| D89 | Other disorders involving the immune mechanism, not elsewhere classified | NON-BILLABLE CODE |
| D89.0 | Polyclonal hypergammaglobulinemia | BILLABLE CODE |
| D89.2 | Hypergammaglobulinemia, unspecified | BILLABLE CODE |
| D89.3 | Immune reconstitution syndrome | BILLABLE CODE |
| D89.4 | Mast cell activation syndrome and related disorders | NON-BILLABLE CODE |
| D89.40 | Mast cell activation, unspecified | BILLABLE CODE |
| D89.41 | Monoclonal mast cell activation syndrome | BILLABLE CODE |
| D89.42 | Idiopathic mast cell activation syndrome | BILLABLE CODE |
| D89.43 | Secondary mast cell activation | BILLABLE CODE |
| D89.44 | Hereditary alpha tryptasemia | BILLABLE CODE |
| D89.49 | Other mast cell activation disorder | BILLABLE CODE |
| D89.8 | Other specified disorders involving the immune mechanism, not elsewhere classified | NON-BILLABLE CODE |
| D89.81 | Graft-versus-host disease | NON-BILLABLE CODE |
| D89.810 | Acute graft-versus-host disease | BILLABLE CODE |
| D89.811 | Chronic graft-versus-host disease | BILLABLE CODE |
| D89.812 | Acute on chronic graft-versus-host disease | BILLABLE CODE |
| D89.813 | Graft-versus-host disease, unspecified | BILLABLE CODE |
| D89.82 | Autoimmune lymphoproliferative syndrome [ALPS] | BILLABLE CODE |
| D89.83 | Cytokine release syndrome | NON-BILLABLE CODE |
| D89.831 | Cytokine release syndrome, grade 1 | BILLABLE CODE |
| D89.832 | Cytokine release syndrome, grade 2 | BILLABLE CODE |
| D89.833 | Cytokine release syndrome, grade 3 | BILLABLE CODE |
| D89.834 | Cytokine release syndrome, grade 4 | BILLABLE CODE |
| D89.835 | Cytokine release syndrome, grade 5 | BILLABLE CODE |
| D89.839 | Cytokine release syndrome, grade unspecified | BILLABLE CODE |
| D89.84 | IgG4-related disease | BILLABLE CODE |
| D89.89 | Other specified disorders involving the immune mechanism, not elsewhere classified | BILLABLE CODE |
| D89.9 | Disorder involving the immune mechanism, unspecified | BILLABLE CODE |
