Evaluation of the frequency and diagnostic delay of primary immunodeficiency disorders among suspected patients based on the 10 warning sign criteria: A cross-sectional study in Iran

Validating inborn error of immunity prevalence and risk with nationally representative electronic health record data

BACKGROUND

The 10 Warning Signs of Primary Immunodeficiency were created 30 years ago to advance recognition of inborn errors of immunity (IEI). However, no population-level assessment of their utility applied to electronic health record (EHR) data has been conducted.

OBJECTIVE

We sought to quantify the value of having ≥2 warning signs (WS) toward diagnosing IEI using a highly representative real-world US cohort. A secondary goal was estimating the US prevalence of IEI.

METHODS

In this cohort study, we accessed normalized and de-identified EHR data on 152 million US patients. An IEI cohort (n = 41,080), in which patients were defined by having at least 1 verifiable IEI diagnosis placed ≥2 times in their record, was compared with a matched set of controls (n = 250,262). WS were encoded along with relevant diagnoses, relative weights were calculated, and the proportion of IEI cases versus controls with ≥2 WS was compared.

RESULTS

The proportion of IEI cases with ≥2 WS significantly differed from controls (0.33 vs 0.031; P < .0005, χ2 test). We also estimated a US IEI prevalence of 6 per 10,000 individuals (41,080/73,165,655; 0.056%). WS 9 (≥2 deep-seated infections), 7 (fungal infections), 5 (failure to thrive) and 4 (≥2 pneumonias in 1 year) were the most heavily weighted among the IEI cohort.

CONCLUSIONS

This nationally representative US-based cohort study demonstrates that presence of WS and associated clinical diagnoses can facilitate identification of patients with IEI from EHR data. In addition, we estimate that 6 in 10,000, or approximately 150,000 to 200,000 individuals are affected by IEI across the United States.

Combined immunodeficiency and impaired PI3K signaling in a patient with biallelic LCP2 variants

BACKGROUND

Inborn errors affecting components of the T-cell receptor signaling cascade cause combined immunodeficiency with various degrees of severity. Recently, homozygous variants in LCP2 were reported to cause pediatric onset of severe combined immunodeficiency with neutrophil, platelet, and T- and B-cell defects.

OBJECTIVE

We sought to unravel the genetic cause of combined immunodeficiency and early-onset immune dysregulation in a 26-year-old man who presented with specific antibody deficiency, autoimmunity, and inflammatory bowel disease since early childhood.

METHODS

The patient was subjected to whole-exome sequencing of genomic DNA and examination of blood neutrophils, platelets, and T and B cells. Expression levels of the Src homology domain 2-containing leukocyte protein of 76 kDa (SLP76) and tonic and ligand-induced PI3K signaling were evaluated by flow-cytometric detection of phosphorylated ribosomal protein S6 in B and T cells.

RESULTS

Compound heterozygous missense variants were identified in LCP2, affecting the proline-rich repeat domain of SLP76 (p.P190R and p.R204W). The patient's total B- and T-cell numbers were within the normal range, as was platelet function. However, neutrophil function, numbers of unswitched and class-switched memory B cells, and serum IgA were decreased. Moreover, intracellular SLP76 protein levels were reduced in the patient's B cells, CD4+ and CD8+ T cells, and natural killer cells. Tonic and ligand-induced levels of phosphorylated ribosomal protein S6 and ligand-induced phosphorylated PLCγ1 were decreased in the patient's B cells and CD4+ and CD8+ T cells.

CONCLUSIONS

Biallelic variants in LCP2 impair neutrophil function and T-cell and B-cell antigen-receptor signaling and can cause combined immunodeficiency with early-onset immune dysregulation, even in the absence of platelet defects.

The Evolutionary Scenario of Pediatric Unclassified Primary Antibody Deficiency to Adulthood

BACKGROUND

Unclassified primary antibody deficiency (unPAD) is a relatively novel inborn error of immunity (IEI) condition that can vary with time to more defined entities. Since long-term follow-up (FU) studies are scarce, we aimed to provide insight into the evolutionary clinical and immunological scenario of unPAD children to adulthood and identification of biomarkers of primary immune deficiency (PID) persistence.

METHODS

A total of 23 pediatric unPAD patients underwent clinical and immunological FU for a mean time of 14 years (range 3-32 years, median 16 years).

RESULTS

UnPAD diagnosis may change over time. At the last FU, 10/23 (44%) children matched the diagnosis of transient hypogammaglobulinemia of infancy and 13/23 (56%) suffered from a persistent PID. In detail, an unPAD condition was confirmed in 7/23 (30%) patients, whereas 3/23 (13%), 2/23 (9%), and 1/23 (4%) were reclassified as common variable immunodeficiency, selective IgA deficiency, and isolated IgM deficiency, respectively. Low IgA, low specific antibody response to pneumococcus, and lower respiratory tract infections at diagnosis were independently associated with IEI persistence.

CONCLUSIONS

Long-term monitoring of unPAD patients is required to define their outcome and possible evolution towards a definitive IEI diagnosis.

