Primary Immunodeficiency Disorders Among North Indian Children

The sufficiency of genetic diagnosis in managing patients with inborn errors of immunity during prenatal care and childbearing

Individuals with inborn errors of immunity face challenges in fertility, pregnancy, and genetic disorder transmission. Prenatal genetic counseling is crucial, especially in tribal societies with consanguineous unions. Ten families with confirmed inborn errors of immunity were studied, revealing diverse pregnancy decisions: An architect with autosomal dominant STAT-1 gain of function underwent prenatal diagnosis despite initial plans for preimplantation genetic diagnosis. In a consanguineous family, two children died from leukocyte adhesion deficiency type 1 because the father refused prenatal diagnosis. First cousins opted against terminating the second pregnancy, resulting in two children affected by Bruton disease. Another consanguineous couple, with two children afflicted by ataxia-telangiectasia, chose oocyte donation for their third child, ensuring a healthy birth. Recurrent pregnancy loss was observed in a mother subsequently diagnosed with ZAP70 deficiency. A mother with Wiskott-Aldrich syndrome child opted for in vitro fertilization, leading to a healthy birth post-prenatal diagnosis. A misdiagnosis of anaplastic anemia occurred in a family with multiple instances of Wiskott-Aldrich syndrome. A leukocyte adhesion deficiency type 1 case led to parental dissolution due to the father's refusal to acknowledge the condition. In a non-consanguineous couple, the father's diagnosis of TACI deficiency influenced the mother's decision to discontinue pregnancy post-prenatal diagnosis. Genetic diagnosis alone cannot optimize prenatal care for immune dysregulation disorders. Various factors, including patient education, societal norms, ethics, and economics, impact pregnancy decisions. Clinical immunologists must integrate these elements into guidance strategies to enhance patient outcomes.

Profile of 208 patients with inborn errors of immunity at a tertiary care center in South India

Primary immune deficiencies or inborn errors of immunity (IEI) are a heterogeneous group of disorders that predispose affected individuals to infections, allergy, autoimmunity, autoinflammation and malignancies. IEIs are increasingly being recognized in the Indian subcontinent. Two hundred and eight patients diagnosed with an IEI during February 2017 to November 2021 at a tertiary care center in South India were included in the study. The clinical features, laboratory findings including microbiologic and genetic data, and treatment and outcome details were analyzed. The diagnosis of IEI was confirmed in a total of 208 patients (198 kindreds) based on relevant immunological tests and/or genetic tests. The male-to-female ratio was 1.8:1. Of the 208 patients, 72 (34.6%) were < 1 yr, 112 (53.8%) were 1-18 years, and 24 (11.5%) were above 18 years. The most common IEI in our cohort was SCID (17.7%) followed by CGD (12.9%) and CVID (9.1%). We also had a significant proportion of patients with DOCK8 deficiency (7.2%), LAD (6.2%) and six patients (2.8%) with autoinflammatory diseases. Autoimmunity was noted in forty-six (22%) patients. Molecular testing was performed in 152 patients by exome sequencing on the NGS platform, and a genetic variant was reported in 132 cases. Twenty-nine children underwent 34 HSCT, and 135 patients remain on supportive therapy such as immunoglobulin replacement and/or antimicrobial prophylaxis. Fifty-nine (28.3%) patients died during the study period, and infections were the predominant cause of mortality. Seven families underwent prenatal testing in the subsequent pregnancy. We describe the profile of 208 patients with IEI, and to the best of our knowledge, this represents the largest data on IEI from the Indian subcontinent reported so far.

Clinical and Genetic Spectrum of Inborn Errors of Immunity in a Tertiary Care Center in Southern India

OBJECTIVES

To study the incidence, clinical manifestations, and genetic spectrum of primary immunodeficiency diseases (PID)/inborn errors of immunity (IEI) in a tertiary care hospital in Southern India.

METHODS

A retrospective analysis of all patients with a clinical suspicion of PID/IEI seen at a tertiary care hospital was performed. All patients had at least one or more warning signs of PID. Serum immunoglobulin levels and other targeted investigations were performed as warranted by the clinical presentation. All families with suspected PID were counseled and offered genetic testing.

