Impaired Immune Recovery Research Articles

Thymic Exhaustion and Increased Immune Activation Are the Main Mechanisms Involved in Impaired Immunological Recovery of HIV-Positive Patients under ART.

Decades of studies in antiretroviral therapy (ART) have passed, and the mechanisms that determine impaired immunological recovery in HIV-positive patients receiving ART have not been completely elucidated yet. Thus, T-lymphocytes immunophenotyping and cytokines levels were analyzed in 44 ART-treated HIV-positive patients who had a prolonged undetectable plasma viral load. The patients were classified as immunological non-responders (INR = 13) and immunological responders (IR = 31), according to their CD4+ T cell levels. Evaluating pre-CD4+ levels, we observed a statistically significant trend between lower CD4+ T cell levels and INR status (Z = 3.486, p < 0.001), and during 18 months of ART, the CD4+ T cell levels maintained statistical differences between the INR and IR groups (WTS = 37.252, p < 0.001). Furthermore, the INRs were associated with an elevated age at ART start; a lower pre-treatment CD4+ T cell count and a percentage that remained low even after 18 months of ART; lower levels of recent thymic emigrant (RTE) CD4+ T cell (CD45RA + CD31+) and a naïve CD4+ T cell (CD45RA + CD62L+); higher levels of central memory CD4+ T cells (CD45RA-CD62L+); and higher immune activation by CD4+ expressing HLA-DR+ or both (HLA-DR+ and CD38+) when compared with IRs. Our study demonstrates that thymic exhaustion and increased immune activation are two mechanisms substantially implicated in the impaired immune recovery of ART-treated HIV patients.

Effects of Various ATG Doses on Rejection Rate and Immune Recovery in Haploidentical T and B Cell Depleted Stem Cell Transplantation

T and B cell depletion of haploidentical stem cells with CD3/CD19 coated magnetic microbeads prevents from GvHD and allows to coinfuse donor NK cells and other accessory cells. Additional in vivo depletion of the graft by serotherapy is not necessary. Thus, a dosing scheme of ATG is needed, which provides a rejection prophylaxis by depleting lymphocyte subsets of the patients but which does not harm the graft, in particular cotransfused NK cells. We retrospectively analyzed the impact of various Grafalon (anti-human T-lymphocyte immunoglobulin = ATLG; formerly ATG-Fresenius) doses given at day -12 on engraftment rate and on posttransplant immune recovery.A total of 50 pediatric patients received either 3x5 (n=7), 3x10 (n=34) or 3x20mg/kg (n=9) ATLG starting at day -12 to day -9, followed by fludarabine (160 mg/m2, d -8 to -5), thiotepa (10 mg/m2 d -4) and melphalan (140 mg/m2 d -3 to -2). Diagnoses were: ALL/AML n=10, relapsed solid tumors n=33, nonmalignant diseases n=7. Most patients received MMF until day 30-60. ATLG serum levels were measured in 24 patients by flow cytometry (T cell specific rabbit IgG). Apoptosis/necrosis of donor NK cells was assessed with Annexin V/PI staining.A median number of 16x106 CD34/kg and 65x106 NK cells/kg with 29x103 T cells/kg were infused. Median time to ANC>500/µl was 9.5 days. Graft rejection occurred in 3/7 patients with 15mg (42%), in 7/34 patients with 30mg (20%) and in 1/9 patients with 60mg ATLG (11%). All rejectors could be rescued by reconditioning and 2nd stem cell donation or by infusion of autologous back ups. Acute GvHD grade 0-I occurred in 47 patients (94%), GvHD grade II and III-IV was observed in 1 and 2 patients (2%, 4%), respectively. Chronic GvHD occurred in 9 patients (18%). TRM at 1 year was 10% for the entire group. Immune recovery of CD3+ T cells was influenced by the various amounts of ATLG given in the 3 subgroups (15 vs 30 vs 60mg/kg) with a median number of 98 vs 10 vs 2 cells/µl at day +30, 95 vs 100 vs 2 cells/µl at day +90 and 75 vs 218 vs 239 cells/µl at day +180 (figure 1a). Recovery of CD56+ NK cells was fast and reliable and reached peaks of 459 vs 342 vs 155 cells/µl at day +30. Later on NK cells dropped to normal levels of 152 vs 167 vs 104 cells/µl at day +90 and 118 vs 172 vs 99 cells /µl at day +180. ATLG serum levels reached mean peak values of 9.6 µg/ml ±4.7 vs 22.1±13.8 µg/ml vs 53.7 ±13.9 µg/ml at day -8 and dropped to 1.4 ±1µg/ml vs and 3.0 ±1.98 µg/ml and 11.5 ±5.8 µg/ml at day 0 (15 vs 30 vs 60mg/kg, figure 1b). In vitro incubation of isolated NK cells from healthy donors with comparable ATLG doses (1 or 10 µg/ml) resulted in 26 (41)% apoptosis and 0.2 (0.2)% necrosis after 24 hours. Thus, vitality of 73 (59)% of NK cells were preserved.Conclusions: Our aim was to reduce the rejection rate and to improve immune recovery in patients receiving CD3/19 depleted haploidentical peripheral stem cells, in particular without hampering donor NK cells in the grafts. Administration of 15, 30 or 60 mg/kg ATLG was started at an early time point (day -12) of the regimen. Higher ATLG doses correlated with higher serum levels. Peak levels at day -8 provided a rejection prophylaxis. At day 0, various lower levels were achieved and minimized further in vivo depletion. Increased ATLG doses were associated with a lower rejection rate. On the other hand, recovery of T cells was slower after 60mg/kg ATLG in the early posttransplant phase with lower CD3 counts at day 30 and 90. Since all rejectors were successfully regrafted, it may be reasonable to balance between rejection risk and impaired immune recovery and to use an average dose (30mg). Further studies should investigate if serotherapy might be given even earlier than in this analysis. [Display omitted] DisclosuresLang:Miltenyi Biotec GmbH: Patents & Royalties, Research Funding. Schlegel:Miltenyi Biotec GmbH: Patents & Royalties, Research Funding. Martinius:Neovii Biotech: Employment. Handgretinger:Miltenyi Biotec GmbH: Patents & Royalties, Research Funding.

