Immunoglobulin prophylaxis against cytomegalovirus infection in patients at high risk of infection following allogeneic hematopoietic cell transplantation

The effect of pre-conditioning immunoglobulin and absolute lymphocyte count on the outcomes of allogeneic hematopoietic cell transplantation

INTRODUCTION

The prevention of mortality and morbidity related to the increasingly used allogeneic hematopoietic cell transplantation (allo-HCT), along with the effects of pre- and post-transplant immune status on transplant outcomes, have become the focus of the studies conducted on this subject in recent years. In parallel, this study was designed to investigate the effects of pre-conditioning immunoglobulin (pre-conditioning-Ig) and pre-conditioning absolute lymphocyte count (pre-conditioning-ALC) levels on transplant outcomes.

METHODS

This study was designed as a retrospective, observational and cross-sectional study. The objective of the study is to investigate the effects of pre-conditioning-Ig and ALC levels primarily on the rate of patients with febrile neutropenia (FEN) and the duration of FEN and length of hospital stay (LoS), and secondarily on acute graft-versus-host disease (aGVHD), cytomegalovirus (CMV) viremia, and mortality in the acute leukemia patients who underwent allo-HCT.

RESULTS

A total of 104 acute leukemia patients, of whom 55 had acute lymphoblastic leukemia (ALL) and 49 had acute myeloid leukemia (AML), were included in the study. Compared to the AML group, the median pre-conditioning-IgG, IgA, and IgM levels were found to be significantly lower in the ALL group (11.3 vs. 6.6, p < 0.001; 1.8 vs. 0.9, p < 0.001; and 0.7 vs. 0.4, p < 0.001; respectively). But, there was no significant difference between the groups in pre-conditioning-Ig and ALC levels and transplant outcomes. However, subgroup analysis revealed that high pre-conditioning-ALC levels were significantly correlated with aGVHD levels (Odds Ratio: 1.02; p = 0.034) and low pre-conditioning-IgM levels were significantly correlated with increased mortality rate (Hazard Ratio: 0.08; p = 0.042) in AML patients.

CONCLUSION

The significant difference determined between the ALL and AML groups in pre-conditioning-Ig levels was not reflected on the effects of pre-conditioning-Ig and ALC levels on transplant outcomes. However, we observed that pre-conditioning-IgM and ALC levels have an impact on transplant outcomes in AML patients.

Compatibility at amino acid position 98 of MICB reduces the incidence of graft-versus-host disease in conjunction with the CMV status

Graft-versus-host disease (GVHD) and cytomegalovirus (CMV)-related complications are leading causes of mortality after unrelated-donor hematopoietic cell transplantation (UD-HCT). The non-conventional MHC class I gene MICB, alike MICA, encodes a stress-induced polymorphic NKG2D ligand. However, unlike MICA, MICB interacts with the CMV-encoded UL16, which sequestrates MICB intracellularly, leading to immune evasion. Here, we retrospectively analyzed the impact of mismatches in MICB amino acid position 98 (MICB98), a key polymorphic residue involved in UL16 binding, in 943 UD-HCT pairs who were allele-matched at HLA-A, -B, -C, -DRB1, -DQB1 and MICA loci. HLA-DP typing was further available. MICB98 mismatches were significantly associated with an increased incidence of acute (grade II-IV: HR, 1.20; 95% CI, 1.15 to 1.24; P < 0.001; grade III-IV: HR, 2.28; 95% CI, 1.56 to 3.34; P < 0.001) and chronic GVHD (HR, 1.21; 95% CI, 1.10 to 1.33; P < 0.001). MICB98 matching significantly reduced the effect of CMV status on overall mortality from a hazard ratio of 1.77 to 1.16. MICB98 mismatches showed a GVHD-independent association with a higher incidence of CMV infection/reactivation (HR, 1.84; 95% CI, 1.34 to 2.51; P < 0.001). Hence selecting a MICB98-matched donor significantly reduces the GVHD incidence and lowers the impact of CMV status on overall survival.

Effectiveness of immunoglobulin prophylaxis in reducing clinical complications of hematopoietic stem cell transplantation: a systematic review and meta-analysis

BACKGROUND

Prophylactic immunoglobulin has been used with varying efficacy to reduce complications in hematopoietic stem cell transplant recipients.

STUDY DESIGN AND METHODS

A systematic review and meta-analysis was conducted of randomized controlled trials that assessed clinical outcomes (overall survival, transplant-related mortality, graft-versus-host disease [GVHD], veno-occlusive disease [VOD], interstitial pneumonitis, disease relapse, cytomegalovirus [CMV] infection and disease, non-CMV infection) of immunoglobulin prophylaxis versus placebo in hematopoietic stem cell transplant recipients. MEDLINE, EMBASE, EBM Reviews, and the Cochrane Central Register of Controlled Trials were searched up to June 2017. Quality of included studies and outcomes were evaluated via Risk of Bias assessment and Grading of Recommendations, Assessment, Development and Evaluation criteria, respectively.

