Diagnosis and treatment of primary immunodeficiency disease: the role of the otolaryngologist

A stepwise approach to the adult immunodeficiency evaluation for the rhinologist

PURPOSE OF REVIEW

Patients with an immunodeficiency may present to their Rhinologist with a history of recurrent, severe, and chronic infections. Therefore, it is essential for the Rhinologist to have a basic understanding of clinically relevant immune deficiencies.

RECENT FINDINGS

After describing different types of immunodeficiencies, their presentations, and management strategies, an evaluation algorithm is described.

SUMMARY

Through a collaborative approach, Rhinologists and Clinical Immunologists can provide comprehensive medical care to patients with immunodeficiencies.

Guardians of Immunity: Advances in Primary Immunodeficiency Disorders and Management

Primary immunodeficiency disorders (PIDs) are a heterogeneous group of genetic conditions profoundly impacting immune function. The investigation spans various PID categories, offering insights into their distinct pathogenic mechanisms and clinical manifestations. Within the adaptive immune system, B-cell, T-cell, and combined immunodeficiencies are dissected, emphasizing their critical roles in orchestrating effective immune responses. In the realm of the innate immune system, focus is directed toward phagocytes and complement deficiencies, underscoring the pivotal roles of these components in initial defense against infections. Furthermore, the review delves into disorders of immune dysregulation, encompassing hemophagocytic lymphohistiocytosis (HLH), autoimmune lymphoproliferative syndrome (ALPS), immune dysregulation, polyendocrinopathy, enteropathy, and X-linked(IPEX), and autoimmunity polyendocrinopathy candidiasis-ectodermal dystrophy(APECED), elucidating the intricate interplay between immune tolerance and autoimmunity prevention. Diagnostic strategies for PIDs are explored, highlighting advancements in genetic and molecular techniques that enable precise identification of underlying genetic mutations and alterations in immune function. We have also outlined treatment modalities for PIDs, which often entail a multidisciplinary approach involving immunoglobulin replacement, antimicrobial prophylaxis, and, in select cases, hematopoietic stem cell transplantation. Emerging therapies, including gene therapy, hold promise for targeted interventions. In essence, this review encapsulates the complexity of PIDs, emphasizing the critical importance of early diagnosis and tailored therapeutic interventions. As research advances, a clearer understanding of these disorders emerges, fostering optimism for enhanced patient care and management in the future.

Safety and tolerability of IgPro10 in Japanese primary immunodeficiency patients: a registrational study

Studies investigating the safety of IgPro10 (Privigen^®, CSL Behring, King of Prussia, PA, USA) in Japanese patients with primary immunodeficiency (PID) are lacking. This study evaluated safety and tolerability of IgPro10 in Japanese patients with PID. In this prospective, open-label, single-arm, registrational study for Japan, IgPro10 was administered intravenously at pre-study doses of 138-556 mg/kg body weight per 3-/4-weekly dosing cycle for up to 4 months. Frequency and intensity of adverse events (AEs), their relationship to IgPro10 and AE rate per infusion (AERI) were evaluated. Of 11 enrolled patients, 10 completed the study. The median (range) total duration of exposure was 16.14 (4.1-16.3) weeks. Eight patients reported 19 AEs, none severe (based on maximum severity), giving an AERI of 0.442. One AE was deemed related to IgPro10 treatment. Three patients experienced temporally associated AEs. No serious AEs or deaths were reported. Nine patients (90%) who completed the study tolerated flow rates of ≥ 8 mg/kg/min; 5 tolerated 12 mg/kg/min (7.2 mL/kg/h), translating into a threefold decrease in mean infusion time. IgPro10 was well tolerated at a flow rate of up to 12 mg/kg/min. Safety and tolerability findings were consistent with previously reported studies in non-Japanese patients with PID.

Pharmacometric Analysis of IgPro10 in Japanese and Non-Japanese Patients With Primary Immunodeficiency

PURPOSE

Immunoglobulin (Ig) G replacement therapy, administered intravenously (IVIG) or subcutaneously (SCIG), is the standard treatment in patients with primary immunodeficiencies (PID). We aimed to characterize the pharmacokinetic (PK) characteristics of serum IgG following administration of IgPro10 every 3 or 4 weeks in Japanese patients with PID, and compare with PK in non-Japanese patients. A previously developed population PK (PPK) model was validated, and predicted parameters were compared with the results from the clinical study.

