A cross sectional observational study on clinical profile and etiology of children with suspected Primary Immunodeficiency Disorders.

Background and purpose of the study:

Primary Immunodeficiency Disorders (PIDs) are caused by germline variants in single genes and mostly present with recurrent or chronic infections.(1,2) The clinical presentation of PIDs is highly variable with many of them having routine infections of respiratory tract and ears due to which they may go undetected(3) . Although usual infections are common in children, an infection exceeding the expected frequency or involving multiple sites or a single, severe, unusual infection can also indicate immunodeficiency(4) . PIDs are classified into various categories by International Union of Immunological Societies (IUIS). The 2019 IUIS classification includes 430 diverse IEIs classified into categories based on the clinical and laboratory features observed in these patients(5 ).Jeffrey Modell Foundation, which is active in research, education, support and public awareness of PIDs, devised 10 warning signs of PIDs for early identification of PIDs(6,7) and includes recurrent manifestations like Sino-pulmonary infections, deep seated abscesses, failure to gain weight etc. It is estimated that around 6 to 8 million people live with PIDs worldwide, with 70% to 90% patients remaining undiagnosed(8) . High proportion of patients remaining undiagnosed can be attributed to low level of awareness among physicians, differences in diagnostic capabilities and treatment of PIDs between various regions (8,9) . In India, prevalence data of PIDs doesn’t exists, but it is estimated that more than 1 million such cases might be present(10). The Indian scenario is complicated due to lack of literature in this area, with only few centres having the clinical and laboratory experience(11,12). Although there have been advancements in the laboratory capabilities in India, there are many economical, ethical and cultural challenges that need to be addressed(10) .It is also observed that PIDs are more likely to be recognized when under 5 mortality is below 15/1000 live births, as for healthcare planners, PIDs become more relevant when deaths due to common infections gets controlled. This thus necessitates recognizing and describing such patients in the Indian scenario which has very high under 5 mortality rate and may have different clinical profile than western countries. Patients with such disorders in Asia have unique patterns of infections, especially involving organisms like Mycobacterium tuberculosis, Mycobacterium bovis, Burkholderia pseudomallei, disseminated BCGosis, etc(13) . Most of all identified PIDs are caused by defects in antibody production(8) .Patients with PID tend to have different infections by various organisms depending on the affected cell type(14,15). Complete blood count, serum immunoglobulins and flow cytometry has been used for the diagnosis of PID(15).Also, there have been many new innovations in diagnosis of PIDs including the use of Next Generation Sequencing (NGS), which not only detects specific genetic defects associated with each PID but has also led to detection of novel mutations/expanding the list of PIDs. Antimicrobial treatment, sometimes aggressive and as prophylaxis is obviously needed in some patients with PID. Patients with immunoglobulin deficiency may need intravenous (IVIG) or subcutaneous immunoglobulin (SCIG) replacement(16). Gene therapy has been used to treat patients with T cell deficiencies though the expertise and resources required is expected to limit its outreach in India. This study is therefore undertaken to add to the literature which is already in the evolving stage in the Indian scenario, as described earlier. Very few such studies are conducted, in which patients with suspected PIDs will be taken into consideration, thus providing the frequency of PIDs in suspected patients apart from describing clinical profile and etiology of such patients who get referred to the study site from varied geographic locations. Children need to be evaluated not only for primary immunodeficiency disorders, but also for other risk factors of recurrent/severe infections, especially in India where infectious disease burden predominate. This will also highlight the importance of early identification of such patients and may encourage further studies for prevention of recurrent/severe infections, as there are many such preventable risk factors.

Aims and objectives:

Primary Objective: To describe the clinical and etiological profile of patients with Primary Immunodeficiency Disorders (PIDs).

Secondary Objectives:

1.To determine the frequency of PIDs in patients with suspected PIDs

2.To identify risk factors of recurrent/severe infections in patients not confirmed as PID.

Methodology:-

Ethics: The study will be initiated after seeking approval from the “Institutional Ethics Committee (IEC)” of the hospital. The study will be conducted in compliance with the “Ethical Guidelines for Biomedical Research on Human Participants” By the Indian Council of Medical Research.

Consent and assent: Case enrollment will be done after a written informed consent from the parent/ guardian for patients with age between 1 month to 12 years. Assent will also be procured from patients aged 7 years and above.

Study design: Cross sectional, observational, single centre study.

Study duration: The study will be conducted over a period of 18 months after approval from the IEC.

Study Site: The study will be conducted in the department of pediatrics of a tertiary care hospital.

Inclusion Criteria: This study will include:

1. Children of age between 1month to 12 years.
2. Children meeting at least 2 criteria as per Jeffrey Modell Foundation’s 10 warning signs6,7 .

Warning signs in children

1. ≥ 4 new ear infections within 1 year
2. ≥ 2 serious sinus infections within 1 year
3. ≥ 2 months on antibiotics with little effect
4. ≥ 2 pneumonias within 1 year
5. Failure of an infant to gain weight or grow normally
6. Recurrent, deep skin or organ abscesses
7. Persistent thrush in mouth or fungal infection on skin
8. Need for IV antibiotics to clear infections
9. ≥ 2 deep-seated infections including septicemia
10. A family history of PID

Exclusion Criteria:

1. Patients whose parent/guardian refuses to give informed consent.
2. Patients with secondary immunodeficiency.

Confidentiality: The participant’s details will not be disclosed at any point of time.

