Disseminated Histoplasmosis and <i>Campylobacter jejuni</i> Bacteremia Coinfection Revealing Autosomal Dominant NFKB1 Deficiency-Related Common Variable Immunodeficiency

This report presents the case of a Thai male in his twenties presenting prolonged fever, generalized lymphadenopathy and hepatosplenomegaly. Blood cultures isolated Campylobacter jejuni, while lymph node cultures isolated Histoplasma capsulatum. A gene panel for immunodeficiency revealed nuclear factor kappa B subunit 1 (NFKB1) deficiency, leading to a final diagnosis of common variable immunodeficiency (CVID) due to autosomal dominant NFKB1 deficiency. The patient was initially treated with amphotericin B (0.7 mg/kg/day) for 3 weeks, followed by itraconazole 200 mg orally twice daily, and received intravenous azithromycin 500 mg once daily for C. jejuni bacteremia for 14 days. After three months of treatment, the patient demonstrated partial clinical and radiologic improvement. Additionally, intravenous immunoglobulin was administered to treat CVID. After 12 months of itraconazole, the follow-up computed tomography showed reduced lymphadenopathy to subcentimetric nodes and resolved hepatomegaly. Patients with disseminated atypical infections should be evaluated for primary immunodeficiency disorders, even when considered healthy.