Predominantly antibody deficiencies in children and adults in Latvia 1994–2020

Predominantly antibody deficiencies (PAD) are the most common primary immunodeficiencies in children and adults. Clinical manifestations of these conditions are variable, including predisposition to recurrent or unusual infections, autoimmunity, autoinflammatory diseases, atopic diseases, polyclonal lymphocytic infiltrations, and malignancy. The aim of the study was to analyze patients with predominantly antibody deficiencies in population of Latvia. We retrospectively analyzed data from Children’s Clinical Univestity Hospital and Pauls Stradins Clinical University Hospital during time period from 1994 till 2020. After exclusion of patients with selective IgA deficiency, transient hypogammaglobulinemia of infancy, and patients who were followed up by hematologists, a total of 39 patients were diagnosed with predominantly antibody deficiency. Two pediatric male patients were diagnosed with X-linked agammaglobulinemia, both cases were genetically confirmed to have a mutation in the BTK gene. Common variable immune deficiency (with no gene defect specified) was diagnosed in 27 patients, 13 of whom were diagnosed before the age of 18, and 14 in adulthood. The median age of diagnosis was 35.0 (IQR=29.0) years of age, 15 of these patients were male (55.6%). All patients are treated with immunoglobulin substitution therapy. Six of these patients deceased during the study period, at the age median age 38.7 (IQR:23.8). Two pediatric patients – a boy and a girl - were diagnosed with Activated p110δ syndrome. The gain of function mutation in the PIK3CD gene was confirmed in both cases. Isolated IgG subclass deficiency was found in two females, and IgG subclass deficiency in combination with selective IgA deficiency was found in three female adult patients. Three pediatric patients had an unclassified antibody deficiency. Primary antibody deficiencies could be diagnosed at any age. Timely diagnosis of antibody deficiency is important for prognosis and monitoring of these patients in order to predict the possible complications.Latvian Council of Science project lzp-2020/1-0269