Patients and Methods

The study was conducted in Hacettepe Üniversity İhsan Dogramacı Children’s Hospital, Ankara, Turkey. The hospital serves as a referral tertiary hospital. We assessed a retrospective medical record of 27,000 patients who admitted to Pediatric Immunology department. To define selective IgM deficient patients, The European Society for Immunodeficiencies (ESID) Registry criteria have been used [3-5]. Patients who had repeatedly (at least twice in a 6-month period) low serum IgM level according to age referrals were evaluated in the study. Fifty-five patients were found in this cohort (Figure 1). Thirteen patients who were diagnosed with a primary immunodeficiency had also low IgM levels with normal IgG and IgA levels. Forty-two patients fulfilling the diagnosis of sIgM deficiency were evaluated over a five-year period (2013-2018).
As transient hypogamaglobulinemia may prolong to five years of age[12], we determined the patients who got the diagnosis less than five years of age. Eighteen of 42 patients had taken the diagnosis of sIgMD before five years of age. Out of 18, in nine patients sIgM deficiency continued after five years of age, in two patients IgM levels normalized, and seven patients lost follow-up. Eventually, 33 patients were fulfilling the disease criteria [13].
Cases of sIgMD were reviewed for the symptoms on admission, concurrent conditions, and clinical course. Patients with genetic mutations, chromosomal abnormalities and associated immunological disorders were also recorded. Laboratory findings; complete blood counts, serum immunoglobulin levels and lymphocyte subsets were noted. To evaluate vaccination response antiHbs antibody and isohemaglutinins were used.
The patients with PID (n=13) and patients who got the diagnosis of sIgMD at less than 5 years of age (n=9) were evaluated separately (Figure 1), and their characteristics are given after the results of patients with sIGMD.
The study was approved by the ethical committee of Hacettepe University Medical School Hospital (GO 18/182-20).

Statistical analysis

All the data collected during the study were uploaded to SPSS statistical program. Parametrical tests (Student t-test) were used to analyze the variables which distributed normally. The variables that did not have normal distribution were analyzed by nonparametric tests (Mann-Whitney U test). Categorical and qualitative variables were analyzed by Fisher Exact test and Chi-Square test. A p value lower than 0.05 was considered to be statistically significant.