CURRENT CHALLENGES IN SECONDARY IMMUNODEFICIENCY: A LITERATURE REVIEW

This review provides a definition of secondary immunodeficiency (SID), substantiates its role within the framework of multimorbidity, and examines the clinical consequences of multimorbidity when SID is present. The article summarizes the limited available epidemiological data on the prevalence of SID, analyzes the most common risk factors and causes of immunodeficiency, and highlights the expanding spectrum of these factors in light of recent advances in understanding disease pathogenesis and the pharmacodynamics of modern drugs that may adversely affect immune cells and mediators.

A structured clinical pathway for medical management is proposed, starting with the identification of risk factors and early clinical manifestations of SID—particularly severe and recurrent infections as key clinical markers—and culminating in the diagnosis of immunodeficiency. These recommendations are based on expert consensus statements developed by multidisciplinary teams of clinicians and immunologists.

The review also presents a detailed diagnostic algorithm for patients with suspected secondary immunodeficiency, including comprehensive medical history taking and clinical assessment to guide appropriate laboratory evaluation, including immunological testing. It is emphasized that normal immune parameters do not exclude the diagnosis of SID in patients with severe or recurrent infections.

Approaches to differentiated anti-infective prophylaxis across various risk groups are discussed, along with the main therapeutic strategies for SID, including vaccination and immunoglobulin therapy. At the same time, the limited evidence regarding the efficacy and safety of vaccines and immunoglobulins in the treatment of SID is highlighted. The article concludes that optimal management of patients with SID requires a multidisciplinary clinical team, with mandatory involvement of a clinical immunologist.

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