A national survey of screening and management of hypogammaglobulinemia in Canadian transplantation centers

SARS-CoV-2 antibody responses in solid organ transplant recipients

Antibody responses among immunocompromised solid organ transplant recipients (SOT) infected with Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) may be diminished compared to the general population and have not been fully characterized. We conducted a cohort study at our transplant center to investigate the rate of seroconversion for SARS-CoV-2 IgG antibodies among SOT recipients who were diagnosed with Coronavirus disease 2019 (COVID-19) and underwent serum SARS-CoV-2 IgG enzyme-linked immunosorbent assay (ELISA) testing. The 61 patients who were included in the final analysis underwent initial SARS-CoV-2 IgG testing at a median of 62 days (Interquartile range 55.0-75.0) from symptom onset. Note that, 51 of 61 patients (83.6%) had positive SARS-CoV-2 IgG results, whereas 10 (16.4%) had negative IgG results. Six (60%) out of 10 seronegative patients underwent serial IgG testing and remained seronegative up to 17 weeks post-diagnosis. Use of belatacept in maintenance immunosuppression was significantly associated with negative IgG antibodies to SARS-CoV-2 both in univariate and multivariate analyses (Odds ratio 0.04, p = .01). In conclusion, the majority of organ transplant recipients with COVID-19 in our study developed SARS-CoV-2 antibodies. Further longitudinal studies of the durability and immunologic role of these IgG responses and the factors associated with lack of seroconversion are needed.

Subcutaneous immunoglobulin in allogeneic hematopoietic cell transplant patients: A prospective study of feasibility, safety, and healthcare resource use

BACKGROUND

We evaluated feasibility, safety, and total resource use of subcutaneous immunoglobulin (SCIG) in a pilot study of patients who underwent allogeneic hematopoietic cell transplant (HCT) over a 6-month period.

METHODS

A total of 20 eligible patients were treated with SCIG at 0.1 g/kg/week for up to 6 months. Patients were matched to 20 concurrent intravenous immunoglobulin (IVIG) controls. Clinical outcomes measured included adverse reactions, healthcare resource use, patient satisfaction, and quality of life (QOL). (ClinicalTrials.gov Identifier: NCT03401268.) RESULTS: Groups were comparable in terms of age, weight, sex, transplant indication, donor type, and conditioning intensity. All 20 IVIG patients completed 6 consecutive months of therapy compared with 13/20 (65%) SCIG patients. There were no adverse reactions in IVIG patients, compared with six (30%) SCIG patients. All adverse reactions in SCIG patients were grade I, transient, and required no medical intervention. Median overall cost per patient was lower with SCIG than with IVIG ($9,756 vs. $13,780, p = .046). Among patients who completed 6 months of SCIG, median preference and satisfaction scores were 100%. Over the 6-month period, QOL scores remained stable in SCIG patients.

CONCLUSIONS

In a subgroup of patients, SCIG was associated with high patient satisfaction and a reduction in total healthcare costs compared with IVIG in a cohort of HCT patients.

Secondary immunodeficiencies with predominant antibody deficiency: multidisciplinary perspectives of Polish experts

At present, secondary immune deficiencies have become a clinical problem, recognized in different specialties. The aim of this paper was to increase awareness and support the need for screening at-risk populations. Secondary immune deficiencies result in variety of conditions, but not all of them require immunoglobulin replacement therapy, as specific antibody response might be preserved. Moreover, the management of secondary immune deficiencies vary between countries and different medical disciplines. This literature review presents the most common causes and clinical presentation of secondary immunodeficiencies with predominant impaired antibody production. We present diagnostic guidelines for patients at-risk, with an emphasis on the role of prophylactic vaccination as a treatment and diagnostic tool. This review considers the specificity and disparities of the Polish healthcare system and ultimately, suggests that management teams should include a clinical immunologist experienced in the treatment of humoral immunodeficiencies.

Hypogammaglobulinemia: a diagnosis that must not be overlooked

Humoral immunological defects are frequent and important causes of hypogammaglobulinemia, leading to recurrent infections, autoimmunity, allergies, and neoplasias. Usually, its onset occurs in childhood or during the second and third decades of life; however, the diagnosis is made, on average, 6 to 7 years afterwards. As a consequence, antibody defects can lead to sequelae. Here we describe the clinical-laboratory characteristics, treatment, and prognoses of patients with hypogammaglobulinemia. An observational, cross-sectional, and retrospective study of patients attending the recently established outpatient group of Clinical Immunology between 2013 and 2018 was carried out. Patients with IgG levels below 2 standard deviations from the mean values for the age and/or impaired antibody response were included. Eight patients (3 F and 5 M; median age=41 years (16–65), average symptom onset at 25 years (1–59), and time to diagnosis of 10 years were included. The main infections were: sinusitis in 7/8, pneumonia in 6/8, otitis in 2/8, tonsillitis and diarrhea in 2/8, and diarrhea in 2/8 patients. Hypothyroidism was identified in 4/8 (50%) patients. Rhinitis was found in 7/8 (87.5%) and asthma in 3/8 (37.5%) patients. The tomographic findings were consolidations, atelectasis, emphysema, ground glass opacity, budding tree, bronchial thickening, and bronchiectasis. Immunoglobulin reposition was used between 466 and 600 mg/kg monthly (514.3 mg·kg^-1·dose^-1). Prophylactic antibiotic therapy was included in 7/8 (87.5%) patients. Airway manifestations prevailed in patients with hypogammaglobulinemia. There is a need for educational work to reduce the time of diagnosis and initiation of treatment, avoiding sequelae.