Total number of patients to be studied (sample size calculation): The sample size was calculated based on the findings of similar study conducted by Madkaikar M, Mishra A, Desai M, Gupta M, Mhatre S, Ghosh K titled “Comprehensive Report of Primary Immunodeficiency Disorders from a Tertiary Care Center in India” 17 . We used the prevalence formula for sample size calculation. Z = 1.96 P= 0.1574 D=0.06 Assuming the above conditions the final sample size calculated was 142.

Data Recording: Data/ information will be recorded in a pre-designed case record form- CRF (from medical history/patient’s hospital case sheets/ indoor medical papers) from all the consecutive patients meeting the inclusion criteria.

Plan for Statistical Analysis: Data will be descriptively analyzed using mean, standard deviation, median and interquartile range for continuous variables and frequency, proportion for categorical variables. Frequency of Primary Immunodeficiency Disorders will be represented in percentage with 95 % CI. The clinical profile and etiology of patients with PIDs will be represented by frequency and percentage. Association of patients who do not have Primary Immunodeficiency Disorder with risk factors will be calculated using Chi Square or Fisher Exact Test. Multivariate Logistic Regression will be used to assess the risk factors. Odds ratios (OR), 95% confidence intervals (95% CI) and p-values will be calculated for each potential predictor variable. The Hosmer Lemeshow test will be used to check the goodness-of-fit of the model. A 2-tailed P < 0.05 was considered to be statistically significant. Statistical analysis will be performed by appropriate statistical tests using IBM SPSS v26 (statistical package for social sciences) software.

References:

1.Tangye SG, Al-Herz W, Bousfiha A, CunninghamRundles C, Franco JL, Holland SM, et al. Human inborn errors of immunity: 2022 update on the classification from the International Union of Immunological Societies Expert Committee. J Clin Immunol 2022;42(7):1473–507.

2.Keller M. Inborn errors of immunity (primary immunodeficiencies): Overview of management [Internet]. www.uptodate.com. 2023 [cited 2023 Spring 7]. Available from: https://www.uptodate.com/contents/inborn-errors-ofimmunity-primary- immunodeficiencies-overview-of-management

3.McCusker C, Upton J, Warrington R. Primary immunodeficiency. Allergy Asthma Clin Immunol 2018;14:141

4. K, Buckley R. Evaluation of Suspected Immunodeficiency. In: Kliegman R, author. Nelson Textbook of Pediatrics Elsevier; 2019.p. 1097.

5. Bousfiha A, Jeddane L, Picard C, Al-Herz W, Ailal F, Chatila T, et al. Human Inborn Errors of Immunity: 2019 update of the IUIS phenotypical classification. J Clin Immunol 2020;40:66–81.

6. Subbarayan A, Colarusso G, Hughes SM, Gennery AR, Slatter M, Cant AJ, et al. Clinical features that identify children with primary immunodeficiency diseases. Pediatrics 2011;127:810–6.

7. ESID - European Society for Immunodeficiencies [Internet]. Esid.org. [cited 2023 Jul 19]. Available from: https://esid.org/Working-Parties/Clinical-WorkingParty/Resources/10-Warning-Signs-of-PID-General

8. Abolhassani H, Azizi G, Sharifi L, Yazdani R, Mohsenzadegan M, Delavari S, et al. Global systematic review of primary immunodeficiency registries. Expert Rev Clin Immunol 2020;16:717–32.

9. Hernandez-Trujillo HS, Chapel H, Lo Re V 3rd, Notarangelo LD, Gathmann B, Grimbacher B, et al. Comparison of American and European practices in the management of patients with primary immunodeficiencies: ESID practices in PID. Clin Exp Immunol 2012;169:57–69.

10. Gupta S, Sehgal S. Editorial: Advances in primary immunodeficiencies in India. Front Immunol 2021;12:701335.

11. Singh S, Gupta S. Primary immunodeficiency diseases: Need for awareness and advocacy in India. Indian J Pediatr 2016;83:328–30.

12. Gupta S, Madkaikar M, Singh S, Sehgal S. Primary immunodeficiencies in India: a perspective: PID in India. Ann N Y Acad Sci 2012;1250:73–9.

13. Pilania RK, Chaudhary H, Jindal AK, Rawat A, Singh S. Current status and prospects of primary immunodeficiency diseases in Asia. Genes Dis 2020;7:3–11.

14. Conley ME, Dobbs AK, Farmer DM, Kilic S, Paris K, Grigoriadou S, et al. Primary B cell immunodeficiencies: comparisons and contrasts. Annu Rev Immunol 2009;27:199–227.

15. Locke BA, Dasu T, Verbsky JW. Laboratory diagnosis of primary immunodeficiencies. Clin Rev Allergy Immunol 2014;46:154–68.

16. Paris K, Wall LA. The treatment of primary immune deficiencies: Lessons learned and future opportunities. Clin Rev Allergy Immunol 2023;65:19–30.

17. Madkaikar M, Mishra A, Desai M, Gupta M, Mhatre S, Ghosh. Comprehensive Report of Primary Immunodeficiency Disorders from a Tertiary Care Center in India. J Clin Immunol 2013;3:507–512