rituximab (R) treatment decreases the incidence of Epstein-Barr virus (EBV) posttransplantation lymphoproliferative disease, but the extent of immune deficiency related to R in patients who received allogeneic hematopoietic stem-cell transplantation is unclear. The aim of our study was to evaluate the incidence of late infections and immune reconstitution after preemptive R treatment of EBV infection. METHODS: Seventy-eight patients receiving preemptive R between January 2005 and January 2010 were studied. Fifty-two of them could be matched with controls (not receiving R) according to administration of antithymoglobulin, stem-cell source and donor type, age and grade of acute graft-versus-host disease. RESULTS: Among the 78 patients with EBV reactivation treated with R, the 36-month cumulative incidence of bacterial, viral, and fungal infections was 64%, 59%, and 23%, respectively. When compared with controls, bacterial infection incidence was significantly higher in R patients (55% vs. 35%), and a slower reconstitution of B cells was observed. R patients had modest but not significantly higher nonrelapse mortality (35% vs. 15%) than controls. CONCLUSION: R has dramatically decreased risks of posttransplantation lymphoproliferative disease but is followed by a prolonged and profound B-cell deficiency associated with an excess risk of bacterial infection and higher mortality. R should be given with caution, and immunoglobulin replacement should be provided to limit these excess risks.

Characteristics of non-Hodgkin lymphoma arising in HIV-infected patients with suppressed HIV replication.

OBJECTIVE: Despite effective treatment of HIV infection, some patients still develop non-Hodgkin lymphoma (NHL). We analysed patients with HIV-associated NHL and undetectable plasma HIV-RNA, according to the duration of HIV suppression. METHODS: Out of 388 patients included in a prospective cohort of HIV-associated NHL from 1996 to 2008, 128 (33%) had a plasma HIV-RNA below 500 copies/ml and were included in the study. Patients with long-term HIV suppression (>18 months) were compared with patients with recent HIV suppression (< or = 18 months). RESULTS: All patients but three were treated with combination antiretroviral therapy, with a median duration of 2.2 years. The median duration of HIV suppression was 10.1 months. Most cases (65%) occurred within 18 months following HIV suppression. In the more than 18 months group, patients developed NHL at a higher CD4 cell count than patients with 18 months or less of HIV suppression (359 versus 270 cells/microl, P = 0.02). None of the NHL characteristics were different between the two groups. Outcome was similar in the two groups (complete remission, 64 versus 72.5%; P = 0.35 and 3-year survival, 46 versus 56%; P = 0.08). In addition, 52% of the tumours were Epstein-Barr virus or human herpesvirus 8 associated, without any difference in the proportion of virus-associated tumours according to the duration of HIV suppression. CONCLUSION: In patients with undetectable HIV-RNA, NHL occurred mainly within the first 18 months following HIV suppression. In patients developing NHL after long-term HIV suppression, the level of CD4 cell count was higher, but the association with Epstein-Barr virus or human herpesvirus 8 and the prognosis were similar to that observed in patients with recent HIV suppression.

Kaposi's sarcoma in HIV-negative men having sex with men.

