A 35-year-old man with a late-onset combined immunodeficiency (LOCID) variant of common variable immunodeficiency, severe plaque psoriasis, psoriatic arthritis, and Crohn's disease attended Regional Hospital of Presidente Prudente and HC-FMUSP, São Paulo, Brazil. Anti-IL-12/IL-23 (ustekinumab) monoclonal antibody was prescribed due to failure of other treatments (phototherapy, oral acitretin) for psoriasis and Psoriasis Area Severity Index <10. We evaluated the impact of ustekinumab, a potent immunosuppressor, on the risk of infectious diseases in this patient followed for 8 years. Four quarterly doses of ustekinumab 90 mg and human immunoglobulin replacement (10,000 mg at 28-day intervals) were administered. Immunophenotyping, culture of lymphocytes, genetic sequencing, and whole exome sequencing were performed to investigate the primary immunodeficiency. Normal lymphocyte proliferation, absence of pathogenic variants in the genes analyzed and no clinically significant variants were detected in the whole exome. The main infections included chronic sinusitis, tonsillitis, fungal and bacterial otitis, gastroenteritis, and community-acquired pneumonia. The patient was infected with COVID-19, dengue (twice), and influenza and was hospitalized three times for intravenous antibiotic therapy. Ustekinumab did not influence susceptibility to severe infections and significantly improved psoriasis, psoriatic arthritis, and Crohn's disease in a patient with LOCID.

Our aim was to determine the secondary antibody deficiency profiles of patients in a mesoregion of São Paulo state, Brazil, focusing on infectious diseases. Demographic characteristics, clinical and laboratory data were obtained from electronic files; infections were classified as organ-specific and graded as mild, moderate, life-threatening, and fatal. Non-Hodgkin lymphoma (NHL) accounted for 30% of patients, nephrotic syndrome (NS) 25%; chronic lymphocyte leukemia 20%, and multiple myeloma 15%. Patients with NS were younger than those in other groups, and hypo-γ-globulinemia was detected in 94.1%, IgG <400 mg/dL in 60.0%, IgA <40 mg/dL in 55.0%, and CD19 <20 cells/mm³ in 30.0%. One hundred and one infections were found; 82.1% were classified as mild or moderate, 7.9% as life-threatening, and 1.9% as fatal. Respiratory tract infections were more prevalent (41.5%), and pneumonia accounted for 19.8%. Lower levels of infections were found in patients with NS compared with NHL (P=0.0001). Most patients progressed to hypo-γ-globulinemia and secondary antibody deficiency after treatment with immunosuppressants, and mild and moderate infections were predominant. These therapies are increasing in patients with different diseases, therefore monitoring hypo-γ-globulinemia and infections may help to identify patients at high risk for severe complications, antibiotic prophylaxis or treatment, and immunoglobulin replacement