Clinical and genetic analysis of immunodeficiency-related diseases associated with PIK3CD mutations

Genetic Etiologies and Outcomes in Malignancy and Mortality in Activated Phosphoinositide 3-Kinase Delta Syndrome: A Systematic Review

INTRODUCTION

This analysis evaluated literature on patients with activated phosphoinositide 3-kinase delta syndrome (APDS) to better understand the genetic etiologies and occurrence of mortality in this population.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach, including all articles published in English prior to March 13, 2023, in PubMed and Embase. Patients included in the study had reported either (1) APDS diagnosis or (2) ≥ 1 clinical sign consistent with APDS and a first-degree relative with genetically confirmed APDS. Reported age at last observation was also a required outcome. Publications not meeting these criteria were excluded. Data were summarized using descriptive statistics.

RESULTS

The search identified 108 publications describing 351 unique patients with 39 distinct disease-causing variants. Among these, 41 (12%) deaths were reported, with a mean age at last follow-up of 19.6 (range, 1-64) years. A cause of death was reported for 80% (33/41) of deaths; lymphoma (24%, 10/41) and infections (22%, 9/41) were the most common causes. Types of infections causing death were severe uncontrollable infections (n = 3), sepsis (n = 2), viral infection (varicella zoster pneumonitis [n = 1], cytomegalovirus and adenovirus [n = 1], and Epstein-Barr virus [n = 1]), and infection (n = 1). Mean age at death for lymphoma was 24.9 (range, 1-41) years, and all nine patients who died from infections died before the age of 15 years. The mean age at first APDS symptom was 2.0 (range, < 1-22) years, and mean age at APDS diagnosis was 13.4 (range, 0-56) years; the mean time between symptoms and diagnosis was 10.6 (range, 0-44) years. Limitations of the study were primarily related to the data source.

CONCLUSION

Patients with APDS suffer early mortality, largely from lymphoma and infection, with large time gaps between symptoms and diagnosis. These findings highlight the need for improved diagnostics, earlier genetic testing for APDS, increased awareness of familial testing, and targeted therapies.

Protecting children and adults with primary antibody deficiencies against common and emergent pathogens and non-infectious complications

Prevention and treatment of infections are primary goals of treatment of children and adults with primary immune deficiencies due to decreased antibody production. Approaches to these goals include immunoglobulin replacement therapy, vaccination, and prophylactic treatment with antimicrobials. In this review, the infectious and non-infectious complications of antibody deficiencies will be discussed along with the limited number of studies that support the effective use of the available therapies and to drive the development of new therapies. Some illustrative case studies will be presented and the outlook for additional controlled clinical trials and potential for therapies driven by the underlying disease genetics will be considered.

[Activated phosphoinositide 3-kinase delta syndrome: report of seven cases]

OBJECTIVES

To summarize the clinical data of 7 children with activated phosphoinositide 3-kinase delta syndrome (APDS) and enhance understanding of the disease.

METHODS

A retrospective analysis was conducted on clinical data of 7 APDS children admitted to Hunan Provincial People's Hospital from January 2019 to August 2023.

RESULTS

Among the 7 children (4 males, 3 females), the median age of onset was 30 months, and the median age at diagnosis was 101 months. Recurrent respiratory tract infections, hepatosplenomegaly, and multiple lymphadenopathy were observed in all 7 cases. Sepsis was observed in 5 cases, otitis media and multiple caries were observed in 3 cases, and diarrhea and joint pain were observed in 2 cases. Lymphoma and systemic lupus erythematosus were observed in 1 case each. Fiberoptic bronchoscopy was performed in 4 cases, revealing scattered nodular protrusions in the bronchial lumen. The most common respiratory pathogen was Streptococcus pneumoniae (4 cases). Six patients had a p.E1021K missense mutation, and one had a p.434-475del splice site mutation.

CONCLUSIONS

p.E1021K is the most common mutation site in APDS children. Children who present with one or more of the following symptoms: recurrent respiratory tract infections, hepatosplenomegaly, multiple lymphadenopathy, otitis media, and caries, and exhibit scattered nodular protrusions on fiberoptic bronchoscopy, should be vigilant for APDS. Citation:Chinese Journal of Contemporary Pediatrics, 2024, 26(5): 499-505.

HLH as an additional warning sign of inborn errors of immunity beyond familial-HLH in children: a systematic review

Background

Hemophagocytic Lymphohistiocytosis (HLH) is a rare and life-threatening condition characterized by a severe impairment of the immune homeostasis. While Familial-HLH (FHL) is a known cause, the involvement of other Inborn Errors of Immunity (IEI) in pediatric-HLH remains understudied.

Objective

This systematic review aimed to assess the clinical features, triggers, laboratory data, treatment, and outcomes of pediatric HLH patients with IEI other than FHL (IEInotFHL), emphasizing the importance of accurate identification and management.

Methods

A systematic search for studies meeting inclusion criteria was conducted in PubMed, EMBASE, MEDLINE, and Cochrane Central. Quality assessment was performed through JBI criteria.

