Monocytopenia

A severe deficiency or absence of monocytes can occur in patients with mutations of the hematopoietic transcription factor gene, GATA2. Dendritic cells are decreased, and there may also be lymphocytopenia Lymphocytopenia Lymphocytopenia is a total lymphocyte count of < 1000/mcL ( 1 × 10⁹/L) in adults or < 3000/mcL (< 3 × 10⁹/L) in children < 2 years. Sequelae include opportunistic... read more (mainly natural killer and B cells), or pancytopenia.

Despite near-absence of circulating monocytes, tissue macrophages are usually preserved. Also, immunoglobulin levels are usually normal even when circulating B cells are depressed. Bone marrow is hypocellular and can show fibrosis and multilineage dysplasia. Karyotypic abnormalities, including monosomy 7 and trisomy 8, may be present.

Infections with Mycobacterium avium complex (MAC) or other nontuberculous mycobacterial infections are common (MonoMAC syndrome). Fungal infections (ie, histoplasmosis Histoplasmosis Histoplasmosis is a pulmonary and hematogenous disease caused by Histoplasma capsulatum; it is often chronic and usually follows an asymptomatic primary infection. Symptoms are those... read more , aspergillosis Aspergillosis Aspergillosis is an opportunistic infection that usually affects the lower respiratory tract and is caused by inhaling spores of the filamentous fungus Aspergillus, commonly present in... read more ) also are typical. Infections with human papillomavirus Human Papillomavirus (HPV) Infection Human papillomavirus (HPV) infects epithelial cells. Most of the > 100 subtypes infect cutaneous epithelium and cause skin warts; some types infect mucosal epithelium and cause anogenital warts... read more (HPV) may occur with subsequent risk of progression to secondary cancers. There is a high risk of progression to hematologic disorders (myelodysplasia Myelodysplastic Syndrome (MDS) The myelodysplastic syndrome (MDS) is group of clonal hematopoietic stem cell disorders typified by peripheral cytopenia, dysplastic hematopoietic progenitors, a hypercellular or hypocellular... read more , acute myeloid leukemia Acute Myeloid Leukemia (AML) In acute myeloid leukemia (AML), malignant transformation and uncontrolled proliferation of an abnormally differentiated, long-lived myeloid progenitor cell results in high circulating numbers... read more , chronic myelomonocytic leukemia, lymphomas Overview of Lymphoma Lymphomas are a heterogeneous group of tumors arising in the reticuloendothelial and lymphatic systems. The major types are Hodgkin lymphoma Non-Hodgkin lymphoma See table Comparison of Hodgkin... read more ) with a resulting poor prognosis.

Unvaccinated patients should be given HPV vaccination Human Papillomavirus (HPV) Vaccine Human papillomavirus (HPV) infection is the most common sexually transmitted disease. HPV can cause skin warts, genital warts, or certain cancers, depending on the type of HPV. Vaccines are... read more . Any infections are treated with appropriate antimicrobials. Allogeneic hematopoietic stem cell transplantation Hematopoietic Stem Cell Transplantation Hematopoietic stem cell (HSC) transplantation is a rapidly evolving technique that offers a potential cure for hematologic cancers ( leukemias, lymphomas, myeloma) and other hematologic disorders... read more is the treatment of choice and should be considered for patients who get frequent infections or with refractory cytopenias.