Undernutrition and HIV Infection in Sub-Saharan Africa: Health Outcomes and Therapeutic Interventions.

Sub-Saharan Africa (SSA) is disproportionately burdened by the twin epidemics of food insecurity and HIV infection, and protein-calorie undernutrition is common among persons with HIV (PWH) initiating antiretroviral therapy (ART) in the region. In this review, we discuss the intersection of HIV infection and undernutrition, health outcomes among undernourished PWH starting ART, and the demonstrated and potential benefits of therapeutic interventions such as micro/macronutrient supplementation and pharmacological agents. A low body mass index (BMI), used as a general indicator of poor nutrition in most studies, is associated with impaired immune recovery and increased mortality in the early ART period. The increased risk of mortality is multifactorial, and contributors include undernutrition-related immune system dysfunction, increased susceptibility to opportunistic infections, and metabolic and cardiovascular dysregulation. Clinical trials of micro/macronutrient supplementary feeding, appetite stimulants (hormones and anabolic agents), and recombinant adipokines have shown a benefit for weight gain and metabolic health, but there are few data on mortality or immune recovery. A substantial proportion of PWH in SSA are undernourished, and undernutrition contributes to an increased risk of mortality and other adverse health outcomes. To date, there have been few prospective trials of nutritional supplementation and/or pharmacologic therapy among undernourished PWH in SSA, though findings from other settings suggest a potential benefit in this population.

Malnutrition in HIV-Infected Children Is an Indicator of Severe Disease with an Impaired Response to Antiretroviral Therapy.

This observational study aimed to describe immunopathogenesis and treatment outcomes in children with and without severe acute malnutrition (SAM) and HIV-infection. We studied markers of microbial translocation (16sDNA), intestinal damage (iFABP), monocyte activation (sCD14), T-cell activation (CD38, HLA-DR) and immune exhaustion (PD1) in 32 HIV-infected children with and 41 HIV-infected children without SAM prior to initiation of antiretroviral therapy (ART) and cross-sectionally compared these children to 15 HIV-uninfected children with and 19 HIV-uninfected children without SAM. We then prospectively measured these markers and correlated them to treatment outcomes in the HIV-infected children at 48 weeks following initiation of ART. Plasma levels of 16sDNA, iFABP and sCD14 were measured by quantitative real time PCR, ELISA and Luminex, respectively. T cell phenotype markers were measured by flow cytometry. Multiple regression analysis was performed using generalized linear models (GLMs) and the least absolute shrinkage and selection operator (LASSO) approach for variable selection. Microbial translocation, T cell activation and exhaustion were increased in HIV-uninfected children with SAM compared to HIV-uninfected children without SAM. In HIV-infected children microbial translocation, immune activation, and exhaustion was strongly increased but did not differ by SAM-status. SAM was associated with increased mortality rates early after ART initiation. Malnutrition, age, microbial translocation, monocyte, and CD8 T cell activation were independently associated with decreased rates of CD4% immune recovery after 48 weeks of ART. SAM is associated with increased microbial translocation, immune activation, and immune exhaustion in HIV-uninfected children and with worse prognosis and impaired immune recovery in HIV-infected children on ART.

