immune system disorder immune system disease or disorder A disorder resulting from an abnormality in the immune system. ICD9:279.9 ICD9:279.8 NANDO:2100202 disorder of immune system immune dysfunction ICD9:279.49 immune disease UMLS:C0021053 NCIT:C3507 immune system disorder immune disorder NANDO:1100004 MESH:D007154 disease of immune system MEDGEN:5759 SCTID:414029004 DOID:2914 ICD9:279.1 EFO:0000540 ICD9:279.4 disease or disorder of immune system ICD9:279.19 ICD9:279.10 ICD9:279 disease by body system or component