The only way to keep the CD4 count high and to increase it further is to use HIV meds. Nothing else, including multi vitamins, supplements or herbal remedies can increase your CD4 count.
HIV drugs work by stopping the virus from replicating. The main aim is to reduce the viral load to an undetectable level – less than 50 copies. Once the viral load starts to go down, one's immune system will start to repair itself. This means that his/her CD4 count will slowly go up, but not to the level before infection.
One must take the advice of a medical practitioner about starting treatment. It is wise to start to consult when CD4 count starts to drop below 350, as one of the main reasons is because people with a low CD4 count (less than 200) are more prone to other opportunistic illnesses (OIs). This does not mean that one will be infected by OIs, it just means that they are more susceptible to it.
Can I ask whether this is question is for general knowledge or for your personal? If it is personal, currently are you receiving any support? Getting support from your local support group or a counsellor can help you to come to terms living with HIV. Also you will be able to gain and share experiences with others who are in the similar situation as you, rather than having to deal with it in isolation.
This information is offered as a guide only. Decisions about your treatment should always be taken in consultation with your doctor. All the best.