Gamma heavy chain disease and rheumatoid arthritis

Gamma heavy chain disease associated with rheumatoid arthritis: a case report

Background

Gamma heavy chain disease (γ-HCD) is a monoclonal gammopathy defined by an abnormal clonal and isolated production of incomplete heavy chain gamma (γ), unable to bind with light chains kappa or lambda. This disease is rare and remains poorly described. Its association to lymphoid neoplasm is well established, but exceptional forms of γ-HCD may also accompany auto-immune diseases. We report here a new case of γ-HCD characterized by an indolent course with a 4-year follow-up, and its association with quiescent rheumatoid arthritis (RA).

Case presentation

We report the case of a 85-year old French white man followed for quiescent anti-CCP+ rheumatoid arthritis treated by prednisolone 4 mg/day and hydroxychloroquine 200 mg/day since 10 years, and a monoclonal gammopathy of undetermined significance for 6 years, who was hospitalized for costal fractures after a fall. Serum protein electrophoresis showed a stable small monoclonal peak, and capillary electrophoresis/immunosubtraction technique identified an isolated clonal γ-heavy chain (HC). Bone marrow aspiration was normal and he had no other lymphoproliferation. The monoclonal peak remained stable after 4 years of follow-up.

Conclusions

In case of monoclonal peak without complete monoclonal Ig on serum protein electrophoresis, the diagnosis of γ-HCD should be discussed and capillary electrophoresis/immune-subtraction is a mean to detect isolated monoclonal heavy chain (HC). Gamma-HC disease is rare, may be associated to RA, and may have an indolent course.

Gamma heavy chain disease (γ-HCD) as iatrogenic immunodeficiency- associated lymphoproliferative disorder: Possible emergent subtype of rheumatoid arthritis-associated γ-HCD

Gamma heavy chain disease (γ-HCD) is a rare B-cell neoplasm that produces a truncated immunoglobulin γ-heavy chain lacking the light chain. The clinical features of γ-HCD are heterogeneous, resembling different types of B-cell lymphomas. Although rheumatoid arthritis (RA) is one of the common underlying diseases of γ-HCD, the therapeutic modality for RA has changed greatly in recent years; therefore, γ-HCD as iatrogenic immunodeficiency-associated lymphoproliferative disorder (LPD) should be taken into consideration. Here, we report such a γ-HCD case. A 69-year-old female was admitted because of fever, multiple lymph node swelling in the abdominal cavity, and peritoneal effusion. She had been treated using methotrexate for RA for 14 years, and using infliximab and adalimumab for Crohn’s disease for one year. The serum concentration of IgG was 3,525 mg/dL, which was revealed to be monoclonal IgG lacking the light chain by rocket immunoselection assay. CD19⁺/CD20^-/smκ⁻/smλ⁻ large abnormal lymphocytes were observed in the peritoneal fluid, which were demonstrated to be clonal B-cells by PCR examination. Discontinuation of methotrexate did not improve her condition and she died of pneumonia. Many abnormal lymphocytes positive for IgG and EBER but negative for the light chain were found on immunohistological examination of necropsy specimens from the spleen and bone marrow.

Gamma-heavy chain disease: review of 23 cases

We report the cases of 23 patients with gamma-heavy chain disease seen at our institution (8 patients previously reported, 15 new patients). There were 15 women and 8 men; the median age at diagnosis was 68 years (range, 42-87 yr). Sixteen patients had an associated lymphoplasma cell proliferative disorder, 3 had a lymphoplasma cell proliferative disorder and an autoimmune disorder, another 3 had an autoimmune disorder only, and 1 had no underlying disease. The lymphoplasma cell proliferative disorder was disseminated in 10 patients and localized in 6. Patients with localized lymphoplasma cell proliferative disorder included 3 with plasmacytoma (1 tongue, 1 submandibular area, and 1 thyroid), 2 with lymphoplasma cell proliferative disorder involving the bone marrow only, and 1 with amyloid of the skin. At the time of diagnosis, lymphadenopathy was present in 8 patients, splenomegaly in 7, and hepatomegaly in 1. A monoclonal spike on serum protein electrophoresis was documented in 19 patients. gamma-Heavy chain was documented by immunofixation in the serum of all patients; 2 had an additional immunoglobulin M-lambda. gamma-Heavy chain was present in the urine in 19 of 22 patients. Sixteen patients were treated for lymphoplasma cell proliferative disorder or autoimmune disorder (14 with chemotherapy, 1 splenectomy, and 1 thyroidectomy followed by radiation therapy). For 5 patients, treatment was not felt to be necessary; 2 patients were thought to be too sick for treatment. Of the 16 patients treated, 6 had a complete clinical response (in 2, gamma-heavy chain disappeared; in 2, gamma-heavy chain persisted; and for 2, no serologic follow-up was available); in 10 patients, clinical disease persisted (in 3, gamma-heavy chain disappeared; in 6, it persisted; and for 1, no serologic follow-up was available). Of 7 patients not treated, 2 died within 5 months; 1 died after 15 months; 2 had no clinical disease at latest follow-up, although gamma-heavy chain persisted; and 2 had no change in clinical and serologic status. The median duration of follow-up was 33 months (range, 1-261 mo). Median survival was 7.4 years.

Immunoglobulin heavy-chain-associated amyloidosis

Immunoglobulin- or multiple myeloma-associated amyloidosis has been distinguished by the tissue deposition of Congophilic, fibrillar protein consisting of light chains or light-chain fragments (AL amyloidosis). We now report the isolation and characterization of another form of immunoglobulin-associated amyloid obtained from a patient who had extensive systemic amyloidosis and in whom the amyloid deposits consisted not of light chains but rather of an unusual form of heavy chain. This component, isolated from splenic amyloid extracts, represented an internally deleted IgG1 heavy chain as evidenced by immunochemical, electrophoretic, and amino acid sequence analyses. A comparable immunoglobulin-related monoclonal protein, consisting only of IgG heavy chains, was present in the patient's urine. Based on serologic reactivity with a battery of anti-immunoglobulin antisera, these two immunoglobulin-related components were antigenically identical; however, when compared to normal IgG, both were deficient in Fc-associated gamma-chain determinants. The structural abnormality of the amyloid gamma-chain protein was further evidenced by SDS/PAGE and immuno-blotting analyses: An unusually low molecular mass of approximately 22 kDa was found for this material vs. the expected value of approximately 55 kDa for a normal gamma heavy chain. Despite the lack of certain Fc determinants, the amyloid and urinary heavy-chain proteins expressed the IgG1 subclass allotype marker G1m(a) located on the third constant region (CH3) domain of the internally deleted IgG1 heavy chains. That the amyloid protein contained an intact CH3 domain was established through amino acid sequence analyses of cyanogen bromide fragments and peptides generated by a lysine-specific protease. These studies also revealed that the gamma-chain amyloid protein contained the complete heavy-chain variable (VH) domain [including the diversity (DH) and joining (JH) segments] that was contiguous with the CH3 domain. The low molecular mass of the protein resulted from the total absence of the first (CH1), hinge, and second (CH2) heavy-chain constant regions. Such extensive CH deletions and the presence of a complete VH distinguish this amyloid-associated heavy chain from all other heretofore characterized gamma-heavy-chain disease proteins. This heavy-chain-related form of immunoglobulin-associated amyloidosis is tentatively designated AH amyloidosis.