BACKGROUND: Four epidemiologic forms of Kaposi's sarcoma have been described, all of which are associated with the human herpesvirus-8. In western countries, human herpesvirus-8 is more prevalent in homosexual men than in the general population, and anecdotal cases of Kaposi's sarcoma in HIV-negative homosexual men have been reported. PATIENTS AND METHODS: We included HIV-negative homosexual and bisexual male patients with histologically proven Kaposi's sarcoma in a retrospective study. Clinical data were collected using a standardized form. Risk factors for human herpesvirus-8 infection and for the development of Kaposi's sarcoma were systematically recorded. RESULTS: Between 1995 and 2007, 28 men met the defined inclusion criteria. Mean age at first symptoms of Kaposi's sarcoma was 53 years. Clinical presentation resembled classical Kaposi's sarcoma, with limited disease in most patients. No cellular or humoral immunodeficiency was observed. Serologic tests for human herpesvirus-8 (latent immunofluorescence assay) were positive in 88% of patients, and only two patients displayed human herpesvirus-8 viremia at the time of Kaposi's sarcoma diagnosis. Three patients developed lymphoproliferative disorders (Castleman disease, follicular lymphoma and Burkitt lymphoma). In this population, alpha-interferon was well tolerated and gave a complete response, but most patients require only local treatment, if any. CONCLUSION: Kaposi's sarcoma may develop in homosexual or bisexual men without HIV infection. This type of Kaposi's sarcoma has clinical features in common with classical Kaposi's sarcoma but occurs in younger patients. Its prognosis is good, as Kaposi's sarcoma is generally limited, but clinicians should be aware of the association with lymphoproliferative diseases, which may affect prognosis.

Multicentric Castleman disease is associated with polyfunctional effector memory HHV-8-specific CD8+ T cells.

Multicentric Castleman disease (MCD) is a devastating human herpesvirus 8 (HHV-8)-related lymphoproliferative disorder that occurs in immunocompromised persons. To determine the role of immune responses in MCD, we studied the frequency, antigenic repertoire, differentiation, and functional profile of HHV-8-specific CD8(+) T cells in MCD patients and in human immunodeficiency virus-coinfected asymptomatic HHV-8 carriers (AC). Screening CD8(+) T-cell responses with ELISpot interferon-gamma (IFN-gamma) assays using 56 peptides on 6 latent and lytic HHV-8 proteins showed that MCD and AC patients had responses of similar magnitude and antigenic repertoire and identified a new 10-mer human leukocyte antigen B7 CD8 epitope in K15. Intracellular IFN-gamma staining showed significantly more CD45RA(-)CCR7(-)CD27(-) CD8(+)IFN-gamma(+) cells (late phenotype) and significantly fewer CCR7(-)CD27(+)CD45RA(-) cells (early and intermediate phenotype) in MCD than in AC patients. This phenotypic shift was not found for Epstein-Barr virus-specific CD8(+) T cells tested as controls. HHV-8 viral loads were negatively correlated with early and intermediate effector memory cells. HHV-8-specific T cells were polyfunctional (secretion of IFN-gamma, tumor necrosis factor-alpha, macrophage inflammatory protein-1beta, and/or CD107a) in both MCD and AC patients. In conclusion, MCD is not associated with a lack of HHV-8-specific CD8(+) T cells or limitation of their functional profile. Their differentiation increases with HHV-8 viral load. These results offer new insight into the pathophysiology of MCD.

Patterns of cytomegalovirus reactivation are associated with distinct evolutive profiles of immune reconstitution after allogeneic hematopoietic stem cell transplantation.

T cell-mediated immunity is essential for the control of cytomegalovirus (CMV) infections in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Our aims were to identify patterns of CMV-specific immune responses associated with multiple or prolonged reactivations. We analyzed findings in 116 recipients during the course of infection or reactivation and latency. CD8(+) T cell responses were determined weekly, using HLA class I tetramers together with extended phenotypic analyses. Our results confirmed that recipients of allo-HSCT from unrelated donors were more susceptible to multiple reactivations and that the donor's CMV serological status influenced the occurrence of prolonged reactivations. We found that a lack of CMV-specific T cells after the first episode of reactivation was associated with multiple subsequent reactivations. In patients with uncontrolled reactivations, CMV-specific T cells of the late differentiation phenotype CD45RA(+)CD27(-)CD28(-) did not develop. Longitudinal evaluation of CD27 and CD45RA expression within the tetramer-positive subset could help identify patients in whom a protective immune response is developing. Evaluation of CMV-specific immune responses during the first episode of reactivation, together with extended phenotypes, could thus improve immune monitoring, especially in recipients at risk of uncontrolled viral reactivation.