RESULTS

Of 899 citations screened, 27 studies (n = 3934) were included. Immunoglobulin prophylaxis had no impact on survival (risk ratio [RR], 0.94; 95% confidence interval [CI], 0.88-1.01; 11 studies, n = 1962) but decreased risk of acute GVHD (RR, 0.78; 95% CI, 0.65-0.94; eight studies, n = 1097) and CMV disease (RR, 0.52; 95% CI, 0.28-0.97; two studies, n = 167). Meta-analysis revealed increased risk of VOD (RR, 3.04; 95% CI, 1.10-8.41; three studies, n = 384) and disease relapse (RR, 1.26; 95% CI, 1.07-1.49; seven studies, n = 1647). Other outcomes were small in sample size or nonsignificant. Results should be interpreted cautiously given the low quality of studies and evidence of outcomes.

CONCLUSION

Immunoglobulin prophylaxis did not have a significant effect on survival. Positive clinical effects were shown for acute GVHD and CMV disease and negative effects against VOD and disease relapse. No studies examined the effect of immunoglobulin treatment in hypogammaglobulinemic patients despite current guidelines, warranting further studies in this population.

Challenges in the Role of Gammaglobulin Replacement Therapy and Vaccination Strategies for Hematological Malignancy

Patients with chronic lymphocytic leukemia (CLL) and multiple myeloma (MM) are prone to present with antibody production deficits associated with recurrent or severe bacterial infections that might benefit from human immunoglobulin (Ig) (IVIg/SCIg) replacement therapy. However, the original IVIg trial data were done before modern therapies were available, and the current indications do not take into account the shift in the immune situation of current treatment combinations and changes in the spectrum of infections. Besides, patients affected by other B cell malignancies present with similar immunodeficiency and manifestations while they are not covered by the current IVIg indications. A potential beneficial strategy could be to vaccinate patients at monoclonal B lymphocytosis and monoclonal gammopathy of undetermined significance stages (for CLL and MM, respectively) or at B-cell malignancy diagnosis, when better antibody responses are attained. We have to re-emphasize the need for assessing and monitoring specific antibody responses; these are warranted to select adequately those patients for whom early intervention with prophylactic anti-infective therapy and/or IVIg is preferred. This review provides an overview of the current scenario, with a focus on prevention of infection in patients with hematological malignancies and the role of Ig replacement therapy.

HLA haploidentical peripheral blood stem cell transplantation using reduced dose of posttransplantation cyclophosphamide for poor-prognosis or refractory leukemia and myelodysplastic syndrome

Nonmyeloablative, human leukocyte antigen (HLA) haploidentical, T-cell-replete bone marrow transplantation followed by high-dose posttransplantation cyclophosphamide (PT/Cy) has recently been developed. This transplantation milieu has resulted in favorable outcomes with low transplantation-related mortality, owing to a low incidence of graft-versus-host disease (GVHD), without increased infectious complications. However, the high relapse rate remains a major concern. We therefore performed a prospective pilot study of HLA haploidentical peripheral blood stem cell transplantation (PBSCT) with intensified conditioning, followed by two lower doses of PT/Cy. A total of 20 patients with refractory or poor-prognosis myelodysplastic syndrome (MDS) and leukemia were enrolled in the study. A trend toward a lower incidence of grade III-IV acute GVHD at day 100 in the group receiving 25 mg/kg × 2 doses of PT/Cy, compared with the group receiving 25 mg/kg of PT/Cy (9.1% vs. 33%, p = 0.20), was noted. However, the cumulative incidence of chronic GVHD was low, at 10% irrespective of PT/Cy dose. The number of infused CD34(+) cells significantly correlated with the grade of acute GVHD (p = 0.004). In addition, the occurrence of BK virus hemorrhagic cystitis was significantly more common in the double-dose PT/Cy group (25% vs. 0%, p = 0.043), especially when combined with busulfan. The probability of overall survival at 1 year in the double-dose group tended to be better compared with that in the single-dose group (64% vs. 44%, respectively; p = 0.20). In conclusion, HLA haploidentical, T-cell-replete PBSCT with 25 mg/kg × 2 doses of PT/Cy might be a feasible option for treating high-risk leukemia and MDS.

The immune response to cytomegalovirus in allogeneic hematopoietic stem cell transplant recipients. Cell Mol Life Sci. 2015;72:4049-4062. [PMID: 26174234 DOI: 10.1007/s00018-015-1986-z]

Approximately, up to 70 % of the human population is infected with cytomegalovirus (CMV) that persists for life in a latent state. In healthy people, CMV reactivation induces the expansion of CMV-specific T cells up to 10 % of the entire T cell repertoire. On the contrary, CMV infection is a major opportunistic viral pathogen that remains a leading cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Due to the delayed CMV-specific immune recovery, the incidence of CMV reactivation during post-transplant period is very high. Several methods are currently available for the monitoring of CMV-specific responses that help in clinical monitoring. In this review, essential aspects in the immune recovery against CMV are discussed to improve the better understanding of the immune system relying on CMV infection and, thereby, helping the avoidance of CMV disease or reactivation following hematopoietic stem cell transplantation with severe consequences for the transplanted patients.