RESULTS

A total of 225 children were evaluated for PID during the study period of 6 y. Fifty-six of them did not meet the European Society of Immunodeficiencies (ESID) criteria (working definition of clinical diagnosis) and were excluded. An IEI was found in 30/49 (61.2%) patients. The most frequent reason for referral was recurrent/unusual or serious infections (28%), or cytopenia (16%). Group IV diseases of immune dysregulation was the most common category (19%), followed by group III predominant antibody deficiencies in 23/163 (14%), as per the International Union of Immunological Societies (IUIS) classification.

CONCLUSIONS

This study highlights the heterogeneity of the present cohort, the underuse of genetic tests, and efforts to provide optimal care for children with possible IEI in this center.

Diverse clinical features and diagnostic delay in monogenic inborn errors of immunity: A call for access to genetic testing

BACKGROUND

Inborn errors of immunity (IEIs) are a group of conditions affecting immune system development and function. Due to their clinical heterogeneity and lack of provider awareness, patients suffer from long diagnostic delays that increase morbidity and mortality. Next-generation sequencing facilitates earlier diagnosis and treatment of IEIs, but too often patients are unable to see the benefit of this technology due to gaps in providers' knowledge regarding which patients to test and barriers to accessing sequencing.

METHODS

Here, we provide detailed clinical phenotyping and describe the impact of genetic sequencing on a cohort of 43 patients with monogenic IEIs seen in a tertiary care center from 2014 to 2019. Data were abstracted from a chart review, and a panel of clinical immunologists were consulted on the impact of genetic sequencing on their patients.

RESULTS

We found that our patients had significant diagnostic delays, averaging 3.3 years; had diverse manifestations of immune system dysfunction; and had demonstrated highly complex medical needs, with on average 7.9 subspecialties involved in their care and 4.9 hospitalizations prior to definitive treatment. Our results also demonstrate the benefits of genetic testing, as it provided the majority of our patients with a diagnosis, and positively impacted their treatment, follow-up, and prognosis.

CONCLUSION

This paper expands the paucity of literature on genetically confirmed IEIs in North America and supports the expansion of access to genetic testing for patients with clinical features suggesting IEI, such as those presented in our cohort.

Utility of Immunohistochemistry and Immunofluorescence in Determining the Pathogenic Variants of Chronic Granulomatous Disease

BACKGROUND

Chronic granulomatous disease (CGD) is a primary immunodeficiency disorder of phagocytes due to defects in any of the five subunits of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. An initial diagnosis of CGD is made by flow cytometry-based dihydrorhodamine assay or nitro blue tetrazolium test, which is further confirmed by molecular assays. Expression of five subunits of NADPH oxidase components by either flow cytometric or western blot analysis provides clues toward the potential gene targets which are subsequently confirmed by various genetic assays. Immunohistochemistry (IHC) and immunofluorescence (IF) have never been earlier used to determine the expression of different subunits of NADPH oxidase system. We evaluated the utility of IHC and IF in determining the underlying pathogenic variants of CGD.

MATERIALS AND METHODS

Twelve genetically confirmed cases of CGD, comprising of biopsy specimens (n = 6), tissue blocks from autopsy cases (n = 3), and cellblocks of cell pellet prepared from peripheral blood (n = 4) were included. IHC for p67phox and p47phox subunits and IF for cytochrome b558 were performed.

RESULTS

All 4 cases with pathogenic variation of NCF2 gene showed loss of expression for p67phox subunit. Two cases with pathogenic variation of NCF1 gene showed loss of expression for p47phox subunit. Five cases, except a single case with CYBB gene pathogenic variation, showed loss of expression for cytochrome b558 on IF. Thus, loss of expression consistently matched with the underlying genetic defects assessed by sequencing.

CONCLUSIONS

Our results confirm our hypothesis that IHC and IF are two rapid, economical, pathologist-friendly techniques providing pertinent information regarding the underlying pathogenic variants and such immuno-analysis can be easily performed on the tissue.