Neutropenia is common in HIV infection (16% of patients in one study of over 130,00 individuals in a primary care setting) and should trigger testing for HIV infection. ¹⁸ Neutropenia may be due to HIV infection itself, autoimmune neutropenia, infections such as MAC and tuberculosis (TB), marrow infiltration by malignancy (commonly lymphoma), hypersplenism and drugs.  Treatment   is directed at the underlying cause: ART for HIV infection; antibiotics for infection; and the withdrawal of potentially causative drugs. Granulocyte colony stimulating factor (G-CSF) will usually correct severe neutropenia in refractory cases and may allow marrow suppressive drugs such as ganciclovir to be continued until infection has resolved. Infection or undiagnosed fever associated with severe neutropenia (neutrophil count <0.5 x 109/L) should be considered a medical emergency with immediate commencement of broad-spectrum antibiotics and supportive therapies such as G-CSF.1

All of the causes of individual cytopenias may produce a generalised pancytopenia. Late HIV infection commonly causes a myelodysplasia-type syndrome with impaired bone marrow function. Pancytopenia with severe lymphopenia and eosinophilia are commonly observed in the blood. Examination of the bone marrow commonly demonstrates normal or increased cellularity suggesting the impaired marrow function is due to inhibition of cellular maturation and production. Marrow plasmacytosis, lymphoid aggregates, granulomata and fibrosis are common.19