Selective IgM Immunodeficiency in pediatric age, Clinical and immunological characteristics

Primary selective IgM deficiency (selective IgM immunodeficiency; SIgMID) is a form of hypogammaglobulinemia characterized by absent or reduced serum immunoglobulin M levels (less than 2 SD of the values obtained from healthy controls of the same age or an absolute value <20 mg / dl in pediatric age), in the absence of immunoglobulin deficiency of the other classes. In this study we aimed to characterize the clinical phenotype and immunological characteristics of 46 pediatric patients (between 4 to 18 years of age) with Selective IgM Immuno-deficiency (SIgMID) evaluated in our Pediatric department, IRCCS Polyclinic San Matteo Foundation, or through the Italian Primary Immunodeficiency Network (IPINET) and to monitor changes in their diagnosis over a time frame that ranges from several months to several years. Results: 46 patients with SIgMID mean IgM levels of 34.2mg/dL were monitored for clinical and immunological characteristics. The most common clinical manifestations in our study were bronchitis (30%), pharyngitis (28%), atopic dermatitis (28%), rhinoconjunctivitis (26%) and otitis (26%). 16 patients had long term follow up during which 14 (87.5%) preserved their SIgMID diagnosis, 2 patients (12.5%) showed reduction in IgA in addition to low IgM. Conclusions: The main clinical manifestations of SIgMID in our study were largely infections and atopy. Autoimmune diseases are less abundant, and we did not have any neoplastic disease in our patients. We think that it is crucial to follow the patients regularly, to check their immune characteristics and if their symptoms are well managed with therapy. It is essential to change the treatment in accordance with patient clinical state.