Genetics of Inborn Errors of Immunity in highly consanguineous Middle Eastern and North African populations

Consanguineous marriages in Middle Eastern and North African (MENA) countries are deeply-rooted tradition and highly prevalent resulting into increased prevalence of autosomal recessive diseases including Inborn Errors of Immunity (IEIs). Molecular genetic testing is an important diagnostic tool for IEIs since it provides a definite diagnosis, genotype-phenotype correlation, and guide therapy. In this review, we will discuss the current state and challenges of genomic and variome studies in MENA region populations, as well as the importance of funding advanced genome projects. In addition, we will review the MENA underlying molecular genetic defects of over 2457 patients published with the common IEIs, where autosomal recessive mode of inheritance accounts for 76% of cases with increased prevalence of combined immunodeficiency diseases (50%). The efforts made in the last three decades in terms of international collaboration and of in situ capacity building in MENA region countries led to the discovery of more than 150 novel genes involved in IEIs. Expanding sequencing studies within the MENA will undoubtedly be a unique asset for the IEI genetics which can advance research, and support precise genomic diagnostics and therapeutics.

Evaluation of the 10 Warning Signs in Primary and Secondary Immunodeficient Patients

Objectives

Ten warning signs of primary immunodeficiency (PID) were suggested by the Jeffrey Modell Foundation (JMF), to increase physician awareness of PID. These warning signs have not yet been evaluated for patients with secondary immunodeficiency (SID). This study investigated whether the 10 warning signs used for the diagnosis of PID were also sufficient for the diagnosis of SID, and explored the possibility of additional signs.

Methods

This prospective study was conducted between June and December 2020. The mothers of 162 patients with PID and SID, and mothers of 200 healthy children, were asked to complete a questionnaire about family and personal history in addition to the warning signs of PID developed by the JMF. A JMF score was created by giving one point for each "Yes" answer for the 10 warning signs of PID. Medical records of the patients were evaluated for possible additional warning signs for PID and SID.

Results

The JMF scores of the PID (3.36 ± 1.65) and SID (3.72 ± 1.12) groups were significantly higher than the scores of the control group (0.34 ± 0.61) (p < 0.05). A sign for immunological evaluation in two patients without warning signs in the PID group was found to be chronic diarrhea. In addition to the 10 JMF warning signs, we found that consanguinity and a family history of tuberculosis were statistically significant in our PID group, compared with the SID and control groups.

Conclusions

The JMF warning signs are important for early diagnosis of PID. Our study showed that these signs may also be used for the early diagnosis of SID in patients and, according to our results, in addition to the 10 JMF signs for PID, parental consanguinity, chronic diarrhea, and a family history of tuberculosis may also be considered warning signs for the early diagnosis of PID.

Cytometric analysis and clinical features in a Moroccan cohort with severe combined immunodeficiency

Severe combined immunodeficiency (SCID) is a form of primary immunodeficiency disease (PID). It is characterized by a serious abnormality of the cellular and sometimes humoral system due to a deficiency in development of T cells, B cells and/or NK cells. The early diagnosis of SCID improves the prognosis. Typically, the initial consideration of SCID is made based on low lymphocyte counts. Notwithstanding, the heterogeneity of lymphocyte count presentation makes the diagnosis of SCID a significant challenge. The objective of this cross-sectional retrospective study was to analyze the lymphocyte subpopulation counts along with clinical manifestations within a Moroccan cohort diagnosed as SCID compared to children diagnosed with non-PID diseases. Thirty-five SCID confirmed patients were selected in the period between 2008 and 2018 and compared with non-PID patients. Results of peripheral blood T, B, and NK lymphocyte subpopulation counts were measured by flow cytometry for each SCID subtype. As expected, T cell count was less than 300 cells/μL in most patients with SCID (85.5%). Unexpectedly, significantly higher T cell counts were detected in some patients with a confirmed clinical diagnosis and family history of SCID. 5.7% of our SCID Moroccan cohort had T cell numbers in the range between 300 and 500 cells/μL. 8.7% of our SCID Moroccan cohort had T cell numbers higher than 500 cells/μL. Of the SCID subtypes, the proportion of SCID with B cell deficiencies was highly represented in our cohort. 71.4% of Moroccan SCID patients (25 out of 35 patients) were of T-B-subtype. Furthermore, 40% of the patients (14 out of 35 patients) had a T-B-NK+ profile and 31.4% had a T-B-NK- profile (11 out of 35 patients). The most common clinical manifestations observed in our SCID cohort were pneumonia, failure to thrive, candidiasis, diarrhea, bronchitis and urinary tract infections. Our results not only highlight the relatively frequent presence of atypical SCID in the Moroccan population with unexpectedly high T cell numbers, but also describes the incidence pattern of common SCID subtypes in Morocco. Physicians in Morocco may find this local region-specific difference in SCID important for making improved early diagnosis of this disease.

The Epidemiology and Clinical Presentations of Atopic Diseases in Selective IgA Deficiency

Selective IgA deficiency (sIgAD) is the most common primary immunodeficiency disease (PID), with an estimated occurrence from about 1:3000 to even 1:150, depending on population. sIgAD is diagnosed in adults and children after the 4th year of age, with immunoglobulin A level below 0.07 g/L and normal levels of IgM and IgG. Usually, the disease remains undiagnosed throughout the patient's life, due to its frequent asymptomatic course. If symptomatic, sIgAD is connected to more frequent viral and bacterial infections of upper respiratory, urinary, and gastrointestinal tracts, as well as autoimmune and allergic diseases. Interestingly, it may also be associated with other PIDs, such as IgG subclasses deficiency or specific antibodies deficiency. Rarely sIgAD can evolve to common variable immunodeficiency disease (CVID). It should also be remembered that IgA deficiency may occur in the course of other conditions or result from their treatment. It is hypothesized that allergic diseases (e.g., eczema, rhinitis, asthma) are more common in patients diagnosed with this particular PID. Selective IgA deficiency, although usually mildly symptomatic, can be difficult for clinicians. The aim of the study is to summarize the connection between selective IgA deficiency and atopic diseases.