Immune Activation and Bacterial Translocation: A Link between Impaired Immune Recovery and Frequent Visceral Leishmaniasis Relapses in HIV-Infected Patients.

The maintenance of chronic immune activation due to leishmaniasis or even due to microbial translocation is associated with immunosenescence and may contribute to frequent relapses. Our aim was to investigate whether patients with HIV-associated visceral leishmaniasis (VL/HIV) who experience a single episode of VL have different immunological behaviors in comparison to those who experience frequent relapses. VL/HIV patients were allocated to non-relapsing (NR, n = 6) and relapsing (R, n = 11) groups and were followed from the active phase of VL up to 12 months post-treatment (mpt). The patients were receiving highly active antiretroviral therapy (HAART) and secondary prophylaxis after VL therapy. During active VL, the two groups were similar in all immunological parameters, including the parasite load. At 6 and 12 mpt, the NR group showed a significant gain of CD4+ T cells, a reduction of lymphocyte activation, and lower soluble CD14 and anti-Leishmania IgG3 levels compared to the R group. The viral load remained low, without correlation with the activation. The two groups showed elevated but similar percentages of senescent T cells. These findings suggest a decreased ability of the R group to downmodulate immune activation compared to the NR group. Such functional impairment of the effector response may be a useful indicator for predicting clinical prognosis and recommending starting or stopping secondary prophylaxis.

Unrecognised tuberculosis at antiretroviral therapy initiation is associated with lower CD4+ T cell recovery

To investigate whether an unrecognised diagnosis of tuberculosis (TB) at the start of antiretroviral therapy (ART) influences subsequent CD4+ T cell (CD4) count recovery in an urban HIV clinic in Uganda. In a retrospective cohort study, a multivariable polynomial mixed effects model was used to estimate CD4 recovery in the first 96 weeks of ART in two groups of patients: prevalent TB (started ART while on TB treatment), unrecognised TB (developed TB within 6 months after start ART). Included were 511 patients with a median baseline CD4 count of 57 cells/mm(3) (interquartile range: 22-130), of whom 368 (72%) had prevalent TB and 143 (28%) had unrecognised TB. Compared with prevalent TB, unrecognised TB was associated with lower CD4 count recovery at 96 weeks: -22.3 cells/mm(3) (95% confidence interval -43.2 to -1.5, P = 0.036). These estimates were adjusted for gender, age, baseline CD4 count and the use of zidovudine-based regimen. Unrecognised TB at the time of ART initiation resulted in impaired CD4 recovery compared with TB treated before ART initiation. More vigilant screening with more sensitive and rapid TB diagnostics prior to ART initiation is needed to decrease the risk of ART-associated TB and sub-optimal immune reconstitution.

Impaired CD4 T-Cell Count Response to Combined Antiretroviral Therapy in Antiretroviral-Naive HIV-Infected Patients Presenting With Tuberculosis as AIDS-Defining Condition

