Chronic Pulmonary Histoplasmosis Identified in a Young Patient with Selective Immunoglobulin M Deficiency

Abstract

Chronic histoplasmosis is typically diagnosed in patients who are immunocompromised or severely debilitated and who either live in or who have travelled to endemic areas. We report the case of a young, otherwise immunocompetent male patient who presented to a New York hospital with lobar consolidation and was found to have chronic pulmonary histoplasmosis. He described no history of travel to an endemic area. Immunological workup later revealed selective immunoglobulin M (IgM) deficiency. The literature has suggested a link between IgM deficiency and fungal infections. Recent research has also proposed a link between autoimmunity and IgM deficiency. Our clinical vignette describes the case of a patient with selective IgM deficiency who was diagnosed with pulmonary histoplasmosis without any clinical evidence of autoimmune disease.

Histoplasma seropositivity and environmental risk factors for exposure in a general population in Upper River Region, The Gambia: A cross-sectional study

“…During an initial antigen challenge, IgM represents the first immunoglobulin isotype expressed by immature B cells in the immunocompetent host, and is the target of the LAT. On sustained or recurrent antigen exposure, isotype switching results in an immune response characterised by IgG and IgA production [ 36 , 42 ]. Based on evidence suggesting Histoplasma is endemic in The Gambia, initial exposure in immunocompetent children may result in an IgM response detectable by LAT, which diminishes with age with chronic exposure.…”

Epidemiologia Da Histoplasmose No Brasil

“…Possui uma distribuição mundial, no Brasil, No Brasil foram relatados 26 microepidemias em oito estados, Paraíba, Rio de Janeiro, Distrito Federal, Rio Grande do Sul e São Paulo, sendo que em cinco destes estados o fungo foi isolado (Oliveira et al, 2006). Uma parcela de infectados (<10%) podem apresentar manifestações clinicas que variam de histoplasmose aguada (que geralmente acomete individuos que realizam atividades em locais endemicos Rocha-silva et al, 2014) á disseminada (Ferguson-paul et al, 2018Wheat et al, 2016), podendo apresentar quadros de histoplasmose pulmonar cavutária crônica e mediastinite granulomatosa ( Preneta et al, 2018Thompson-Souza et al, 2020. A gravidade da doença depende da intensidade da exposição a micronichos do patógeno, da quantidade do inóculo e da interação dinamica entre a imunidade celular mediada por células T CD4+, dos fatores de virulência, dos genótipos das linhagens isoladas e as respostas inata e adquirida do hospediro (Ferreira;Borges, 2009, Fregonezi 2020.…”