The association between inborn errors of immunity and Hodgkin lymphoma—A register‐based case–control study in Sweden

Summary Immune dysfunction is implicated in the aetiology of Hodgkin lymphoma (HL), but the association between inborn errors of immunity (IEI) and HL remains poorly understood. We conducted a retrospective, register‐based case–control study in Sweden over five decades to investigate the relationship between IEI and HL. Individuals diagnosed with HL in the Swedish Cancer Register between 1969 and 2019 were matched with population controls. Data were linked to the National Patient Register to identify recorded the International Classification of Diseases (ICD)‐coded IEI diagnoses. Odds ratios (ORs) for HL associated with any IEI and IEI subgroups were estimated using conditional logistic regression. The study included 10 549 HL patients and 42 225 controls. Median age at HL diagnosis was 49 years, and 57% were male. Twenty‐two HL cases and 11 controls had a recorded IEI diagnosis; most were predominantly antibody deficiencies (PAD; 14 cases and 8 controls). Any IEI was associated with increased odds of HL (OR 8.0; 95% confidence interval [CI] 3.9–16.5). No clear differences in HL risk were observed between IEI subtypes. IEI was strongly associated with increased odds of HL. These findings support a role for IEI in HL pathogenesis and may suggest a distinct aetiological pathway for HL compared with other IEI‐associated lymphomas.