Evaluation of Polysaccharide Typhim Vi Antibody Response as a predictor of Humoral Immunodeficiency in Haematological Malignancies

Access and use of immunoglobulins in supportive cancer care: A thematic analysis of a systematic review data set

Background

Secondary immunodeficiency (SID) disorders are known to occur in patients with haematological malignancies (HM) due to immunosuppressive treatments. Recurring infections causing subsequent morbidity and mortality commonly occur in this patient cohort. Immunoglobulin replacement therapy (IgRT) benefits patients with primary antibody deficiencies. However, evidence supporting their therapeutic role is not as explicit in SID-associated antibody deficiencies, which raises the questions regarding its use in SID and the knock-on effects of this use on its access and availability more generally.

Objectives

This study aimed to learn about the use of immunoglobulins in SID, identify themes concerning its use and access and suggest methods for improving access.

Design

This study included a thematic analysis of a published data set of 43 articles concerning immunoglobulin use and access in SID.

Data Sources and Methods

The data set used to perform the thematic analysis is based on research articles identified from Excerpta Medica Database (EMBASE) and PubMed databases, published as part of a systematic review and part 1 of this two-part publication series.

Results

A thematic synthesis was conducted to identify recurrent themes. The three primary themes included (1) the context for IgRT prescription, which included patient characteristics and cost burden of IgRT administration, and its use in different countries; (2) factors contributing to inappropriate IgRT use, including health care professionals' awareness of IgRT, disparity between guidelines and actual clinical practice, and the effect of shortages on prescription and chemotherapy-induced hypogammaglobulinemia (HGG); and (3) measures identified to improve IgRT use and access, which included multidisciplinary involvement, improved diagnostic tools and safer withdrawal and stewardship protocols.

Conclusions

IgRT use is increasing in HM as a supportive therapy but without comprehensive clinical guidelines and appropriate prescribing recommendations, medication wastage may occur with consequences for immunoglobulin access.

Access and use of immunoglobulins in secondary supportive cancer care: A systematic literature review

Background

Immunoglobulin replacement therapy (IgRT) benefits patients with primary immuno deficiency (PID) originating from the innate or polygenic defects in the immune system. However, evidence supporting their therapeutic role is not as explicit in secondary immuno deficiency (SID) resulting from the treatment of haematological malignancies.

Objectives

This study aimed to (1) create a dataset of relevant research papers, which explore the use of IgRT in SID for analysis, (2) assess the risk of bias within this dataset and (3) study the characteristics of these papers.

Design

This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. In addition to the risk of bias, the study characteristics explored in this article included study design, study geographical location and year of publication.

Data Sources and Methods

To identify studies relevant to the research question, EMBASE and PubMed databases were searched. The Population, Intervention, Comparison and Outcome (PICO) framework was used to assess study quality. Risk of bias and quality of studies were assessed in accordance with the study design. As one model was not appropriate to assess bias in all articles, several tools were used.

Results

A total of 43 studies were identified from the literature search as relevant to the research objective. The most common study design was a retrospective case-control cohort study (n = 16/43), and randomised trials were among the least commonly used approaches (n = 1). Research in this area is occurring around the globe including the United States (n = 7), Italy (n = 7), China, India, Japan and throughout Europe. The annual number of papers in this area has varied from 2012 (n = 1) to 2021 (n = 7). The studies in this article demonstrated a varied risk of bias, with 9 of the 20 cohort studies scoring less than 5 out of 9 stars.

Conclusions

Randomised controlled trials are less frequently used to assess access and use of immunoglobulins. More commonly, a retrospective case-control cohort study was used which correlates with the higher risk of bias seen in the studies in this article. Most of the research concerning immunoglobulin use and access occurs in higher-income countries.

Combined Immune Defect in B-Cell Lymphoproliferative Disorders Is Associated with Severe Infection and Cancer Progression

B cell chronic lymphoproliferative diseases (B-CLPD) are associated with secondary antibody deficiency and other innate and adaptive immune defects, whose impact on infectious risk has not been systematically addressed. We performed an immunological analysis of a cohort of 83 B-CLPD patients with recurrent and/or severe infections to ascertain the clinical relevance of the immune deficiency expression. B-cell defects were present in all patients. Patients with combined immune defect had a 3.69-fold higher risk for severe infection (p = 0.001) than those with predominantly antibody defect. Interestingly, by Kaplan–Meier analysis, combined immune defect showed an earlier progression of cancer with a hazard ratio of 3.21, than predominantly antibody defect (p = 0.005). When B-CLPD were classified in low-degree, high-degree, and plasma cell dyscrasias, risk of severe disease and cancer progression significantly diverged in combined immune defect, compared with predominantly antibody defect (p = 0.001). Remarkably, an underlying primary immunodeficiency (PID) was suspected in 12 patients (14%), due to prior history of infections, autoimmune and granulomatous conditions, atypical or variegated course and compatible biological data. This first proposed SID classification might have relevant clinical implications, in terms of predicting severe infections and cancer progression, and might be applied to different B-CLPD entities.

