Primary immunodeficiency diseases in two neighboring pediatric centers: registry data bring out a wide spectrum of diseases with complex clinical presentations

In the last decades, the spectrum of primary immunodeficiency diseases (PIDs) has greatly widened, including disorders that can variably impair different immune functions. Although several case series have been published for each disorders, no data is available on how these changes have reflected in the clinical practice of pediatric departments. Aim of the study: Based on the analysis of registry data, we evaluated the distribution of diagnoses among different PID categories, the clinical features and diagnostic investigations at disease onset in two pediatric departments, namely in Slovenia and in Italy. Results: 136 patients have been diagnosed at the two centers, with a widespread distribution into different disease categories. Considering the 109 patients who were still alive at the last follow-up, prevalence of pediatric-onset-PID in our area was roughly estimated to be around 31 per million inhabitants. Diagnosis was genetically confirmed in 79 cases (58.1%), with 29 different genes found mutated. The most common presenting symptoms were: recurrent infections (52.2%), inflammatory manifestations (36.7%), specific syndromic features (30.8%), unusual infections (1.6%) and failure to thrive/growth retardation (22.8%). Treatments at follow-up include antimicrobials (20), hematopoietic stem cell transplantation (17), immunoglobulin replacement therapy (16), and immunosuppressants (9). Conclusions: A huge number of different PIDs are encountered in pediatric departments, often presenting with complex clinical pictures. Our results suggest that the identification of PID may be improved by a multidisciplinary approach, attaching importance not only to infections but also to other symptoms arising from a defective immune function.