Role of antibodies in confining cytomegalovirus after reactivation from latency: three decades' résumé

Cytomegaloviruses (CMVs) are highly prevalent herpesviruses, characterized by strict species specificity and the ability to establish non-productive latent infection from which reactivation can occur. Reactivation of latent human CMV (HCMV) represents one of the most important clinical challenges in transplant recipients secondary to the strong immunosuppression. In addition, HCMV is the major viral cause of congenital infection with severe sequelae including brain damage. The accumulated evidence clearly shows that cellular immunity plays a major role in the control of primary CMV infection as well as establishment and maintenance of latency. However, the efficiency of antiviral antibodies in virus control, particularly in prevention of congenital infection and virus reactivation from latency in immunosuppressed hosts, is much less understood. Because of a strict species specificity of HCMV, the role of antibodies in controlling CMV disease has been addressed using murine CMV (MCMV) as a model. Here, we review and discuss the role played by the antiviral antibody response during CMV infections with emphasis on latency and reactivation not only in the MCMV model, but also in relevant clinical settings. We provide evidence to conclude that antiviral antibodies do not prevent the initiating molecular event of virus reactivation from latency but operate by preventing intra-organ spread and inter-organ dissemination of recurrent virus.

Clinical outcomes of polyvalent immunoglobulin use in solid organ transplant recipients: A systematic review and meta-analysis - Part II: Non-kidney transplant

Immunoglobulin (IG) is commonly used to desensitize and treat antibody-mediated rejection in solid organ transplant (SOT) recipients. The impact of IG on other outcomes such as infection, all-cause mortality, graft rejection, and graft loss is not clear. We conducted a similar systematic review and meta-analysis to our previously reported Part I excluding kidney transplant. A comprehensive literature review found 16 studies involving the following organ types: heart (6), lung (4), liver (4), and multiple organs (2). Meta-analysis could only be performed on mortality outcome in heart and lung studies due to inadequate data on other outcomes. There was a significant reduction in mortality (OR 0.34 [0.17-0.69]; 4 studies, n = 455) in heart transplant with hypogammaglobulinemia receiving IVIG vs no IVIG. Mortality in lung transplant recipients with hypogammaglobulinemia receiving IVIG was comparable to those of no hypogammaglobulinemia (OR 1.05 [0.49, 2.26]; 2 studies, n = 887). In summary, IVIG targeted prophylaxis may decrease mortality in heart transplant recipients as compared to those with hypogammaglobulinemia not receiving IVIG, or improve mortality to the equivalent level with those without hypogammaglobulinemia in lung transplant recipients, but there is a lack of data to support physicians in making decisions around using immunoglobulins in all SOT recipients for infection prophylaxis.

Clinical outcomes of polyvalent immunoglobulin use in solid organ transplant recipients: A systematic review and meta-analysis

Polyvalent immunoglobulin is commonly used for desensitization and treatment of antibody-mediated rejection in kidney transplantation but its impact on other outcomes is not known. This systematic review investigated the impact of immunoglobulin prophylaxis on infection, rejection, graft loss, and death following kidney transplantation. A comprehensive literature search located 18 studies (n = 8 randomized controlled trials). None examined the effect of immunoglobulin prophylaxis in transplant recipients with hypogammaglobulinemia. Quality of included studies was variable with high to very high risk of bias. In the randomized trials, immunoglobulin use did not reduce cytomegalovirus infection (OR 0.68 [0.39, 1.21]; 6 studies, n = 295), rejection (OR 0.96 [0.50, 1.82]; 4 studies, n = 187), or graft loss (OR 1.03 [0.46, 2.30]; 6 studies, n = 265). In non-randomized studies, immunoglobulin did not reduce cytomegalovirus infection (OR 0.63 [0.20, 1.94]; 6 studies, n = 361) or death (OR 1.32 [0.05, 38.79]; 3 studies, n = 222) but reduce rejection (OR 0.47 [0.24, 0.94]; 4 studies, n = 268) and graft loss (OR 0.15 [0.05, 0.43]; 2 studies, n = 118). Data were scarce and sample size of current evidence was small. Adequately powered randomized trials are needed to determine if immunoglobulin is an effective intervention to reduce infection, rejection, graft loss, or death following kidney transplantation with and without hypogammaglobulinemia.

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.