HIV-Associated Monoclonal Gammopathy: A Retrospective Analysis of 25 Patients

Abstract

Background. Monoclonal gammopathy of undetermined significance (MGUS) is unusual in the general population aged <60 years. Various reports indicate a much higher incidence of monoclonal gammopathy among human immunodeficiency virus (HIV)–infected patients and a significantly younger age at diagnosis. We sought to describe the laboratory findings and clinical course of MGUS, including association with plasma cell disorders, other malignancies, and infections, in 25 HIV-infected patients with a detectable serum monoclonal protein.

Methods. We reviewed the patients' demographic characteristics, stage of HIV infection, and clinical course. Laboratory studies included determination of CD4⁺ T lymphocyte cell counts, HIV type 1 loads, and quantitative immunoglobulin levels; serum and urine protein immunoelectrophoresis; and determination of serum viscosity indices. Skeletal surveys and bone marrow biopsies were performed in selected cases.

Results. Twenty-four of 25 patients were male, and the median age of patients was 50 years (range, 21–69 years). The median CD4⁺ T lymphocyte count was 350 cells/µL (range, 40–1029 cells/µL; mean, 355 cells/µL), and the median HIV load was <75 copies/mL (range, <50 to 100,000 copies/mL; mean, 20,800 copies/mL). Thirteen of 25 patients had HIV viremia, despite receiving highly active antiretroviral therapy (HAART). After a mean follow-up duration of 21 months, 7 patients (28%) received a diagnosis of a malignancy (multiple myeloma, in 1 patient; non-Hodgkin lymphoma, in 1; Hodgkin lymphoma, in 1; Kaposi sarcoma, in 2; and plasmacytoma, in 2). Ten patients were coinfected with hepatitis B virus and/or hepatitis C virus; 6 were anemic. No patients developed renal failure or hypercalcemia. Nine (56%) of 19 evaluable patients had a decrease of serum monoclonal protein (mean, 0.5 g/dL) while receiving HAART.

Conclusions. Patients in our study were characterized by the detection of a monoclonal protein at a younger age and the increased presence of other viral infections (infection with hepatitis B or C virus or Kaposi sarcoma herpesvirus) than is typically seen in an HIV-uninfected cohort. CD4⁺ T lymphocyte counts were relatively robust. HAART appeared to have a favorable impact on the serum monoclonal protein level in 9 patients. Long-term follow-up is needed to better define the natural history of MGUS and the link to other possible contributing factors.