The impact of human immunodeficiency virus (HIV)-associated tuberculosis on CD4 T-cell count response to combined antiretroviral therapy (cART) is poorly investigated. A collaborative analysis including HIV-infected patients prospectively enrolled in 4 Italian clinical cohorts was conducted. Patients were grouped according to Centers for Disease Control and Prevention stage at the start of cART as having tuberculosis, having AIDS but not tuberculosis (nontuberculosis AIDS), and not having AIDS (AIDS free). Time to CD4 T-cell count of at least 100, 200, and 300 cells/μL above pre-cART levels and to CD4 T-cell count of >500 cells/μL were major end points. Survival analysis with time-fixed and time-dependent covariates was used. A total of 6528 patients were eligible; 125 patients (2%) had tuberculosis, 1062 (16%) had nontuberculosis AIDS, and 5341 (82%) were AIDS free. Patients with tuberculosis had a significantly reduced chance of CD4 T-cell count increase compared with AIDS-free patients as well as those with nontuberculosis AIDS, regardless of the primary outcome considered for a given value of confounders measured at baseline (eg, for >200 cells/μL above baseline; relative hazard, 0.71; P = .02), although it was no longer significant after further adjustment for current level of viral load suppression (relative hazard, 0.80; P = .11). There was a trend for reduced virological response in patients treated concomitantly for tuberculosis and HIV infection compared with those who were treated separately in time (P = .09). HIV-infected patients starting cART with a tuberculosis diagnosis showed an impaired immune recovery to cART compared with AIDS-free patients and those with nontuberculosis AIDS. It seems to be driven mainly by a delay in achieving viral suppression. Whether this may be due to interactions between antituberculosis drugs and antiretrovirals needs to be investigated.

Clinicohistologic Assessment of Bone Marrow Engraftment In Patients with Hematologic Malignancies Received Double Umbilical Cord Blood Transplantation – A Single Institutional Observation

Abstract 4578 Background:Double umbilical cord blood transplantation (dUCBT) has been gradually accepted as an alternative for the treatment of patients with hematologic malignancy requiring allogeneic hematopoietic stem cell transplant but who lack suitable adult donors. The therapeutic strategy has achieved success with either reduced intensity conditioning (RIC) or myeloablative regimens (MAC). According to large series, the 3-year event free survival (EFS) and median overall survival (OS) for RIC-dUCBT approaches 39% and 45%, respectively. Nevertheless, early mortality and development of graft-versus host disease (GVHD) exist. In addition, since UCB contains 10-fold fewer hematopoietic stem cells (HSCs) than adult donor HSC sources, engraftment takes longer even with protracted or double dosage hematopoietic growth factor administration. The relationship between bone marrow (BM) status and delayed engraftment and survival in UCBT patients is not well illustrated. This study aims to retrospectively evaluate our institutional UCBT cases and correlate the bone marrow findings with the clinical outcome. Design:Clinical and pathologic data from patients with hematopoietic malignancies receiving dUCBT between 11/2009 and 05/2011 were reviewed. Sequential BM biopsies from each patient pre- and post- dUCBT were reviewed by two hematopathologists. BM cellularity and peripheral blood counts about day 21, 30, and 90 were correlated with CBCs, chimerism and the clinical outcomes as well as survival. Results:Thirty-one patients with hematologic malignancies (AML = 13, ALL = 6, CLL = 3, FL = 2, DLBCL = 2, HL = 1, MCL = 1, PTCL =1, Myeloma =1, and MDS = 1) received conditioning with chemotherapy and total body irradiation (MAC = 12; RIC = 19) followed by dUCBT. The median age was 45.7 years (range, 18–68 years) with a male to female ratio of 1.1:1. All patients received GvHD prophylaxis with cyclosporine and MMF and G-CSF from day +1 until engraftment. The median time to neutrophil engraftment was 22 days (range, 15 – 59) following MAC and 22 days (range 6 – 43) following RIC. Bone marrow cellularity, the corresponding WBC, and chimerism data are shown (Table 1). On the day 21 BM assessment, 80% (8/10) of patients receiving MAC achieved a marrow cellularity at or above the median and 87.5% (7/8) were alive at last follow-up. Following RIC, 59% (10/17) of patients achieved at least the median cellularity (10%) and 70% (7/10) survived. For patients below the median cellularity at day 21, survival was only 50% (1/2) and 43% (3/7) following MAC and RIC, respectively. With a median follow-up for survivors of 264 days (range 72 – 613) (MAC 286 days; RIC 239 days), the estimated overall survival at 1 year was 47% (28 – 68%). Thirteen patients died due to infection (n = 6), relapse (n = 3), GvHD (n = 2), or hemorrhage (n = 2).Table 1Post UCBT bone marrow status in correlation with clinical and laboratory parametersVariableMyeloablative Conditioning (n = 10)Reduced Intensity Conditioning (n = 17)Myeloablative Conditioning (n=7) (nReduced Intensity Conditioning (n=11) (nDay 21Number alive at last follow-up with value ≥ medianDay 21Number alive at last follow-up with value ≥ medianDay 28Number alive at last follow-up with value ≥ medianDay 28Number alive at last follow-up with value ≥ medianBM % cellularity Median (range)5% (4-20)8/1010% (4-35)10/1128% (25-45)4/720% (5-50)5/11% Blast count (%) Median (range)4% (0.5-10.5)5/71.85% (0-17)4/81.5% (0-8)1/31% (0-1.5)4/6WBC ( x 109/L) Median (range)0.85 (0.04-2.5)6/60.4 (0-1.4)5/105 (0-7.6)4/62 (1-4)2/5≥90% donor Number (%)7/10 (70%)5/85/17 (29.4%)4/94/6 (66.7%)3/66/11 (54.5%)3/5 Conclusion:Our results demonstrate that the bone marrow cellularity early post-transplant may serve as a predictor of survival following transplant. Since 6 of 13 patients (46%) died due to infection, this may indicate further impaired immune recovery regardless of total WBC. Larger case series are needed to elucidate a correlation between the bone marrow environment and the long term survival following dUBCT. Disclosures:No relevant conflicts of interest to declare.

