I, Evgeny Ivanovich Semenovich, an emergency medical technician, present a clinical case of selective IgA deficiency in a 25-year-old patient complicated by T-cell exhaustion (CD8+ 0.44) and hyperviscosity (hematocrit 48.6%). A pathogenetic model linking IgA deficiency with chronic inflammation, herpesvirus reactivation, and microcirculatory disorders is proposed. It is shown that the syndrome is not detected by standard protocols and requires extended immunological and hematological examination. Practical significance: justification for screening IgA and T‑cell subsets in patients with unexplained multisystem symptoms.