• INCLUSION CRITERIA:

Greater than or equal to 18 years old.

Ability to sign informed consent.

For women of child-bearing potential, negative result on a serum or urine pregnancy test within 1 week prior to the procedure.

Willingness to allow storage of blood or biopsy samples for possible future use to study HIV/AIDS, related diseases or the immune system; willingness to permit HLA testing.

FOR PATIENTS UNDERGOING BIOPSIES:

No medical contraindication to tonsillar, lymph node, or intestinal biopsy.

For tonsillar biopsy, presence of visible tonsillar tissue; for lymph node biopsy, palpable lymph nodes.

No aspirin or piroxicam (Feldene) for 10 days prior to the procedure; other non steroidal anti-inflammatory drugs (e.g. ibuprofen) must be discontinued the day prior to the procedure. Acetaminophen [Tylenol] is permitted at any time.

FOR PATIENTS UNDERGOING BAL:

Hematocrit greater than 27 percent, platelets greater than 50,000/ml.

Baseline pulse-oximetry recording of 94 percent or greater unless clinical indication for bronchoscopy.

No medical contraindication to bronchoscopy.

In addition to the above:

FOR HIV POSITIVE VOLUNTEERS:

HIV infection must be confirmed by ELISA and western blot or dot blot. For patients with acute HIV infection and negative HIV serology, plasma HIV viral load greater than 10,000 copies/ml.

FOR HEALTHY VOLUNTEERS:

No underlying significant medical problem, especially an immunodeficiency or autoimmune disease, or an underlying problem requiring immunosuppressive therapy.

Absence of HIV infection as confirmed by negative ELISA and, if indicated, western blot or dot blot.

FOR ICL PATIENTS:

Patients must meet the definition of ICL according to the CDC criteria: documented absolute CD4 T lymphocyte count of less than 300 cells per cubic millimeter or of less than 20 percent of total T cells on more than one occasion usually two to three months apart, without evidence of HIV infection or any defined immunodeficiency or therapy associated with depressed levels of CD4 T cells.

Absence of HIV infection as confirmed by negative ELISA and, if indicated, western blot or dot blot.

EXCLUSION CRITERIA:

FOR ALL VOLUNTEERS UNDERGOING BIOPSIES:

Platelet count less than 75,000 platelets/mm(3).

PT or PTT prolonged by greater than 2 seconds unless patient has documented lupus anticoagulant/anti-phospholipid syndrome, which is not associated with an increased bleeding risk

Known underlying bleeding disorder.

Pregnancy.

FOR HIV-POSITIVE OR ICL VOLUNTEERS FOR LYMPH NODE BIOPSIES:

Use of narcotics (other than as prescribed by a physician) or cocaine less than 1 week prior to the date of biopsy.

FOR ALL VOLUNTEERS FOR INTESTINAL BIOPSIES:

Use of narcotics (other than as prescribed by a physician) or cocaine less than 1 week prior to the date of biopsy.

Significant heart valve abnormalities.

Presence of pacemaker, artificial joint or vascular surgery graft.

FOR ALL VOLUNTEERS FOR BAL:

Use of narcotics (other than as prescribed by a physician) or cocaine less than 1 week prior to the date of biopsy.

Pregnancy.

Any medical condition for which the investigators believe bronchoscopy may be contraindicated.

Allergy to lidocaine.

History of asthma requiring therapy.