Early Adjuvant Treatment after Risk-Adapted Autologous Stem Cell Transplant for Systemic Light-Chain Amyloidosis: Increased Hospitalizations and Impaired Immune Recovery but Improved Responses and Overall Survival.

High-dose melphalan (MEL) with autologous stem cell transplant (SCT) is an effective therapy for systemic light-chain amyloidosis (AL) and a risk-adapted approach to MEL dosing minimizes transplant-related mortality (BJH 2007; 139). The depth and duration of hematologic response to treatment with SCT or conventional chemotherapy have been shown to correlate with overall survival (OS). Patients who do not achieve a complete hematologic response (CR) after SCT and are initially observed have a median OS of 24 months (Leukemia Lymphoma 2000; 37:245). In an effort to improve the OS of those not achieving CR, and based partly on trials in multiple myeloma showing benefit, we have explored adding early adjuvant therapy (AT) to the treatment of AL patients with persistent clonal plasma cell disease post-SCT. We have enrolled patients on two consecutive SCT+AT protocols, the first utilizing adjuvant dexamethasone (Dex) +/− Thalidomide (Thal) and the second Dex + Bortezomib (Bort). AT was added at 2 or 3 months post-SCT for those with partial hematologic response or stable hematologic disease. We assessed the outcomes on these protocols with respect to AT-related mortality, hospitalizations in the first year post-SCT, immune recovery and OS. Sixty-four patients enrolled on these trials and 59 survived 2 to 3 months post-SCT to be evaluated for hematologic response. Seventeen were observed without AT while 42 received AT (10 Dex, 21 Dex+Thal, 11 Dex+Bort). There were no deaths due to AT. Thirteen of the 42 patients receiving AT (31%) were hospitalized during the first year post-SCT (6 with pneumonia [5 viral, 1 fungal]; 1 with sinusitis and S. pneumo bacteremia; 3 with congestive heart failure; 2 with pulmonary emboli; 1 with avascular necrosis of the hip) as compared to 2 hospitalizations (1 with engraftment syndrome; 1 with diarrheal illness) in the 17 patients not receiving AT (12%; p= 0.23 by χ2). At 1 year post-SCT median absolute lymphocyte counts (ALC) and IgG levels were lower in the AT group (ALC: 1.0 (0.4–2.9) vs 1.7 (0.9–5.1), p=0.01; IgG: 569 (205–1650) vs 867 (635–1200), p=0.04, two-tailed Mann-Whitney), and IgA recovery at 1 year was impaired in the AT group as well (p=0.07). Twenty-four of the 42 patients receiving AT (57%) had improved hematologic responses, including 10 of 11 patients receiving Dex+Bort, with 13 of 42 achieving CR (31%). Median overall survival has not been reached for those with CR to SCT and is 59 months for those who received AT (p=0.06). In sum, AL patients in this series receiving early AT post-SCT were more frequently hospitalized in the first year and had impaired immune recovery. However, over half of the AT patients had improved hematologic responses and, as a cohort, the median overall survival of AT patients was more than twice that of historical controls receiving SCT followed by observation alone.

