AIDS:What types of cells are particularly affected and how does this account for the symtoms of this disease?

HIV (the virus that can lead to AIDS) attacks the immune system by destroying CD4 or Tcells, which are the cells that help us fight infections. When the Tcell or CD4 cell count reaches 200 or below, diagnosis changes from HIV+ to AIDS. When the CD4 or Tcell count drops, a person is susceptible to other illnesses, such as colds, flu, and pneumonia, which a person with a healthy immune system may not catch, or would not have any problems fighting. A person whose immune system has been damaged by HIV or other issues, however, could die from these infections.

These days, medications can help people with HIV live longer, healthier, and they can increase the amount of time between a diagnosis of HIV and diagnosis of full blown AIDS. The medications do have side effects, though.

It affects the immune system and makes it so the cells cant start the bodys reactions to common sicknesses and there are no symptoms until you are diagnosed with aids, you can get tested for HIV fighter cells and if you have them you have HIV, and by the time you get diagnosed with "full-blown AIDS" its too late

AIDS is the syndrome (illness) caused by HIV, the virus. The acronyms HIV and AIDS are not interchangeable. HIV attacks T-cells, primarily CD4 T-cells. T-cells are one type of white cell and, like all white cells, they fight infection. CD4s are the white cells on the front lines of the immune system and when T-cell counts drop to 200 or less, the body is prone to infections, sometimes fatal infections.

That answers both parts of your question.