Insights:

In the early acute phase, HIV can present like any viral infection, with fever, sore throat and malaise. There may be aseptic meningitis.

A long clinical latency period may be seen, where very few symptoms occur.

As CD4 count drops, the rate of opportunistic infections increase. These can be viral, fungal, bacterial, protozoal and parasitic.

Oncoviral infection is also associated with specific neoplasms. Indeed Kaposi sarcoma, invasive cervical carcinoma and primary brain lymphoma (a type of NHL) are AIDS-defining illnesses.

Clinical markers include viral load (plasma HIV mRNA levels) and CD4+ count. Viral load predicts the clinical course of infection: during clinical latency, mRNA levels exist at a 'viral set point' and increase drastically in later stages. CD4+ count is a marker of disease severity and susceptibility to opportunistic infection. A count less than 200/microlitre is synonymous with AIDS and less than 50/microlitre is fatal is untreated.

Reference

Kumar, V. (2017). Robbins basic pathology international edition. [S.l.]: Elsevier - Health Science.

Abbas, A., Pillai, S. and Lichtman, A. (2018). Cellular and molecular immunology. Philadelphia [etc.]: Elsevier.