Ultrasonic-Assisted Extraction of Codonopsis pilosula Glucofructan: Optimization, Structure, and Immunoregulatory Activity

In recent years, multiple edible polysaccharides from Codonopsis pilosula were mainly isolated with high average molecular weights and exhibited various bioactivities, but it was proven that low-molecular-weight polysaccharides could exert stronger activities due to the superior water solubility and permeability. In the present study, the water-soluble polysaccharide C. pilosula with low molecular weight was isolated under ultrasonic assistance at 30 °C, the extraction process was optimized via response surface method (RSM), and the structure and immunoregulatory activity were further investigated. The maximum yield (4.86%) for crude polysaccharides (cCPPs) was obtained under following parameters: ultrasonic power of 370 W, liquid/material ratio of 33 mL/g, ultrasonic time of 81 min. Subsequently, the cCPPs were further purified through dialysis and Sephadex G-25 column to acquire purified polysaccharide (CPPs). Structural analysis indicated that CPPs was a glucofructan (average molecular weight of 4.23 × 10³ Da) with (2→1)-β-D-Fruf and (1→)-α-D-Glcp as the backbone branched by (2→6)-β-D-Fruf. Additionally, CPPs could enhance immunoregulatory function by stimulating NO production and cytokine (IL-6 and TNF-α) secretion of RAW264.7 macrophages dose-dependently, which presented no cytotoxic effects. These data suggest that CPPs have the potential to be used as a nutritional dietary compound and natural immunostimulant supplement in the food industry.

B-cell haematological malignancies and SARS-CoV-2 infection: Could immunological interventions influence the outcome?

B cell haematological malignancies (HMs) have been described as the worst cancer type for concomitant COVID-19 in terms of mortality, with rates up to 65%. This risk factor for COVID-19 cannot only be explained by comorbidities and advanced age of patients, but aggravated by secondary immunodeficiency (SID). We aimed at evaluating the impact of COVID-19 on 86 HM patients with concomitant SID from a single centre. Only 14 HM patients of 86 (16.28%) patients suffered COVID-19, with mortality rate of 7%. When we considered patients according to B-cell defect only or multiple immune defect overlap (B-T-cell/NK cells/complement), patients with immune defect overlap presented 5.30-fold higher risk of COVID-19 than only B cell defect (95% CI, 1.67-17.0) (p = 0.004). Seven (50%) patients were on active IgRT; while five (36%) had received prior mucosal vaccines for respiratory infections. Our results show that modelling SID in HM may contribute to better prediction of infectious risk and to prompt more targeted and timely preventive therapies.

Variable immunodeficiency score upfront analytical link (VISUAL), a proposal for combined prognostic score at diagnosis of common variable immunodeficiency

The broad and heterogeneous clinical spectrum that characterizes common variable immunodeficiency (CVID) is associated with quite different disease course and prognosis, highlighting the need to develop tools that predict complications. We developed a multianalyte VISUAL score (variable immunodeficiency score upfront analytical link) aimed to predict severity using individual CVID patient data at baseline of a cohort of 50 CVID patients from two different centers in Portugal and Spain. We retrospectively applied VISUAL to the CVID clinical severity scores proposed by Ameratunga and Grimbacher after 15 years follow-up of our cohort. VISUAL score at CVID diagnosis showed adequate performance for predicting infectious and non-infectious severe complications (Cluster B). Compared to switched memory B lymphocyte phenotype alone, VISUAL provided a more accurate identification of clinically meaningful outcome, with significantly higher sensitivity (85% vs 55%, p = 0.01), and negative predictive value (77% vs 58%) and AUC of the ROC curves (0.72 vs 0.64), with optimal cut-off level of 10. For every increase of 1 point in the VISUAL scale, the odds of being in the higher risk category (Cluster B) increased in 1.3 (p = 0.005) for Ameratunga's severity score and 1.26 (p = 0.004) for Grimbacher's severity score. At diagnosis of CVID, VISUAL score ≥ 10 showed 8.94-fold higher odds of severe prognosis than below this threshold. Kaplan-Meier estimates for the VISUAL ≥ 10 points showed significantly earlier progression to Cluster B than those with VISUAL < 10 (p = 0.0002). This prognostic laboratory score might allow close monitoring and more aggressive treatment in patients with scores ≥ 10 on a personalized basis approach. Further studies are needed to prospectively validate VISUAL score.

Serum Free Immunoglobulins Light Chains: A Common Feature of Common Variable Immunodeficiency?

