Reconstitution of IgG Subclasses following Immunoglobulin Therapy in Adult Primary Hypogammaglobulinemia

Subcutaneous immunoglobulin use in immunoglobulin-naive patients with primary immunodeficiency: a systematic review

Aim: Identify and describe published literature on the use of subcutaneous immunoglobulin (SCIG) as initial immunoglobulin (IG)-replacement therapy for patients with primary immunodeficiency diseases (PID). Methods: We systematically identified and summarized literature in MEDLINE, Embase, BioSciences Information Service and Cochrane Library assessing efficacy/effectiveness, safety/tolerability, health-related quality-of-life (HRQoL) and dosing regimens of SCIG for IG-naive patients with PID. Results: Sixteen studies were included. In IG-naive patients, SCIG managed/reduced infections and demonstrated similar pharmacokinetic parameters to IG-experienced patients; adverse events were mostly minor injection-site pain or discomfort. Three studies reported improvements in HRQoL. Quality of studies was difficult to assess due to limited reporting. Conclusion: Although studies were lacking, available data suggest IG-naive and IG-experienced patients initiating SCIG likely have similar outcomes.

Reconstitution of IgG Subclasses Following Immunoglobulin Administration in Adult Patients with Common Variable Immune Deficiency

BACKGROUND

Immunoglobulin (Ig) therapy reduces the frequency and severity of infection among patients with antibody deficiency disorders. However, a subset of patients lacks adequate clinical response.

OBJECTIVE

The purpose of this study was to determine in adult common variable immune deficiency (CVID) patients (A) if lack of clinical response to Ig therapy correlates with lack of reconstitution of IgG subclass (es), (B) correlation between Ig dosing and/or IgG trough levels and IgG subclass reconstitution, (C) and most common impaired Streptococcus pneumoniae (S. pneumoniae) serotype antibody response.

METHODS

Single-institution, retrospective chart review for CVID patients at immunology clinics from 2015 to 2019. Patients were monitored every 3-6 months for IgG dosage, IgG trough levels, IgG subclass reconstitution, infectious episodes (chronic sinusitis, bronchitis, upper respiratory, and lower respiratory tract infections), urinary tract infections, and antibiotic use. Follow-up was calculated in patient years.

RESULTS

Twenty-five of 41 patients achieved complete reconstitution of all IgG subclasses, and 16/41 demonstrated intermittent or lack of reconstitution. There were significantly less (p < 0.001) infections among fully reconstituted patients (0.66 ± 0.19 infections per patient year) as compared to those with intermittent or lack of reconstitution (1.26 ± 0.13 infections per patient year). There was a significant correlation between IgG trough levels and IgG subclass reconstitution. Most common impaired S. pneumoniae serotype included 3, 4, 9n, 10a, 11a, 12f, and 15b.

CONCLUSIONS

Incomplete IgG subclass reconstitution was associated with increased frequency of infections. IgG trough levels correlate with IgG subclass reconstitution. A limited number of S. pneumoniae serotype antibodies are commonly impaired in CVID.