Poor Initial CD4+ Recovery With Antiretroviral Therapy Prolongs Immune Depletion and Increases Risk for AIDS and Non-AIDS Diseases

Low CD4+ increases risk for both AIDS- and non-AIDS-related morbidity and mortality. The magnitude of CD4+ recovery early after initial antiretroviral therapy (ART) is important in the ultimate duration of immune depletion. We examined CD4+ recovery among 850 participants in the Community Program for Clinical Research on AIDS Flexible Initial Retrovirus Suppressive Therapies study with virologic suppression (ie, achieved an HIV RNA level <400 copies/mL) with 8 months of initial ART and determined subsequent risk for AIDS, non-AIDS diseases (non-AIDS cancers and cardiovascular, end-stage renal, and liver diseases), or death using Cox regression during a median 5-year follow-up. Mean pretreatment CD4+ was 221 cells/microL; 18% (n = 149) had a poor CD4+ recovery (<50 cells/microL) after 8 months of effective ART, resulting in lower CD4+ over 5 years. Older age (hazard ratio 1.34/10 yrs, P = 0.003) and lower screening HIV RNA (hazard ratio 0.65 per log10 copies/mL higher, P = 0.001), but not screening CD4+, were associated with a poor CD4+ recovery. After 8 months of effective ART, 30 patients experienced the composite outcome of AIDS, non-AIDS, or death among participants with a poor CD4+ recovery (rate = 5.8/100 person-years) and 74 patients among those with an adequate recovery (>or=50 cells/muL; rate = 2.7/100 person-years) (adjusted hazard ratio = 2.24, P < 0.001). The risk of this composite outcome associated with a poor CD4+ recovery declined when ART was initiated at higher CD4+ counts (P < 0.01). Impaired immune recovery, despite effective ART, results in longer time spent at low CD4+, thereby increasing risk for a broad category of HIV-related morbidity and mortality conditions.

349: Higher-order cytokine flow cytometry reveals distinct functional signatures of maturation subsets of CD4+ and CD8+ T cells

Our clinical studies have suggested that impaired immune recovery after SCT is associated with greater proportions of circulating memory and late memory cells, as defined by phenotyping. To characterize the relationship between immunophenotypic markers of T cell maturation and functional attributes of T cells, we optimized an 8-color, 10-parameter cytokine flow cytometry (CFC) approach and examined PBMC in 3 healthy donors. PBMC were exposed to stimuli that both bypass and signal through the T cell receptor (PMA/Ionomycin—P:I and staph enterotoxin B—SEB, respectively) and stained with CD45RA and CD27 to demarcate naı̈ve (N, CD45RA+CD27+), memory (M, CD45RA-CD27-) and late-memory (LM, CD45RA+CD27-) CD4+ and CD8+ T cells. We assessed the production of effector cytokines (IL-2, IFNγ, TNFα and MIP1β) within the three maturation subsets. Following PMA and SEB stimulation, all maturation subsets (N, M and LM) of CD4+ and CD8+ T cells produced IFNγ. TNFα production was similarly distributed after P:I stimulation. However, after SEB stimulation, LM CD4+ and CD8+ cells produced only 2.5% and 8.5% of total TNFα, respectively. Production of IL-2 and MIP1-β was much more skewed, with LM cells contributing little to total IL-2 production after stimulation with P:I (0.2% of total, CD4; 0%, CD8) or SEB (CD4, 2.1%; CD8, 2.8%). While LM cells produced little or no IL-2, they produced the bulk of MIP1-β following stimulation with P:I (96.5%, CD4; 84.8%, CD8) or SEB (97.5%, CD4; 70.7%, CD8). Co-production of IL-2 and IFNγ in T cells has recently been postulated to be important for protective immunity. Importantly, no IL-2+IFNγ+ cells were seen in the LM compartment following P:I stimulation (CD4+ Distribution: 8.9% N, 91.1% M, 0% LM; CD8: 15.7% N, 84.3% M, 0% LM). Results following SEB stimulation were similar (CD4: 3.3% N, 94.9% M, 1.8% LM; CD8: 12.2% N, 87.8% M, 0% LM). Overall, these results suggest that: 1) T cell maturation stage does correlate strongly with functional capacity; 2) Nearly all IL-2 production occurs in N and M cells; 3) LM cells produce little or no IL-2; but most of total MIP-1β; 4) IL-2/IFNγ co-production is absent in LM cells, perhaps suggesting why late-stage skewing after SCT is associated with functional T cell impairment; and 5) Maturation stage appears to be more closely associated with functional status than CD4 or CD8 lineage. These results may have important implications for clinical studies of post-SCT immune recovery and GVHD.