Serum free light chain (sFLC) is a recently proposed biomarker for CVID diagnosis. Most CVID patients present low or undetectable sFLC up to 10-fold lower compared to other primary antibody deficiencies. Given that κ and λ light chains are normally secreted in excess with respect to immunoglobulins, this finding points to an intrinsic defect of B cell differentiation in CVID. sFLC levels were prospectively evaluated in a cohort of 100 primary immunodeficiency (PID) patients and in 49 patients with secondary immunodeficiency to haematological malignancy (SID). CVID patients had significantly lower κ and/or λ values (mean: κ: 1.39 ± 1.7 mg/L and λ: 1.97 ± 2.24 mg/L) compared to "other PIDs" (κ: 13.97 ± 5.88 mg/L and λ: 12.92 ± 7.4 mg/L, respectively, p < 0.001 both), and SID (κ 20.9 ± 22.8 mg/L and λ 12.8 ± 8.7 mg/L, respectively, p < 0.001 both). The sum of kappa and lambda (sum κ + λ) in CVID patients (7.25 ± 7.90 mg/L) was significantly lower respect to other PIDs (26.44 ± 13.25 mg/L, p < 0.0001), and to SID patients (28.25 ± 26.24 mg/L, p = 0.0002). ROC analysis of the sum κ + λ disclosed an area under the curve (AUC) of 0.894 for CVID diagnosis (SD 0.031; 95% CI: 0.83-0.95, p < 0.0001), with optimal cut-off of 16.7 mg/L, giving the highest combination of sensitivity (92%), specificity (75%) and NPV (98%). The Relative Risk (RR) for patients presenting a sum κ + λ below 16.7 mg/L was 20.35-fold higher (95%, CI: 5.630-75.93) for CVID than below this threshold. A similar behavior of the sFLC in our CVID cohort with respect to previously published studies was observed. We propose a cut-off of sum κ + λ 16.7 with diagnostic application in CVID patients, and discuss potential specific defects converging in low or undetectable sFLC.

IGA Antibody Induced by Immunization With Pneumococcal Polysaccharides Is a Prognostic Tool in Common Variable Immune Deficiencies

The evaluation of the response to vaccination in patients with inborn errors of immunity is a tool to evaluate T-dependent and T-independent antibody residual function of B lymphocytes and it is part of the diagnostic definition for Common Variable Immune Deficiencies. Currently used classifications for Common Variable Immune Deficiencies patients are based on the frequency of B cell subsets, and have been proven as a valid instrument for identification of patients at higher risk of infectious and non-infectious complications. This 6-years period observational study delineated the measurement of specific IgA antibodies induced by a 23-valent pneumococcal polysaccharides vaccine by a standardized ELISA for the quantification of IgA antibodies to all 23 pneumococcal serotypes as an additional prognostic marker in 74 CVID patients. The inability to mount an IgA-mediated response against the pneumococcal polysaccharide antigens or the inability to maintain the antibody response over time identified poor IgA CVID responders with severe immunological impairment, great risk of co-morbidities, and poor prognosis. The division of CVID patient into specific IgA-non responders and IgA-responders discriminated better than other CVID classifications for infectious risk, while it overlapped for non-infectious complications. Our study suggested to add the evaluation of the antibody response by the 23-valent IgA assay in the clinical monitoring of CVID patients.

Typhim vi immunization assists to discriminate primary antibody responses in hematological malignancies

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Typhim Vi response have been proposed as a new strategy for the assessment of specific polysaccharide antibody response in SID due to HM.

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Different biostatistical methodologies may stablish the best cut-off value to discriminate Typhim Vi response.

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Typhim Vi IgG responses may better discriminate primary Ab responses showing relevant clinical correlate.

Assessment of specific antibody (Ab) production to polysaccharide antigens is clinically relevant, identifying patients at risk for infection by encapsulated bacteria and thus enabling a more rigorous selection of patients that can benefit of immunoglobulin replacement therapy. Classically, the gold-standard test is the measurement of antibody production to pure polysaccharide pneumococcal (PPV) immunization. Several factors, including introduction of conjugate vaccination schedule, serotyping analysis, high baseline Ab levels, have hindered the evaluation of polysaccharide antigens. This is even more difficult in secondary immunodeficiencies (SID), where patients can show secondary responses despite lack of primary antibody responses and present with recurrent or severe infections. Assessment of specific Ab production to pure Salmonella typhi Vi polysaccharide (TV) immunization has been proposed as a complementary test to PPV, given its low seroprevalence. To set the optimal cut-off value for PPV and TV response in SID, we tested different biostatistical methodologies, including ROC analysis, Youden index, Union index and Closest-topleft in a cohort of 42 SID patients and 24 healthy controls. The statistically chosen cut-offs value pre-post TV Ab ratio was ≥5, (sensitivity of 90%, specificity of 100%) and a postvaccination TV concentration of 28.5 U/mL (sensitivity of 90%, specificity of 95%), showing relevant clinical correlate.