METHODS

The previously developed PPK model, containing IgG concentration data from 5 non-Japanese studies, was supplemented with data from 3 Japanese studies of IgPro10 or IgPro20 to compare the IgG PK parameters between Japanese and non-Japanese patients. The model was externally validated by simulating IgG concentration-time profiles in Japanese patients to predict serum IgG PK characteristics and to compare them with observed Japanese PK data from Study IgPro10_3004.

FINDINGS

The analysis included 4502 serum IgG concentration values (from 34 Japanese and 168 non-Japanese patients). PPK estimates from the current analysis demonstrated a clearance (CL) of 0.139 L/d, central volume (V2) of 4.01 L, inter-compartmental clearance (Q) of 0.30 L/d, and peripheral volume of 3.51 L. These results were consistent with those from the previously published PPK model, with similar bootstrap means and 95% CIs. Goodness-of-fit criteria indicated that the final PPK model was consistent with observed data, with no systemic bias in model prediction. Prediction-corrected visual predictive checks confirmed a good description of data on both SCIG and IVIG. PK parameters were equivalent between Japanese and non-Japanese patients. Body weight was determined to be a significant covariate on both CL and V2. Simulated and observed AUC and maximum and minimum serum IgG concentrations were similar, with 90% CIs overlapping between simulated and observed IgG concentrations in Japanese patients.

IMPLICATIONS

PK parameter estimates of serum IgG were similar between Japanese and non-Japanese patients with PID. The PPK model, updated with Japanese data, was consistent with the previously published PPK model and could accurately predict both individual and population serum IgG concentration-time profiles following IgPro10 IV infusions every 3 or 4 weeks. EudraCT identifier: 2016-001631-12.

Economic impact of infections among patients with primary immunodeficiency disease receiving IVIG therapy

PURPOSE

There are limited data on the cost of infections among patients with primary immunodeficiency disease (PIDD) in clinical practice. The purpose of this study was to assess the economic impact, from the US commercial payer perspective, of infections in a cohort of patients with PIDD who were administered intravenous immunoglobulin (IVIG) therapy.

METHODS

This study used administrative claims from the MarketScan(®) Database. Patients with a PIDD diagnosis, one or more prescription(s) for IVIG therapy between January 1, 2008 and February 28, 2010, and one or more prescription(s) for IVIG at least 3 months following first IVIG prescription, were selected. The study period consisted of a 7-month window following first IVIG prescription. Study measures included infection-related medical resource use and expenditures. Adjusted infection-related hospitalization expenditures were estimated using a generalized linear model, controlling for demographics, comorbidities, and infection type.

RESULTS

A total 1,742 patients with PIDD and consistent IVIG use were identified, with 490 patients (mean age 43; 58.8% female) having one or more infection(s) during the 7-month study period. Infection-related inpatient hospitalizations were the most expensive component of care (US$38,574 per hospitalized patient). In multivariate modeling, the presence of a blood infection during the hospitalization (versus [vs] no blood infection), having diabetes, and younger age (<18 vs 55-64) were associated with significant increases in infection-related hospitalization expenditures (49.3%, 55.3%, and 76.5%, respectively) (P<0.05).

CONCLUSION

Health care expenditures for infections in PIDD patients receiving IVIG therapy can be substantial, particularly for inpatient care. Future evaluations assessing the incremental cost of optimizing IVIG therapy should include evaluation of the effects on infection-related medical expenditures.

The 10 warning signs: a time for a change?

PURPOSE OF REVIEW

It is 20 years since the 10 Warning Signs of primary immunodeficiency (PID) were first published and with over 180 PIDs now identified it is timely to evaluate their effectiveness, given the broadening clinical spectrum of PID.

RECENT FINDINGS

Two recent studies have sought to define the features that best identify patients with PID and compare these with the 10 Warning Signs. They suggest the 10 Warning Signs discriminate poorly between those with and without PID, and that other features identify about one-third of patients with PID in whom none of the 10 Warning Signs was present. Recent literature describes the diverse presenting features that may assist in more accurately identifying those with PID.

SUMMARY

Further development and refinement of early warning signs in light of the growing knowledge of how PIDs manifest clinically may allow relatively simple yet effective guidelines targeted at different groups to better detect PID.