Classification, Indicator diseases for AIDS, CCR5 and AIDS

Summary of classification system for HIV infection

Group I	Acute infection
Group II	Asymptomatic infection
Group III	Persistent generalized lymphadenopathy
Group IV	Symptomatic infection
Subgroup A	Constitutional disease - ARC
Subgroup B	Neurological diseases
Subgroup C	Secondary infectious diseases
C 1	Specified infectious diseases listed in the CDC surveillance definition for AIDS, such as P. carinii pneumonia, crypdosporidosis, toxoplasmosis, generalized strongiloidosis, cryptococcosis, CMV or herpes diseases, etc.
C 2	Other specified secondary diseases, such as oral hairy leukoplakia, salmonella bacteremia, nocardiosis, tuberculosis, thrush.
Subgroup D	Secondary cancers, such as Kaposi’s sarcoma, lymphomas.
Subgroup E	Other conditions.

The spectrum of the illness associated with HIV infection is broad.

Although several classifications are available the above classification is widely used.

Since 1993 the definition of AIDS has differed between the USA and Europe.

The USA definition includes individuals with CD cell counts of less than 200mm-3 in addition to the clinical classification based on the presence of specific indicator diagnoses shown bellow.

In Europe the definition remains based on the diagnosis of special clinical conditions with no inclusion of CD4 lymphocyte counts.

The following can be used as indicator diseases for AIDS providing other causes of immunodeficiency have been excluded (congenital immune deficiency, lymphoma, leukaemia, recent use of steroids or other immunosuppressive drugs.)

Bacterial chest infection (recurrent in 12 month period)
Candidiasis- trachea, bronchi or lungs.
Cervical carcinoma, invasive
Coccidioidomycosis, disseminated or extrapulmonary
Cryptococcus, extrapulmonary
Cryptosporidosis, with diarrhoea for >1 month
Cytomegalovirus disease (onset after age one month) not in liver,
spleen or nodes.
Encepholopathy (dementia) due to HIV.
Herpes simplex ulcers for 1 month or bronchitis, peumonitis or
oesophagitis (onset in infants >1 month old.)
Histoplasmosis, disseminated or extrapulmonary
Isosporiasis with diarrhoea for >1 month
Kaposi’s sarcoma
Lymphoid interstitial pneumonitis &/or pulmonary lymphoid
hyperplasia in a child aged <13 years.
Mycobacteriosis (including extrapulmonary tuberculosis),
disseminated.
Mycobacteriosis, pulmonary tuberculosis
Pneunocystis carinii pneumonia.
Progressive multifocal leucoencephalopathy
Salmonella (non-typhoid) septicaemia, recurrent
Toxoplasmosis of brain, onset after one month age
Wasting syndrome due to HIV (weight loss >10% baseline, with
no other cause identified.)

USA definition also includes those with a CD4 count <200 mm-3

CCR5 and AIDS

Some HIV positive people either develop AIDS very slowly or do not develop at all. Though these people have detectable sings of the presence of HIV in their bodies, they do not progress towards the killer disease of AIDS.

Scientists believe that these persons have something in their bodies that protect them from the virus.

This is called CCR5; the protein receptors having two copies of gene mutation called Delta 32.

So, while people with HIV and a normal CCR5 get full blown AIDS, people with a defective CCR5 move very slowly towards AIDS. People who do not have CCR5 do not get AIDS at all.

CCR5 was never found defective in the natives of the Africa or Japan. This indicates that the native of Africa and Japan are more prone to AIDS if they are infected with HIV.