This group will receive Rituximab as follows: initial 1gm divided into 2 doses (500 mg each) given 2 weeks apart then another 1gm will be given after 6 months. Vials will be diluted on 500 ml normal saline 0.9% and will be given as intravenous infusions.

This group will receive 500 ml normal saline 0.9% as intravenous infusions. Another dose will be given after 6 months

Rituximab 1gm vial diluted on 500 ml normal saline 0.9%

The Symbol Digit Modalities Test (SDMT) presents a series of nine symbols, each paired with a single digit in a key at the top of a standard sheet of paper. Patients are asked to identify the digit associated with each symbol as rapidly as possible for 90 seconds. The outcome measure is the number of correct responses over the 90 seconds time span.

The Brief Visuospatial Memory Test-Revised (BVMT-R) constitutes of six abstract designs presented to the patient for 10 seconds. The display is removed from view and patients render the stimuli via pencil on paper manual responses. Each design receives from 0 to 2 points representing accuracy and location. Thus, scores range from 0 to 12. There are three learning trials. The outcome measure is the total number of points earned over the three trials.

The California Verbal Learning Test-II (CVLT-II) begins with the examiner reading a list of 16 words. Patients listen to the list and report as many of the items as possible. After recall is recorded, the entire list is read again followed by a second attempt at recall. Altogether, there are five learning trials. The outcome measure is the total number of recalled items over the five trials.

The Nine-Hole Peg Test (9-HPT) is a wood or plastic board with 9 holes (10 mm diameter, 15 mm depth) and a container. It is administered by asking the patient to take the pegs from a container, one by one, and place them into the holes on the board as quickly as possible. Participants must then remove the pegs from the holes, one by one, and replace them back into the container. The outcome measure is the time taken to complete the activity, recorded in seconds.

Using MS-QLQ27 questionnaire, which contains 27 items covering physical, mental, and treatment-specific impairments as well as items relating to leisure, social, and work life issues. Scaling of items is a 5 point scale ranged from 1: "not at all impaired" to 5: "extremely impaired.