• INCLUSION CRITERIA - ALL VOLUNTEERS:

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 BRONCHOALVEOLAR LAVAGE:

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.

FOR HIV POSITIVE VOLUNTEERS: (In addition to the above)

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

FOR HIV-NEGATIVE VOLUNTEERS: (In addition to the above)

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.

EXCLUSION CRITERIA:

FOR ALL VOLUNTEERS UNDERGOING BIOPSIES:

Platelet count less than 100,000 platelets/mm(3).

PT or PTT prolonged by greater than 2 seconds.

Known underlying bleeding disorder.

Pregnancy.

FOR HIV-POSITIVE 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 BRONCHOSCOPY:

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.