Unrelated Donor Status and High Donor Age Independently Affect Immunologic Recovery after Nonmyeloablative Conditioning

The risk of cytomegalovirus (CMV) infection is higher after HLA-matched unrelated donor (URD) than after HLA-matched related donor (MRD) nonmyeloablative hematopoietic cell transplantation (HCT). We therefore investigated factors affecting immune recovery in 94 patients given HCT from MRDs (n = 51) and URDs (n = 43) after 2-Gy total body irradiation with or without fludarabine and postgrafting immunosuppression with mycophenolate mofetil and cyclosporine. CD4 T cells counts remained below normal values during the first year after HCT in both patient groups. This included abnormally low counts each of naive CD4 T cells and memory CD4 T cells. Conversely, CD8 T cell counts reached the 10th percentile of normal 6 months after HCT in MRD and URD recipients. On day 30 after HCT, URD recipients had lower counts of B cells ( P = .02), naive CD4 T cells ( P = .04), memory CD4 T cells ( P = .005), memory CD8 T cells ( P = .005), and CMV-specific T helper cells ( P = .007) than had MRD recipients. This delay in CMV-specific immune reconstitution translated into increased frequency of CMV antigenemia among URD recipients during the first 100 days after HCT. Older donor age was associated with low counts of naive CD4 T cells on days 180-365 after HCT ( P = .003). Further, low numbers of T cells and CD34 + cells in the graft and development of acute graft-versus-host disease were associated with impaired immune recovery of naive CD4 T cells and B cells. In summary, immunologic recovery was poor the first year after nonmyeloablative conditioning and was delayed among URD recipients in comparison with MRD recipients. Other factors significantly associated with delayed immune recovery were advanced donor age, low numbers of CD34 and T cells in the graft, and development of graft-versus-host disease.

Dose-dependent influence of didanosine on immune recovery in HIV-infected patients treated with tenofovir

Antiretroviral therapy (ART) containing tenofovir disoproxil fumarate (TDF) and didanosine (ddI) has been associated with poor immune recovery despite virologic success. This effect might be related to ddI toxicity since ddI exposure is substantially increased by TDF. To analyze whether immune recovery during ART with TDF and ddI is ddI-dose dependent. A retrospective longitudinal analysis of immune recovery measured by the CD4 T-cell slope in 614 patients treated with ART containing TDF with or without ddI. Patients were stratified according to the tertiles of their weight-adjusted ddI dose: low dose (< 3.3 mg/kg), intermediate dose (3.3-4.1 mg/kg) and high dose (> 4.1 mg/kg). Cofactors modifying the degree of immune recovery after starting TDF-containing ART were identified by univariable and multivariable linear regression analyses. CD4 T-cell slopes were comparable between patients treated with TDF and a weight-adjusted ddI-dose of < 4.1 mg/kg per day (n = 143) versus TDF-without-ddI (n = 393). In the multivariable model the slopes differed by -13 CD4 T cells/mul per year [95% confidence interval (CI), -42 to 17; P = 0.40]. In contrast, patients treated with TDF and a higher ddI dose (> 4.1 mg/kg per day, n = 78) experienced a significantly impaired immune recovery (-47 CD4 T cells/microl per year; 95% CI, -82 to -12; P = 0.009). The virologic response was comparable between the different treatment groups. Immune recovery is impaired, when high doses of ddI (> 4.1 mg/kg) are given in combination with TDF. If the dose of ddI is adjusted to less than 4.1 mg/kg per day, immune recovery is similar to other TDF-containing ART regimen.

Patterns of Early Infectious Complications in Adult Unrelated Cord Blood Transplantation (UCBT). A Single Center Experience.