Results

A comprehensive search yielded 108 records meeting inclusion criteria, involving 178 patients. We identified 46 different IEI according to IUIS 2022 Classification. Combined immunodeficiencies, immune dysregulation disorders, and phagocyte defects were the IEI most frequently associated with HLH. In 75% of cases, HLH preceded the IEI diagnosis, often with an unrecognized history of severe infections. Triggers reflected the specific infection susceptibilities within IEI groups. Liver and central nervous system involvement were less common than in FHL cases. Treatment approaches and outcomes varied, with limited long-term follow-up data, limiting the assessment of therapeutic efficacy across IEI groups.

Conclusion

A comprehensive evaluation encompassing immunological, infectious, and genetic aspects is essential in pediatric-HLH. Relying solely on FHL or EBV susceptibility disorders tests is insufficient, as diverse other IEI can contribute to HLH. Early recognition of HLH as a potential warning sign can guide timely diagnostic investigations and facilitate tailored therapeutic interventions for improved outcomes.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=371425, PROSPERO, CRD42022371425.

Immunodeficiency due to a novel variant in PIK3CD: a case report

BACKGROUND

Primary immunodeficiencies are immunological disorders caused by gene mutations involved in immune system development and activation. Recently, activated phosphoinositide 3-kinase delta syndrome (APDS) due to mutations in the phosphoinositide 3-kinase (PI3K), phosphatidylinositol-4, 5-bisphosphate 3-kinase, catalytic subunit delta gene (PIK3CD), and phosphoinositide 3-kinase regulatory subunit 1 (PIK3R1) genes have been reported to induce a combined immunodeficiency syndrome leading to senescent T cells, lymphadenopathy, and immunodeficiency. The exact diagnosis of these deficiencies is essential for treatment and prognosis. In recent years, targeted treatment with selective PI3Kd inhibitors has had a significant effect on controlling the symptoms of these patients.

CASE PRESENTATION

In this case report, we represent a 27-month-old girl with recurrent fever, an increased level of inflammatory markers, and erythema nodosum, who was referred to the rheumatology clinic. In the course of evaluations, because of the lack of clinical improvement with usual treatments, and a history of frequent respiratory infections, combined immunodeficiency was diagnosed in the immunological investigations. Moreover, whole-exome sequencing was performed for her.

CONCLUSION

The genetic analysis found a novel variant of PIK3CD (c.1429 G > A) in the patient. Following daily antibiotic prophylaxis and monthly IV therapy, the patient's frequent infections and fevers were controlled.

Infections in activated PI3K delta syndrome (APDS)

Activated PI3K-delta Syndrome (APDS), also called PI3K-delta activating mutation causing senescent T cells, lymphadenopathy, and immunodeficiency (PASLI), is an autosomal dominant disorder caused by inherited or de novo gain-of-function mutations in one of two genes encoding subunits of the phosphoinositide-3-kinase delta (PI3Kδ) complex. This largely leukocyte-restricted protein complex regulates cell growth, activation, proliferation, and survival. Patients who harbor these mutations have early onset immunodeficiency with recurrent infections, lymphadenopathy, and autoimmunity. The most common infection susceptibilities are sinopulmonary (encapsulated bacteria) and herpesviruses. Multiple defects in both innate and adaptive immune function are responsible for this phenotype. Apart from anti-microbial prophylaxis and immunoglobulin replacement, patients are treated with a variety of immunomodulatory agents and some have needed hematopoietic stem cell transplants. Here, we highlight the spectrum of infections, immune defects, and therapy options in this inborn error of immunity.

Case Report: EBV Chronic Infection and Lymphoproliferation in Four APDS Patients: The Challenge of Proper Characterization, Therapy, and Follow-Up

Activated PI3K-kinase Delta Syndrome (APDS) is an autosomal-dominant primary immunodeficiency (PID) caused by the constitutive activation of the PI3Kδ kinase. The consequent hyperactivation of the PI3K-Akt-mTOR pathway leads to an impaired T- and B-cells differentiation and function, causing progressive lymphopenia, hypogammaglobulinemia and hyper IgM. Patients with APDS show recurrent sinopulmonary and chronic herpes virus infections, immune dysregulation manifestations, including cytopenia, arthritis, inflammatory enteropathy, and a predisposition to persistent non-neoplastic splenomegaly/lymphoproliferation and lymphoma. The recurrence of the lymphoproliferative disorder and the difficulties in the proper definition of malignancy on histological examination represents the main challenge in the clinical management of APDS patients, since a prompt and correct diagnosis is needed to avoid major complications. Targeted therapies with PI3Kδ-Akt-mTOR pathway pharmacologic inhibitors (i.e., Rapamycin, Theophylline, PI3K inhibitors) represent a good therapeutic strategy. They can also be used as bridge therapies when HSCT is required in order to control refractory symptoms. Indeed, treated patients showed a good tolerance, improved immunologic phenotype and reduced incidence/severity of immune dysregulation manifestations. Here, we describe our experience in the management of four patients, one male affected with APDS1 (P1) and the other three, a male and two females, with APDS2 (P2, P3, P4) presenting with chronic EBV replication, recurrent episodes of immune dysregulation manifestations and lymphomas. These cases highlighted the importance of a tailored and close follow-up, including serial endoscopic and lymph nodes biopsies control to detect a prompt and correct diagnosis and offer the best therapeutic strategy.