The major cause of non-relapse transplant related mortality (TRM) in UCBT continues to be infectious, with blood stream infections (BSI) constituting the majority of these events. However, CMV antigenemia and BK virus associated late onset hemorrhagic cystitis (LOHC) are increasingly important causes of morbidity and mortality. We review our single institution experience. We identified 13 patients with hematological malignancies in our database that had undergone UCBT in the period June 2002 - January 2005 and analyzed these data to document the incidence and patterns of infectious complications. The median age was 48 (range 19–62) years. All patients received infectious prophylaxis with Ciprofloxacin, Acyclovir, Voriconazole, Bactrim/nebulized Pentamidine. Eleven patients underwent conditioning with standardized Thiotepa/Busulfan/Cytoxan and GVHD prophylaxis with Tacrolimus/Mycphenalate Mofetil/ATG and the remaining 2 patients received TBI based conditioning. The median total nucleated cell (TNC) was 1.70E+07 and the median CD34 (+) cell count was 8.0E+04. The HLA matches were 4/6 in 9, 5/6 in 3 and 6/6 in 1 patient. All patients engrafted with a median time to neutrophil engraftment (TNE) of 25 (range 16–34) days. Twelve of thirteen patients achieved full donor chimerism at day 30 and 10 of 12 patients with full chimerism at day 100. Five patients developed grade II-IV acute GVHD requiring additional steroid therapy and 1 patient died of steroid refractory GVHD at day 50. Four patients had positive blood cultures at transplant. All patients developed documented bacterial infections: Gram positive in 12 (92%) (VRE in 23%, Steotrophomonas maltophilia in 31%); Gram negative in 8 (61%) (E. cloacae in 15%, Acinobacter spp. in 2 cases). Ten patients were CMV seropositive and 9 of these developed antigenemia requiring Gancyclovir/Foscarnet therapy. Nine patients had documented BK viruria with consequent late onset hemorrhagic cystitis (LOHC) and 5 patients developed BK viremia. There was 1 case of fungal BSI, while 8 patients had documented fungal tongue cultures. Four patients had positive bronchial washings (3 bacterial, 1 C. glabrata). Twelve (92%) patients were alive at day 100. Of note 62% of BSI and all cases of LOHC and CMV antigenemia developed after neutrophil engraftment. In our series of patients, viral infections (CMV, BK virus) were the most significant causes of morbidity. The high rate of BSI, especially after myeloid recovery, argues for a major influence of impaired immune recovery.

Bone marrow transplantation and approaches to avoid graft-versus-host disease (GVHD).

Haematopoietic stem cell transplantation (HSCT) offers promise for the treatment of haematological and immune disorders, solid tumours, and as a tolerance inducing regimen for organ transplantation. Allogeneic HSCTs engraftment requires immunosuppression and the anti-tumour effects are dependent upon the immune effector cells that are contained within or generated from the donor graft. However, significant toxicities currently limit its efficacy. These problems include: (i) graft-versus-host disease (GVHD) in which donor T cells attack the recipient resulting in multi-organ attack and morbidity, (ii) a profound period of immune deficiency following HSCT, and (iii) donor graft rejection. Currently available methods to prevent or treat GVHD with systemic immunosuppression can lead to impaired immune recovery, increased opportunistic infections, and higher relapse rates. This review will provide an overview of GVHD pathophysiology and discuss the roles of various cells, pathways, and factors in the GVHD generation process and in the preservation of graft-versus-tumour effects. Variables that need to be taken into consideration in attempting to extrapolate preclinical results to the clinical paradigm will be highlighted.

Developments in T-cell depletion of allogeneic stem cell grafts.

The quantitative depletion of T-cells has long been established as a highly effective way to prevent graft-versus-host disease. The disadvantages associated with T-cell depletion (TCD), including loss of the graft-versus-leukemia effect and impaired immune recovery have been important drawbacks for application on a wider scale. Recently, however, new approaches such as the use of peripheral blood stem cells and the application of TCD, in conjunction with delayed donor lymphocyte infusion, have opened new possibilities. The first clinical studies addressing the merits of these approaches suggest that effective prevention of graft-versus-host disease may be achieved by TCD, whereas the graft-versus-leukemia effect may be maintained by delayed donor lymphocyte infusion. Also, immune recovery may be accelerated by the use of peripheral blood stem cells. New techniques to manipulate stem cell grafts in vitro are being developed with the purpose to either selectively delete alloantigen specific T cells or tolerize such T cells by blocking costimulatory pathways. As a result, the in vitro manipulation of T cells of allogeneic stem cell grafts currently enjoys renewed scientific interest.